Right ventricular infarction: Unusual electrocardiographic and electrophysiological manifestations

Right ventricular infarction occurs in 19–43% of patients with acute inferior wall infarction (Lorell _{et al.}, 1979). Its clinical, hemodynamic, and anatomic features are well known and include associated inferior wall infarction, distended neck veins, clear lung fields, hypotension, and heart block (Cintron _{et al.}, 1981; Coma‐Canella _{et al.}, 1979; Lloyd _{et al.}, 1981; Lopez‐Sendon _{et al.}, 1981; Raabe and Chester, 1978; Rotman _{et al.}, 1974). Isolated right ventricular infarction is less frequent and occurs in 2.5–4.6% of autopsy studies of myocardial infarction (Cohn _{et al.}, 1974; Erhardt _{et al.}, 1976; Wartman and Hellerstein, 1948). This report describes a patient with isolated right ventricular infarction with unusual electrophysiological findings. Her initial electrocardiogram showed atrial escape rhythm with incomplete right bundle‐branch block and left posterior hemiblock. Later, she developed atrioventricular (AV) block with supra‐ and infra‐Hisian, “phase 4,” conduction defects. The sinus malfunction and high degree AV block persisted over 2 weeks and an atrioventricular sequential pacemaker was implanted. Hymodynamic study showed that her cardiac output was highly dependent on the heart rate and properly timed AV interval, and the pacemaker was programmed accordingly.