Abstract
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 (cm(2)) 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.