Jenny, a 3 year old female spayed Coonhound, was evaluated at RVRC by CVCA for a newly ausculted heart murmur. The owners had noticed that she had become progressively more lethargic on walks, was panting more, and had been coughing, especially at night. She was still eating and drinking well.
Her physical exam revealed a gallop, as well as a grade III/VI systolic murmur with the point of maximal intensity over the mitral valve. Her heart rate was 190 bpm with occasional premature beats. She was panting but had normal breathing effort and normal lung sounds. Her pulse quality was moderate with occasional deficits. Her abdominal palpation was unremarkable.
Thoracic radiographs, taken by her primary care veterinarian 1 week prior, showed a moderately enlarged heart and left atrium with a VHS of 12.5. No discreet edema was visible, but a trace amount of pleural effusion was seen. An ECG revealed sinus tachycardia with infrequent ventricular premature contractions. Her echocardiogram revealed a severely dilated left ventricle with severely depressed contractility, severe left atrial dilation and severe mitral regurgitation. She also had moderate to severe secondary pulmonary hypertension.
She was diagnosed with dilated cardiomyopathy (DCM) and mild congestive heart failure. She was treated with furosemide (1 mg/kg BID), Vetmedim (0.25 mg/kg BID), Enalapril (0.5 mg/kg BID) and Spironolactone (2 mg/kg q 24 h). Within a few days, her cough had resolved and her energy had returned to normal.
Given her young age and the fact that she is not a typical breed to develop DCM, the diagnosis was surprising. We know that certain breeds such as Boxers, Doberman Pinschers, Great Danes and Irish Wolfhounds have a genetic predisposition to DCM. Recently, the veterinary cardiology community has noticed an uptick in the number of cases of dilated cardiomyopathy in breeds not genetically prone. Further investigation found that most of these dogs were being fed a grain free diet. The reason for this link is not yet understood. Some of the affected dogs had a low Taurine level which is a known cause of DCM and these dogs improved with Taurine supplementation and diet change. Some of the dogs, however, had a normal Taurine level but also improved with diet change and Taurine supplementation. So, it appears that Taurine may not be the sole issue and that there is a seperate and as yet unknown factor involved in some dogs. A current hypothesis is that diets high in legumes (such as peas, lentils, or other legume seeds) or potatoes may be affecting the ability to absorb key nutrients in some dogs, since most of the affected dogs were on diets with high level of these nutrients. Currently the FDA, in collaboration with CVCA, is enrolling dogs with atypical DCM in a study to try further investigate this potential link.
Jenny had been on a boutique diet for years. Although her diet was not completely grain free, it was high in legumes and Potatoes. Jenny was enrolled in the FDA study and will be transitioned to a more traditional diet, as well as started on Taurine supplementation. The hope is that her disease is diet related and will be reversible. We will plan to recheck her heart function in 6 months to see if she improves. For now her symptoms have resolved and she is back to her old self.