Risk-Stratification following Acute Coronary Syndromes Using a Novel Electrocardiographic Technique to Measure Variability in Morphology

We propose a new technique that quantifies the extent to which subtle ECG morphology changes exist from beat to beat. Termed morphological variability (MV), this variable measures changes in the shape and timing characteristics of cardiac events in sequential pairs of heart beats. In contrast to other techniques that focus on one specific aspect of the ECG, our approach integrates information from all waves and intervals in the beat, with the goal of providing a more global assessment of cardiac electrical performance. When tested on 400 patients following ACS, an increased risk of death was seen during a follow-up period of 90 days for patients with high MV (HR=5.96; p=0.002). This relationship could be observed even after adjusting for HRV measures (adjusted HR=3.56; p=0.05).