Sudden Cardiac Death Early After Myocardial Infarction

Abstract

Sudden cardiac arrest is the leading cause of death in adults in the United States and globally. The vast majority of cardiac arrests occur in patients who have had a myocardial infarct (MI) at a rate 4 to 6 times that of the general population. Primary prevention is defined as prevention of sudden cardiac death (SCD) in individuals who are at risk for but have not yet had a cardiac arrest. An implantable cardioverter-defibrillator (ICD) is currently the accepted therapy for primary prevention of SCD. However, a mortality benefit has only been demonstrated with prophylactic ICD implantation months to years after MI, despite a significantly higher risk of SCD in the first month after MI. This review focuses on the incidence and pathogenesis of SCD early after MI, with an evaluation of the current risk stratification methods available for early primary prevention. Sudden cardiac arrest is the commonest cause of death in the United States, claiming ≈350 000 to 400 000 lives annually.1,2 The vast majority of SCDs occur in patients with underlying coronary artery disease, with the risk particularly high in patients who have suffered an MI. Many large observational and randomized studies have assessed SCD after MI with an overall incidence ranging from 2%/y to 4%/y.3–5 The most notable study to assess the time dependence of SCD risk was the Valsartan in Acute Myocardial Infarction Trial (VALIANT),5 which enrolled 14 609 post-MI patients with either impaired left ventricular (LV) function or heart failure. The SCD rate was found to be 10-fold higher in the first 30 days at a rate of 1.4%/mo, decreasing exponentially over the first 6 months to reach a steady rate of 0.14%/mo at 2 years (Figure 1). This significantly increased risk of SCD within the first month …