Introduction:
Prior studies suggested better outcomes in cardiac resynchronization therapy (CRT) patients with true bipolar left ventricular (LV) pacing compared to unipolar or extended bipolar LV pacing. However, we lack confirmatory data from larger patient cohorts.
Methods:
We reviewed de-identified device data from 65,620 HF patients with an RF-enabled CRT-D device followed on the LATITUDE system (LATITUDE® system, Boston Scientific, St. Paul, MN). Long-term survival was assessed by LV lead pacing polarity. Patients with LV bipolar leads paced between the LV tip and ring were identified as LV true bipolar pacing, while those with LV bipolar leads paced between the LV tip or LV ring to the RV coil were identified as LV extended bipolar pacing. Unipolar LV pacing was assessed as a separate sub-group. Kaplan-Meier survival analysis and multivariable Cox hazards regressions models were utilized to assess all-cause mortality by LV lead pacing polarity.
Results:
There were 24,033 patients (37%) with LV true bipolar pacing, 38,327 patients (58%) with extended bipolar LV pacing, and 3260 patients (5%) with LV unipolar pacing. LV true bipolar pacing was associated with a significantly higher likelihood of survival during follow-up compared to patients with LV unipolar pacing (log-rank p<0.001), that translated into a significant 28% reduction in all-cause mortality (HR 0.72, 95% CI: 0.65-0.80, p<0.001) after adjustment for age and gender (Figure). The survival benefit between LV true bipolar pacing and LV extended bipolar pacing was smaller, but nevertheless statistically significant (HR=0.91, 95% CI: 0.65-0.80; p<0.001).
Conclusion:
In this large patient cohort, true bipolar LV pacing was associated with better long-term survival in cardiac resynchronization therapy patients compared to LV unipolar or LV extended bipolar pacing. When feasible, programming true bipolar LV lead pacing polarity should be considered in cardiac resynchronization therapy patients.
Interaction of Left Ventricular Size and Sex on Outcome of Cardiac Resynchronization Therapy Among Patients With a Narrow QRS Duration in the EchoCRT Trial