Heart Problems in Greyhounds
I am grateful to Larry P. Tilley, D.V.M., for his time and enthusiasm in providing information for this article. Dr. Tilley received his D.V.M. from Iowa State University and performed his internship and residency in cardiology at the Animal Medical Center in New York City, from 1969-1972. In 1999, he was named the Waltham International Recognized Veterinarian of the Year; he was awarded the Speaker of the Year Award from the North American Veterinary Conference in 1997 and the Animal Medical Center Distinguished Alumnus Award in 1992. He has written hundreds of articles and over a dozen text books including Essentials of Canine and Feline Electrocardiography and Manual of Canine and Feline Cardiology and Self-Assessment:Small Animal Arrhythmias and, The 5 Minute Veterinary Consult (1st and 2nd Edition), which is available on Amazon.com. In 1989, Dr. Tilley was named the United States Veterinarian of the Year by the American Animal Hospital Association and also received the Outstanding Service to Veterinary Medicine Award by the New York State Veterinary Society in 1987. Dr. Tilley has been an invited speaker on veterinary medicine throughout the world, giving over 400 presentations on internal veterinary medicine and cardiology.
Many greyhound adopters across the country have been confronted with alarming news from their veterinarians concerning various heart abnormalities in their retired racers. Everything from heart murmur to severely enlarged heart, congestive heart failure, and tachycardia or arrhythmia has been offered as an explanation for various, vague symptoms and findings, with minimal evidence to support the diagnosis. And often, these conditions fail to present themselves upon evaluation by a veterinary cardiologist.
According to Care of the Racing Greyhound - A Guide for Trainers, Breeders and Veterinarians, The greyhound has a large heart for its body size compared with other breeds. It has been shown that part of this is a genetic or inherited trait and part of it is the result of the exercise or work that a racing greyhound does. However, Dr. Larry Tilley states that their hearts are really not necessarily any bigger, rather, there are some false changes because of the unique chest conformation of the greyhound that may give the appearance of a larger than normal heart.
As with any athlete, human or canine, the more exercise the body endures, the more conditioned it will become and all muscles, including the heart will exhibit some degree of hypertrophy (thickening or enlarging). According to Dr. Tilley, greyhounds have totally different heart values, particularly in relation to ultrasound testing, and cannot be compared to other breeds. An enlarged heart, as determined by ultrasound studies, does not always indicate disease of the heart. Certain physical conditions, such as obesity, natural aging changes or low thyroid can result in an enlarged heart, however the presence of actual cardiomyopathy (heart disease) such as congestive heart failure is not always the culprit.
Ultrasound studies of the heart (echocardiography), X-rays and electrocardiograms (ECGs) are the most reliable methods by which an accurate diagnosis can be made when there is a question of any heart abnormality. The inexperienced eye may erroneously diagnose enlarged heart in a greyhound if relying only on x-ray, due to the narrow chest and resulting elongated appearance of the greyhound heart. ECG results may register unusual and misleading large voltage readings due to the closeness of the heart to the chest wall, however, a veterinary cardiologist can discern these faux abnormalities and distinguish a physiologically normal heart from that of a diseased or abnormal heart.
Irregular heartbeats in greyhounds are not any more common than in most other breeds, and do not necessarily indicate a problem, as this may be present during a veterinary examination due to anxiety and nervousness in the greyhound. A diagnosis of arrhythmia or tachycardia may well be inaccurate unless confirmed by electrocardiography.
Heart murmurs in greyhounds appear to occur at a younger age than most breeds, however are likely to be genetic rather than indicative of pathology. As a general rule, though, greyhounds are no more likely to have heart murmurs than other large breed dogs. Only about 10% of all large breed dogs will present with a true heart murmur compared to approximately 85% of all small breed dogs. Murmurs can be detected in almost all breeds over the age of 10 years. If medication is being considered, ultrasound and/or ECG should be performed to determine the severity of the murmur . In Dr. Tilleys opinion, medicating an asymptomatic dog for heart murmur is most likely of little or no benefit. Preventative antibiotics are not recommended in canines with heart murmurs (as in the case of pre-dental or pre-anesthesia) as they do not manifest infection the way humans with murmurs can.
In Dr. Tilleys opinion, prescribing medication for an enlarged heart is not indicated unless the ultrasound is abnormal and the dog is symptomatic. The most common symptoms of congestive heart failure or other types of cardiomyopathy are chronic coughing accompanied by extreme lethargy.
The encouraging side of all the above is that the tests needed to rule out the presence of heart disease are surprisingly inexpensive and completely non-invasive. Anesthesia is not necessary and the expertise of a veterinary cardiologist is as close as the nearest computer terminal. Any x-ray, ultrasound or ECG can be transmitted via computer for evaluation by a veterinary cardiologist in an office such as Dr. Tilleys.
If your greyhound (or other canine or feline) has been diagnosed with any type of heart abnormality, a thorough cardio evaluation would likely put your mind at ease. Ask your veterinarian about the possibility of a referral to a veterinary heart specialist - the peace of mind is well worth the time and reasonable fees and you may even avoid future expense in heart medication that is unnecessary. Some breeds are predisposed to heart disease, such as dobermans and boxers, but generally the greyhounds most common heart diagnosis would more likely be athletic heart; indicative of a history of vigorous exercise rather than disease.