Abstract 17407: Patients without Left Bundle Branch Block May Still Benefit from Cardiac Resynchronization Therapy
INTRODUCTION Recent analyses of the major biventricular pacing trials have suggested that patients with LBBB most stand to benefit from CRT. However, LBBB was not uniformly defined between studies. We tested the hypothesis that patients with LBBB as defined by the World Health Organization (WHO) criteria were indeed most likely to benefit from CRT.
METHODS Between April 2008 and December 2011, 132 patients received new CRT devices at UNC Hospital. Thirty-four of these had follow-up visits after 3 months along with pre and post-implantation echocardiograms. Within this subgroup, 18 had LBBB at baseline as defined by the WHO criteria and were grouped as “predicted responders.” The other 16 were grouped as “predicted non-responders.”
RESULTS A comparison between the two groups is shown in the table. Of the predicted responders, 100% had improvements in their EF, and 56% had improvements of >5%. Of the predicted non-responders, 50% had improvements in their EF, and 31% had improvements of >5%. Among those with an improvement in EF of greater than 5%, the average increase in EF was greater in the predicted non-responders than in the predicted responders (19% vs. 15%). There were no significant differences in demographic data, cardiac diagnosis, coronary sinus (CS) lead location, or a variety of ECG characteristics (rate, rhythm, QRS duration, QRS axis, time to second R peak, septal Q waves) that distinguished those that did from those that did not meet their predicted response in either of the two groups.
CONCLUSIONS In patients with an improvement in EF of >5% post-CRT, the average increase in EF was greater in those without LBBB. Although our data set is small, our observations suggest that indications for CRT should not be limited to patients with LBBB. Further investigation is needed to identify factors capable of accurately predicting the response to CRT, particularly in patients without LBBB.
- © 2012 by American Heart Association, Inc.