Right isthmus ablation reduces supraventricular arrhythmias after surgery for chronic atrial fibrillation

Clinical, electrocardiographic, and echocardiographic results of atrial fibrillation (AF) ablation by left mini-Maze, with or without concomitant cavotricuspid isthmus ablation, during cardiac surgery were analyzed.

Eighty-seven patients undergoing radiofrequency left mini-Maze without (group A) or with (group B) concomitant cavotricuspid isthmus ablation underwent serial electrocardiography and echocardiography to assess sinus rhythm recovery and atrioventricular remodelling. Recurrence of AF, incidence of atrial flutter, hospital readmission, and episodes of congestive heart failure were recorded. Predictors of AF recurrence were evaluated.

Follow-up of 33.4 +/- 11.2 months demonstrated 88.5% had sinus rhythm recovery, with normalized E/A velocity in 90.9%. Freedom from AF recurrence, congestive heart failure, and hospital readmission was 72.6% +/- 7.8%, 93.3% +/- 5.5%, and 79.9% +/- 8.2%, respectively, without differences between the two groups. Atrial flutter developed in group A more frequently during hospitalization (19.5% versus 2.2%; p = 0.009) and follow-up (12.2% versus 0%; p = 0.02); freedom from atrial flutter was thus lower (79.6% +/- 7.8% versus 100%; p = 0.024). Although no differences were recorded in postoperative and follow-up New York Heart Association (NYHA) functional class or in postoperative or follow-up echocardiographic indicators between the two groups, AF patients displayed a worse NYHA than did sinus rhythm patients (discharge p = 0.009; follow-up p = 0.0002). Accordingly, only sinus rhythm patients showed reverse remodelling of longitudinal (discharge p = 0.002; follow-up p = 0.0001) and transverse diameter (discharge p = 0.0001; follow-up p = 0.001), and of follow-up left ventricular diastolic diameter (p = 0.0001). Mitral valve disease and high postoperative and follow-up echocardiographic pulmonary pressures were independent predictors of AF recurrence. Left + right ablation was the only protective factor against AF recurrence.

Concomitant cavotricuspid isthmus ablation should be routinely considered in AF surgery, given the shorter hospitalization, low incidence of atrial flutter onset, and beneficial effect on AF recurrences.