Atrial tachycardia in patients with repaired tetralogy of Fallot; its characteristics and catheter ablation outcome

Background

Patients with repaired tetralogy of Fallot (TOF) now live longer. However, dysrhythmia becomes prevalent in adults with repaired TOF, especially atrial tachyarrhythmia.

Objective

To identify the characteristics of patients who develop atrial tachycardia (AT) and the mechanism of the clinical AT and the induced one.

Method

Seventy-seven patients with repaired TOF were enrolled. The patients were divided into two groups (AT and non-AT). Clinical and electrophysiologic data were studied.

Results

The mean age was 34 years. Twenty-three patients had AT (30 %). In AT group, the left ventricular ejection fraction was lower (58 ± 6 vs 62 ± 5; P = 0.011), the right and left atrial area (cm²) was larger (29 ± 13 vs 15 ± 5; P < 0.001, and 19 ± 3 vs 16 ± 4; P < 0.001, respectively), and the right ventricular S′ wave (cm/s) was smaller (8 ± 2 vs 10 ± 3; P = 0.029).

Patients with AT underwent catheter ablation, and 32 AT were ablated. The mechanism of AT was intra-atrial reentrant tachycardia in 14 AT (44 %), cavotricuspid isthmus-dependent in 12 AT (37 %), and focal activity in the remaining 6 AT (19 %). An important finding was that after the first AT was ablated, another AT was induced in 7 patients. The mechanism was focal in about half of them, in contrast to the first ablated AT, where the focal mechanism was the least common. After a median follow-up of 37 months, four patients had AT recurrence.

Conclusion

The patients with AT had biventricular dysfunction and bi-atrial dilatation. Aggressive induction and ablation of the induced AT may reduce the future AT recurrence.