Why the study?
Limited evidence is available on concomitant changes in ventricular depolarization and repolarization and long-term outcomes of biventricular pacing.
Does the pattern of concomitant changes in ventricular depolarization and repolarization after biventricular pacing predict long-term mortality and ventricular arrhythmias in BiV-defibrillator recipients?
Cohort (n=528)
No
Does the pattern of concomitant changes in ventricular depolarization and repolarization after biventricular pacing predict long-term mortality and ventricular arrhythmias in BiV-defibrillator recipients?
In BiV-defibrillator recipients, a decrease in QRS duration combined with an increase in JTc interval is associated with the most favorable long-term survival free of LV assist device, heart transplantation, and sustained ventricular arrhythmias.
QRS/JTc response patterns after BiV pacing may stratify mortality risk in CRT-D recipients; leaves open prospective validation before guiding programming.
Background Biventricular (BiV) pacing increases transmural repolarization heterogeneity due to epicardial to endocardial conduction from the left ventricular (LV) lead. However, limited evidence is available on concomitant changes in ventricular depolarization and repolarization and long‐term outcomes of BiV pacing. Therefore, we investigated associations of BiV pacing‐induced concomitant changes in ventricular depolarization and repolarization with mortality (i.e., LV assist device, heart transplantation, or all‐cause mortality) and sustained ventricular arrhythmia endpoints. Methods Consecutive BiV‐defibrillator recipients with digital preimplantation and postimplantation electrocardiograms recorded between 2006 and 2015 at Duke University Medical Center were included. We calculated changes in QRS duration and corrected JT (JTc) interval and split them by median values. For simplicity, these variables were named QRS decreased (≤ −12 ms), QRS increased (> –12 ms), JTc decreased (≤22 ms), and JTc increased (> 22 ms) and subsequently used to construct four mutually exclusive groups. Results We included 528 patients (median age, 68 years; male, 69%). No correlation between changes in QRS duration and JTc interval was observed ( P = .295). Compared to QRS decreased /JTc increased , increased risk of the composite mortality endpoint was associated with QRS decreased /JTc decreased (hazard ratio [HR] = 1.62; 95% confidence interval [CI] = 1.09‐2.43), QRS increased /JTc decreased (HR = 1.86; 95% CI = 1.27‐2.71), and QRS increased /JTc increased (HR = 2.25; 95% CI = 1.52‐3.35). No QRS/JTc group was associated with excess sustained ventricular arrhythmia risk ( P = .400). Conclusion Among BiV‐defibrillator recipients, QRS decreased /JTc increased was associated with the most favorable long‐term survival free of LV assist device, heart transplantation, and sustained ventricular arrhythmias. Our findings suggest that improved electrical resynchronization may be achieved by assessing concomitant changes in ventricular depolarization and repolarization.
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Polcwiartek et al. (2020) conducted a cohort in BiV-defibrillator recipients (n=528). QRS increased / JTc increased vs. QRS decreased / JTc increased was evaluated on composite mortality endpoint (LV assist device, heart transplantation, or all-cause mortality) (HR 2.25, 95% CI 1.52-3.35).
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