Abstract 10856: Prognostic Significance of Left Ventricular Lead Pacing Polarity in CRT-D Patients - A MADIT-CRT Substudy
Background: There are limited data on the significance of left ventricular (LV) lead pacing polarity. This study aimed to determine the predictive value of LV lead pacing polarity for heart failure (HF) events, ventricular tachyarrhythmias (VTA), or death in patients with mild HF and a wide QRS enrolled in MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy), receiving a cardiac resynchronization therapy device with implanted cardioverter defibrillator (CRT-D).
Methods: LV pacing polarity was obtained from the last device interrogation. Patients with LV bipolar leads paced between ring and tip were identified as True Bipolar while those with LV bipolar leads paced between LV tip or LV ring to RV coil were identified as Extended Bipolar. Patients with unipolar leads were identified as Unipolar. Kaplan-Meier analyses and multivariate Cox proportional hazards regression models were utilized.
Results: Of the 973 (89%) patients with a CRT-D, 681 (70%) had left bundle branch block (LBBB) ECG morphology and of those, 313 had True Bipolar pacing while the rest had Extended Bipolar (n=302) or Unipolar (n=66) pacing. Among patients with LBBB, True Bipolar pacing had a lower cumulative incidence of death (p=0.017) (Figure) and HF/Death (p=0.031) compared to those with Extended Bipolar/Unipolar LV pacing. No association was seen between LV lead polarity and risk of VTA. After adjustment for clinical covariates, True Bipolar LV pacing in LBBB patients was associated with a 59% lower risk for death (HR: 0.41; 95% CI: 0.21-0.79; p=0.008) and 36% lower risk for HF/death (HR: 0.64; 95% CI: 0.43-0.94; p=0.024) compared to Extended Bipolar/Unipolar LV pacing. No difference in endpoints was seen in non-LBBB patients.
Conclusion: True Bipolar LV pacing is associated with a significantly lower risk of HF/death and all-cause mortality in CRT-D patients with LBBB.
- © 2013 by American Heart Association, Inc.