[Arrhythmogenic right ventricular cardiomyopathy mimicking right ventricular outflow tract tachycardia]

Ventricular tachycardia may be mistaken for right ventricular outflow tract tachycardia in patients with arrhythmogenic right ventricular cardiomyopathy. A 27-year-old man had complaints of palpitation and syncope. The admission electrocardiogram (ECG) showed sustained monomorphic ventricular tachycardia with left bundle branch block and inferior axis morphology. The ECG obtained during sinus rhythm was normal. Transthoracic echocardiography showed both ventricles in normal function and size. During electrophysiologic study, ventricular tachycardia was induced consistent with the clinical tachycardia. It was thought to originate from the left ventricular outflow tract and was terminated by radiofrequency ablation. However, the patient presented again, after a year, complaining of palpitations. The admission ECG was similar to that obtained before with sustained ventricular tachycardia, whereas the ECG during sinus rhythm showed negative T waves in leads V1-3. During electrophysiologic study, another ventricular tachycardia was induced with left bundle branch block and horizontal axis morphology as well as that consistent with the clinical tachycardia. The former was terminated spontaneously. The presence of a different morphology and negative T waves on the ECG suggested arrhythmogenic right ventricular cardiomyopathy. On angiography, the right ventricle was dilated and hypocontractile. Cardiac magnetic resonance imaging confirmed the diagnosis by showing decreased wall thickness and wall motion abnormality in the right ventricle.