Cardiology: What's good for treating one type of heart disease, isn't good for all

Lawndale, Calif. — Treating heart disease in companion animals is an ever-evolving science. And, especially for the aging U.S. pet population, the risks for heart disease increase.

DVM Newsmagazine asked an expert veterinary cardiologist, Michael Lesser, DVM, Dipl. ACVIM (cardiology), to answer questions of current interest to general practitioners.

Lesser is medical director and head cardiologist at Advanced Veterinary Care in Lawndale, Calif., a cardiology referral practice. His areas of expertise include non-invasive techniques such as echocardiography, color flow Doppler ultrasound, electrocardiography and non-invasive blood-pressure monitoring. He also performs interventional cardiology procedures, including pacemaker implantation, balloon valvuloplasty, angiography and coil occlusion for patent ductus arteriosus.

Q: In dealing with heart disease in geriatric patients, what is the most significant challenge for general practitioners?

A: I believe what you're asking is what do I, as a cardiologist, think is the most significant challenge for general practitioners. For me, cardiology is all I do. It's what I know. But the challenge for general practitioners is what do they do, since they're not board-certified?

The biggest challenge for general practitioners, as I see it, is keeping up with new medications and when to use them. There is a great deal of information on new medications to treat heart failure and heart disease. What's important is knowing when to use what medication. In addressing that, it's extremely important that veterinarians keep up on current literature. Practitioners also want to make sure they're getting their information from reliable sources. With the advent of the Internet and these types of resources, a lot of misinformation is out there. Veterinarians need to be vigilant, and always make sure to check sources.

Q: You mention the great challenge in keeping up with new medications. What are some of the new options?

A: Pimobenden and spironolactone are two relatively new drug treatment options.

It's also important to mention that some drugs, although not necessarily the ones I've just mentioned, are being touted for benefits in human medicine. There is much in the literature about improved heart-related therapies in human medicine. But some of that data doesn't cross over to animal patients at this time. In some cases, there is not enough literature to support the cross-over with therapies; in other cases, you just have to drill deeper to find appropriate data to apply to animal patients.

Q: If you had one longstanding myth to bust about cardiology, what might it be?

A: The myth I'd like to bust is this: What's good for one type of heart disease is good for all. Therapies and treatment approaches for humans with heart disease are not always best for dogs or cats with heart disease. Some clients may say, "My sister has heart disease and is on this drug. Why isn't my cat on this same medication?" People often get different types of heart disease than what is seen in dogs and cats.

Q: Could you offer advice on distinguishing a cardiac rhythm disorder from a respiratory arrhythmia?

A: The gold standard in determining one from the other is the ECG. Nothing replaces that. Every cardiologist would tell you this. It's really the only way to truly know the difference. You simply can't diagnose with a stethoscope. I get calls from general practitioners saying, "I've diagnosed this arrhythmia based on listening to the dog." You just can't do that.

Q: As the pet population ages, what breeds (dogs and cats) are most susceptible to cardiac problems?

A: As far as the aging population goes, all breeds of dogs and cats are prone to heart disease. It's not breed-specific in the aging population. Heart disease is a common illness in geriatric patients, whether dogs or cats. The reality is that they're living longer with better preventive health-care and wellness exams. Owners are more in tune with pet health issues.

In the younger population, however, heart disease definitely is purebred- specific.

Q: Could you discuss heart murmurs and their role in a clinical evaluation of heart disease?

A: Detection is extremely important in evaluating for early heart disease. Especially in the case of an asymptomatic patient, if a veterinarian finds a heart murmur, that's a clue that something is not right with the heart. That's why it is highly recommended that clients bring patients in for yearly exams, especially older patients. The onset of a murmur can be the beginning of other symptoms. Catching it early and providing aggressive treatment potentially can prolong survival in these animals.

Q: What about auscultation as an assessment of a cardiac patient?

A: Listening with the stethoscope is a very important, integral part of an assessment of any cardiac patient. X-rays and other diagnostics all contribute to the exam, but the stethoscope is a part that can't be skipped. That's why all of us walk around with one.

Q: What are some trends you see within the veterinary cardiology specialty?

A: One of the trends, in one person's view, is that a lot more work is being done to decipher the underlying cause of heart disease itself.

Research is exploring the cause for degenerative valve changes or the genetics underlying heart disease in cats. Researchers are trying to get down to the underlying cause of why diseases occur, as opposed to being focused on just therapeutics or diagnostics. In the past, there was a lot of emphasis on diagnostic technique and a certain amount of emphasis on therapies. Underlying causes is the new trend in research.

Q: Any other comments?

A: Today in veterinary medicine, we are fortunate to have many specialists in particular areas — cardiology, oncology, internal medicine. My only comment is that it's important that people seek advice of specialists trained in their particular area when looking for diagnostics and therapeutic treatments for a specific type of disease.

It may sound obvious, but cardiologists are best trained to deal with cardiology issues. Neurologists are best equipped to deal with neurology issues and so on. Needless to say, this guidance is not always followed.

Dr. Lesser earned his DVM degree from Tufts University School of Veterinary Medicine in 1987. After finishing his residency at the Animal Medical Center in New York, he assumed a leadership role in clinical cardiology service at AMC until 1991, when he moved to Southern California. In California, he achieved Diplomate status in the specialty of cardiology.