Interaction of Left Ventricular Size and Sex on Outcome of Cardiac Resynchronization Therapy Among Patients With a Narrow QRS Duration in the EchoCRT Trial

Abstract

BackgroundLonger QRS duration (QRSd) improves, but increased left ventricular (LV) end‐diastolic volume (LVEDV) reduces, efficacy of cardiac resynchronization therapy (CRT). QRSd/LVEDV ratios differ between sexes. We hypothesized that in the EchoCRT (Echocardiography Guided Cardiac Resynchronization Therapy) trial enrolling patients with heart failure with QRSd <130 ms, those with larger LVEDV would deteriorate but those with the highest QRSd/LVEDV would improve with CRT.Methods and ResultsPrimary outcome in patients (n=787, 72% men, 93% New York Heart Association class III, QRSd <130 ms, LV ejection fraction ≤35%, LV dilation and dyssynchrony) randomized to CRT‐ON or CRT‐OFF and followed up for 19 months was compared according to LVEDV (height indexed) or QRSd/LVEDV ratio, in multivariable analysis. Structural remodeling was assessed echocardiographically 6 months after implantation. Patients with baseline LVEDV higher than or equal to median worsened with CRT (death/heart failure hospitalization: CRT‐ON versus CRT‐OFF, 35.2% versus 24.5% [hazard ratio, 1.64; 95% confidence interval, 1.11–2.42; P=0.012]), but those with LVEDV lower than median remained unaffected. Patients with the highest QRSd/LVEDV ratio improved with CRT (death/heart failure hospitalization in top quartile: 20.9% in CRT‐ON [n=91] versus 28.3% in CRT‐OFF [n=106] [hazard ratio, 0.64; 95% confidence interval, 0.34–1.24; P=0.188], versus the remaining quartiles: 31.7% in CRT‐ON [n=300] versus 24.8% in CRT‐OFF [n=290] [hazard ratio, 1.47; 95% confidence interval, 1.07–2.02; P=0.016], test for interaction P=0.046). QRSd and dyssynchrony were similar between groups. The 3‐way test for interaction indicated no sex‐specific effects. However, numerically, men with LVEDV higher than or equal to median accounted for worse outcomes of CRT‐ON. Women, with the highest QRSd/LVEDV ratio exhibited significant reverse remodeling.Conclusion CRT has opposite effects among patients with heart failure with QRSd <130 ms according to LV size: worsening outcomes in patients with larger LV, but inducing beneficial effects in those with smaller LV.Clinical Trial RegistrationURL: https://www.clinicaltrials.gov/. Unique identifier: NCT00683696.

Sex-Dependent QRS Guidelines for Cardiac Resynchronization Therapy Using Computer Model Predictions

“…This is consistent with studies on CRT with narrow QRSd, in which unlike males, females with narrow QRSd did not have increased mortality rates with CRT ( 5 ). A recent study also found that a smaller LV size was associated with improved CRT response in patients with QRSd <130 ms ( 21 ), supporting lower narrow QRSd threshold for females who generally have smaller LV sizes.…”

Ventricular remodeling in ischemic heart failure stratifies responders to stem cell therapy

“…The degree of LV dilatation has been linked to a range of efficacy experienced with pharmacological, device or surgical treatments. 23,24 It is further unmasked herein as a determinant of stem cell-promoted cardiac repair. in vivo functional and structural restoration was reinforced by molecular validation at proteome level.…”

Efficacy of Cardiac Resynchronization Therapy in Patients with a Narrow QRS Complex

“…ey describe the efficacy of CRT, as well as the existence of dyssynchrony in patients with a narrow QRS complex [14,[20][21][22]. Varma et al reported efficacy in patients with a narrow QRS complex <130 ms from the EchoCRT trial and concluded that CRT may be beneficial in patients with HF with a narrow QRS and smaller ventricles [23]. Indeed, in clinical practice, we often see patients who respond well to CRT despite the fact that their QRS is relatively narrow at <130 ms [15,24].…”