MANAGEMENT OF ACUTE MYOCARDIAL INFARCTION COMPLICATED BY ADVANCED ATRIOVENTRICULAR BLOCK - ROLE OF ARTIFICIAL PACING

Twenty-five patients with acute myocardial infarction and advanced atrioventricular block were treated with transvenous artificial pacing. Eighteen patients survived (72 per cent), including some with recognized factors of risk such as anterior wall infarction, severe congestive heart failure, cardiogenic shock, recurrent episodes of heart block, long standing or persistent advanced A-V block, previous myocardial infarction, idioventricular mechanism, associated arrhythmias, syncopal episodes and resuscitation procedures. Complications including perforation of the myocardium, infection, or embolization did not occur with the use of electrode catheters. Periods of competition were observed in 9 patients at the time of re-establishment of sinus rhythm, with ventricular tachycardia seemingly induced in 1 of them. The use of demand pacemakers should eliminate this complication. Early introduction of a transvenous electrode catheter is recommended in the following circumstances: (1) normal sinus rhythm associated with the emergence of intraventricular conduction disturbances; (2) second degree A-V block, including Wenckebach rhythm; (3) third degree A-V block; (4) episodes of cardiac arrest. Active pacing should be initiated in groups 2, 3 and 4. Simple P-R prolongation is a controversial indication for catheterization, since these patients usually progress more slowly towards advanced A-V block, providing enough time for insertion of an electrode catheter, should the need arise. Electrode catheters should be left in place, on a standby basis for an additional three to four weeks after re-establishment of sinus rhythm, in order to cover possible late recurrences of heart block. © 1969.