Assessment of global longitudinal strain (GLS) is superior to ejection fraction (EF) in the evaluation of left ventricular (LV) function in patients with stable coronary artery disease (CAD). However, the role of mechanical dispersion (MD) in this context remains unresolved. We aimed to evaluate the potential role of MD as a marker of LV dysfunction and long-term prognosis in stable CAD. EF, GLS and MD were assessed in 160 patients with stable CAD, 1 year after successful coronary revascularization. Serum levels of high-sensitivity cardiac troponin I (hs-cTnI) and amino-terminal pro B-type natriuretic peptide (NT-proBNP) were quantified as surrogate markers of LV dysfunction. The primary endpoint was defined as all-cause mortality, the secondary endpoint was defined as the composite of all-cause mortality and hospitalization for acute myocardial infarction or heart failure during follow-up. Whereas no associations between EF and the biochemical markers of LV function were found, both GLS and MD correlated positively with increasing levels of hs-cTnI (R = 0.315, P < 0.001 and R = 0.442, P < 0.001, respectively) and NT-proBNP (R = 0.195, P = 0.016 and R = 0.390, P < 0.001, respectively). Median MD was 46 ms (interquartile range [IQR] 37-53) and was successfully quantified in 96% of the patients. During a median follow-up of 8.4 (IQR 8.2-8.8) years, 14 deaths and 29 secondary events occurred. MD was significantly increased in non-survivors, and provided incremental prognostic value when added to EF and GLS. NT-proBNP was superior to the echocardiographic markers in predicting adverse outcomes. MD may be a promising marker of LV dysfunction and adverse prognosis in stable CAD.
Keywords: Amino-terminal pro-B-type natriuretic peptide; High-sensitivity troponin I; Mechanical dispersion; Myocardial strain; Speckle tracking echocardiography; Stable coronary artery disease.