His-bundle pacing versus cardiac resynchronisation therapy: Effect on ECG parameters of repolarization
Rakesh Sarkar1, Muthiah Subramanian2, Vickram Vignesh Rangaswamy2
1Department of Pacing and Electrophysiology, Medanta-The Medicity, Gurgaon, Haryana, India.
Insights
His bundle pacing (HBP) significantly reduces ventricular repolarization abnormalities compared to cardiac resynchronization therapy (CRT). This study found HBP improved key ECG repolarization parameters, unlike CRT.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Cardiac resynchronization therapy (CRT) using biventricular pacing (BiV) can potentially worsen ventricular repolarization.
- The effects of His bundle pacing (HBP) on repolarization in patients with left ventricular systolic dysfunction are not well-documented.
Purpose of the Study:
- To compare ECG repolarization parameters between His bundle pacing (HBP) and cardiac resynchronization therapy (CRT) in patients with left ventricular systolic dysfunction.
Main Methods:
- A comparative study involving 20 patients undergoing HBP and 18 patients undergoing CRT (BiV).
- Repolarization parameters (QTc, Tp-e, Tp-e/QTc) were measured pre-implantation, within 24 hours post-implantation, and at 6 weeks post-implantation.
- Clinical and echocardiographic parameters were assessed during a 6-month follow-up.
Main Results:
- Both HBP and CRT groups showed similar baseline characteristics.
- HBP demonstrated a significant reduction in Tp-e and Tp-e/QTc immediately and at 6 weeks post-implantation compared to baseline.
- These improvements in repolarization parameters were not observed in the CRT group.
- NYHA class and LV function remained comparable between groups at 6 months.
Conclusions:
- His bundle pacing is associated with a significant improvement in ventricular repolarization indices (Tp-e and Tp-e/QTc) compared to cardiac resynchronization therapy.
- Further research is required to determine if these repolarization improvements translate to a reduction in clinical arrhythmic events.
Introduction:
Cardiac resynchronization therapy (CRT) by biventricular pacing (BiV) may worsen indices of ventricular repolarization. The impact of His bundle pacing (HBP) on repolarization is not well studied in patients with left ventricular systolic dysfunction. The aim of the study is to compare the repolarization parameters in ECG between these two pacing modalities.
Methods:
Baseline and post implant parameters of 20 patients who had undergone HBP were compared with 18 patients who underwent CRT (BiV) implantation. Repolarization parameters were monitored before implantation, within 24 hours and after 6 weeks of implantation. Patients were followed up till 6 months with clinical and echocardiographic parameters.
Result:
Baseline clinical, electrocardiographic and echocardiographic parameters were similar in both groups. Significant differences were noted in QTc, Tp-e and Tp-e/QTc between HBP and CRT groups both on immediate post implant and after 6 weeks of implantation. Compared to pre-implantation,significant shortening of Tp-e and Tp-e/QTc was observed immediately (90.54 ± 24.35 vs 69.62 ± 12.92, p < 0.05 and 0.20 ± 0.05 vs 0.15 ± 0.03, p < 0.05) and after 6 weeks (90.54 ± 24.35 vs 66.08 ± 14.95, p < 0.05 and 0.20 ± 0.05 vs 0.15 ± 0.02, p < 0.05) in HBP implant (group A). However, these changes were not present in CRT cohort (group B). During a follow up of 6 months, NYHA class and LV function between two groups remain comparable.
Conclusion:
HBP is associated with significant reduction of Tp-e and Tp-e/QTc compared to CRT. Further evaluation is needed to determine whether this improvement in indices of repolarization is associated with reduction in clinical arrhythmic events or not.
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