[Heart rate variability and chemoreflex sensitivity. Proved and new methods in risk prediction of malignant arrhythmias].

For the analysis of a disturbed autonomic function as a risk predictor for ventricular tachyarrhythmias, tonic and phasic procedures are available. The heart rate variability as a tonic procedure shows significant differences between patients with an increased risk of malignant arrhythmias and patients without increased risk. This can be demonstrated in patients with survived myocardial infarction, dilated cardiomyopathy and congestive heart failure. But the positive predictive value amounts only to about 50%. The chemoreflex sensitivity as a new phasic method represents a new possibility for the evaluation of a dysfunction of autonomic reflex arches. It is reduced due to a decreased left ventricular function and increasing age. Furthermore, it shows significant differences between patients with ventricular arrhythmias and patients without. The predictive accuracy concerning malignant ventricular arrhythmias in a population of 60 patients in the chronic postinfarction stadium amounts to 55%, the relative risk to 7.6. Thus, this method shows a high predictive power, but more investigations in larger patient cohorts are necessary to corroborate these results.