Intraoperative right to left ventricular interlead delay predicts outcome in CRT recipients

Abstract

Background: Prior studies suggested that right to left ventricular interlead sensed electrical delay (RL-IED) is predictive of echocardiographic response to cardiac resynchronization therapy (CRT). There is limited data on the effect of RL-IED on all-cause mortality in patients receiving a CRT device. Methods: We evaluated patients with RL-IED data available measured during the implantation procedure. Data on all-cause mortality was assessed using follow-up data and the Hungarian National Healthcare Fund Death Registry. Kaplan-Meier survival analyses and multivariate Cox proportional hazards regression models were used to analyze mortality in patients stratified by the median RL-IED (106.5 ms). Results: From 2000 to 2011, 494 patients (44%) of 1122 CRT implantation had RL-IED measurements available. Patients with RL-IED >106.5 ms were younger, had wider QRS complexes, less often atrial fibrillation and more dilated left ventricles. Left ventricular ejection fraction was similar in both groups (RL-IED ≤ 106.5 ms 28.1±7.5% vs. RL-IED > 106.5 ms 27.7±6.8%, p>0.5). During the median follow-up of 28 months, 145 (29%) patients died, 80 patients (16%) with RL-IED > 106.5 ms, and 65 patients (13%) with RL-IED ≤ 106.5 ms. RL-IED > 106.5 ms was associated with a significant, 48% risk reduction in all-cause mortality (HR= 0.52, 95% CI: 0.31-0.88, p= 0.01) after adjustment for clinical covariates (Fig. 1). ![Figure][1] Figure 1 Conclusions: In CRT patients, a longer right to left ventricular interlead electrical delay at the time of device implantation is associated with a significant mortality benefit as compared to those with shorter interlead delay. Right to left ventricular interlead electrical delay is an independent predictor of all-cause mortality in CRT patients. [1]: pending:yes