Two simultaneous right ventricular tachycardias in a case of arrhythmogenic right ventricular dysplasia.

A 51 year old woman with arrhythmogenic right ventricular dysplasia had two types of ventricular tachycardia--(a) a regular and sustained tachycardia and with normal frontal plane axis on electrocardiography and (b) an irregular non-sustained tachycardia with a leftward frontal plane axis. Changes in the QRS complex were sometimes seen during the sustained ventricular tachycardia. The clinical, electrocardiographic, and electrophysiological data were consistent with the diagnosis of two different and sometimes simultaneous tachycardias originating in the right ventricle. This case suggests a possible new mechanism for the multiform appearances of the ventricular tachycardia.