Sudden cardiac death after early-onset myocardial infarction. A multicentre longitudinal cohort study with 20 years' follow-up.

Abstract

Sudden cardiac death (SCD) is a serious consequence of a myocardial infarction (MI), but identifying patients at risk of developing SCD remains a major clinical challenge especially in the case of juvenile MI. The aim of this study was to identify predictors of SCD after early-onset MI using long-term follow-up data relating to a large nationwide patient cohort. The Italian Genetic Study on Early-onset MI enrolled 2,000 patients experiencing a first MI before the age of 45 years, who were followed up for a median of 19.9 years. Fine-Gray proportional hazard models were used to assess the associations between their clinical, demographic and index event data and the occurrence of SCD. SCD occurred in 195 patients, who were more frequently males, hypertensive and/or diabetic; had a history of previous thromboembolic events with a greater atherosclerotic burden; and had a lower left ventricular ejection fraction (LVEF) after the index event. Multivariable analysis showed that the independent predictors of SCD were diabetes, hypertension, previous thromboembolic events, higher Syntax score, and a lower LVEF. There was no clear evidence of the clustering of SCD events during follow-up. SCD was the first post-MI clinical event in 101 patients; the remaining 94 experienced SCD after a non-fatal MI or hospitalisation for coronary revascularisation. SCD frequently occurs during the 20 years after early-onset MI. The nature of the identified predictors and the absence of clustering suggests that the pathophysiological basis of SCD may be related to progressive coronary atherosclerosis.