Association between ventricular arrhythmias and myocardial mechanical dispersion assessed by strain analysis in patients with nonischemic cardiomyopathy

Background Mechanical dispersion (MD), defined as the standard deviation of time to maximum myocardial shortening assessed by 2D speckle tracking echocardiographic strain imaging (2DS), has been recently proposed as a predictor for ventricular tachycardia or fibrillation (VT/VF) in patients with ischemic cardiomyopathy and long QT syndrome. However, the role of MD in patients with non-ischemic cardiomyopathy (NICM) has not yet been studied. Methods and results In 20 patients with NICM (mean age 62 ± 11 years, 75 % male, mean EF 32 ± 6 %, mean QRS duration 102 ± 14 ms), we measured longitudinal strain by 2DS in a 16-segment left ventricular model and calculated the MD. Patients were divided into two groups, defined by the presence or absence of documented VT/VF. In 11 patients (55 %), VT/VF was documented. The median time from VT/VF to echocardiographic examination was 26 (IQR 15–58) months. There were no significant differences in baseline characteristics between patients with and without index events. MD was significantly greater in patients with VT/VF as compared to those without arrhythmias (84 ± 31 ms vs. 53 ± 16 ms, p = 0.017). The analysis of the ROC curve (AUC 0.81, 95 % CI 0.63–1.00, p = 0.017) revealed that dispersion >50 ms is associated with twelve times higher risk of VT/VF in patients with NICM (OR 12.5, 95 % CI 1.1–143.4, p = 0.024). Conclusions In this small cohort of NICM patients, greater MD was associated with a higher incidence of VT/VF.