EXPRESS: Emergency cardiac defibrillation for ventricular fibrillation in a Sphynx cat presenting with ventricular tachycardia, hypertrophic cardiomyopathy and congestive heart failure

Case summary: A 10-year-old, male neutered, 7.5kg Sphynx cat was referred for patient stabilization for presumed acute congestive heart failure (CHF). On presentation, the patient was tachypnoeic (44 breaths/min) and tachycardic with poor femoral pulses (HR 300bpm). Emergency cardiac assessment identified sustained monomorphic ventricular tachycardia (VT) associated with hypertrophic cardiomyopathy phenotype and concurrent B-lines. Four boluses of IV lidocaine (0.5mg/kg) and subsequently IV esmolol (0.1 mg/kg) were administered with no success. The VT acutely deteriorated into ventricular fibrillation, at which point the patient lost consciousness, with absent pulses. Emergency biphasic defibrillation was performed at 30 J and was successful in restoring sinus rhythm; return to spontaneous circulation did not require additional chest compressions. Oral sotalol and CHF treatment were started. A complete echocardiogram identified an area of hypokinesia in the left ventricular free wall. Speckle tracking echocardiography identified global reduction in longitudinal and circumferential systolic function. High-sensitivity troponin I was 7.75ng/ml at presentation and decreased over time (7 days later 0.43 ng/ml and 0.44 2 months later). The patient was free from clinical signs for 4 months, after which he developed refractory CHF. Relevance and novel information: Ventricular tachycardia is an uncommon clinical presentation in cats with hypertrophic cardiomyopathy and can acutely deteriorate leading to cardiac arrest. In the present case, cardiac defibrillation was effective in restoring sinus rhythm and preventing arrhythmic death. Although prognosis in the acute setting seemed poor, good quality of life was achieved for 4 months since emergency presentation.