Correlation between Myocardial Microalternans Index and Left- Ventricular Ejection Fraction in Stable Coronary Artery Disease

Background Left ventricular ejection fraction (LVEF) is a widely accepted prognostic marker in coronary artery disease (CAD), yet echocardiography is only available in specialized settings. The Myocardial Microalternans Index (MMI), derived from ECG-dispersion mapping, may offer a simple screening tool. We evaluated the correlation between MMI and echocardiographic LVEF and determined an MMI threshold to identify reduced LVEF (< 40%). Methods We conducted a single-centre, cross-sectional study of patients with stable CAD. MMI was measured using the HealthEXPRESS™ system (Medical Computer Systems, Russia). LVEF was obtained by transthoracic echocardiography (biplane Simpson). We assessed the correlation using Spearman correlation and a prespecified partial rank correlation adjusting for clinical covariates. Discrimination for LVEF < 40% was evaluated by ROC analysis. Results Among 146 patients (median age 60 years; 82% male), 64% had prior myocardial infarction and 70% had left ventricular hypertrophy. Median LVEF was 48% (IQR 35–60) and median MMI 19% (IQR 16–30). Reduced LVEF (< 40%) occurred in 36% patients. MMI showed a significant, moderate inverse correlation with LVEF (Spearman r = − 0.524; p < 0.001), which remained significant after adjustment with history of myocardial infarction and presence of left ventricular hypertrophy (partial r = − 0.46; p < 0.001). The ROC AUC for MMI to classify LVEF < 40% was 0.78. An MMI cutoff ≥ 24% yielded 63.3% sensitivity and 80.4% specificity. Conclusion MMI is moderately and inversely associated with LVEF, and an MMI ≥ 24% moderately discriminates reduced LVEF in stable CAD, MMI could support triage and referral in resource-limited settings. Validation in multicentre and prospective cohorts is warranted.