Ambulatory ECG-based T-wave alternans and heart rate turbulence can predict cardiac mortality in patients with myocardial infarction with or without diabetes mellitus

We prospectively enrolled 248 consecutive patients: 96 with MI (post-MI patients); 77 MI with DM (post-MI？+？DM patients); 75 controls without cardiovascular disease (group control). Both TWA and HRT were measured on ambulatory electrocardiograms (AECGs). HRT was assessed by two parameters ─ turbulence onset (TO) and turbulence slope (TS). HRT was considered positive when both TO ≥0% and TS ≤2.5？ms/R-R interval were met. The endpoint was cardiac mortality.TWA values differed significantly between MI and controls. Post-MI？+？DM patients had higher TWA values than post-MI patients (58？±？21？μV VS 52？±？18？μV, P？=？0.029). Impaired HRT--increased TO and decreased TS were observed in MI patients with or without DM. During follow-up of 578？±？146？days, cardiac death occurred in ten patients and three of them suffered sudden cardiac death (SCD). Multivariate analysis determined that a HRT-positive outcome [HR (95% CI): 5.01, 1.33–18.85; P？=？0.017], as well as the combination of abnormal TWA (≥47？μV) and positive HRT had significant association with the endpoint [HR (95% CI): 9.08, 2.21–37.2; P？=？0.002)].This study indicates that AECGs-based TWA and HRT can predict cardiac mortality in MI patients with or without DM. Combined analysis TWA and HRT may be a convenient and useful method of identifying patients at high risk for cardiovascular death.Numerous studies over the past decades have provided a sound scientific basis for employing T-wave alternans (TWA), monitored during exercise testing, pacing, daily activities or from defibrillator electrogram as an index of vulnerability to ventricular arrhythmias and sudden cardiac death, as it represents an increased heterogeneity of ventricle repolarization on a beat-to-beat basis, and may provide a substrate for reentry [1-6]. Currently, there are both frequency domain- and time domain-based analysis methods of determining TWA. Our study used a time domain-based modified moving average (MMA) to analyze TWA measured on ambulatory elec