A 9 year-old Doberman presented to the Cornell University Hospital for Animals on April 19th, 2016 for three syncopal episodes within 12 hours and a non-productive cough of 24-hour duration. On presentation, the Doberman was tachycardic with weak and asynchronous pulses and a grade III/VI basilar heart murmur was auscultated. ECG revealed sustained atrial fibrillation and intermittent bursts of ventricular tachycardia. Thoracic radiographs were consistent with congestive heart failure and an echocardiogram was consistent with dilated cardiomyopathy. The patient was administered oral diltiazem and digoxin to control the heart rate, and fitted with transthoracic defibrillation patches for continuous ECG monitoring in the ICU. Shortly after ICU admission, the patient developed rapid, sustained ventricular tachycardia and lost consciousness. The rhythm then degenerated into ventricular fibrillation. The patient was immediately defibrillated with one 200J biphasic DC shock. Both the ventricular rhythm and the atrial fibrillation converted to sinus rhythm with occasional VPCs. The following day, the rhythm remained sinus with occasional VPCs, and the patient was discharged. Two subsequent re-checks were performed one week and two months later. At both re-check exams, the patient remained in normal sinus rhythm with occasional VPCs.
Emergency medical management was warranted for this case. It has been shown that treatment of supraventricular arrhythmias may prevent the myocardial ischemia that gives rise to ventricular tachycardia and fibrillation. The described case proved difficult to treat, as severe supraventricular and ventricular arrhythmias were concurrently present. Here, control of the ventricular response rate was attempted first, in order to both lessen myocardial ischemia and decrease ventricular tachycardia. The use of lidocaine to directly treat ventricular tachycardia was considered contraindicated in the face of severe systemic hypotension. Transthoracic biphasic electrical cardioversion has been shown to be an alternative to emergency medical management, as restoration of sinus rhythm provides the most complete relief of symptoms. While not planned, electrical cardioversion (which occurred serendipitously during ventricular defibrillation) was successful in this case, and the patient continues to do well four months after discharge. Long-term prognosis for dogs with DCM is guarded, with an average life expectancy of six months after development of clinical signs. Prognosis for DCM with concurrent atrial fibrillation is poor, with an average life expectancy of two to three months. Long term management proves to be essential in controlling both heart failure and life-threatening arrhythmias