Abstract 2850: Morphological Variability: A New Electrocardiographic Technique for Risk Stratification After NSTEACS
Background: ECG parameters such as low heart rate variability (HRV) identify patients at high risk post-ACS. We recently developed morphological variability (MV), a novel technique that quantifies differences in the morphology of entire beats using a dynamic time-warping algorithm. MV incorporates strictly more information than HRV, potentially offering a more complete evaluation of the ECG. We assessed the relationship among MV, HRV, and outcomes after NSTEACS.
Methods: MV and HRV were calculated in 863 pts from the DISPERSE2 trial using the first 24 hrs of continuous ECG (CECG) after randomization for NSTEACS. Using each measure, pts were split into high and low variability groups (cutpoint for HRV (SDNN)= 75ms and for MV=0.7). Ischemia on CECG was defined as ≥1mm ST dep lasting ≥1min.
Results: A total of 144 (16.7%) pts had high MV and 58 (6.7%) had low HRV. Pts with high MV experienced higher rates of death, death/MI/severe recurrent ischemia (SRI), and ischemia detected on CECG compared to low MV. (Table-Figure⇓) This relationship remained consistent in pts with no ischemia on CECG (hazard ratio for D/MI/SRI =2.5, p=0.016). There was no difference in mortality or ischemia on CECG in pts with low HRV v high HRV, but pts with low HRV did have higher rates of death/MI/SRI. (Table)
Conclusions: MV correlates significantly with poor cardiovascular outcomes, including death, after NSTEACS, even after controlling for other high risk features and even among pts without electrocardiographic evidence of ischemia. MV may offer a new non-invasive measure for risk stratification after ACS.