The Great Dane has a big heart figuratively and literally -- he's known for his loyalty and social, loving nature, and also for a condition called dilated cardiomyopathy, a heart muscle that's stretched beyond an efficient size to do its job.
The unfortunate reality regarding this disease is that its cause is largely unknown, according to Pet MD. Researchers at several university veterinary programs are ing ongoing studies, trying to pinpoint the exact biological factors leading to this deadly condition. Nutritional deficiency related specifically to inadequate levels of the amino acids taurine and carnitine has been established as a contributing factor to enlarged hearts in dogs. According to the Dog Health Guide, taurine plays a role in regulating heartbeat and preventing calcium overload in the heart. Carnitine helps muscle cells convert fatty acids into energy. It is theorized that if these two acids are not working properly, strain on the heart muscle occurs.
What It Is
An enlarged heart may seem pretty straightforward, but the functional reality is a bit more complex. As explained on the Louisiana State University School of Veterinary Medicine website, the heart muscle over time becomes dilated or stretched and can no longer pump blood efficiently. The ventricles cannot efficiently push the blood out of the heart, which works harder and harder to pump less and less blood to the lungs, where it is supposed to pick up oxygen on its way through the body and back to the heart. Eventually all of this inefficient overworking of the heart muscle leads to congestive heart failure.
This disease does not quickly announce its presence. According to the Great Dane Club of America, it is an adult-onset disease that is progressive in nature, with no obvious signs for months or even years. Further disheartening is the fact that once clearly recognizable symptoms emerge, the damage is already done. Its major symptoms, according to Pet MD, include lethargy, rapid and excessive breathing, shortness of breath, coughing and abdominal distension. This last listed symptom -- abdominal distension or an enlarged abdomen -- is due to fluid buildup; it can indicate the disease has progressed to a later stage, according to the Dog Health Guide.
As an enlarged heart is not easy to spot, it will take some dedication and keen observation on your part to be able to alert your veterinarian to a potential problem. The LSU vet school recommends owners of Great Danes regularly count their canine friends' resting respiration rate. This is accomplished by observing the dog while he is asleep. Count the number of respiration for 15 seconds and multiple by four. If the resulting number is regularly more than 40, have a veterinarian conduct a thorough evaluation.
Only after running a series of tests can a veterinarian determine if your Great Dane has an enlarged heart. These tests can include X-ray imagining to identify enlargement of ventricles and the presence of fluid in the lungs, an EKG or electrocardiogram to document the rapid beating of the heart, or an ultrasound of the heart. None of these exams is inexpensive, but they are necessary for a conclusive diagnosis.
Once the heart is enlarged, it can't shrink back. The Dog Health Guide is rather blunt: There is no cure for an enlarged heart. The American Kennel Club Canine Health Foundation is just as straightforward in stating there is no cure but does offer a glimpse into what hope veterinary medicine does offer: medications that help control symptoms by reducing fluid retention and aiding in contraction of the heart muscle. However, the AKC cautions that the reality of this disease is that its progressive nature often equates to increased medications and medication management over time. The Canine Inherited Disorders Database maintained by the Atlantic Veterinary College at the University of Prince Edward Island and the Canadian Veterinary Medical Association recommend avoiding strenuous exercise and salty foods as part of at-home care for Great Danes diagnosed with enlarged hearts.
Amy M. Armstrong is a former community news journalist with more than 15 years of experience writing features and covering school districts. She has received more than 40 awards for excellence in journalism and photography. She holds a Bachelor of Arts in communications from Washington State University. Armstrong grew up on a dairy farm in western Washington and wrote agricultural news while in college.