Cardiovascular Surgery and Interventions 2021, Vol 8, Num 1 Page(s): 044-052
The influence of left ventricular pacing polarity on ventricular repolarization parameters in cardiac resynchronization therapy and its clinical reflections on ventricular tachyarrhythmias

Mohammed Abusharekh1, Akar Yılmaz1, Çetin Alak2, Emre Ertürk1, Emin Evren Özcan2, Hakan Göçer3, Ahmet Barış Durukan4

1Department of Cardiology, Izmir University of Economics, Faculty of Medicine, Izmir, Turkey
2Department of Cardiology, Dokuz Eylül University, Faculty of Medicine, Izmir, Turkey
3Department of Cardiology, Edremit Körfez Hospital, Balıkesir, Turkey
4Department of Cardiovascular Surgery, Salihli Private Medigüneş Hospital, Manisa, Turkey

Keywords: Cardiac resynchronization therapy, depolarization, pacing polarity, tachycardia, ventricular
Objectives: This study aims to investigate the effects of the left ventricular (LV) pacing polarities on ventricular repolarization patterns and to examine novel parameters taking depolarization into account.

Patients and methods: This prospective study included a total of 54 patients (39 males, 15 females; mean age: 65.2±11.6 years; range, 40 to 89 years) with successful cardiac resynchronization therapy using quadripolar LV leads between January 2014 and February 2017. The patients were divided into two groups as the true bipolar group (n=25) and the unipolar/extended bipolar group (n=29). Ventricular repolarization parameters and novel markers, i.e., TpTe/QRS, Tpec/QRS, TpTe/(QRS ¥ QTc) and Tpec/(QRS ¥ QTc), were measured before implantation within 48 h following the procedure and at six months. Evaluation of ventricular tachyarrhythmias was performed using device records during follow-up.

Results: The median follow-up was 17.7 (range, 12.6 to 31.2) months. The mean ejection fraction was 23.3±5.5% in the bipolar group and 23.62±6.24% in the unipolar/extended bipolar group. Bipolar LV pacing was associated with higher Tpec/QTc values (acute, bipolar vs. unipolar, +0.011 vs. -0.0008, p=0.019; long-term, bipolar vs. unipolar, +0.005 vs. - 0.015, p=0.005, respectively). There was no significant difference between the groups in terms of other repolarization parameters. Bipolar pacing was associated with significantly higher novel markers values and more frequent sustained and non-sustained ventricular tachyarrhythmias.

Conclusion: The LV pacing polarity significantly affects Tpec/QTc, but not the other ventricular repolarization parameters. Novel arrhythmia predictors, i.e., TpTe/QRS, Tpec/QRS, TpTe/(QRS x QTc), and Tpec/(QRS x QTc), are more influenced in bipolar pacing associated with more frequent ventricular tachyarrhythmias.

DOI : 10.5606/e-cvsi.2021.1075