Siberian husky puppy with heart rhythm disorder and fainting

Abstract

A seven-month-old male Siberian husky was presented with a recent history of anorexia, hindlimb weakness and syncope. Physical examination revealed severe tachycardia, tachypnoea and dyspnoea. Mucous membranes were pale and femoral pulses were weak. An electrocardiogram showed sustained ventricular tachycardia with a left bundle branch block configuration. Thoracic radiographs revealed slight right ventricular enlargement and two-dimensional echocardiography revealed mild right ventricular dilation at the cardiac apex and some hyperechogenic areas on the right side of the interventricular septum. Administration of intravenous lignocaine converted the ventricular tachycardia to sinus rhythm. The maintenance antiarrhythmic therapy consisted of oral procainamide and propranolol. Three weeks later the dog died suddenly. On postmortem examination, the right ventricular free wall was very thin at the apex, infundibulum and caudal aspect of the right ventricular parietal wall, similar to the 'triangle of dysplasia' of human patients. Histopathological examination revealed replacement of several areas of right ventricular free wall myocardium with connective tissue and fat. The right atrium and left ventricle were less severely affected by the same lesions. The clinical and pathological findings are similar to those reported in young people with arrhythmogenic right ventricular dysplasia/cardiomyopathy.