Reproducibility,Circadian Variability,and Limit Values of Ventricular Late Potentials in Healthy Men

Objectives: The aim of the study was to examine the reproducibility of late potential parameters over time and to assess the influence of circadian rhythm, type of activity (rest, exercise) and autonomous state on these parameters in healthy subjects. Background: Late potentials are used as a marker for an elevated arrhythmic risk in patients after myocardial infarction. The method is increasingly used in cardiovascular hospital departments. However, the relatively high percentage of false-positive results compared to the outcome of electrophysiological testing precludes its more general use. Methods: In a population of healthy volunteers, the normal values, the reproducibility, and the dependence from a circadian rhythm of ventricular late potentials were examined. The dependence of the late potentials from the type of activity was studied. Results: The limit values of the late potential parameters found in this study did not differ from the proposed standard limits in the Euro-American guidelines. Circadian variability of heart rate and duration of QRS and QT-interval were documented. No circadian variation was found in the late potential parameters in the subjects studied. The values for late potential parameters did not significantly differ in measurements repeated after 24 hours and 7 days, thus resulting in good reproducibility. The heart rate changes induced by ergometry and autonomous blockade had no influence on late potential parameters. Conclusions: Late potential parameters are reproducible and are not changed significantly by circadian rhythm, type of activity, or autonomous state in these healthy volunteers.