Left ventricle mechanical dispersion is a new universal marker of malignant ventricular tachyarrhythmias in patients with structural heart disease

Abstract

Aim. To evaluate the possibility to use parameters of global, segmental longitudinal left ventricle (LV) strain and LV mechanical dispersion (MD) as new possible markers of malignant ventricular tachyarrhythmias (MVT) in patients with structural heart disease and reduced and intermediate LV ejection fraction (EF). Methods. The study included 113 patients (105 male, age 66 [59;73] year) with ischemic (n=89) or non-ischemic (n=24) dilated cardiomyopathy and LVEF<50%, implanted cardioverter-defibrillators, cardiac resynchronization therapy devices-defibrillators, pacemakers or documented MVT. All patients underwent transthoracic echocardiography with an assessment of speckle-tracking echocardiography parameters (global and segmental longitudinal LV strain, LV MD). Comparative univariate and ROC-analyses were performed between patients with and without MVT separately for patients with LVEF <35% (n=60) and LVEF 36-50% (n=53) LVEF. Results. The group of patients with LVEF ≤35% with MVT (n=30) was characterized by lower values of longitudinal strain of the basal segment of the LV septum wall (-5[-6,5;-0,5] vs -6,8[-11;-4.4], р=0,01, respectively) and the middle segment of the LV inferior wall (-3[-6;2] vs -6[-9;-1,5], р=0,04, respectively). The group of patients with LVEF 36-50% with MVT (n=33) was distinguished by a large value of LV end-diastolic volume (166,5[146,3;193] vs 156[133,8;165,5], р=0,04, respectively). The greater values of LV MD were noted in both groups of patients with MVT. The optimal cutoff value of LV MD was 120 ms (area under the ROC curve 0.817, sensitivity-73,3%, specificity-80%) for patients with LVEF≤35%, and 90 ms (area under the ROC curve 0.761, sensitivity-72.7%, specificity-75%) for patients with LVEF 36-50%. Conclusion. Speckle-tracking echocardiography parameters may serve as additional markers of increased risk of MVT in patients with structural heart disease and impaired LVEF. Only LV MD is useful for risk stratification of MVT in patients with either reduced or intermediate LVEF.