Electrocardiographic Characteristics and Ablation Outcomes Associated With Para-Hisian Ventricular Arrhythmias
Anugrah Nair1, Jenish P Shroff1, Lukah Q Tuan1
1Australian National University, Canberra, Australian Capital Territory, Australia; Canberra Heart Rhythm Centre, Canberra, Australian Capital Territory, Australia.
Insights
Para-Hisian (PH) ventricular arrhythmias (VAs) have distinct ECG characteristics that aid in ablation. These PH-VAs can be effectively treated without impacting atrioventricular conduction.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Ventricular arrhythmias (VAs) near the His-bundle account for 9% of unexplained VAs.
- Ablation of these Para-Hisian (PH) VAs is challenging due to the risk of atrioventricular block.
Purpose of the Study:
- To investigate the electrocardiographic (ECG) and electrophysiological characteristics of PH VAs.
- To compare PH VAs with septal right ventricular outflow tract VAs.
- To identify features differentiating left/right and supra/infra-Hisian PH VAs.
Main Methods:
- Retrospective analysis of 210 patients with VAs (2018-2024).
- Inclusion of 31 patients with PH-VAs and 23 with septal right ventricular outflow tract VAs.
- Comparison of ECG characteristics and identification of differentiating features.
Main Results:
- PH-VAs exhibited narrower QRS complexes and a higher prevalence of R-wave in lead aVL compared to septal RVOT VAs.
- Specific ECG features differentiated left/right and supra/infra-Hisian PH VAs, including R-wave transition timing and S-wave depth in specific leads.
- Only one patient experienced post-procedure heart block.
Conclusions:
- Para-Hisian VAs possess unique ECG signatures based on their anatomical origin.
- Effective ablation of PH-VAs is achievable while preserving atrioventricular conduction.
Background:
Ventricular arrhythmias (VAs) near the His-bundle comprise 9% of unexplained VAs and present challenges for ablation caused by the risk of atrioventricular block.
Objectives:
The authors studied the electrocardiographic (ECG) and electrophysiological characteristics of Para-Hisian (PH) VAs, comparing them with septal right ventricular outflow tract VAs.
Methods:
From 210 patients with VAs between 2018 and 2024, 31 (14.7%) with PH-VAs and 23 (10.9%) with septal right ventricular outflow tract VAs were included. ECG characteristics of both were compared, and features differentiating left and right PH and supra- and infra-Hisian VAs were identified.
Results:
Of 31 patients, 15 had VAs from the right PH site and 16 from the left. Median follow-up was 15 months (Q1-Q3: 14-21 months) for left infra-Hisian, 16 months (Q1-Q3: 14-20 months) for left supra-Hisian, and 14 months (Q1-Q3: 14-16 months) for right infra-Hisian and right supra-Hisian VAs (Q1-Q3: 14-15 months). PH-VAs had narrower QRS complexes (134 ± 19.6 ms vs 169 ± 24 ms; P < 0.05), R-wave in lead aVL (100% [31 of 31] vs 4.3% [1 of 23]; P < 0.001), and earlier R-wave transition at or before lead V3 (80.6% [25 of 31] vs 47.8% [11 of 23]; P < 0.05). Left PH-VAs had earlier R-wave transition at lead V2 (50% [8 of 16] vs 20% [3 of 15]; P = 0.036). Right PH VAs had deeper S-wave relative to the preceding sinus beat in lead V1 (73.3% [11 of 15] vs 37.5% [6 of 16]; P = 0.04) and lead aVR (80% [12 of 15] vs 56.3% [9 of 16]; P = 0.01). Postprocedure heart block occurred in 1 patient.
Conclusions:
PH-VAs exhibit unique ECG features based on their origins, and can be effectively treated without affecting atrioventricular conduction.
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