Abstract 8680: Long Term Outcomes in Patients with Borderline Prolonged QRS Durations Following Cardiac Resynchronization Therapy
Background: The majority of patients enrolled in clinical trials of cardiac resynchronization therapy (CRT) have had significant QRS prolongation with some studies excluding patients with a QRS duration ≤130ms. Current ACC/AHA/HRS guidelines suggest CRT is appropriate for patients with significant LV dysfunction and a QRS duration ≥120ms. Long-term outcomes in patients with only mildly prolonged QRS durations following CRT have not been evaluated.
Methods: We collected clinical and electrocardiographic data on a cohort of 895 patients who presented for the initiation of CRT at our institution between 10/29/2003 and 8/6/2007. For inclusion in the final cohort, patients had a valid US social security number, NYHA class II-IV heart failure, a QRS duration ≥ 120 ms, and an LVEF≤40%. Patients with mild baseline QRS prolongation (QRS duration 120-130ms) were compared to patients with more significant QRS prolongation (QRS>130ms) in terms of all-cause mortality.
Results: 694 patients met inclusion criteria of which 65 met criteria for a mildly prolonged QRS duration. Over a mean follow up of 4.3±2.0 years, there were 273 deaths, 35 in the mildly prolonged group (53.8%) vs. 238 in patients with significant QRS prolongation (27.8%)(p=0.016). In Cox multivariate regression analysis, patients with mild QRS prolongation had significantly worse long term outcomes compared to those with more significant prolongation(hazard ratio 1.5 (1.02-2.21, p=0.038).
Conclusions: Patients with left ventricular dysfunction and only mild QRS prolongation undergoing CRT have increased all-cause mortality compared to more traditionally studied patients with significant QRS widening.
- © 2011 by American Heart Association, Inc.