Abstract P90: Does Extended Bipolar Pacing Improve The Response To Cardiac Resynchronization Therapy?
Introduction: To obtain optimal pacing threshold voltages and to avoid diaphragmatic stimulation, we often use extended bipolar pacing configuration instead of conventional bipolar pacing. However, its impact on the response to cardiac resynchronization therapy (CRT) has not been delineated. We hypothesized that extended bipolar pacing improves response to CRT.
Methods: We retrospectively studied 57 consecutive patients (Male 40, Female 17, age 68.5± 10.2 years) who had CRT implantation between 2003 and 2006. Extended bipolar pacing configuration was utilized in 39 patients. All patients had echocardiogram before and at last follow up of CRT. Positive response to CRT was defined as a decrease in left ventricular end systolic volume (LVESV) by more than 15%. Implantation lead parameters were recorded.
Results: During follow-up of 16± 11.2 months after CRT, left ventricular ejection fraction (LVEF) by echocardiogram significantly increased from 21.3± 7.0% to 28± 12.5% (p= 0.0006). 44% of our patient population (25/57) had positive response to CRT (baseline and post CRT LVESV 168.9± 81.2 ml vs. 153.4± 74.5 ml, p< 0.05). After adjustment for gender, age and clinical characteristics by multivariate analysis, CRT response negatively correlated with extended bipolar pacing configuration (p< 0.05), Table 1⇓.
Conclusion: Extended bipolar pacing had a statistically significant negative correlation with CRT response. This suggests that extended bipolar pacing configuration may not further improve the response to CRT. Future randomized trials may be needed to further understand the role of extended bipolar pacing in CRT devices.