Radiofrequency ablation of figure-8 double-loop tachycardias in patients with prior surgical atriotomy required ablation at two isthmuses, resulting in no recurrences after 19 months.
Observational (n=5)
BACKGROUND: Dual-loop atrial reentrant tachycardias have not been clinically described. METHODS AND RESULTS: Five patients (3 men, 2 women; mean age, 48+/-16 years) were studied 24+/-15 years after surgical closure of an ostium secundum atrial septal defect for drug-resistant atrial tachycardia. Complete tachycardia mapping was performed in the right atrium with multipolar catheters and a 3-dimensional electroanatomic mapping system (Biosense), followed by linear radiofrequency ablation of the narrowest part of each complete loop. Six tachycardias with a typical flutter morphology, a cycle length of 262+/-40 ms, and a superior f-wave axis (-77+/-11 degrees ) were mapped, 4 with a Biosense map including 106+/-32 points. Five figure-8 tachycardias had a counterclockwise loop around the tricuspid valve sharing a common anterior channel with a clockwise loop around the lateral atriotomy scar. One tachycardia was thought to have 2 counterclockwise loops around the same obstacles. Radiofrequency delivery in the cavotricuspid isthmus in each case transformed the tachycardia without any pause in a different morphology tachycardia with an inferior P-wave axis (50+/-42 degrees ) and nearly the same cycle length (272+/-39 ms) but with the periatriotomy loop alone. This arrhythmia required ablation of a second isthmus: between the lower end of the atriotomy and the inferior vena cava in 4 and the superior tricuspid annulus in 1. After a follow-up of 19+/-6 months, there were no recurrences. CONCLUSIONS: Figure-8 double-loop tachycardias mimicking the ECG pattern of a common atrial flutter occur in some patients after a surgical atriotomy. Ablation of 1 loop produces a sudden transformation to a new reentrant tachycardia formed of the remaining loop that requires ablation at a second isthmus.
Shah et al. (Tue,) conducted a observational in Drug-resistant atrial tachycardia (n=5). Radiofrequency ablation was evaluated on Recurrence of tachycardia. Radiofrequency ablation of figure-8 double-loop tachycardias in patients with prior surgical atriotomy required ablation at two isthmuses, resulting in no recurrences after 19 months.