Heart rate variability and chemoreflexsensitivity - Proved and new methodsfor 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. Th e heart rate variability as a tonic procedure shows significant differences between patients with an increased risk of malignant arrhythmias and patie nts without increased risk. This can be demonstrated in patients with survi ved myocardial infarction, dilative cardiomyopathy and congestive heart fai lure. But the positive predictive value amounts only to about 50%. The chemoreflexsensitivity as a new phasic method represents a new possibil ity for the evaluation of a dysfunction of autonomic reflex arches. It is r educed due to a decreased left ventricular function and increasing age. Fur thermore, it shows significant differences between patients with ventricula r arrhythmias and patients without. The predictive accuracy concerning mali gnant ventricular arrhythmias in a population of 60 patients in the chronic postinfarction stadium amounts to 55 %, the relative risk to 7.6. Thus, th is method shows a high predictive power, but more investigations in larger patient cohorts an necessary to corroborate these results.