[Long term electrophysiological study on patients with acute myocardial infarction and complete heart block. Is cardiac pacing always necessary? (author's transl)].

Unlabelled: Of 335 consecutive patients (pts) admitted to the coronary care unit (CCU) for acute myocardial infarction (AMI), 34 (10%) evidenced complete heart block (HB). The overall inhospital mortality was 14% (47 pts) versus 39% of the HB group (13 pts). No previous conduction disturbances were documented in 58% of pts before appearance of complete HB. Complete HB was preceded in 52% of pts by first or second degree HB or bundle branch block. Of 21 pts with HB discharged from the hospital, 5 (23%) died between 5 and 24 months (mean 12): no patients had sudden death; 16 pts (76%) are still alive after 13 to 45 months (mean 30). His bundle electrophysiologic (HBE) study was performed in 10 pts of the HB group after 4 to 40 months: 4 pts with anterior versus 6 with inferior AMI. Conduction disturbances were no longer present in all but one pt who had H-V 60 msec. Ajmaline (50 + 50 mg iv) prolonged A-H over 130 msec in 4 pts; H-V was not significantly increased in 8 of the 10 pts, while in two pts was 100 msec. One pt in the acute phase and one pt 12 months later, required pacemaker (PM) implant (both had inferior MI).

In Conclusion: no sudden death was documented during the follow-up period. The late HBE study, before and after ajmaline, did not allow to recognize critical conduction abnormalities suggessting prophylactic PM implantation.