Epicardial Approach in Recurred Atrial Fibrillation

Atrial electrical activity during atrial fibrillation depends on the distribution of myocardial tissue. Circumferential and longitudinal muscular bundles are multi-level crossing across the entire thickness of atrial wall. At radiofrequency catheter ablation for atrial fibrillation, transmural lesions are important to reduce the arrhythmogenic substrates and to prevent recurrence of scar-related atrial tachyarrhythmias.

Radiofrequency ablation applying electric current depends on impedance between patch and the tip electrode of a catheter. Increased impedance results in increased tissue heating, following an irreversible damage. However, overheating limits to create deep lesion formation because an increased impedance impedes the energy delivery to tissue. Furthermore, prolonged ablation time may result in severe complications, such as steam pop, cardiac perforation, and char formation. Therefore, both endocardial and epicardial ablations may be more effective to create a transmural lesion compared with only endocardial ablation.

Organized atrial tachycardia is common in patient who underwent ablation for atrial fibrillation. Activation mapping for atrial tachycardia is critical for ablating an isthmus. However, when the amplitude of endocardial potentials after previous ablations is decreased as system does not detect, summation of data from endocardium may give us wrong information about atrial tachycardia. Data from epicardial potential during tachycardia may be helpful to terminate a tachycardia.

We aimed to assess the benefit of epicardial mapping and ablation in patients with recurred atrial tachyarrhythmias after single procedure for atrial fibrillation. We hypothesize that both endocardial and epicardial approach is superior to only endocardial approach with regards to clinical recurrence. Participants are randomized into a hybrid approach or an endocardial approach.

Inclusion criteria

• Patients with persistent AF (AF episode lasting > 7 days)
• Patients with symptomatic AF that is refractory to at least one antiarrhythmic medication
• Patients with recurrent arrhythmia after prior catheter ablation
• Patients undergoing a repeat ablation procedure for AF
• At least one episode of AF must have been documented by ECG, Holter, loop recorder, telemetry, trans telephonic monitoring (TTM), or implantable device within last 2 years of enrollment in this investigation
• Patients must be able and willing to provide written informed consent to participate in this investigation

Exclusion criteria

• Patients with permanent AF;
• Permanent AF will be defined as a sustained episode lasting more than 1 years and sinus rhythm never be observed .
• Patients for whom cardioversion or sinus rhythm will never be attempted/pursued;
• Patients with AF felt to be secondary to an obvious reversible cause
• Patients with contraindications to systemic anticoagulation with heparin or warfarin or a direct thrombin inhibitor;
• Moderate to severe valvular disease
• Patients who are pregnant. Pregnancy will be assessed by patients informing the physicians.