Abstract 2936: Intraoperative Optimization of Cardiac Resynchronization Therapy using Intracardiac Echocardiography can maximize benefits in patients with Refractory Heart Failure
Background: Cardiac resynchronization therapy (CRT) is used for refractory heart failure (HF) but its benefit has been unpredictable. Intraoperative programming of rate, atrioventricular(AV) or interventricular (V-V) intervals is not routinely performed.
Methods: We examined the feasibility of intracardiac echocardiography (ICE) to reliably visualize LV function & aortic flow (AO) intraoperatively during CRT device implant. Phased array imaging at 7– 8.5 Hz was performed using an ICE catheter placed in the RV and/or RA. LV ejection fraction (EF), septal-to-posterior wall motion delay, LV regional wall motion abnormality (RWMA) & aortic flow velocity/ejection indices (AO) were measured. Acute response to CRT programming was studied by varying rate, AV interval & V-V timing .
Results: 17 pts (14 men), mean age 69 yrs, mean QRS duration 154 ms, underwent ICE imaging. ICE showed global hypokinesis in 5 pts, RWMA in 10 pts & both in 2 pts. Optimized CRT modes included AV intervals ranging from 150 to 200 ms & V-V timing using simultaneous RV-LV pacing (1 pt), LV only (1 pt), & staggered LV-RV stimulation (15 pts). ICE guided CRT programming resulted in improvement in mean LVEF from 27 ± 8% to 40 ± 12% (p < .001, Figure⇓). AO flow velocity & velocity time integral increased with optimized programming with uniform laminar flow replacing turbulent discontinuous flow patterns. NYHA heart failure class improved from mean of 3.05 ± 0.6 at implant to 1.7 ±.0.5 (p < .01) after a mean follow up of 6 mos.
Conclusions: 1. ICE permits immediate assessment of ventricular dysysynchrony & response to CRT programming. 2.ICE guided optimization of CRT parameters can significantly improve LV performance & HF status.