Purpose: Cardiac Resynchronization Therapy (CRT) is recommended for the treatment of symptomatic Heart Failure (HF) patients with a baseline QRS duration (QRSd) >120ms to reduce morbidity and mortality. Our aim was to assess the impact of pre-implantation QRSd on clinical outcomes in HF patients receiving CRT.
Methods: A consecutive series of 114 HF patients were identified from our institution's heart pacing clinic. Data on baseline QRSd and the composite clinical outcome of HF related hospitalization or death were retrospectively recorded. Based on baseline QRSd patients were divided into three groups: group A (>150ms, n=77), group B (136-150ms, n=22) and group C (121-135ms, n=15). Kaplan-Meyer analysis was conducted to assess the impact of QRSd on clinical outcomes and multivariate Cox-regression analysis to adjust for the effect of confounders.
Results: During a median ± IQR follow-up of 1.8±2.4 years a total of 50 events were recorded. Freedom from HF hospitalization or death was progressively decreasing from group A to group C (log rank test p=0.00002). Multivariate Cox regression analysis revealed that baseline QRSd was positively and independently associated with improved outcomes (p=0.0002) even after adjusting for conventional disease modifiers including age, NYHA class, ejection fraction, HF aetiology, anaemia, chronic kidney disease and background beta-blocker and ACEi/ARB therapy (Figure 1). Compared to group A patients, the composite end-point was met approximately two times [OR: 2.191; 95% CI: 1.009-4.758] and nearly six times [OR: 5.794; 95% CI: 2.489-13.489] more frequently in group B and group C patients respectively.
Publication information
Dimitrios Konstantinou, Kaushik Guha, Christopher Cook, Rakesh Sharma. QRS duration and clinical outcomes in heart failure patients receiving cardiac resynchronization therapy. ESC 2013.