By Hannah Beers
UI College of Veterinary Medicine
We hear about the risks and dangers heart disease poses to human lives all the time, but did you know that forms of heart disease could also impact your dog?
Heart disease — a broad term that encompasses multiple diagnoses — is a very common disease in dogs and increases in prevalence with age, according to Dr. Jordan Vitt, a veterinary cardiologist who recently joined the UI Veterinary Teaching Hospital in Urbana. He explains how this potentially devastating malady affects the canine population and offers tips on early detection.
"The most commonly acquired form of heart disease in dogs is known as chronic degenerative valve disease," Vitt said. "While we don't yet know all of the underlying mechanisms that cause degenerative valve disease to occur, we do know there are genetic components to the disease. We know that certain breeds, especially those that weigh less than 40 pounds, are at higher risk of developing degenerative valve disease. However, it is important to note that nearly all older dogs will develop some degree of valvular degeneration leading to a heart murmur."
In chronic degenerative valve disease, the valves that separate the chambers of the heart break down over time and cause the valves to leak or "regurgitate." This regurgitation or valve leak leads to development of a heart murmur, which can be heard with a stethoscope. In some dogs, this regurgitation can cause the heart to become very enlarged, putting the dogs at a high risk of congestive heart failure, a life-threatening condition.
Annual exams catch murmurs early
The first signs typically noted by owners include difficulty breathing and coughing, sometimes accompanied by lethargy or a decreased appetite.
"Unfortunately, by the time these symptoms are evident, patients are already in the advanced stages of heart disease," Vitt said. "Respiratory distress generally means that the dog is in heart failure and needs treatment. The effectiveness of treatment is much greater when you catch the disease at an early stage. Your veterinarian will listen for murmurs during your dog's yearly physical examination."
If a murmur is detected, Vitt advises taking radiographs (X-rays) of the dog's chest to determine whether there is heart enlargement. An echocardiogram (ultrasound of the heart) by a veterinary cardiologist is recommended for dogs with an enlarged heart; a recent study showed that early intervention with medication can prolong the lifetime of dogs with enlarged hearts.
Diagnosis of a heart murmur should also prompt your veterinarian to check your dog for high blood pressure, which can worsen the valve leak. Annual X-rays and blood pressure readings will allow your veterinarian to monitor changes in your dog's heart condition. Approximately 30 percent of patients with heart enlargement from valvular degeneration will progress to clinical signs of congestive heart failure, typically within two years.
"This is why it is so important to get your pet checked every year," Vitt said. "The sooner we detect signs of valvular disease, the sooner we can intervene with medical management, allowing the patient to have a better quality of life."
Heart disease app for owners
Owners can monitor their pet's heart health each week at home by measuring his or her breathing rate while sleeping. If the rate is over 35 breaths per minute or there is a greater than 25 percent increase in the baseline breathing rate, the pet may be developing congestive heart failure and should be seen by a veterinarian as soon as possible.
Vitt recommends a free app called "Your Dog's Heart," which reminds owners to check their dog's respiration rate weekly and tracks the data collected.
For dogs with enlarged hearts, medications, usually in the form of daily pills, are available to delay the progression of disease. X-rays, a blood pressure reading and auscultation (listening to the dog's heart) should be repeated every six months to monitor the disease and the effectiveness of the medication.
Surgery to repair damage to the heart valves can be done in people, but this procedure is not yet readily available for dogs. Recent studies show certain medications can delay the progression of the disease, but there is no way to reverse the damage already done.
"The best thing you can do for your dog in regard to heart disease is to catch the problem as soon as it starts," Vitt said.
An archive of pet columns from the UI College of Veterinary Medicine is available at vetmed.illinois.edu/petcolumns/. Requests for reprints of this article may be directed to Chris Beuoy at beuoy@illinois.edu.
