Download left ventricular reverse remodeling with biventricular versus right

3027
Cat: Internal defibrillation/implantable antiarrhythmic devices/pacing
LEFT VENTRICULAR REVERSE REMODELING WITH BIVENTRICULAR
VERSUS RIGHT VENTRICULAR PACING IN PATIENTS WITH
ATRIOVENTRICULAR BLOCK AND LEFT HEART FAILURE IN THE
BLOCK HF TRIAL
M. St. John Sutton1, A.B. Curtis2, S.J. Worley3, T. Plappert1, P.B. Adamson4,
E.S. Chung5
1. University of Pennsylvania, Philadelphia, PA, USA
2. University at Buffalo, Buffalo, NY, USA
3. Lancaster General Hospital, Lancaster, PA, USA
4. Oklahoma Foundation for Cardiovascular Research, Oklahoma City, OK, USA
5. The Heart and Vascular Center at The Christ Hospital, Cincinnati, OH, USA
Background: In patients with heart failure (HF), biventricular pacing (BIV) attenuates
adverse left ventricular (LV) remodeling in addition to improving survival and relieving
symptoms. However, little is known about the effects of BIV pacing in HF patients with
atrioventricular (AV) block.
Methods: The BLOCK HF trial randomized patients with AV block, NYHA class I-III
heart failure, and LV ejection fraction (EF) less than or equal to 50% to BIV or right
ventricular (RV) pacing. Doppler echocardiograms (DE) were obtained at randomization
(30-60 days post-implant) and at 6, 12, 18, and 24 months. Data analysis comparing
changes in 10 pre-specified echo parameters over time was conducted using a Bayesian
adaptive design and all objectives were evaluated with intention-to-treat analyses.
Results: There were 624 subjects among the 691 randomized subjects who had paired
DE data for one or more analyses. LV volumes, EF, diastolic function and intraventricular mechanical delay (IVMD) were estimated at all time points. BIV pacing
resulted in LV reverse remodeling, with significant reduction in LV end systolic and end
diastolic volume indices and in IVMD and improvement in EF. By contrast, none of these
parameters changed with RV pacing, indicating that no reverse remodeling occurred postrandomization.
Conclusions: Patients with AV block, depressed LV function, and HF symptoms benefit
from BIV pacing with regard to cardiac structure and function. This DE analysis has
important clinical implications in supporting the use of BIV pacing rather than RV pacing
for patients with HF and AV block.