Implant Electrical Characteristics Predict Response to Cardiac Resynchronization Therapy

摘要

Background: The optimal site for left ventricular (LV) lead placement in cardiac resynchronization therapy (CRT) remains uncertain. Intra-procedural measures for predicting response to CRT have shown mixed results. Hypothesis: This study analyzed intracardiac electrogram (IEGM) characteristics at implant and assessed patients’ response rates (RR) to CRT. Methods: Forty-one consecutive patients undergoing CRT were enrolled. Medically optimized patients in sinus rhythm, with ejection fraction (EF) 34 were included. Right ventricular (RV) leads were positioned mid-septum. LV leads were targeted to the latest mechanical activation on echocardiography. IEGMs were measured, assessing intrinsic RV-to-LV delay (int RV-LV), RV-paced delay (RVp-LV), and LV-paced delay (LVp-RV). The difference between LVp-RV and RVp-LV was recorded as delta-LV. Response was defined as improvement of EF > 10%, reduction in LVEDD > 15% and improvement of ≥1 NYHA class. Results: Overall RR was 79%. LV leads were placed in the target location in 91%. Int RV-LV was 101 ± 14 ms in responders;78 ± 11 ms in non-responders (p 100 had a RR of 87%;int RV-LV 40 ms had a RR of 56%;delta-LV < 40 ms had a RR of 85%. There was no significant correlation between lead position, DI, QRS duration or EF and IEGM measurements. Conclusions: IEGM measures at implant are easily obtained. Significant intrinsic electrical delay and shorter delta-LV both predict response, even when LV leads are implanted in the targeted mechanically-delayed segment. These assessments of electrical dyssynchrony may be used to determine optimal lead positions and response to CRT.