Role of catheter-induced mechanical traum in localization of target sites of radiofrequency ablation in automatic atrial tachycardi

Objectives. We compared the efficacy of two different mapping techniques in identifying the ablation site for atrial tachycardia. Moreover, we evaluated the additive positive predictive value of mechanical interruption of atrial tachycardi to reduce the number of ineffective radiofrequency applications. Background. Radiofrequency catheter ablation has been suggested as highly effective technique to treat drug-resistant atrial tachycardia. However, irrespective of the mapping technique utilized, success was most often achieved with large number of radiofrequency applications. Methods. Forty-five patients with atrial tachycardi underwent radiofrequency catheter ablation. Mapping techniques included identification of earliest atrial activation and pace-mapping concordant sequence. Results. Atrial tachycardi was successfully treated in 42 (93.3%) of 45 patients with mean of 3.9 radiofrequency pulses/ patient. An interval between the onset of the intracavitary atrial deflection and the onset of the P wave during atrial tachycardi (AP interval) ≥30 ms (p < 0.001) and pace-mapping concordant sequence (p = 0.01) were all significant predictors of outcome. An AP interval ≥30 ms and pace-mapping concordant sequence were highly sensitive (92.8%, 95% confidence interval [CI] 80.5% to 98.5%; 85.7%, 95% CI 71.5% to 94.6%, respectively) but less specific (47.8%, 95% CI 37.9% to 58.2%; 36.8%, 95% CI 27.6% to 47.2%, respectively) in identifying the site of ablation. By using atrial tachycardi mechanical interruption combined with the AP interval >30 ms or the pace-mapping concordant sequence, we obtained specificity of 76.5% (95% CI 66.4% to 84.0%) and 73.5% (95% CI 63.2% to 81.4%), respectively, and positive predictive value of 49.2% and 44.6%, respectively. Conclusions. An AP interval ≥30 ms and pace-mapping concordant sequence were reliable mapping features for predicting the outcome of the ablation procedure. Mechanical interruption of atrial tachycardi improved the specificity and positive predictive value of these two mapping techniques.