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

BackgroundFragmented 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).ObjectiveTo investigate the relationship between the fQRS complex and global and regional left ventricular (LV) functions in patients with CAD.MethodsThe 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.ResultsFifty-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).ConclusionsOur 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.