Double ectopic accelerated ventricular and nonaccelerated ventricular or supraventricular rhythms.

Three patients with acute inferior wall myocardial infarction has accelerated idioventricular rhythms alternating and (or) coexisting with: (a) AV junctional (or low atrial) rhythm (Case 2); (b) paroxysmal ventricular tachycardia and another accelerated idioventricular rhythm (Case 3); and (c) AV junctional rhythm, paroxysmal ventricular tachycardia and accelerated idioventricular rhythm from another center (Case 4). The tracings from a fourth patient (Case 1) served to focus attention on one of the most pertinent features of accelerated idioventricular rhythms, namely the gradual decrease in rate to values below that of the preexisting basic rhythm. Cardioacceleration with atropine and cardiosuppression with lidocaine failed to abolish the arrhythmias or relieve the symptoms in cases 3 and 4. Atrial stimulation proved the most effective mode of therapy in these two patients.