Identification of patients after myocardial infarction at risk of life-threatening arrhythmias

The prospective identification of survivors of myocardial infarction (MI) prone to sudden arrhythmogenic death remains a challenge for clinical cardiologists, particularly as total mortality after MI is decreasing. There are a multitude of risk-assessment methods available which can be used for this purpose. Invasive methods such as electrophysiological testing are impractical because they can be carried out only at specialized referral centres. Accordingly, various noninvasive risk stratification methods have been proposed. The mainstay of these techniques is the determination of residual left ventricular function; total mortality increases with a left ventricular ejection fraction (LVEF) <35-40%. To enrich the arrhythmogenic risk of infarct survivors, other risk stratifiers should be used in combination with the determination of LVEF. At present, most of the evidence indicates that markers of impaired autonomic tone, such as heart rate variability or baroreflex sensitivity, are probably the most useful of these risk stratifiers. This review summarizes current knowledge concerning the problem of sudden death after MI and assesses the risk of serious ventricular tachyarrhythmias and sudden death as a result of using contemporary therapeutic modalities such as thrombolysis.