Arrhythmias & electrophysiology
Epicardial-to-Endocardial Activation Gradients and Conduction Block During Atrial Fibrillation in the Human Left Atrial Posterior Wall
Authors' conclusion
Endocardial-epicardial LAPW asynchrony may be observed during human persistent AF and is characterized by: (1) greater epicardial compared with endocardial bipolar voltages, (2) more frequent epicardial-to-endocardial activation gradients during AF, and (3) conduction block commonly seen between the epicardial and endocardial surfaces during AF. Although the study was predominantly descriptive in nature, the observations suggest a dynamic 3-dimensional arrhythmogenicity of the LAPW and the potential importance of the epicardial layer, with implications for ablation therapies. Future prospective studies are required to determine the significance of these findings to clinical ablation outcomes.
Study context
- Population
- Patients with symptomatic nonparoxysmal atrial fibrillation (AF) who had unsuccessful antiarrhythmic or catheter ablation therapy referred for hybrid epicardial-endocardial AF ablation and left atrial appendage ligation19 men, median 69 years, 55% long-standing persistent AF
- Participants
- Twenty-seven patients
- Comparison
- Epicardial vs endocardial LAPW
- Outcome
- LAPW bipolar voltages during AF
Methodological detailspredominantly descriptive
- Predominantly descriptive
Main finding
As reported in the abstract
- Significantly greater epicardial compared with endocardial LAPW bipolar voltages during AF
Further findings
Voltage in areas of low endocardial bipolar voltage
- Normal endocardial unipolar voltage corresponded to normal epicardial bipolar voltage
Asynchronous endocardial-epicardial LAPW AF activation
- Universal during simultaneous endocardial-epicardial mapping
LAPW AF activity rate
- More rapid epicardial compared with endocardial LAPW AF activity
Conduction block between endocardial and epicardial LAPW surfaces
- Common during organized AF, with isolated or multiple blocked beats, Wenckebach conduction, and sustained endocardial LAPW entrance block with ongoing epicardial AF
- Epicardial-to-endocardial entrance block infrequently observed during sinus rhythm
Freedom from atrial arrhythmias · 12-month follow-up
- Freedom from atrial arrhythmias
- 68%
Original publication
Summarised from the published abstract; every number is checked against it