Subclinical left ventricular dysfunction revealed by circumferential 2D strain imaging in patients with coronary artery disease and fragmented QRS complex

Abstract

Background: Fragmented QRS (fQRS) complexes on a routine 12-lead electrocardiogram were associated with adverse cardiac events, including sudden death in patients with coronary artery disease (CAD). Objective: To investigate the relationship between the fQRS complex and global and regional left ventricular (LV) functions in patients with CAD. Methods: The study consisted of 176 patients (68 ± 9 years; 145 [82%] men) with CAD with narrow QRS duration and preserved LV ejection fraction (>45%). All patients underwent detailed 2-dimensional speckle-tracking echocardiography to determine global and segmental (basal, middle, and apical) LV strains and strain rates and were prospectively followed-up in the outpatient clinic. Results: Fifty-five patients (31%) had fQRS complexes. Global, middle, and apical LV longitudinal, radial, and circumferential strains and strain rates were significantly lower in the fQRS group than in the non-fQRS group (all P <.05). Multivariate logistic regression analysis revealed that the fQRS complex was associated with decreased global circumferential strain (odds ratio 1.19; 95% confidence interval 1.06-1.33; P =.003) and multivessel disease (odds ratio 3.69; 95% confidence interval 1.35-10.08; P =.011). Kaplan-Meier analysis revealed that event-free survival for cardiac events was significantly lower in the fQRS group than in the non-fQRS group (P =.036). Conclusions: Our results demonstrated that the fQRS complex in patients with CAD with preserved LV ejection fraction was associated with subclinical global and regional LV dysfunctions as detected by 2-dimensional speckle-tracking imaging, and the results also predicted adverse cardiac events. © 2012 Heart Rhythm Society. All rights reserved.