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

The prospective identification of survivors of myocardial infarction (MI) p rone to sudden arrhythmogenic death remains a challenge for clinical cardio logists, 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 impract ical because they can be carried out only at specialized referral centres. Accordingly, various noninvasive risk stratification methods have been prop osed. The mainstay of these techniques is the determination of residual lef t ventricular function; total mortality increases with a left ventricular e jection fraction (LVEF) <35-40%. To enrich the arrhythmogenic risk of infar ct survivors, other risk stratifiers should be used in combination with the determination of LVEF. At present, most of the evidence indicates that mar kers of impaired autonomic tone, such as heart rate variability or barorefl ex sensitivity, are probably the most useful of these risk stratifiers. Thi s review summarizes current knowledge concerning the problem of sudden deat h after MI and assesses the risk of serious ventricular tachyarrhythmias an d sudden death as a result of using contemporary therapeutic modalities suc h as thrombolysis.