Abstract 3320: VV Optimization May Partially Offset the Effects of a Suboptimal Left Ventricular Lead Position in Patients Undergoing Cardiac Resynchronization Therapy: An Acute Hemodynamic Study
Introduction Left ventricular (LV) lead placement to the latest site offers the greatest benefit to cardiac resynchronization therapy (CRT). Interventricular (VV) delay optimization can enhance the acute hemodynamic benefits of biventricular pacing. We hypothesized that VV optimization may be able to overcome the deleterious effects of a suboptimal lead position. We assessed the impact of VV optimization on acute changes in cardiac output (CO) in patients with and without LV pacing of the latest site.
Methods Fifty-five patients (age 69 +/− 8, NYHA III/IV − 50/5, ischemic 58%, ejection fraction 23 +/− 7%, QRS width 154 +/− 9 ms) were assessed before and within 7 days of CRT. The latest site was determined by speckle tracking radial strain and the LV lead position from biplane fluoroscopy. Patients were classified into one of three groups according to the relation of LV lead position to the latest site: Concordant (C - lead position at latest site), Adjacent (A - within one segment) or Remote (R - 2 or more segments away from latest site). AV and VV delays were optimized according to the maximal transmitral VTI and LVOT VTI. Cardiac output (CO) was measured using a commercially available validated method (NICOM, Cheetah, US). A 20% increase in acute CO from baseline (CRT off) was used to define acute response to CRT. Comparisons were made in acute improvements in CO in groups C, A and R during simultaneous (SIM) and sequential (SEQ) biventricular pacing.
Results The proportion of patients in group C, A and R was 39%, 33% and 28% respectively. In all patients, compared to SIM pacing, SEQ CRT is associated with a greater rise in CO (5.42 +/− 1.1 vs 5.73 +/− 1.1 L/min, p<0.05) and higher acute response rates (51% vs 65% p=0.02).). In groups C and A, compared to SIM pacing, SEQ CRT increased response rates (C: 67 vs 88% p<0.01, A: 50 vs 69% p<0.01). VV optimization had no effect on acute response rates in group R (27 vs 27% p=NS)
Conclusion VV optimization can improve acute response in patients where the LV lead is either at or in the vicinity of the optimal site but not in patients with significant discordance. This suggests that VV optimization may overcome some but not all of the deleterious effects of a suboptimal lead position. The impact of VV optimization on LV reverse remodeling is yet to be defined.