Abstract 3518: Impact of QRS Duration on Clinical Response With Cardiac Resynchronization Therapy: Results From the REVERSE Trial
Background: Cardiac Resynchronization Therapy (CRT) is well established in patients (pts) with advanced systolic heart failure (HF) and QRS prolongation. The role of mechanical dyssynchrony to predict clinical outcomes with CRT is controversial. In contrast, electrical dyssynchrony, as measured by QRS duration, is predictive of the acute hemodynamic response and reverse remodeling. In the present analysis, we evaluated the relationship between baseline QRS duration and clinical response among pts with mild HF.
Methods: Pts in the REsynchronization reVErses Remodeling in Systolic left vEntricular dysfunction (REVERSE) trial have NYHA I or II HF, QRS duration ≥120 ms and LVEF ≤40%. The primary endpoint was the % of patients with worsened clinical composite score (CCS) at 12 months. Secondary endpoints included time to death or HF hospitalization. Baseline QRS width was divided into quartiles for analyses.
Results: There were 610 pts randomized, 419 to CRT ON and 191 to CRT OFF. Multivariate analysis showed that CRT (p=0.01) and QRS duration interacting with CRT (p=0.004) were predictors of the primary endpoint (Figure⇓). The % of pts with worsened CCS decreased markedly as QRS duration increased in the CRT ON group, but was unchanged with CRT OFF. Similarly, there was a significant interaction between CRT and QRS (p=0.02) with regard to time to death or HF hospitalization, such that the observed event rate at 12 months in CRT ON pts decreased from 9.5% to 5.9% to 4.5% to 1.1% across QRS quartiles whereas the CRT OFF rates were 9.8%, 6.4%, 11.4%, and 8.7%.
Conclusion: Baseline QRS duration is an independent and strong predictor of clinical response with CRT in mild HF.