Prognostic value of intra-QRS and ST-T micro-variability - a 2 year follow-up

Previously, we found that patients with malignant ventricular arrhythmias show an increased beat-to-beat micro-variability of de- and repolarization, indicated by an increased variability of QRS duration and an increased intra-QRS (QVI)and ST-T (TVl) variability compared to healthy subjects. In this study we investigated the prognostic value of the previously found markers QVI and TVI of beat-to-beat variability in terms of mortality. Patient (960) assignment had to be to one of the following subgroups: (a) no organic heart disease, (b) coronary artery disease, or (c) spontaneous or inducible ventricular tachycardia or ventricular fibrillation. High-resolution ECGs were recorded. Beat-to-beat micro-variability measurement was based on 200 consecutive sinus beats per individual. Total and cardiac mortality was highest in the group with malignant arrhythmias (13.3% and 12%). The Cox proportional hazards regression model on the singular factors of QVl and TVl revealed a connection to survival. This was valid for both the 1-year (QVl p = 0.006, TVl p = 0.009) and 2-year (QVI p = 0.015, TVI p = 0.008) follow-up. We conclude that increased QRS- and T-variability indicating increased anisotropy of de- and repolarisation is associated with an increased mortality.