Abstract 14930: Comparative Outcomes after Cardiac Resynchronization Therapy in Patients with Right Ventricular Pacing versus Native Wide Left Bundle Branch Block
Introduction: Current updated clinical guidelines for cardiac resynchronization therapy (CRT) favor as Class I indications patients with native wide QRS width (≤150ms) and left bundle branch block (LBBB). However, the comparative long term outcome in patients who receive CRT who had right ventricular (RV) pacing at baseline is unknown.
Hypothesis: We tested the hypothesis that long-term survival after CRT in patients who were upgraded from RV pacing is similar to those with native wide LBBB.
Methods: We studied 146 consecutive CRT patients with either native LBBB and QRS duration ≥150ms or who were RV paced at baseline. All were New York Heart Association Class II, III, or ambulatory IV with ejection fraction <35%. There were 76 (52%) with ischemic disease. Outcome events were predefined as death, heart transplantation or LV assist device (LVAD) implantation over 4 years after CRT.
Results: Of the 146 CRT patients, 116 (79%) had native LBBB ≥150ms and 30 (21%) were upgraded from RV pacing. Baseline QRS width was similar in both groups: 178±28ms vs.174±18ms (p=0.3). Baseline LV EF was lower in LBBB patients: 24±7 vs. 27±6% (p=0.01). There were 29 events (25%) in intrinsic LBBB and only 2 events (7%) in RV paced patients at the end of 4 years after CRT (Log Rank p =0.03, figure). When analyzed by disease etiology, upgraded RV paced patients had significantly better outcomes than either ischemic or non-ischemic patients with wide LBBB.
Conclusion: Heart failure patients with low EF who are upgraded from RV pacing have sustained favorable long term outcomes after CRT. Their outcomes appear to be comparatively more favorable than those with native LBBB and QRS ≥150ms. These findings support CRT for low EF heart failure patients who are RV paced.
Author Disclosures: B. Tayal: None. A. Delgado-Montero: None. A. Goda: None. K. Ryo: None. S. Saba: Research Grant; Modest; Boston scientific, St Jude, medtronic. N. Risum: None. P. Sogaard: Research Grant; Modest; Biotronik, GE Health Care. J. Gorcsan: Research Grant; Modest; St jude, Biotronik, Medtronic, Toshiba, GE.
- © 2014 by American Heart Association, Inc.