Comparative studies of heart rate variability (HRV) using Holter-ECG-systems and high resolution ECG-systems in patients with acute myocardial infarction and dilatative cardiomyopathy and healthy volunteers

Patients with decreased left ventricular function due to either acute myocardial infarction or idiopathic dilatative cardiomyopathy are known to have an increased risk of sudden death due to malignant ventricular arrhythmias. The heart rate variability (HRV) representing the influence of the autonomic nervous system on the heart is one parameter for risk stratification in these conditions, since decreased HRV correlates with increased risk for sudden death. The authors investigate: 1) whether there is a comparable sensitivity in HRV sampling ECG systems with either high (1000 Hz) or low (200 Hz) sampling rate during simultaneously short time measurements (10 minutes) and; 2) if there are differences in HRV parameter after short time measurements (10 minutes) and long time measurements (24 hours) on behalf of its usefulness for risk stratification.