Catheter ablation is an important therapeutic option for atrial tachycardias in patients with CHD. As a result of extensive scarring and surgical repair, multiple intra-atrial re-entrant tachycardia circuits develop and serve as a substrate for arrhythmias. The best ablation approach for patients with multiple intra-atrial re-entrant tachycardias has not been investigated. Here, we compared substrate-based ablation using extensive scar modification to conventional ablation.

The present study included patients with surgically corrected CHD that underwent intra-atrial re-entrant tachycardia ablation. Extensive scar modification was defined as substrate ablation based on a dense voltage map, aimed to eliminate all potentials in the scar region. The control group had activation mapping-based ablation. A clinical composite endpoint was assessed. Points were given for type, number, and treatment of intra-atrial re-entrant tachycardia recurrence.

In 40 patients, 63 (extensive scar modification 13) procedures were performed. Acute procedural success was achieved in 78%. Procedural duration was similar in both groups. Forty-nine percent had a recurrence within 1 year. During a 5-year follow-up (2.5–7.5 years), 46% required repeat catheter ablation. Compared to baseline, clinical composite endpoint significantly decreased by 46% after 12 months (p = 0.001). Acute procedural success, procedural parameters, recurrence and repeat ablation were similar between extensive scar modification and activation mapping-based ablation.

Catheter ablation using extensive scar modification for intra-atrial re-entrant tachycardias occurring after surgically corrected CHD illustrated similar short- and long-term outcomes and procedural efficiency compared to catheter ablation using activation mapping-based ablation. The choice of ablation approach for multiple intra-atrial re-entrant tachycardia should remain at the discretion of the operator.

Adults with tetralogy of Fallot experience atrial tachyarrhythmias; however, there are a few data on the outcomes of radiofrequency ablation. We examined the characteristics, outcome, and predictors of recurrence of atrial tachyarrhythmias after radiofrequency ablation in tetralogy of Fallot patients.

Retrospective data were collected from 2004 to 2013. In total, 56 ablations were performed on 37 patients. We identified two matched controls per case: patients with tetralogy of Fallot but no radiofrequency ablation and not known to have atrial tachyarrhythmias. Acute success was 98%. Left atrial arrhythmias increased in frequency over time. The mean follow-up was 41 months; 78% were arrhythmia-free. Number of cardiac surgeries, age, and presence of atrial fibrillation were predictors of recurrence. Lone cavo-tricuspid isthmus-dependent flutter reduced the likelihood of atrial fibrillation. Right and left atria in patients with tetralogy of Fallot were larger in ablated cases than controls. NYHA class was worse in cases and improved after ablation; baseline status predicted death. Of matched non-ablated controls, a number of them had atrial fibrillation. These patients were excluded from the case–control study but analysed separately. Most of them had died during follow-up, whereas of the matched ablated cases all were alive and the majority in sinus rhythm.

Patients with tetralogy of Fallot and atrial tachyarrhythmias have more dilated atria than those without atrial tachyarrhythmias. Radiofrequency ablation improves functional status. Left atrial ablation is more commonly required with repeat procedures. There is a high prevalence of atrial tachyarrhythmias, particularly atrial fibrillation, in patients with tetralogy of Fallot; early radiofrequency ablation may have a protective effect against this.