Clinical and electrophysiological characteristics and long term outcomes of catheter ablation for right and left atrial tachycardias

Atrial tachycardias (AT) are complex supraventricular tachycardias which are refractory to antiarrhythmic drugs that require catheter ablation. In this trial, we aimed to evaulate the outcomes of catheter ablation in patients with symptomatic atrial tachycardia, define the acute procedural success and the recurrence rates in long-term follow-up and determine the clinical and electrophysiological features that affect these outcomes. A total of 666 [mean age: 55 ±16, gender: 344 (51.7%) female] symptomatic patients with AT were enrolled. Prior catheter or surgical ablation history for ATa was present in 199 (29.9%) and 18 (2.7%) of these patients, respectively. Activation mapping was performed during tachycardia in all patients as well as entrainment mapping when needed. Voltage mapping were performed in sinus rhythm in both atriums, late potential mapping was also performed in some patients. Low voltage areas and signals with continuous-fragmented morphology were tagged. Macroreentry was the primary mechanism in right and left atrium (70.2% and 52.8%, respectively). Cavotricuspid isthmus (CTI) dependent macroreentry was the most frequent mechanism in right ATs and perimitral reentry and roof-dependent macroreentry were the most common mechanisms in left ATs. A total of 59 (7.5%) complications were observed in 780 procedures.(2.1% major and 5.5% minor) Acute procedural success was 95.9%. Freedom from ATa was 72.8 % during a mean follow-up of 39±23 months. Freedom from ATa after index procedure was 82.3% at 12 months and 75.9 % at 24 months. After multiple procedures, freedom from ATa was 90% at 12 months and 86 % at 24 months during the follow-up. In multivariate Cox regression analysis, atrial fibrillation (AF) [(HR) 2.43, 95% c(CI) 1.78-3.30; p<0.001] , history of cardiac surgery [(HR) 1.68, 95% (CI) 1.22-2.30; p=0.001] and moderate to severe tricuspid regurgitation [(HR) 1.47, 95% c(CI) 1.08-2.01; p=0.014] were significant predictors of ATa recurrence. Our findings demonstrated that tailored catheter ablation of ATs especially guided by high density mapping has a high acute success rate and favourable long-term outcomes in patients with symptomatic AT episodes.