Tanya

 

TANYA'S

COMPREHENSIVE GUIDE TO

FELINE CHRONIC KIDNEY DISEASE

 

 

 

HEART PROBLEMS, INCLUDING HYPERTROPHIC CARDIOMYOPATHY,

 

ARTERIAL THROMBOEMBOLISMS AND CONGESTIVE HEART FAILURE

 

ON THIS PAGE:


Introduction


Heart Problems and CKD


Symptoms


Diagnosis


Hypertrophic Cardiomyopathy (HCM)


Congestive Heart Failure (CHF)


Arterial Thromboembolism (Blood Clot to the Legs)


Pacemakers


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Home >  Related Diseases > Heart Problems

 


Overview


  • Since the kidneys and heart are closely related, heart problems are relatively common in CKD cats.

  • This page covers the three main heart issues you may be faced with: heart murmurs, hypertrophic cardiomyopathy (HCM), congestive heart failure (CHF), and arterial thromboembolism (a bloodclot to the legs).

  • Although it is a delicate balance, because treatment for the heart condition may put additional strain on the kidneys and vice versa, it is often worth trying treatment.

  • Treating the heart must always take precedence.


Introduction


 

The most common heart problems seen in cats are:

HCM is the most commonly seen heart problem in cats, and as it progresses, CHF and ATE may also occur.

 

Heart murmurs and/or a gallop rhythm are possible symptoms of heart problems in cats. In some cases they turn out to be of minor concern, but their presence should always lead to further investigation.

 

Heart problems are more common in cats with CKD, diabetes or hyperthyroidism.

 

How cats cope with heart problems varies from cat to cat, depending upon the type of problem, how advanced it is and how well the cat responds to treatment, but in most cases I would say it is worth trying treatment. Anything that may be contributing to the heart problems, such as anaemia, hyperthyroidism and hypertension, should be treated - in some cases, this may actually be all that is necessary. Heart problems caused by hyperthyroidism in particular may improve or disappear once the hyperthyroidism is under control. Try to keep stress to a minimum. 

 

Heart Smart is a helpful site from Cummings Veterinary Medical Center at Tufts University

 

Long Beach Animal Hospital has a detailed overview of how the heart works and what can go wrong.

 

Cardiorespiratory diseases of the dog and cat (2002) Martin M & Corcoran B Blackwell Science has detailed information about heart problems in cats.

 


Heart Problems and CKD


 

The heart and kidneys work closely together, so it is not unusual to see a heart patient develop kidney problems and vice versa. In humans there is a syndrome known as cardiorenal syndrome (CRS), which Volume overload and cardiorenal syndromes (2010) Ronco C & Maisel A Congestive Heart Failure 16 Supp 1 ppi-iv describes as "disorders of the heart and kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction of the other.”

 

There is growing interest in the veterinary field in the interaction between the heart and the kidneys. Cardiovascular-renal axis disorders in the domestic dog and cat; a veterinary consensus statement (2015) Pouchelon JL, Atkins CE, Bussadori C, Oyama MA, Vaden SL, Bonagura JD, Chetboul V, Cowgill LD, Elliot J, Francey T, Grauer GF, Luis Fuentes V, Sydney Moise N, Polzin DJ, Van Dongen AM & Van Israël N Journal of Small Animal Practice 56(9) pp537–552 discusses what it terms cardiovascular-renal disorders (CvRD) in cats and dogs. It states "Cardiovascular-renal disorders (CvRD) are defined as disease, toxin or drug-induced structural and/or functional damage to the kidney and/or cardiovascular system, leading to disruption of the normal interactions between these systems, to the ongoing detriment of one or both."

 

The heart-kidney axis with a special focus on renal function in heart failure (2007) Lefebvre HP State of the Art in Renal Disease in Dogs and Cats Proceedings, Vetoquinol Academia discusses (page 44 onwards) how heart and kidney problems interact in dogs, though the mechanism is similar for cats.

 

If a cat has both a heart condition and CKD, the heart problem must always take precedence. Although the treatment for the heart condition may put additional strain on the kidneys and vice versa, making it difficult to manage both conditions, it is usually worth trying treatments, because some cats do well.

 


Symptoms, Including Heart Murmurs and Gallop Rhythm


 

Unfortunately many cats with heart problems are asymptomatic or show very few symptoms, which can make diagnosis difficult. It does not help that some of the possible symptoms are similar to those of CKD, including lack of appetite, lethargy and vomiting. 

 

Some cats have a cardiac cough, though this is more common in cases of congestive heart failure. Other symptoms are discussed immediately below.

 

If you have not noticed your cat's symptoms, please do not blame yourself. Heart disease is difficult to detect in cats (2012) Canadian Veterinary Medical Association says "Heart disease has often been described as a silent killer and this is especially true in cats... Early signs of heart disease in the cat are very easy to miss. This is because early symptoms are either non-existent or so subtle and non-specific as to be rarely noticed by owners. To further complicate matters, cats seem to know their own capabilities and limitations and tend to restrict their level of activity, which can further mask clinical signs. Therefore, it is easy to miss the early signs of feline heart disease." This was certainly true of my cat, whose only symptom was weight loss for which my vet could not find an obvious cause, so we assumed it was age-related (she was sixteen years old).

 

If you suspect heart problems, in many cases you can wait a day or two to see the vet (though I would get my cat in as soon as I could during normal office hours). However, if your cat cannot walk or has a leg that is cold to the touch, it is a medical emergency and you should seek veterinary help immediately. If your cat appears to be having trouble breathing, i.e. an increase in breathing effort or breathing rate, I would take your cat to the vet as soon as possible, particularly if s/he is breathing with the mouth open.

 

Fast Heart Rate (Tachycardia) and High Respiration Rate


One possible sign of heart problems is a fast heart rate. In the case of cats visiting the vet, a fast heart rate may be caused by stress ("white coat syndrome"), but if your cat's heart seems to  be beating very fast when resting at home, I would seek veterinary advice.

 

You may also see faster breathing (respiration).

 

Respirations are normally measured when the cat is resting or asleep. They will always be more frequent when the cat is awake. Breathing in and out once counts as one breath.

 

Surprisingly, there appears to be little agreement on what is normal in terms of pulse and respiration for cats, as the table below shows:

 

Source

Pulse (beats per minute)

Respirations per minute

Merck Veterinary Manual

120 - 140

 

Veterinary Drug Handbook

100 - 120 (old cats)

 

The Cornell Book of Cats

160 - 240

20 - 30

The Pill Book Guide to Medication for Your Dog and Cat

160 - 180

20 - 40

Pet Place

160 - 220

20 - 30

University of Michigan

130 - 160

20 - 30

 

Feline cardiology (2011) Côté E, MacDonald KA, Meurs KM & Sleeper MM Wiley-Blackwell gives reference ranges for heart and respiration rates for cats and kittens both at home and at the vet's.

 

Sleeping and resting respiratory rates in healthy adult cats and cats with subclinical heart disease (2014) Ljungvall I, Rishniw M, Porciello F, Häggström J & Ohad D Journal of Feline Medicine and Surgery 16(4) pp281-290 states "Our data suggest that EN and AH cats [apparently healthy cats with normal heart ultrasound results] without clinical evidence of heart disease, and cats with known subclinical heart disease generally have stable SRR [sleeping respiratory rate] <30 breaths/min in the home environment, and slightly higher and more variable RRR [resting respiratory rate] when measured at home by clients." The study concludes "Cats with SRRmean >30 breaths/min and cats with multiple SRR measurements >30 breaths/min likely warrant additional evaluation."

 

Some people whose cats have heart problems learn how to use a pediatric stethoscope on their cats. Even if you don't do this, ask your vet for guidance on what is normal for your cat.

 

Weight Loss and Muscle Loss (Cardiac Cachexia)


Cats with heart failure may also exhibit loss of weight, in particular lean body mass. The loss of lean body mass (muscle) associated with heart disease is known as cardiac cachexia. Cachexia and sarcopenia: emerging syndromes of importance in dogs and cats (2012) Freeman LM Journal of Veterinary Internal Medicine 26 pp3-17 has a photograph of a dog with this symptom.

 

One of my cats had heart disease (HCM) and her only symptom was weight loss.

 

Heart Murmurs


A heart murmur occurs when blood flows through the heart turbulently rather than smoothly. It is not the same as an arrhythmia. Heart murmurs in cats (2010) Yuill C has a helpful overview of heart murmurs.

 

In most cases the vet will detect a heart murmur when listening to the heart with a stethoscope (auscultation).

 

Heart murmurs are graded from 1 to 6 depending upon their severity:

 

Grade 1

Lowest level at which a murmur can be heard but may only be detectable when the cat is frightened, stressed or in pain.

Grade 2

Always present, regardless of the cat's emotional state, but it is faint and often only audible in certain areas of the heart.

Grade 3

Can be heard at once by the vet.

Grade 4

Can also be heard at once, and there is also a vibration known as a thrill.

Grade 5

This is a very loud murmur.

Grade 6

This is an extremely loud murmur which is often audible without a stethoscope.

 

Veterinary Partner has information on heart murmurs and allows you to listen to a normal heart and to one with a murmur.

 

Heart murmurs may or may not need treatment, depending upon their cause and their severity. Both anaemia and hyperthyroidism may cause a heart murmur which disappears following treatment of the underlying problem.

 

Cats with hypertension may have a heart murmur. Blood pressure in small animals part 2: hypertension  - target organ damage, heart and kidney (2009) Carr AP & Egner BE European Journal of Companion Animal Practice 19(1) pp1-5 states that "A new murmur or gallop rhythm should always lead to a blood pressure measurement."

 

Heart murmurs are not always a sign of a problem (such murmurs are labelled benign, physiologic or innocent heart murmurs). Management of incidentally detected heart murmurs in dogs and cats (2015) Côté E, Edwards NJ, Ettinger SJ, Luis Fuentes V, MacDonald KA, Scansen BA, Sisson DD, Abbott JA; Working Group of the American College of Veterinary Internal Medicine Specialty of Cardiology on Incidentally Detected Heart Murmurs Journal of the American Veterinary Medical Association 246(10) pp1076-88 says that it can be difficult to determine whether a murmur is cause for concern or benign.

 

In Assessment of the prevalence of heart murmurs in overtly healthy cats (2004) Côté E, Manning AM, Emerson D, Laste NJ, Malakoff RL & Harpster NK Journal of the American Veterinary Medical Association 225 pp384-388 22 of 103 apparently healthy cats were found to have a heart murmur but only four of the 22 turned out to have HCM. Prevalence of cardiomyopathy in apparently healthy cats (2009) Paige CF, Abbott JA, Elvinger F & Pyle RL Journal of the American Veterinary Medical Association 234(11) pp1398-1403 found that "in apparently healthy cats, detection of a heart murmur is not a reliable indicator of cardiomyopathy."

 

The grade of the murmur is also not in itself a cause for concern. Heart murmurs and heart disease (2013) Cats Protection says "The grade of murmur heard does not necessarily mean heart disease is more or less severe, or even present...On its own, a heart murmur is not a reliable indicator of heart disease or function and is commonly found in healthy cats."

 

However, some cats have heart murmurs because they have hypertrophic cardiomyopathy. Cardiomyopathy prevalence in 780 apparently healthy cats in rehoming centres (the CatScsan study) (2015) Payne JR, Brodbelt DC & Luis Fuentes V Journal of Veterinary Cardiology 17(Suppl 1) ppS244–25 looked at 780 apparently healthy cats and found that "Heart murmur prevalence was 40.8% (95% confidence interval (CI) 37.3-44.3%), 70.4% of which were considered functional...The positive predictive value of a heart murmur for indicating HCM was 17.9-42.6% (higher in old cats), and the negative predictive value was 90.2-100% (higher in young cats)."

 

Prevalence of echocardiographic evidence of cardiac disease in apparently healthy cats with murmurs (2011) Nakamura RK, Rishniw M, King MK & Sammarco CD Journal of Feline Medicine & Surgery 13 pp266-71, found that 53% of the apparently healthy cats with heart murmurs in their study had cardiomyopathy, so concluded "identification of a heart murmur on routine physical examination in apparently healthy cats warrants further investigation."

 

Other tests may also be performed, such as x-rays or ultrasound.

 

Even if a murmur is determined to be benign, it is important to monitor it.

 

Approach to heart murmurs in small animal patients (2013) Willis R Crieff 2 Day Small Animal CPD Meeting pp19-25 has an algorithm with a suggested approach to heart murmurs.

 

Diagnosis of heart disease (2016) Kittleson MD Merck Veterinary Manual has detailed information on heart murmurs.

 

Colorado State University Auscultation Library lets you listen to feline heart sounds.

 

Pet Place has some information on heart murmurs.

 

Gallop Rhythm


A gallop rhythm may also be heard when listening to the heart with a stethoscope (auscultation). Normally when you listen to the heart there are two sounds (dub-dub) but in cats with a gallop rhythm there are three (dub-dub-dub).

 

Gallop rhythms may be heard in cats with hypertension. Blood pressure in small animals Part 2: hypertension target organ damage heart and kidney (2009) Carr AP & Egner BE European Journal of Companion Animal Practice 19(1) pp1-5 states that "A new murmur or gallop rhythm should always lead to a blood pressure measurement."

 

Gallop rhythms may also be heard in cats as they age. Aging in cats: common physical and functional changes (2016) Bellows J, Center S, Daristotle L, Estrada AH, Fickinger EA, Horwitz DF, Lascelles BDX, Lepine A, Perea S, Scherk M & Shoveller AK Journal of Feline Medicine & Surgery 18 pp533–550 states "Although gallop rhythms are auscultated in many cats with myocardial disease, it is also noteworthy that older feline patients (>10 years of age) may occasionally have a gallop rhythm that is related to an aging, stiff ventricle, in the absence of significant cardiovascular disease."

 

Subtle indications of pre-clinical heart disease in cats (2016) Nguyenba T MedVet Medical & Cancer Centers for Pets says "Even with heart disease severe enough to cause CHF, only half of these cats will exhibit heart murmurs. Finding other auscultable abnormalities, such as gallop sounds and arrhythmias, may be of great benefit, as the addition of these findings may improve sensitivity and specificity for detecting heart disease in cats."

 

Thus a gallop rhythm may or may not be a sign of problems. Nevertheless, I would always ask for additional checks to be performed on a cat with one. Feline hypertrophic cardiomyopathy, hypertension and hyperthyroidism (2010) Meurs K CVC in Kansas City (Proceedings) says "A gallop rhythm may be ausculted indicating abnormal left ventricular filling. Since asymptomatic cats may be affected, we recommend screening with an echocardiogram if a murmur or gallop is ausculted."

 


Diagnosis


 

Your vet may suspect heart problems based on the above signs and symptoms, and may then use some of the diagnostic methods listed below.

 

Although many of these tests can be performed by your vet, if there is a strong suspicion of heart problems I would ask for a referral to a veterinary cardiologist if possible, in order to obtain an accurate diagnosis and a personalised treatment plan. Cavalier Health has details of veterinary cardiologists in the USA, Canada and the UK.

 

Cardiology: making the diagnosis (2001) Pion P Presentation to the World Small Animal Veterinary Association World Congress explains more about how to diagnose heart problems.

 

Heart disease: diagnosis and treatment (2014) Estrada A Clinician's Brief Mar 2014 pp91-95 discusses the diagnosis of feline heart disease.

 

Auscultation (Stethoscope)


Your vet may initially use a stethoscope to check your cat’s heart. This is known as auscultation. Your vet may hear a heart murmur or a gallop rhythm.

 

Do not panic if this is the case. Aging in cats: common physical and functional changes (2016) Bellows J, Center S, Daristotle L, Estrada AH, Fickinger EA, Horwitz DF, Lascelles BDX, Lepine A, Perea S, Scherk M & Shoveller AK Journal of Feline Medicine & Surgery 18 pp533–550 states "Multiple studies in apparently healthy cats and cats with cardiomyopathy have repeatedly shown, however, that cardiac auscultation is insensitive for detecting underlying cardiac disease."

 

Your vet may therefore offer to run additional tests.

 

X-Rays


X-rays can be very useful for cats with breathing issues (breathing fast or heavily). This is the best way to check for and diagnose pleural effusion, pulmonary oedema or ascites, all commonly seen in cases of congestive heart failure. Cardiovascular-renal axis disorders in the domestic dog and cat; a veterinary consensus statement (2015) Pouchelon JL, Atkins CE, Bussadori C, Oyama MA, Vaden SL, Bonagura JD, Chetboul V, Cowgill LD, Elliot J, Francey T, Grauer GF, Luis Fuentes V, Sydney Moise N, Polzin DJ, Van Dongen AM & Van Israël N Journal of Small Animal Practice 56(9) pp537–552 states "Thoracic radiography is recommended to assess the presence or absence of congestive heart failure."

 

Pulmonary pattern recognition (2009) Kunze C & Lo W Idexx Digital Download 2(3) has photos of x-rays, including one of a cat with congestive heart failure.

 

X-rays are of limited use in diagnosing HCM, the most common heart problem in cats. Feline hypertrophic cardiomyopathy, hypertension and hyperthyroidism (2010) Meurs K CVC in Kansas City (Proceedings) says "Radiographs may be useful to evaluate for cardiomegally, chamber enlargement patterns, and evidence of heart failure, but are NOT diagnostic for the specific form of feline heart disease."

 

Although x-rays cannot be used to diagnose HCM in cats, cats with HCM often have a "valentine"-shaped heart, where x-rays show that the heart is enlarged at the bottom. Associations between ‘valentine’ heart shape, atrial enlargement and cardiomyopathy in cats (2015) Winter MD, Giglio RF, Berry CR, Reese DJ, Maisenbacher HW & Hernandez JA Journal of Feline Medicine & Surgery 17(6) pp447-452 found that 82% of the cats in the study with this finding did have cardiomyopathy, but only 18% had hypertrophic cardiomyopathy, and some healthy cats had this finding.

 

Echocardiogram (Ultrasound)


An ultrasound of the heart, ideally with Doppler colour flow imaging, is the most accurate way to diagnose hypertrophic cardiomyopathy (HCM).

 

Cardiovascular-renal axis disorders in the domestic dog and cat; a veterinary consensus statement (2015) Pouchelon JL, Atkins CE, Bussadori C, Oyama MA, Vaden SL, Bonagura JD, Chetboul V, Cowgill LD, Elliot J, Francey T, Grauer GF, Luis Fuentes V, Sydney Moise N, Polzin DJ, Van Dongen AM & Van Israël N Journal of Small Animal Practice 56(9) pp537–552 states "Renal imaging is recommended to improve diagnosis, prognosis and guide potential therapies in CvRD. Conventional abdominal radiographs and ultrasound are recommended to help detect morphological abnormalities and determine underlying aetiology."

 

Images of hypertrophic cardiomyopathy (2012) Tobias R Veterinary Focus 22(1) pp47-48 has examples of how HCM looks on ultrasound.

 

If you cannot visit a veterinary cardiologist, it is sometimes possible for your own vet to perform the ultrasound and send the images through to a veterinary cardiologist for interpretation.

 

NTproBNP Blood Test


NTproBNP Test is a blood test available from IDEXX Laboratories which checks levels of a peptide called NT-proBNP, which it states "can be clinically useful as an initial screening test for cats with suspected cardiac disease."

 

The normal range is usually 0 - 100. NT-proBNP levels increase in the bloodstream when the walls of the heart are under strain and stretch, as may happen in heart failure.

 

The presence of other illnesses may affect the results of this test. Diagnosing feline heart disease (2010) Gordon SG NAVC Clinician's Brief mentions (see the box on page 2) that NTproBNP is cleared by the kidneys, so damaged kidneys could make NTproBNP levels look higher than they actually are. In addition, Circulating natriuretic peptide concentrations in hyperthyroid cats (2012) Menaut P, Connolly DJ, Volk A, Pace C, Luis Fuentes V, Elliott J & Syme H Journal of Small Animal Practice 53(12) pp673-8 found that NT-proBNP levels are elevated in cats with hyperthyroidism. It concluded that "Thyroid status should be taken into account when interpreting NT-proBNP concentrations in cats."

 

There is some debate as to the accuracy of the test. NT-proBNP measurement fails to reliably identify subclinical hypertrophic cardiomyopathy in Maine Coon cats (2011) Singh MK, Cocchiaro MF, Kittleson MD Journal of Feline Medicine & Surgery 12 p942, found that "56% of cats with severe disease in this study would have been considered normal based on a NT-proBNP concentration; the sensitivity for diagnosing severe disease was only 44% (at a cutoff of ≤100 pmol/l). For any other condition less than severe HCM, the measurement of NT-proBNP concentration was found to be insensitive. Cats with equivocal and moderate disease were not identified by this assay."

 

Differentiation of cardiac from non-cardiac pleural effusions in cats using second-generation quantitative and point-of-care NT-proBNP measurements (2016) Hezzell MJ, Rush JE,  Humm K, Rozanski EA, Sargent J, Connolly DJ, Boswood A & Oyama MA Journal of Veterinary Internal Medicine 30(2) pp536-542 looked at the second generation version of the test and found that "measurement of NT-proBNP using a quantitative ELISA in plasma and pleural fluid or POC test in plasma, but not pleural fluid, distinguishes cardiac from noncardiac causes of pleural effusion in cats."

 

This test may be of some use as a starting point to check if the cause of your cat's symptoms is cardiac or non-cardiac, but I would not rely on it alone to diagnose heart disease, particularly not in a cat known to have CKD.

 

Cardiac biomarkers in hyperthyroid cats (2014) Sangster JK, Panciera DL, Abbott JA, Zimmerman KC & Lantis AC Journal of Veterinary Internal Medicine 28(2) pp465-472 discusses the difficulties of determining whether heart changes in cats with hyperthyroidism are caused by heart disease or by the hyperthyroidism. The study looked at the levels of NT-proBNP and cTNI (cardiac troponin I) and found that levels of both were significantly higher in cats with HCM or heart disease compared to healthy cats, but levels reduced in cats with hyperthyroidism after the hyperthyroidism was treated. The study concludes "overall, the findings supported previous work in that thyrotoxic myocardial hypertrophy is largely reversible. NT-proBNP might have a potential use in monitoring the response to treatment of hyperthyroidism. If the plasma concentration of this biomarker remains elevated three months after resolution of hyperthyroidism, this could indicate underlying cardiomyopathy is also present and an echocardiogram would be recommended."

 


Hypertrophic Cardiomyopathy (HCM)


 

Cardiomyopathy means disease of the heart muscle. There are several types of cardiomyopathy seen in cats:

  • hypertrophic cardiomyopathy (HCM)

  • restrictive cardiomyopathy (RCM)

  • dilated cardiomyopathy (DCM)

  • arrhythmogenic right ventricular cardiomyopathy (ARVC)

HCM is the most common form of heart disease in cats, and is more common in male cats. University of California at Davis (2016) says it "was recently reported to affect a startling one in seven cats." The study referred to, Cardiomyopathy prevalence in 780 apparently healthy cats in rehoming centres (the CatScsan study) (2015) Payne JR, Brodbelt DC & Luis Fuentes V Journal of Veterinary Cardiology 17(Suppl 1) ppS244–257, found that "The prevalence of HCM was 14.7%...The HCM prevalence increased with age."

 

In hypertrophic cardiomyopathy, the left ventricle of the heart, which pumps blood through the aorta, the body's largest artery, is enlarged (hypertrophic) with no obvious cause. This prevents the ventricle from working properly, adversely affecting heart function as a whole. Possible complications include:

The other types of cardiomyopathy are rare in cats. Cardiomyopathy prevalence in 780 apparently healthy cats in rehoming centres (the CatScsan study) (2015) Payne JR, Brodbelt DC & Luis Fuentes V Journal of Veterinary Cardiology 17(Suppl 1) ppS244–257, found that "The prevalence of...other cardiomyopathies [is] 0.1% (95% CI 0.0-0.7%)." Dilated cardiomyopathy may be caused by a lack of taurine in the diet, and is very rare since cat food manufacturers began supplementing commercial cat foods with appropriate amounts of taurine.

 

Feline cardiomyopathies - an update (2009) French A Presentation to the World Small Animal Veterinary Association World Congress  describes the various types of cardiomyopathy.

 

Long Beach Animal Hospital explains how the heart works, and the Specific Diseases link discusses HCM.

Hypertrophic Cardiomyopathy Causes


HCM may be caused by hyperthyroidism. Hypertrophic cardiomyopathy and hyperthyroidism in the cat (1984) Liu SK, Peterson ME & Fox PR Journal of the American Veterinary Medical Association 185(1) pp52-57 found that 87% of the cats with hyperthyroidism had some degree of HCM.

 

Other possible causes include high blood pressure or CKD.

 

However, it is also possible for a cat to have HCM without any associated disease. 

 

Hypertrophic Cardiomyopathy Genetic Link


HCM appears to be a genetic problem in certain breeds, such as Maine Coons, Persians, Ragdolls, Birmans and Norwegian Forest Cats. In fact, the University of California Davis uses Maine Coons to study feline heart disease since it is so common in this breed, where it is an inherited autosomal dominant trait.

 

Familial cardiomyopathy in Norwegian Forest Cats (2015) Maerz, Wilkie L, et al. Journal of Feline Medicine and Surgery 17 (8) pp681-691 looked at Norwegian Forest Cats in the UK and concluded "Pedigree data analysis from 871 NFCs was supportive of a familial cardiomyopathy in this breed."

 

Birman cats are also prone to developing cardiomyopathy and the Royal Veterinary College has been investigating this. The researchers have found that around 10% of Birman cats in Europe have cardiomyopathy, with around 7% having HCM. 82% of the cats with HCM were male. Heart murmurs are more common in Birmans with HCM, so any Birman cat with a heart murmur should have an ultrasound performed.

 

I lost one of my Chinchillas to HCM when he was nine months old. He collapsed and died at the vet's, five weeks after we adopted him and less than two months after my 16 year old girl collapsed and died at the vet's (she had been diagnosed with HCM two weeks earlier by a veterinary cardiologist and was at the vet's for a recheck to see if the medications were helping her).

 

The Winn Feline Foundation reports on research which it is funding, including the Birman research.

 

Seeking answers on HCM in Persian cats (2017) Winn Feline Foundation reports on research into Persian cats and HCM but states that studies to date have not been able to identify a single variant for Persians.

 

Top 5 genetic diseases of cats (2016) Bell JS Clinician's Brief Dec 2016 pp74-76 discusses the breeds affected by HCM.

 

International Cat Care discusses the genetic aspects of HCM in some breeds.

 

The Veterinary Cardiovascular Society has information on an HCM screening scheme for UK cats.

 

Hypertrophic Cardiomyopathy Treatments


If your cat has HCM caused by hyperthyroidism or hypertension (secondary HCM), it is essential to treat these conditions. Survival in cats with primary and secondary cardiomyopathies (2016) Spalla I, Locatelli C, Riscazzi G, Santagostino S, Cremaschi E & Brambilla P Journal of Feline Medicine and Surgery 18(6) pp501-509 states "Secondary CMs are more benign conditions, but if the primary disease is not properly managed, the prognosis might also be poor in this group of patients."

 

Otherwise HCM cannot be cured but it can often be controlled with medications. Unfortunately many drugs which help the heart condition put strain on the kidneys, so if your cat has both heart disease and CKD, discuss which drug to use with your vet (preferably a veterinary cardiologist).

 

It must be emphasised that it is essential to treat heart disease if it is present, and that treating the heart disease must take precedence over treating the CKD, which is an academic problem if the heart stops beating. 

 

Even if your cat appears stable once medication has begun, it is a good idea to have an ultrasound examination of your cat's heart undertaken once every year (or more regularly if your cardiologist advises it) and to review medication at that time if appropriate.

 

Some vets choose to treat asymptomatic cats, whilst others choose to wait. Effect of treatment with atenolol on 5-year survival in cats with preclinical (asymptomatic) hypertrophic cardiomyopathy (2013) Schober KE, Zientek J, Li X, Luis Fuentes VL & Bonagura JD Journal of Veterinary Cardiology 15 pp93-104 looked at the effects of giving heart medication to asymptomatic HCM cats. The cats who were medicated were given a beta blocker, atenolol, though some of them also received enalapril, an ACE inhibitor, or clopidogrel. The study states "There was no significant difference in all-cause mortality (P = 0.729) and cardiac mortality (P = 0.897) between cats with HCM treated or untreated with atenolol. Age and left atrial size at diagnosis were the only predictors of 5-year outcome."

 

CEG formulary: cardiac medications for cats (2014) Cardiac Education Group provides an overview of heart medications often used in cats and commonly used dosages.

 

These are the main classes of medication used to treat HCM in cats:

Beta Blockers: Atenolol and Propranolol


Atenolol (Tenormin) is a type of beta blocker commonly used in the USA. In the UK, a similar drug called propranolol (Inderal) may be used. Pharmacokinetics of atenolol in clinically normal cats (1996) Quinones M, Dyer DC, Ware WA & Mehvar R American Journal of Veterinary Research 57(7) pp1050-3 discusses the effects of atenolol on cats.

 

Beta blockers are often used to slow a fast heart rate (tachycardia). Feline hypertension: Part 1 (2012) Atkins C says "Tachycardia not only contributes to hypertension but is also harmful to the cardiovascular system; persistent tachycardia should be managed with atenolol."

 

Pet Place has an overview of atenolol and states "Reducing the heart rate and strength of heart muscle contraction can be beneficial to some cats and dogs with the condition called hypertrophic cardiomyopathy, especially when the heart muscle contracts so vigorously it obstructs the path of blood."

 

The use of beta blockers may be recommended for cats with HCM even if it is sub-clinical, i.e. showing no symptoms as yet. Effect of atenolol on heart rate, arrhythmias, blood pressure, and dynamic left ventricular outflow tract obstruction in cats with subclinical hypertrophic cardiomyopathy (2015) Jackson BL, Adin DB, Lehmkuhl LB Journal of Veterinary Cardiology 17 S296-S305 looked at using atenolol in cats with mild sub-clinical HCM. It concludes "Atenolol decreases HR, murmur grade, and LVOT obstruction, and to a lesser degree, frequency of ventricular ectopy, in cats with subclinical HCM. Further studies are needed to determine if sudden cardiac death or long-term outcome is influenced by atenolol administration."

 

Plumb's Veterinary Drug Handbook states "While atenolol has been used in cats with preclinical hypertrophic cardiomyopathy its use is controversial"  and also states "Atenolol may cause increased morbidity in cats with hypertrophic cardiomyopathy with accompanying left-sided CHF."

 

Some vets believe that beta blockers should not be begun in cats with HCM who also have congestive heart failure. Feline hypertrophic cardiomyopathy, hypertension and hyperthyroidism (2010) Meurs K CVC in Kansas City (Proceedings) says "atenolol should never be started in cats with congestive heart failure (CHF)."

 

Beta Blockers: Dosage


Pet Place says "The typical dose administered to cats is 1 mg per pound (2 mg/kg) once daily. The total daily dose in cats is often 6.25 to 12.5 mg once or twice daily." It does also say "Frequently, atenolol is given with other drugs, especially in pets undergoing treatment for heart failure or arrhythmias (abnormal heart rhythm). In these situations, a lower initial dose may be prescribed."

 

Those I hear from tend to give 6.25mg (a quarter of a 25mg tablet) twice a day. However, some give a lower dose, especially if they are also giving other heart medications. Applying pharmacokinetics to veterinary clinical practice (2013) Trepanier LA Veterinary Clinics of North America. Small Animal Practice 43(5) pp1013-26 recommends a much lower dose for cats with kidney disease as follows:

 

IRIS Stage of CKD

Suggested Dose

Dose for a 10lb (4.5kg) Cat

Stage 2

0.19 mg/kg PO q12-24h

0.86 mg once or twice a day

Stage 3

0.125 mg/kg PO q12-24h

0.56 mg once or twice a day

Stage 4

0.06 mg/kg PO q24h

0.27 mg once or twice a day

 

If you are giving 0.27mg, you would need to divide the smallest tablet available (25mg) into a hundred. I can't see how this is possible, I think you would have to have it compounded into cat-sized dosages instead.

 

Beta Blockers: Side Effects


Side effects are uncommon, but may include lethargy, diarrhoea and hypotension (low blood pressure). Contact your vet if you see these symptoms or if your cat becomes breathless or develops a cough.

 

If you stop the medication after giving it for a while, Plumb's Veterinary Drug Handbook recommends doing so gradually, because stopping it abruptly may make symptoms worse.

 

Angiotensin-Converting-Enzyme Inhibitors (ACE Inhibitors)


ACE inhibitors prevent the conversion of a hormone called angiotensin I into another hormone called angiotensin II, the role of which is to constrict blood vessels. This helps the blood vessels relax, which makes it easier for the heart to pump blood through the body.

 

ACE inhibitors are a popular treatment for HCM. In the USA you will probably be offered enalapril, the trade name of which is Enacard. Mar Vista Vet has information and cautions on the use of enalapril, including when using it in conjunction with diuretics such as furosemide (known as frusemide in the UK) (see below). 

 

In the UK, Europe and Australia you are more likely to be offered benazepril. Benazepril (under the name of Fortekor) is licensed for the treatment of CKD in cats in the UK, Europe and Australia, even for cats without heart disease.

 

Ramipril (marketed as Altace or Vasotop) is an ACE inhibitor that is available in the UK and Europe, though I only know of a couple of people who have used it for their cat. The efficacy, tolerance and safety of the angiotensin converting enzyme inhibitor ramipril in cats with cardiomyopathy with or without hypertension (2002) Schille F & Skrodski M Presentation to the World Small Animal Veterinary Association World  Congress 2002 discusses the use of ramipril.

 

It is not unusual for cats suffering from congestive heart failure to be given both an ACE inhibitor and a diuretic, though in such situations furosemide is a safer choice than spironolactone.

 

You should be careful if you are using ACE inhibitors at the same time as potassium supplements, because they may cause potassium levels to become dangerously high.  

 

More detailed information about ACE inhibitors can be found on the Proteinuria page. 

 

Angiotensin II Receptor Blockers (ARBs)


Angiotensin II receptor blockers (ARBs) are heart medications which work in a slightly different way to ACE inhibitors.

 

Angiotensin II is a hormone, the role of which is to constrict blood vessels. This type of medication works by blocking the receptor to which angiotensin II attaches, thus relaxing the blood vessels, which in turn helps to reduce blood pressure and therefore reduces the work that the heart has to perform to pump blood through the body. These medications are sometimes referred to as angiotensin II receptor antagonists.

 

In human medicine ARBs tend to be used when ACE inhibitors cannot be used for some reason. I have not heard from many people using them for cats with heart disease, though like ACE inhibitors, they may be prescribed for cats with proteinuria. More detailed information about ARBs can be found on the Proteinuria page. 

 

Calcium Channel Blockers


Calcium channel blockers work by slowing the passage of calcium into muscle cells; this makes muscle in the blood vessels relax, so the blood vessels open wider.

 

One member of the calcium channel blocker family, amlodipine, is generally considered to be the best choice for controlling hypertension in cats.

 

Another calcium channel blocker, diltiazem, may be used in the treatment of HCM in cats. I do not hear from many people using diltiazem but if you are using it in a CKD cat, you may need to reduce the dose.

 

Mar Vista Vet has some information about diltiazem.

 

Diltiazem should not be used with beta blockers or cisapride (a treatment for severe constipation). Cimetidine or ranitidine may strengthen the effects of diltiazem.

 

Hypertrophic Cardiomyopathy Research


 

Pimobendan


Pimobendan is a medication that has been successfully used in cats with congestive heart failure secondary to HCM, but its use in cats with HCM only is controversial. It is discussed in more detail in the congestive heart failure section here.

 

MYK-461


A small molecule inhibitor of sarcomere contractility acutely relieves left ventricular outflow tract obstruction in feline hypertrophic cardiomyopathy (2016) Stern JA, Markova S, Ueda Y, Kim JB, Pascoe PJ, Evanchik MJ, Green EM & Harris SP PLoS ONE 11(12) e0168407 looked at the use of a novel drug known as MYK-461 in five cats with genetic HCM and found it seemed to eliminated the left ventricular obstruction commonly seen in HCM in all five cats in the study.

 

University of California at Davis (2016) reports on the study and "hopes to conduct a clinical trial in the near future, which could determine if MYK-461 has the potential to become the accepted protocol for care of cats with HCM."

 

Hypertrophic Cardiomyopathy Prognosis


HCM is a very variable disease. When caught early (which is not always easy), it may be possible to manage it for some time. Does this animal have congestive heart failure? (2015) Luis Fuentes V Presentation to the World Small Animal Veterinary Association states "many cats with hypertrophic cardiomyopathy (HCM) will remain free of clinical signs and will have a normal life expectancy."

 

Population and survival characteristics of cats with hypertrophic cardiomyopathy: 260 cases (1990-1999) (2002) Rush JE, Freeman LM, Fenollosa NK & Brown DJ Journal of the American Veterinary Medical Association 220(2) pp202-207 found that "Median survival time was 709 days (range, 2 to 4,418 days) for cats that survived > 24 hours." This is quite an old study, and treatment protocols have probably improved since then.

 

Plasma cardiac troponin I concentration and cardiac death in cats with hypertrophic cardiomyopathy (2014) Borgeat K, Sherwood K, Payne JR, Luis Fuentes V & Connolly DJ Journal of Veterinary Internal Medicine 28 pp1731-1737 looked at whether levels of NTproBNP or cardiac troponin (cTnl)  might help with predicting cardiac death. The study states "Median survival time (MST) to cardiac death was > 946 days. Cats with a cTnI > 0.7 ng/mL had a significantly MST of 40 days. Those with NT proBNP >250 pmol/L also had a significantly shorter MST of 764 days."

 

The prognosis is worse if the cat develops congestive heart failure or arterial thromboembolism (blood clot in the legs). Prognostic indicators in cats with hypertrophic cardiomyopathy (2013) Payne JR, Borgeat K, Connolly DJ, Boswood A, Dennis S, Wagner T, Menaut P, Maerz I, Evans D, Simons VE, Brodbelt DC & Luis Fuentes V Journal of Veterinary Internal Medicine 27(6) pp1427-36 examined the records of 282 cats diagnosed with HCM between 2004 and 2009. It states "Univariable predictors of an increased risk of cardiac death included older age, absence of a murmur, presence of a gallop sound or arrhythmia, presentation with either CHF or ATE, extreme LV hypertrophy (≥ 9.0 mm), LV fractional shortening (FS%) ≤ 30%, regional wall hypokinesis, increased left atrial size, decreased left atrial function, spontaneous echo-contrast/thrombus or both, absence of left ventricular outflow tract obstruction, and a restrictive diastolic filling pattern."

 

Survival in cats with primary and secondary cardiomyopathies (2016) Spalla I, Locatelli C, Riscazzi G, Santagostino S, Cremaschi E & Brambilla P Journal of Feline Medicine and Surgery 18(6) pp501-509 states that median survival time for cats with HCM was 865 days.

 

I have not had good experiences with HCM myself (see above), but I regularly hear from people whose cats have lived for years with the condition. Therefore I would always try treatment.

 


Congestive Heart Failure (CHF)


 

As heart disease and/or kidney disease progress, congestive heart failure (CHF) may develop.

 

Many people panic when they hear this expression, fearing death is imminent. Some cats with acute CHF are seriously ill and sadly will not make it, however, this is not always the case. The word "failure" when used in a medical context does not necessarily mean the end is nigh (just as CKD used to be called chronic renal failure, but it was and is actually a  chronic condition), so try not to panic, because your cat's case may be manageable. 

 

What happens in congestive heart failure is that the heart's ability to pump blood around the body is impaired. This can adversely affect the kidneys, since as part of that process blood flow through the kidneys is reduced.  The reduced ability to pump blood around the body can also lead to fluid building up in the body (congestion), which needs to be removed.

 

Heart failure (2016) Kittleson MD Merck Veterinary Manual has a detailed overview of heart failure.

Congestive Heart Failure Causes


Most cats develop CHF because they have HCM. Unfortunately it is possible for a cat to have HCM with no symptoms until CHF appears, often acutely.

 

The risk of CHF is higher if a cat has anaemia. It may also occur if a cat is overhydrated via too much fluid therapy (both intravenously and subcutaneously). Fluids are not a benign therapy and should only be given when necessary and not in large quantities.

 

If your cat develops CHF within a week of starting corticosteroids, the medication might be the cause. Population and survival characteristics of cats with hypertrophic cardiomyopathy: 260 cases (1990-1999) (2002) Rush JE, Freeman LM, Fenollosa NK & Brown DJ Journal of the American Veterinary Medical Association 220(2) pp202-207 states "Antecedent events that may have precipitated CHF included i.v. fluid administration, anesthesia, surgery, and recent corticosteroid administration." Corticosteroid-associated congestive heart failure in 12 cats (2004) Smith SA, Tobias AH, Fine DM, Jacob KA & Ployngam T The International Journal of Applied Research in Veterinary Medicine 2 (3) pp159-170 found that some cats developed a unique form of CHF within seven days of starting steroids. Five of the cats died, but the seven that survived did much better than the typical CHF patient once taken off the steroids.

 

Congestive Heart Failure Symptoms


The reduced ability to pump blood around the body can lead to fluid building up in the body (congestion). Signs of fluid build up depend upon whether the body generally or the lungs in particular are affected, but these are some of the symptoms you may see:

  • coughing. Cat cough and congestive heart failure is a video of a cat with a cardiac cough.

  • difficulty breathing

  • fast breathing (see above for normal breathing rates)

  • open mouth breathing

  • loss of appetite (the fluid makes the cat feel full)

  • sitting up and refusing to lie down; this is because it is easier to breathe in this position

  • sudden weight gain

  • swollen abdomen or paws

  • seeking out warm places (because body temperature is low)

You can read more about what to watch for here.

 

If you suspect CHF for the first time, you should seek veterinary help as soon as possible. If your cat has had CHF for some time, you will gradually learn which signs in your particular cat require urgent veterinary help and which require a less urgent vet visit or possibly can be managed at home.

 

Warning signs for congestive heart failure Hayes J is a helpful site about Coco, and gives useful information on what to watch for. Coco had both CKD and heart problems, but she lived comfortably with CHF for quite some time.

 

Pulmonary Oedema or Pleural Effusion


If it is the left side of the heart where the problem lies, fluid will accumulate:

  • in the lungs: pulmonary oedema

  • around the lungs: pleural effusion

Most cats have CHF because of HCM, which affects the left side of the heart. Therefore it is more common to see pulmonary oedema or pleural effusion in cats with CHF.

 

Pet Place has some information about pleural effusion

 

Pet MD discusses pulmonary oedema in cats.

 

Ascites


If it is the right side of the heart where the problem lies, fluid will accumulate:

  • in the abdomen (and occasionally the legs and paws): ascites

Other causes of ascites include cancer (my cat with cancer developed ascites), nephrotic syndrome, liver disease and FIP (around 50% of cats with FIP will develop ascites).

 

Pet Place has some information about ascites.

 

Pet MD has information about ascites.

 

Congestive Heart Failure Diagnosis


Initially the vet will probably listen to your cat's heart with a stethoscope (auscultation) and may hear crackling.

 

X-rays are generally considered to be the only way to diagnose congestive heart failure. However, Heart failure in cats is a study at Ohio State University College of Veterinary Medicine into the use of ultrasound to diagnose heart failure. Participants must have either HCM or CHF secondary to HCM. Contact Dr. Karsten Schober schober.4@osu.edu for more information.

 

When a cat first presents to the vet in respiratory distress, initially it may be difficult to determine if the cause is CHF or a respiratory problem such as asthma. Evaluation of blood cardiac troponin I concentrations obtained with a cage-side analyzer to differentiate cats with cardiac and noncardiac causes of dyspnea (2014) Wells SM, Shofer FS, Walters PC, Stamoulis ME, Cole SG & Sleeper MM Journal of the American Veterinary Medical Association 244 pp425-430 found that levels of cardiac triponin (cTnI) may be of use because levels may be elevated in cats with heart disease, but not in cats with respiratory diseases. It found that levels over 0.66 ng/ml support a heart-related cause and levels below 0.24 ng/ml suggest that CHF can be ruled out. Levels between these values could not be used either way.

 

Does this animal have congestive heart failure? (2015) Luis Fuentes V Presentation to the World Small Animal Veterinary Association discusses differentiating CHF from other health problems.

 

Management of acute heart failure in cats: recognizing acute heart failure (2014) Luis Fuentes V is a five minute video presentation which discusses how to recognise CHF in cats.

 

Congestive Heart Failure Treatments


If left untreated, fluid build-up can kill so it is important to treat it. The cat will often be treated in hospital initially, and then sent home for ongoing care once stabilised. If your cat's case is mild, however, hospitalisation may not be necessary. Cardiovascular-renal axis disorders in the domestic dog and cat; a veterinary consensus statement (2015) Pouchelon JL, Atkins CE, Bussadori C, Oyama MA, Vaden SL, Bonagura JD, Chetboul V, Cowgill LD, Elliot J, Francey T, Grauer GF, Luis Fuentes V, Sydney Moise N, Polzin DJ, Van Dongen AM & Van Israël N Journal of Small Animal Practice 56(9) pp537–552 states "Unstable CvRDH, such as in instances of acute CHF, typically requires hospitalisation to restore or improve cardiac function and to alleviate congestive or low output signs while simultaneously evaluating risk of kidney dysfunction. Standard acute CHF therapy that includes diuretics, ACEI, vasodilators and positive inotropes might need to be adjusted based on frequent assessment of hydration, renal function biomarkers, electrolytes, blood pressure, body weight and urine output."

 

If medication is prescribed for home use, it is important to give it. Association between survival time and changes in NT-proBNP in cats treated for congestive heart failure (2017) Pierce KV, Rush, JE, Freeman LM, Cunningham SM & Yang VK Journal of Veterinary Internal Medicine 31(3) pp678-684 found "Cats whose owners did not have trouble administering medications had a longer survival time compared to cats whose owners had trouble administering medications."

 

Management of acute heart failure in cats: treatment or imaging? (2014) Luis Fuentes V is a seven minute video presentation about treating CHF in cats.

 

Management of heart failure in cats (2012) Luis Fuentes V Presentation to the 73rd SCIVAC International Congress 2012 pp229-230 discusses the therapeutic goals and management of feline heart failure

 

Mar Vista Vet has information on long term therapy for heart failure.

 

Home care of the heart failure patient Washington State University College of Veterinary Medicine has tips on caring for a heart patient at home.

 

CEG formulary: cardiac medications for cats (2014) Cardiac Education Group provides an overview of heart medications often used in cats and commonly used dosages. Feline hypertrophic cardiomyopathy, hypertension and hyperthyroidism (2010) Meurs K CVC in Kansas City (Proceedings) says "atenolol should never be started in cats with congestive heart failure (CHF)."

 

Here are the main treatments for CHF:

Thoracocentesis and Paracentesis


The first step should be to remove the fluid that has built up.

 

If your cat has pleural effusion (fluid build up around the lungs) or ascites (fluid build up in the abdomen), needle aspiration may be offered and offers immediate relief. It entails inserting a fine needle into the chest (thoracocentesis or thoracentesis or chest tap) or abdomen (paracentesis) and drawing the fluid off.

 

I know it sounds horrible, but my cat had this done to remove ascites (caused by cancer in his case) and he didn't even flinch. However, it is a delicate procedure, and skill is required to insert the needle in the right place and remove the correct amount of fluid.

 

Pet Place explains more about thoracocentesis.

 

Diuretics: Furosemide and Spironolactone


Medications known as diuretics may also be used to remove excess fluid build up. If your cat is in crisis in hospital, these may be supplied in the injectable form.

 

In many cases, diuretics will also be used on an ongoing basis to prevent fluid building up again, usually in pill form.

 

For cats with heart disease, diuretics are often used in conjunction with other heart medications, especially ACE inhibitors.

 

For cats with CKD, it sometimes happens that the cat receives both sub-Q fluids (usually in small amounts) as well as a diuretic. This sounds counterintuitive but seems to work for some cats to keep them hydrated while controlling their tendency to develop fluid build up.

 

Diuretics are also used occasionally when a cat in the end stages of CKD has stopped urinating (anuria), in an attempt to "kickstart" the kidneys.

 

Furosemide (Lasix)


The most commonly used diuretic in cats is furosemide (known as frusemide in the UK). Brand names include Lasix and Salix. Drugs has some information about furosemide.

 

Furosemide is a loop diuretic. Diuretics (2016) Dowling PM Merck Veterinary Manual states that "it inhibits the reabsorption of sodium and chloride in the  thick, ascending loop of Henle, resulting in loss of sodium, chloride, and water into the urine. Furosemide induces beneficial hemodynamic effects before the onset of diuresis. Vasodilation increases renal blood flow, thereby increasing renal perfusion and lessening fluid retention."

 

Furosemide is cleared through the kidneys so the kidneys have to work harder to process the fluid that furosemide is removing. Some people have found that another diuretic, spironolactone, is easier for their CKD cats to tolerate. However, furosemide is the best choice during times of crisis because it works faster, whereas spironolactone can take several days to work.

 

Furosemide Dosage


Drugs says of injectable furosemide "Furosemide is a potent diuretic which, if given in excessive amounts, can lead to a profound diuresis with water and electrolyte depletion. Therefore, careful medical supervision is required and dose and dose schedule must be adjusted to the individual patient’s needs."

 

The typical dose for a cat receiving furosemide orally is 1 to 2 mg per kg (0.5 to 1 mg per pound) of cat, once or twice daily, though sometimes less frequently. Cats with CKD may need higher doses: Diuretics (2016) Dowling PM Merck Veterinary Manual states "Chronic therapy in cats and some dogs can be accomplished by therapy every second or third day. Higher than normal doses of furosemide may be required in animals with renal disease due to functional abnormalities of the renal tubule and binding of furosemide to protein in the urine."

 

In some cases, furosemide resistance can occur. Heart failure (2016) Kittleson MD Merck Veterinary Manual states "Furosemide resistance, typically defined by persistent signs of heart failure despite dosages of 4 mg/kg, PO, tid, often develops in advanced cases of CHF. Animals with resistance to chronic high doses of oral furosemide may thus have an improved diuretic response from parenteral (eg, SC) administration of the drug or from addition of other diuretic agents (“diuretic stacking”)."

 

Furosemide Side Effects and Interactions


Diuretics (2016) Dowling PM Merck Veterinary Manual states "Furosemide therapy is associated with a number of adverse effects. By nature of its mechanism of action, it causes dehydration, volume depletion, hypokalemia [low potassium levels], and hyponatremia [low sodium levels], which may be excessive and detrimental."

 

Drugs warns about using lactulose (a constipation treatment) as well as furosemide, stating "Combining these medications, especially over a prolonged period, may increase the risk of dehydration and electrolyte abnormalities. In severe cases, dehydration and electrolyte abnormalities can lead to irregular heart rhythm, seizures, and kidney problems."

 

Spironolactone


Spironolactone is a diuretic which works by inhibiting aldosterone activity. Pet Place explains how spironolactone works.

 

It is not as commonly used as furosemide because it takes longer to work. Diuretics (2016) Dowling PM Merck Veterinary Manual states "The onset of action for spironolactone is slow, and effects do not peak for 2–3 days. Spironolactone is not recommended as monotherapy but can be added to furosemide or thiazide therapy to treat cases of refractory heart failure."

 

Spironolactone Side Effects


Spironolactone is known as a potassium-sparing diuretic, because it does not lower potassium levels in the cat's blood, as may happen with furosemide. Diuretics (2016) Dowling PM Merck Veterinary Manual says "Because of the potential for hyperkalemia, spironolactone should not be administered concurrently with potassium supplements."

 

Drs Foster & Smith give a list of possible side effects and signs of an allergic reaction.

 

Using Diuretics and ACE Inhibitors or ARBs Together


If you use diuretics at the same time as ACE inhibitors or ARBs, you should check your cat's kidney values 7-10 days after starting the treatment. Mar Vista Vet says "monitoring kidney parameters is especially important as both these medications serve to decrease blood supply to the kidney as they support the heart. Should a heart failure crisis occur while a patient is on these two medications, it will become necessary to rely on the diuretic to resolve the crisis. High doses of diuretic are typically needed. This can potentially lead to kidney failure though there is no alternative when the heart is failing."

 

Pimobendan


Pimobendan (Vetmedin) is a heart medication commonly used in dogs. It belongs to a family of drugs known as imodilators. Veterinary Partner has some information about pimobendan.

 

Researchers at Tufts University found that pimobendan appeared to be helpful for cats who developed CHF following intravenous fluids.

 

Use of pimobendan in 170 cats (2006-2010) (2011) MacGregor JM, Rush JE, Laste NJ, Malakoff RL, Cunningham SM, Aronow N, Hall DJ, Williams J, Price LL Journal of Veterinary Cardiology 13(4) pp251-60 found that pimobendan seemed to be effective in cats with advanced heart disease and congestive heart failure when used in conjunction with other heart medications.

 

Effect of oral administration of pimobendan on cats with heart failure (2012) Gordon SG, Saunders AB, Roland RM, Winter RL, Drourr L, Achen SE, Hariu CD, Fries RC, Boggess MM & Miller MW Journal of the American Veterinary Medical Association 241(1) pp89-94 found that pimobendan worked well for certain types of heart failure but that some cats with other types developed hypotension (low blood pressure). It concluded "Additional studies are needed to establish dosages for pimobendan and its effects before it can be recommended for treatment of cats with CHF."

 

A later study, Case-control study of the effects of pimobendan on survival time in cats with hypertrophic cardiomyopathy and congestive heart failure (2014) Reina-Doreste Y, Stern JA, Keene BW, Tou SP, Atkins CE, DeFrancesco TC, Ames MK, Hodge TE & Meurs KM Journal of the American Veterinary Medical Association 245(5) pp534-539, looked at the effects of giving pimobendan to cats with CHF secondary to HCM and HOCM. The study concludes "Cats receiving pimobendan had a significant benefit in survival time. Median survival time of case cats receiving pimobendan was 626 days, whereas median survival time for control cats not receiving pimobendan was 103 days. No significant differences were detected for any other variable. The addition of pimobendan to traditional treatment for CHF may provide a substantial clinical benefit in survival time for HCM-affected cats with CHF."

 

Pimobendan also appears to be effective for cats with dilated cardiomyopathy. Effect of pimobendan on the clinical outcome and survival of cats with non-taurine responsive dilated cardiomyopathy (2012) Hambrook LE & Bennett PF Journal of Feline Medicine & Surgery 14(4) pp233-9 found that cats with dilated cardiomyopathy who received pimobendan lived for four times as long as cats not given pimobendan.

 

There is some debate about the use of pimobendan in cats with HCM. Heart failure (2016) Kittleson MD Merck Veterinary Manual states "There is ongoing debate regarding the use of pimobendan in cats. Pimobendan is not approved for use in cats, and the package insert states that it is contraindicated in cats with hypertrophic cardiomyopathy, although several studies have suggested that the drug is safe in cats, even those with hypertrophic cardiomyopathy, when administered at the same dosage as in dogs. However, a pharmacokinetic study showed that the serum concentration of pimobendan in cats given a canine dose results in a serum pimobendan concentration 10 times that seen in dogs. Cardiac pathology is found in dogs administered 3–5 times the recommended dose. It is unlikely any species that experienced a similar calcium sensitization effect as dogs could survive a dose 10 times the recommended dose, which suggests that cats are somehow very different. This requires more investigation before rational recommendations can be made with regard to using pimobendan in cats. However, anecdotally and in one retrospective study, pimobendan has been used in cats with CHF from any cause and has been beneficial clinically. Consequently, if a cat is no longer responding to conventional heart failure drug therapy, pimobendan (1.25 mg/kg/cat, bid) may be tried."

 

The University of California at Davis School of Veterinary Medicine is currently (2017) investigating the use of pimobendan to treat HCM generally, rather than only cats with HCM who also have congestive heart failure. Participants must have suspected or confirmed HCM. Cats with heart murmurs, congestive heart failure or elevated NT-ProBNP on bloodwork (>100pmol/L) are eligible but cats with other systemic diseases (such as CKD, hypertension or on certain heart medications are not. The trial only lasts one week, but cats may receive a placebo rather than pimobendan. Contact  sterngenetics@ucdavis.edu for more information.

 

The Tufts studies found that Pimobendan not only helped with the congestive heart failure, but the cats' kidney values also improved. Research has since been conducted into its effectiveness in treating CKD in cats. There is more information about this here.

 

In 2010, a member of Tanya's CKD Support Group whose cat had both CKD and HCM was prescribed pimobendan by a vet school. Her cat did very well on it.

 

The Morris Animal Foundation is funding a study at North Carolina State University which is looking into the effectiveness of transdermal pimobendan in cats.

 

Bronchodilators: Theophylline


Bronchodilators open up constricted airways in the lungs. Theophylline is commonly used in the US and may also be offered in the UK, though millophyline-V (etamiphylline) is also used in the UK.

 

Bronchodilators are commonly used to treat asthma. Occasionally they are used to treat CHF, and Pet Care Rx explains more about the use of theophylline in this way.

 

Mar Vista Vet says "Theophylline may increase a patient's heart rate, exacerbating certain types of heart arrhythmias or interfering with the heart's ability to fill. This could especially be an issue with hyperthyroid cats or cats with hypertrophic cardiomyopathy. Heart failure patients tend to clear theophylline from their bodies more slowly than normal patients."

 

Plumb's Veterinary Drug Handbook (2011) says "The theophyllines should be administered with caution in patients with severe cardiac disease, seizure disorders, gastric ulcers, hyperthyroidism, renal or hepatic disease, severe hypoxia, or severe hypertension."

 

I have not heard from anybody using a bronchodilator for CHF for a long time (I used to hear from people using them when the site first began). Overall I think better medications are available, but be guided by your vet.

 

Congestive Heart Failure Diet


The relationship between body weight, body condition, and survival in cats with heart failure (2010) Finn E, Freeman LM, Rush JE & Lee Y Journal of Veterinary Internal Medicine 24(6) pp1369-1374 states "Cats with the lowest and highest body weights had reduced survival times compared with those with body weights in the intermediate ranges, suggesting a U-shaped relationship between body weight and survival."

 

Cachexia and sarcopenia: emerging syndromes of importance in dogs and cats (2012) Freeman LM Journal of Veterinary Internal Medicine 26 pp3-17 says "In cats with CHF, cats with low body weights had shorter survival times compared with cats with moderate or high body weights. These data emphasize the importance of avoiding weight (and muscle) loss in dogs or cats with CHF by careful attention to both the medical and  nutritional aspects of their care. Cardiac cachexia typically is recognized only after CHF has developed."

 

Feeding the aging heart (2010) Freeman LM & Rush JE Presentation to the 2010 Nestle Purina Companion Animal Nutrition Summit gives some advice on food choices for cats with heart disease, including "Reduced protein diets should be avoided in all animals with cardiac disease unless severe renal dysfunction is present." They also say "L-carnitine supplementation may have benefits even if a deficiency is not present by improving myocardial energy production." Also the B vitamins, & "Omega-3 fatty acids appear to be particularly useful in animals with anorexia or cachexia but also may be beneficial in animals with less advanced cardiac disease (e.g., DCM, CVD, HCM)."

 

Beneficial effects of omega 3 fatty acids in cardiovascular disease (2010) Freeman LM Journal of Small Animal Practice 51 pp462-470 explains more about feeding omega 3 fatty acids (essential fatty acids) to cats with heart disease. Omega-3 fatty acid supplementation for dogs and cats with heart disease (2014) Nutrition Service at Cummings Veterinary Medical Center at Tufts University recommends particular brands for cats and dogs with heart disease.

 

CEG formulary: cardiac medications for cats (2014) Cardiac Education Group provides an overview of heart medications often used in cats, and discusses EFA dosages.

 

Nutritional aspects of heart disease (2012) Di Tollo BA Veterinary Focus 22(1) pp11-16 states "Anorexia and the loss of water-soluble vitamins through the urine when diuretics are administered both favor vitamin B complex deficiency. Furthermore, cats with heart disease need more B vitamins than healthy cats. Diets for cats with heart disease should therefore contain levels of water-soluble vitamins 2-3 times higher than that found in food for healthy cats."

 

Managing concurrent kidney and heart disease (2012) Tremayne J Veterinary Practice News Jan 2012 includes some information on diets for patients with both kidney and heart disease.

 

Feeding the cardiac patient Vermont Veterinary Cardiology discusses feeding heart patients and has lists of potentially suitable diets.

 

Oxygen


Cats with CHF may need oxygen. Vets can provide this and you should always seek veterinary assistance if your cat is having trouble breathing, but having an oxygen tent at home may be helpful on occasion, e.g. if you have just given your cat a diuretic and wish to keep him/her comfortable while you wait for the medication to kick in.

 

Some members of Tanya's CKD Support Group have bought the Buster ICU cage and have found it helpful. Jorgensen Labs sell it for US$292.

 

One member of Tanya's CKD Support Group was able to rent an oxygen tent from a local medical supply company with a prescription from her vet.

 

Alternatively, How to build an oxygen tank for your pet explains how to build your own.

 

You will need your vet to provide you with the oxygen or a prescription for it, and to show you how to use the oxygen and the tent properly.

 

Coenzyme Q10


If your cat has heart failure, you may wish to discuss the use of coenzyme Q10 with your vet. Effect of coenzyme Q10 therapy in patients with congestive heart failure: a long-term multicenter randomised study (1993) Morisco C, Trimarco B, Condorelli M Clinical Investigation 71 (8 Supp) pp134-6 demonstrated that in humans "the addition of coenzyme Q10 to conventional therapy significantly reduces hospitalization for worsening of heart failure and the incidence of serious complications in patients with chronic congestive heart failure".

 

The effect of coenzyme Q10 on morbidity and mortality in chronic heart failure. Results from the Q-SYMBIO study (2013) SA Mortensen, A Kumar, P Dolliner, KJ Filipiak, D Pella, U Alehagen, G Steurer, GP Littarru, F Rosenfeldt European Journal of Heart Failure 15 (S1), S20 found that in humans, "CoQ10 treatment was safe with a reduced all cause mortality rate. CoQ10 should be considered as a part of the maintenance therapy of patients with chronic HF."

 

CoQ10 may not be appropriate if your cat is on blood thinners such as aspirin or clopidogrel. University of Maryland Medical Center says "There have been reports that CoQ10 may make medications such as warfarin (Coumadin) or clopidigrel (Plavix) less effective at thinning the blood. If you take blood thinners, ask your provider before taking CoQ10."

 

If you do decide to try CoQ10 with your vet's agreement, please do not stop using it suddenly. There have been several cases of humans and one cat with heart disease who were using CoQ10 relapsing after it was stopped suddenly.

 

There is more information about CoQ10 here.

 

Congestive Heart Failure Monitoring


It is important to monitor cats with CHF in case the fluid build up returns. You should watch for the symptoms discussed above and should monitor your cat's respiration rate and ideally heart rate.

 

Ask your vet to teach you to listen to your cat's heart so you can monitor for any changes that might indicate an approaching crisis. Ideally you will know your cat's baseline measurements so you can tell when things are getting out of kilter. If you did not know them before an episode of CHF, measure them once your cat is stable again so you know what is typical when there is no fluid build up.

 

I would also weigh your cat daily. If your cat's weight increases steadily over the course of a few days, or if it increases abruptly, this may be a sign of congestion.

 

Regular x-rays may also be helpful to avoid crises, though you need to balance the need for these against the stress of vet visits.

 

Management of acute heart failure in cats: monitoring for treatment efficacy and adverse effects (2014) Luis Fuentes V is a two minute video presentation about monitoring cats with CHF.

 

Congestive Heart Failure Prognosis


Sadly, some cats with acute CHF only have a short period to live, but if you can find and treat the cause, your cat's chances are much better. It is usually worth trying to control the condition because, as with CKD, some cats do better than others, especially if the CHF is caught before the cat is in crisis.

 

Population and survival characteristics of cats with hypertrophic cardiomyopathy: 260 cases (1990-1999) (2002) Rush JE, Freeman LM, Fenollosa NK & Brown DJ Journal of the American Veterinary Medical Association 220(2) pp202-207 found that "Median survival time was 709 days (range, 2 to 4,418 days) for cats that survived > 24 hours." This is quite an old study, and treatment protocols have probably improved since then.

 

Association between survival time and changes in NT-proBNP in cats treated for congestive heart failure (2017) Pierce KV, Rush, JE, Freeman LM, Cunningham SM & Yang VK Journal of Veterinary Internal Medicine 31(3) pp678-684 looked at levels of NTproBNP in cats with CHF secondary to HCM. The median survival time was 109 days, though five (out of 31) cats survived for 709 days or longer (almost two years). The study states "Cats with a larger percent decrease in NT-proBNP concentration from admission to discharge had a significantly longer survival time compared to cats with a smaller percent change during hospitalization. Cats that did not have signs of active CHF at the time of the 7–10 day re-evaluation had a longer survival time compared to cats with signs of active CHF at the re-evaluation." The study also notes that NT-proBNP levels reduced a lot further in cats who were given pimobendan, but the study did not conclude that pimobendan helps survival in CHF cats, instead saying further research is needed.

 


Arterial Thromboembolism (ATE): Saddle Thrombus or Blood Clot in the Legs


 

Studies indicate that 12-28% of cats with HCM will develop ATE. Unfortunately in many cats, the ATE is the first sign that the cat has heart disease.

 

An arterial thromboembolism is a blood clot which forms in the atrium (one of the heart's chambers). The clot travels through the aorta (the main artery in the body) until it reaches a place where it is too large to pass through and it lodges there. This often occurs where the artery splits to go down each leg, and an ATE which lodges here is called a saddle thrombus. Depending upon exactly where it lodges, it may stop the blood supply to one leg or to both legs. Pet Education explains more about how this happens (with diagrams).

 

Concurrent diseases and conditions in cats with renal infarcts (2014) Hickey MC, Jandrey K, Farrell KS & Carlson-Bremer D Journal of Veterinary Internal Medicine 28(2) pp319–323 found that cats with renal infarcts (death of kidney tissue caused by a loss of blood supply) detected via ultrasound were more than eight times more likely to experience an ATE than a cat without renal infarcts.

 

An arterial thromboembolism is life-threatening so you should consult a vet as soon as possible.

 

Pet Place has a good overview of saddle thrombus.

 

Mar Vista Vet also has helpful information.

Arterial Thromboembolism Symptoms


Symptoms include:

  • Limping or an inability to use the leg.

  • The affected leg is likely to be cold to the touch.

  • Often only one leg is affected, but in some cases a pair of legs (e.g. both rear legs) may be affected.

  • The affected leg is usually a rear leg, though I have heard of one cat who developed a blood clot in a front leg.

  • Weak legs (as opposed to limping) may also have other causes, see Index of Symptoms and Treatments

Arterial Thromboembolism Diagnosis


Your vet will check your cat's legs, and may run blood tests. Mar Vista Vet says "The diagnosis is often clinched by comparing a blood glucose level taken from the front of the body against one taken from the rear legs."

 

X-rays and an ultrasound may also be performed, especially if the cat has not been previously diagnosed with heart problems.

 

Infrared thermography: a rapid and accurate technique to detect feline aortic thromboembolism (2017) Pouzot-Nevoret C, Barthélemy A, Goy-Thollot I, Boselli E, Cambournac M, Guillaumin J, Bonnet-Garin JM & Allaouchiche B Journal of Feline Medicine and Surgery Epub ahead of print used a special camera to assess the temperature in all four limbs of cats admitted with back leg paralysis and found there was a distint difference in temperature between the front and back legs of cats with ATE, particularly in the left legs. The study concludes "A minimal difference of 2.4°C between ipsilateral affected and non-affected limbs has an excellent specificity and high sensitivity for FATE diagnosis. Infrared thermography seems to be a promising useful, easy, non-invasive and rapid method for detecting aortic thromboembolism in cats, particularly in emergency situations."

 

Arterial Thromboembolism Treatments


The mainstays of treatment are pain management and heart medications. Your cat should be hospitalised initially in order for these treatments to be provided.

 

How to handle feline aortic thromboembolism (2010) Marshall HC & Koors T Veterinary Medicine discusses treatment options and prevention.

 

Thromboembolism: current treatment and future directions (2012) Jandrey K Veterinary Focus 22(1) pp26-31 has an overview of ATE treatments.

 

CEG formulary: cardiac medications for cats (2014) Cardiac Education Group provides an overview of heart medications often used in cats and commonly used dosages.

Painkillers


If your vet proposes a treatment plan, make sure it includes painkillers because this is an extremely painful condition. Arterial thromboembolism: risks, realities and a rational first-line approach (2012) Luis Fuentes V Journal of Feline Medicine and Surgery 14(7) pp459-470 says "Analgesia is the main priority, and severe pain should be managed with methadone or a fentanyl constant rate infusion."

 

Feline arterial thromboembolism a serious consequence of cardiac disease...but not always a lost cause! Kent A says "Analgesia first! Stronger analgesics are recommended initially, such as fentanyl, hydromorphone, morphine or buprenorphine. Butorphanol should only be used if the pain is mild or if there are no other options. Generally pain subsides after 24-48 hours and analgesia can be tapered and eventually discontinued."

 

Bloodthinners: Clopidogrel (Plavix) and Aspirin


Medications are commonly given to thin the cat's blood and reduce the risk of more blood clots forming (antithrombotic treatment). Arterial thromboembolism: risks, realities and a rational first-line approach (2012) Luis Fuentes V Journal of Feline Medicine and Surgery 14(7) pp459-470 says "Thrombolytic therapy is not recommended, but antithrombotic treatment should be started as soon as possible. Aspirin and clopidogrel are well tolerated."

 

Clopidogrel (Plavix)


Previously cats were commonly given aspirin, but clopidogrel (Plavix) now tends to be more popular because of a study, Secondary prevention of cardiogenic arterial thromboembolism in the cat: the double-blind randomized positive-controlled feline arterial thromboembolism; clopidogrel vs aspirin trial (FAT CAT) (2015) Hogan DF, Fox PR, Jacob K, Keene B, Laste NJ, Rosenthal S, Sederquist K & Weng HY Journal of Veterinary Cardiology 17( Suppl 1) S306-17, which compared the use of aspirin and clopidogrel in cats following ATE. Cats receiving aspirin lived for a median time of 192 days until they had another ATE, whereas the clopidogrel group lived for over a year. Clopidogrel (Plavix) and the results of the FAT CAT trial Angell Memorial Hospital reports on the FATCAT trial.

 

The usual dose of clopidogrel for cats is 18.75mg (a quarter of a 75mg tablet) daily but be guided by your vet.

 

The Morris Animal Foundation is funding research at Washington State University into how cats metabolise clopidogrel.

 

Aspirin


Aspirin is still used by some vets to thin the blood, though clopidogrel is becoming more popular than aspirin for this purpose. Plumb's Veterinary Drug Handbook says of aspirin "Likely a weaker, but less expensive option than clopidogrel."

 

Sometimes cats with HCM are also offered low doses of aspirin, but if the cat reacts badly, then aspirin is stopped.

 

Occasionally aspirin is also used to help with proteinuria.

 

One reason aspirin is becoming less widely used is because it can be toxic to cats, who can only metabolise it very slowly. When it is used, aspirin is usually only given in very low doses once every three days.

 

Plumb's Veterinary Drug Handbook states that when used to treat arterial thromboembolism, 5mg per cat can be given every three days, according to one study, but that a later study suggests 81mg (one baby aspirin) every 72 hours, which is a much higher dose. To prevent thromboembolism, it mentions a high dose of 40 mg per cat or a low dose of 5 mg per cat, both orally every 72 hours.

 

Because cats are unable to metabolise aspirin well, you should be alert to the signs of toxicity. Pet MD states "The progression of symptoms can occur quickly. One of the first noticeable signs is loss of appetite. Other signs include vomiting, diarrhea, and intestinal hemorrhage brought on by ulceration in the stomach and small intestines. The central nervous system may also be affected, causing your cat to have trouble walking, appear weak and uncoordinated, or even collapse. Loss of consciousness and sudden death can also occur. It also mentions that "even nontoxic levels can produce these symptoms."

 

Mar Vista Vet has information on aspirin.

 

Diet


Plasma homocysteine, B vitamins, and amino acid concentrations in cats with cardiomyopathy and arterial thromboembolism (2000) McMichael MA, Freeman LM, Selhub J, Rozanski EA, Brown DJ, Nadeau MR, Rush JE Journal of Veterinary Internal Medicine 14(5) pp507-12 found that cats with heart disease who have thrown a clot have significantly lower levels of vitamin B6, vitamin B12 and arginine, an amino acid. The study concludes "We interpret the results of this study to suggest that vitamin B12 and arginine may play a role in CM and ATE of cats." You may therefore wish to discuss using methylcobalamin (vitamin B12) with your vet.

 

Arterial Thromboembolism Research


 

Bosentan


The efficacy of Bosentan, a mixed ETa ETb receptor antagonist, in cats with arterial thromboembolism (2015) Rozanski E & Buckley G Winn Feline Foundation (2015) Rozanski E & Buckley G reports on research into the use of a drug called Bosentan to see if it helps cats with saddle thrombus. Ten cats with ATE were given Bosentan while eight cats with ATE were not. Five of the cats given Bosentan (50%) improved within 24 hours, whereas only two of the cats not given Bosentan (25%) improved.

 

Prospective evaluation of the endothelin-1 receptor antagonist bosentan in feline arterial thromboembolism (2014) Rozanski EA, Buckley GJ, Sharp CR, Cunningham SM & Rush JE 2014 ACVIM Forum Research Abstracts Program C13 p1003 provides more detail about the study.

 

As far as I know, Bosentan is not currently widely available.

 

Tissue Plasminogen Activators (TPA)


Tissue plasminogen activators are used in humans who have had strokes. TPAs are a thrombolytic treatment, as opposed to an antithrombotic treatment, i.e. an attempt is made to dissolve the blood clot.

 

Previous use of TPAs in cats with ATE has not been promising. Prospective evaluation of tissue plasminogen activator in 11 cats with arterial thromboembolism (2010) Welch KM, Rozanski EA, Freeman LM & Rush JE Journal of Feline Medicine and Surgery 12 pp122128 looked at the use of a TPA in cats. Eleven cats were given the TPA and "Pulses were restored in 40% of limbs within 4h and 53% within 24h." However, "Adverse effects were seen in 11/11 cats" and "The study was terminated due to a high frequency of adverse outcomes."

 

Cats with blood clots is a trial at Ohio State University College of Veterinary Medicine into the use of TPAs for cats with ATE. Cats are eligible for the trial if at least two limbs (but not all four) are affected, the event was observed and TPA treatment (an infusion) can be begun within six hours of the ATE occurring. Cats are ineligible if they are moribund or have unstable congestive heart failure, have previously been given TPAs or cannot be hospitalised for 48 hours. It should be noted that a cat participating in the trial has a 50:50 chance of being given a placebo rather than a TPA.

 

Contact: Dr. Julien Guillaumin

guillaumin.2@osu.edu

CVM-ClinicalTrials@osu.edu

Phone (614) 247-8706

 

Rivaroxaban


The Morris Animal Foundation is funding research at the University of Georgia into the use of an anti-clotting drug called rivaroxaban for the prevention of blood clots in cats.

 

Arterial Thromboembolism Prognosis


Sadly the prognosis is poor, especially for cats with more than one leg affected, but some cats do make a recovery, although another episode is possible. Aortic thromboembolism associated with feline hypertrophic cardiomyopathy (2002) Rodriguez D & Harpster N Veterinary Practice Compendium 24(6) says "Although the prognosis is guarded, recovery from TE with considerable disease-free intervals is possible with proper management."

 

Population and survival characteristics of cats with hypertrophic cardiomyopathy: 260 cases (1990-1999) (2002) Rush JE, Freeman LM, Fenollosa NK & Brown DJ Journal of the American Veterinary Medical Association 220(2) pp202-207 reported a survival rate for "cats in the ATE group (184 days; range, 2 to 2,278 days)."

 

Arterial thromboembolism in 250 cats in general practice: 2004 - 2012 (2014) Borgeat K, Wright J, Garrod O, Payne JR & Luis Fuentes V Journal of Veterinary Internal Medicine 28 pp102-108 examined the records of cats with ATE treated by general practitioners in the UK. Over 61% of the cats were euthanised immediately. More than 44% of the remaining cats lived for at least seven days, even though not all the cats were given any treatment. The study concludes "For cats that survived ≥ 7 days, median survival time was 94 (95% CI, 42 – 164) days, with 6 cats alive 1 year after presentation."

 

Who knows how many more cats would have survived and for how long if they had been offered treatment? These two studies report on cats with ATE from 5-27 years ago, and treatments have improved since then. If your cat is given clopidogrel, the chances of survival are probably higher, see above.

 

Feline arterial thromboembolism a serious consequence of cardiac disease...but not always a lost cause! Kent A says "Although the overall prognosis is poor, some cats can recover very well, be discharged from the hospital, and have a good quality of life. These cases can be rewarding.  Euthanasia does not always need to  be the first recommendation."

 

I have heard from a small number of people whose cats lived for several years after an arterial thromboembolism with no known recurrence. Not all of these cats received clopidogrel.

 


Pacemakers


 

Cats tend not to have the sort of heart problem which would benefit from a pacemaker (a slow heart beat or arrhythmias), but one member of Tanya's CKD Support Group received one in early 2017 and is doing well on it.

 

Pacemakers for veterinary patients MSPCA Angell Veterinary Center explains more about pacemakers, including possible costs.

 

Pacemaker implantation in dogs and cats Schroeder N Animal Specialty Hospital of Florida has some information about pacemakers in cats.

 


Support


 

Feline Heart Group is a support group for people with cats with heart conditions including HCM. This group has open archives, meaning anybody can read what you write. However, this does enable you to read about similar cases to your cat's without actually having to join the group if you prefer.

 

Back to Page Index

This page last updated: 10 November 2017

Links on this page last checked: 03 November 2017

 

 

   

*****

 

TREATING YOUR CAT WITHOUT VETERINARY ADVICE CAN BE EXTREMELY DANGEROUS.

 

I have tried very hard to ensure that the information provided in this website is accurate, but I am NOT a vet, just an ordinary person who has lived through CKD with three cats. This website is for educational purposes only, and is not intended to be used to diagnose or treat any cat. Before trying any of the treatments described herein, you MUST consult a qualified veterinarian and obtain professional advice on the correct regimen for your cat and his or her particular requirements; and you should only use any treatments described here with the full knowledge and approval of your vet. No responsibility can be accepted.

 

If your cat appears to be in pain or distress, do not waste time on the internet, contact your vet immediately.

 

*****

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If you wish to link to this site, please feel free to do so. Please make it clear that this is a link and not your own work. I would appreciate being informed of your link.

 

You may print out one copy of each section of this site for your own information and/or one copy to give to your vet, but this site may not otherwise be reproduced or reprinted, on the internet or elsewhere, without the permission of the site owner, who can be contacted via the Contact Me page.

 

This site is a labour of love, from which I do not make a penny. Please do not steal from me by taking credit for my work.

If you wish to link to this site, please feel free to do so. Please make it clear that this is a link and not your own work. I would appreciate being informed of your link.