His bundle pacing in nodal versus infranodal atrioventricular block: a mid-term follow-up study
Catalin Pestrea1,2, Ecaterina Cicala3, Alexandra Gherghina3
1Department of Interventional Cardiology, Brasov County Emergency Hospital, Brasov, Romania pestrea.catalin@gmail.com.
Insights
His bundle pacing (HBP) is a feasible technique for advanced atrioventricular block (AVB), showing high success in nodal AVB. Infranodal blocks present lower success rates but still offer pacing possibilities.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Advanced atrioventricular block (AVB) necessitates pacing solutions.
- His bundle pacing (HBP) offers a potential alternative to conventional pacing.
- Understanding HBP feasibility across different AVB etiologies is crucial.
Purpose of the Study:
- To evaluate the feasibility of His bundle pacing (HBP) in unselected patients with advanced atrioventricular block (AVB).
- To compare procedural success rates of HBP between nodal and infranodal conduction block sites.
- To assess medium-term follow-up outcomes of HBP.
Main Methods:
- Prospective inclusion of 75 consecutive patients with second- or third-degree AVB undergoing HBP.
- Recording of clinical and procedural characteristics at baseline and mid-term follow-up.
- Stratification of patients based on nodal versus infranodal block location.
Main Results:
- HBP procedural success was significantly higher in nodal AVB (84.8%) compared to infranodal AVB (31%).
- Infranodal block, baseline QRS duration, LBBB morphology, and reduced ejection fraction predicted HBP failure.
- No significant differences in paced QRS duration, impedance, thresholds, or fluoroscopy time between groups; stable thresholds at follow-up.
Conclusions:
- Permanent HBP is a feasible pacing strategy for nodal AVB, demonstrating high success and stable medium-term performance.
- While less successful, HBP remains a viable option for infranodal blocks, particularly those within the His bundle.
- Further research may optimize HBP in complex infranodal block scenarios.
Introduction:
This study evaluated the feasibility of His bundle pacing (HBP) in consecutive, unselected patients with advanced atrioventricular block (AVB) over a medium-term follow-up period, comparing procedural characteristics between nodal and infranodal sites of the conduction block.
Materials And Methods:
Seventy-five consecutive patients with second-degree or third-degree AVB in which HBP was attempted were prospectively included in this study. The clinical and procedural-related characteristics of the patients were recorded at baseline and over a mid-term follow-up.
Results:
72% of the patients had normal QRS duration at baseline. Intracardiac electrograms revealed nodal AVB in 46 patients (61.3%). The permanent HBP procedural success was significantly higher in nodal AVB (84.8%) vs infranodal AVB (31%). There was no statistical difference between paced QRS duration, impedance, pacing and sensing thresholds and fluoroscopy time in the two groups. Infranodal block, baseline QRS duration, left bundle branch block morphology and ejection fraction were significantly associated with HBP procedural failure. The patients were followed for a period of 627.71±160.93 days. There were no significant differences in parameters at follow-up. An increase of >1 V in the His bundle (HB) capture threshold was encountered in one patient with infranodal AVB (11.1 %) and in four patients with nodal AVB (10.25%).
Conclusion:
Permanent HBP is a feasible pacing technique in nodal AVB with a high success rate and stable thresholds in the medium term. Most infranodal blocks are located within the HB, so there is still the possibility to capture the conduction system, although with lower success rates.
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