Characterization of Complex Atrial Tachycardia in Patients With Previous Atrial Interventions Using High-Resolution
Nicolas Derval1, Masateru Takigawa1, Antonio Frontera1
1IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac, Bordeaux, France; Cardio-Thoracic Unit, Bordeaux University Hospital (CHU), Pessac, France.
Insights
Ultra-high-resolution mapping revealed complex atrial tachycardia (AT) mechanisms in patients with prior atrial interventions. Despite successful ablation, AT recurrence remains a challenge, highlighting the need for improved therapeutic strategies.
Area of Science:
- Electrophysiology
- Cardiology
- Medical Devices
Background:
- Atrial tachycardia (AT) mechanisms are not fully understood, contributing to high rates of ablation failure.
- Identifying the precise mechanism of AT is crucial for successful catheter ablation outcomes.
Purpose of the Study:
- To systematically evaluate the mechanisms of atrial tachycardia (AT) using ultra-high-resolution mapping.
- To analyze the prevalence and characteristics of different AT mechanisms in a large patient cohort, particularly those with prior atrial interventions.
Main Methods:
- Ultra-high-resolution mapping with a 64-pole catheter was employed in 132 consecutive patients with AT.
- AT mechanisms were defined by activation mapping and confirmed with entrainment in select cases.
- Radiofrequency ablation was performed targeting the identified arrhythmia circuits.
Main Results:
- A total of 214 ATs were mapped, with 96% having a defined mechanism, including macro-re-entry (60%), scar-related localized re-entry (27%), and focal AT (9%).
- Nearly half of the patients (45%) exhibited multiple complex AT circuits with variable transitions.
- Acute ablation success was high, but 46% of patients experienced AT recurrence after a mean follow-up of 13 months.
Conclusions:
- Multiple and complex atrial tachycardia circuits are common in patients with prior atrial interventions, especially after atrial fibrillation ablation.
- Ultra-high-resolution mapping provides detailed delineation of AT circuits.
- Despite high acute success rates, modest long-term freedom from AT suggests ongoing challenges in managing these arrhythmias.
Objectives:
This study systematically evaluated mechanisms of atrial tachycardia (AT) by using ultra-high-resolution mapping in a large cohort of patients.
Background:
An incomplete understanding of the mechanism of AT is a major determinant of ablation failure.
Methods:
Consecutive patients with ≥1 AT (excluding cavotricuspid isthmus-dependent flutter) were included. Mapping was performed with a 64-pole mapping catheter. The AT mechanism was defined based on activation mapping and confirmed by entrainment in selected cases.
Results:
A total of 132 patients were included (60 ± 12 years; 31 [23%] female; 111 [84%] previous atrial fibrillation [AF] ablation; 5 [4%] previous left atriotomy). One hundred four (94%) of the 111 post-AF ablation AT patients had substrate-based ablation during the index AF ablation. A total of 214 ATs were mapped, with complete definition of the AT mechanism in 206 (96%). A total of 129 (60%) had anatomic macro-re-entry (circuit diameter 44.2 ± 9.6 mm), 57 (27%) had scar-related localized re-entry (circuit diameter 25.8 ± 12.2 mm), and 20 (9%) had focal AT. Fifty-eight (45%) patients had multiple ATs (27 [20%] dual-loop re-entry; 60 [43%] sequential AT) with complex and highly variable transitions between AT circuits. A total of 116 (90%) of 129 macro-re-entrant ATs, 56 (98%) of 57 localized AT, and 20 (100%) of 20 focal ATs terminated after radiofrequency ablation. After a mean follow-up of 13 ± 9 months, 57 (46%) patients experienced recurrence of AT.
Conclusions:
Among patients with AT in the context of previous atrial interventions, particularly post-AF ablation patients, multiple complex AT circuits are common. Despite complete delineation of arrhythmia circuits using ultra-high-resolution mapping and high acute ablation success rates, long-term freedom from AT is modest.
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