Abstract 11217: The Effect of Left Ventricular Electrical Delay on the Acute Hemodynamic Response to Cardiac Resynchronization Therapy
Background: Cardiac resynchronization therapy (CRT) improves hemodynamic function. The magnitude of the hemodynamic response is associated with improved outcomes so optimization of this parameter is a goal of therapy. The purpose of this study was to evaluate the effect of left ventricular delay, as assessed by the QLV interval, on the acute hemodynamic response.
Methods: This study included 31 patients undergoing CRT. Invasive left ventricular (LV) dP/dt was measured during biventricular (BV) or LV only pacing at 5 different AV delays, tested in randomized order. The maximum percentage change of LV dP/dt compared with the baseline (%LV dP/dtmax) was calculated for each pacing configuration. The QLV interval was measured at the left ventricular pacing site.
Results: Compared with intrinsic rhythm, CRT increased LV dP/dtmax by 9.5±8.8% with BV pacing and 10.0±9.2% with LV only pacing (p<0.001 for each comparison; p=0.38 for BV vs. LV). The QLV interval was 86±30 ms and ranged from 36 to 152 ms. QLV was strongly correlated with the hemodynamic response in both pacing configurations (Figure). Multivariate analysis of %LV dP/dtmax by QLV, QRS width, bundle branch block morphology, ischemic etiology and ejection fraction showed that QLV was the only independent predictor of the hemodynamic response with a 1.7% increase in %LV dP/dtmax for every 10 ms prolongation of QLV with BV pacing (p=0.01) and 1.8% increase with LV pacing (p=0.01).
Conclusion: Left ventricular electrical delay, as measured by the QLV interval, is a strong predictor of the acute hemodynamic response to CRT so may be useful for guiding lead placement.
- © 2013 by American Heart Association, Inc.