Predictive value of autonomic risk markers after acute myocardial infarction: Results of a prospective long-term follow-up study in 411 consecutive patients

Prognosis of patients surviving acute myocardial infarction has substantial ly improved over the last two decades. However, stratification of patients at risk for death due to arrhythmic events remains a clinical challenge. Du e to the important role of the autonomic nervous system in the genesis of s udden death, autonomic markers such as heart rate variability and barorefle x sensitivity have recently gained attention as risk stratification paramet ers. The present study reports the results of noninvasive risk stratificati on in 411 consecutive postinfarction patients treated due to contemporary t herapeutical guidelines with a high proportion of patients discharged with a patent infarct related artery. The diagnostic arsenal of risk parameters comprised heart rate variability, baroreflex sensitivity, and more traditio nal markers such as non-sustained ventricular tachycardia, left ventricular ejection fraction, and ventricular late potentials. Patients were followed for a mean of 33 +/- 21 months. Stepwise logistic regression analysis reve aled that left ventricular function, both autonomic markers, and the patenc y of the infarct related artery were independent predictors of the prospect ively defined primary study endpoint, i.e., all-cause mortality plus ventri cular tachyarrhythmic events. With respect to the secondary endpoint (ventr icular tachyarrhythmic events), left ventricular function, heart rate varia bility, and infarct vessel patency were independent predictors. Ventricular late potentials and nonsustained ventricular tachycardia had no predictive value with respect to ventricular tachyarrhythmic events. These findings f rom a large prospective long-term study demonstrate the value of markers of cardiac autonomic tone in identifying infarct survivors at risk for malign ant ventricular tachyarrhythmias and sudden death.