[Sudden death and ventricular arrhythmias risk stratification after myocardial infarction].

Fifty percent of deaths associated with acute myocardial infarction are attributable to ventricular arrhythmias and sudden death. Lethal ventricular arrhythmias are caused by an interplay between three basic components: substrate (such as presence of potential reentry circuits within the infarct area), trigger (such as premature ventricular contractions), and modulating factors (such as ischemia, dysfunction of the autonomic nervous system and impaired left ventricular function). Noninvasive techniques, including baroreflex sensitivity, heart rate variability, heart rate turbulence, QT dispersion, T-wave alternant, Signal-Averaged Electrocardiography, exercise testing and ejection fraction can be useful for predicting the patients at risk for sudden death.