Abstract 19881: Pacing to Reduce Angina in Refractory Patients: Results of the Reduce Angina Study
Purpose: Prior experimental studies suggest that ventricular pacing adjacent to ischemic myocardium can reduce workload and metabolic demand. This feasibility trial was designed to test if application of biventricular pacing (BiV-P) with the pacing lead(s) at or near the ischemic region would reduce angina symptoms and improve clinical outcome in patients (pts) with refractory angina due to severe coronary artery disease (CAD).
Methods: We studied 11 CAD pts (71±10 years, 9 men) with stable Canadian Cardiovascular Society Class III Angina or greater, who were not amenable to revascularization and no indication for BiV-P. They were implanted with BiV-P devices with right and left ventricular (via coronary sinus) leads positioned at or adjacent to their ischemic regions as detected by SPECT. All pts were randomized to either pacing turned ON or OFF for 3 months, and then crossed over to the other treatment arm for an additional 3 months. With pacing turned ON, the paced atrioventricular (AV) delay was set with the Dynamic AV delay for approximately 90% and 70% of the intrinsic AV delay at the resting heart rate and at the onset of symptoms, resp.
Results: Overall, with the device ON (97–100% BiV-P) vs. OFF (0% BiV-P), the number of angina episodes (0.5±0.3 vs. 1.2±0.7/wk, mean±SEM, Wilcoxon paired test P=0.03), nitroglycerin use (0.2±0.1 vs. 1.0±0.7/wk, P=0.11) and the sum of FGD-PET scores (7.9±3.5 vs. 12.0±4.0, P=0.11) were lower and the treadmill exercise time was higher (7:07±1:05 vs. 6:48±1:04, P=0.19) with the device ON vs. OFF. Furthermore, there were no significant differences in sum of SPECT scores (20.0±4.9 vs. 19.3±6.1), LV ejection fraction (52±6 vs. 51±5%), and quality of life scores with device programmed ON vs. OFF (all P>0.05). One pt was excluded from the analysis due to a large amount of RV pacing during the OFF periods (24–64%) and due to an inability to properly deliver therapy because of an excessive number of PVCs.
Conclusions: The Reduce Angina feasibility study demonstrated that BiV-P at or near the ischemic region of angina was feasible and associated with significant reductions in angina and trend to improve exercise time and several outcome variables in pts with severe CAD. Adequately powered prospective studies are needed to confirm these findings.
- © 2010 by American Heart Association, Inc.