Acute Myocardial Infarction Complicated by Third Degree Atrioventricular Block Treated With Temporary Pacemaker

During the period Jan. 1, 1968 ‐ Dec. 31, 1970, 57 patients with acute myocardial infarction (AMI) complicated by third degree atrioventricular (AV) block have been treated with temporary pacing. The hospital lethality in anterior AMI (75%) was significantly higher than in inferior AMI (22%). Cardiogenic shock, Adams‐Stokes attacks, prolonged QRS complex and development of third degree AV block directly from sinus rhythm occurred significantly more frequently in anterior wall infarction and were followed by a significantly higher lethality. Age, previous AMI, ventricular fibrillation, route of admission, degree of cardiac incom‐pensation, number of Adams‐Stokes attacks or asystole, heart rate prior to pacing and time from onset of AMI to third degree AV block were found to be of no importance for the lethality. The cumulative survival rate was 50% at 12 and 47% at 24 months after the infarction. In anterior AMI it was 15% at 12 months and in inferior AMI 73% and 65% at 12 and 24 months, respectively. The long‐term prognosis was not improved in patients with anterior AMI treated by pacemaker compared to medically treated patients. In inferior AMI the importance of pacemaker treatment is not yet clarified. Based on the literature and our own results it is concluded that patients with AMI complicated by third degree AV block should still be treated with pacemaker.