Effect of ventricular fibrillation complicating acute myocardial infarction on long-term prognosis: Importance of the site of infarction

Abstract

Identification of high-risk subgroups of patients after acute myocardial infarction (AMI) is essential for evaluation of targeted preventive strategies. A case-control study was performed in 250 post-AMI patients to examine whether an episode of ventricular fibrillation (VF) during the in-hospital period modifies the long-term prognosis for patients with either an anterior or an inferior AMI. After identification of 70 patients with an anterior AMI and 55 patients with an inferior AMI, all complicated by VF and discharged alive, we selected 125 additional patients who had an AMI not complicated by VF (control subjects). To minimize the potential sources of differences in outcome, cases and controls were matched for the following variables: sex (all men), age (same ± 2 years), coronary care unit (same), epoch of AMI (same ± 3 months), and site of AMI (same). Left ventricular dysfunction and prior AMI were present in only a few patients. Patients receiving either acute or long-term treatment with β-adrenergic blocking agents were not included. The average follow up was 59 months (range 12 to 120). The cumulative mortality during the first 5 years for the patients with inferior AMI without VF (6%, 11%, 13%, 13% and 13%) was modest and not significantly different from that of inferior AMI complicated by VF (6%, 11%, 20%, 20%, and 26%). In contrast, a striking difference appeared when the cumulative mortality of patients with anterior AMI without VF (9%, 13%, 17%, 27% and 29%) was compared with that of patients with anterior AMI complicated by VF (32%, 40%, 46%, 49% and 54%) (p < 0.005). This group also had a high incidence of sudden death (71%), particularly in the first year after AMI. This finding is in contrast with the current view that VF does not modify the long-term post-AMI prognosis. In conclusion, patients who are discharged alive after an anterior AMI complicated by VF represent a subgroup at very risk of sudden cardiac death. For patients with an inferior AMI, the occurrence of VF in the acute phase does not modify the long-term prognosis.