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

Abstract

BACKGROUND: Fragmented QRS complexes (fQRS) on a routine 12-lead electrocardiogram, a marker of depolarization abnormality, are associated with adverse cardiac events, including sudden death in patients with coronary artery disease (CAD). METHODS & RESULTS: We investigated the relationships between fQRS with global and regional left ventricular (LV) function in 176 CAD patients (pts, 68±9 year, 145 men) with narrow QRS duration and preserved LV ejection fraction (LVEF,>45%). Detailed 2D speckle-tracking echocardiography was performed to determine global and segmental(basal, middle and apical) LV circumferential strains and strain rates. fQRS was detected in 55(31%) of CAD pts. There were no significant differences in the clinical demographic features and medications between pts with (fQRS gp) and without fQRS (non-fQRS gp). However, wall motion score index (1.26±0.44 vs. 1.10±0.23, P=0.002) and the prevalence of multi-vessel disease (73% vs. 48%, P=0.003) were significantly higher and LVEF were lower (52 vs. 59%, P<0.01) in fQRS gp as compared with non-fQRS gp. Global circumferential strain and strain rate were significantly reduced in fQRS gp compared with non-fQRS gp (Table 1, all P<0.05). Furthermore, segmental circumferential strain and strain rate over apical LV was also decreased in fQRS gp compared with non-fQRS gp (Table 1, all P<0.01). Multivariate linear regression analysis showed that decreased global circumferential strain (Odd ratio [OR] 1.19, 95% confidence interval [CI] 1.06-1.33, P=0.003) and multivessel disease (OR 3.69, 95% CI 1.35-10.08, P=0.011) were predictors for fQRS independent regional wall motion abnormality and LVEF. CONCLUSION: Our results demonstrated that 2D circumferential strain imaging revealed subclinical LV dysfunction in CAD pts with fQRS complex on resting ECG, which may contribute to ventricular depolarization abnormalities and adverse clinical outcomes.