Strategies for phrenic nerve preservation during ablation of inappropriate sinus tachycardia

Background Radiofrequency (RF) ablation can alleviate drug-refractory inappropriate sinus tachycardia (IST). However, phrenic nerve (PN) injury and other complications limit its use. Objective The purpose of this study was to characterize the maneuvers used to avoid PN injury and the long-term clinical outcomes. Methods The study consisted of a retrospective analysis of consecutive patients who underwent ablation for IST. Results RF ablation was performed on 13 consecutive female patients with drug-refractory IST. Eleven patients exhibited PN capture at desired ablation sites. In 1 patient, PN capture was not continuous throughout the respiratory cycle and ventilation holding sufficed to avoid PN injury. In 10 patients, pericardial access (PA) and balloon insertion was required. Initially (n = 4) a posterior PA was used, which was replaced by an anterior PA in the subsequent 6 cases. PA to optimal balloon positioning time was significantly lower in anterior vs posterior PA (16.3 ± 6 minutes vs 58 ± 21.3 minutes, P =.01), as was fluoroscopy time (15.66 ± 16.72 min vs 35.9 ± 1.8 min, P =.03). RF ablation successfully reduced sinus rate to <90 bpm in 13 of 13 patients. Procedure times and total RF times were not significantly different in anterior vs posterior PA. Major complications occurred in 2 patients, including unremitting pericardial bleeding requiring open-chested repair in 1 patient and sinus pauses mandating pacemaker implantation in the other patient. Long-term symptom control after follow-up of 811 ± 42 days was successful in 84.6%. Conclusion Ventilation holding and/or pericardial balloon insertion are frequently warranted in IST ablation. Anterior PA appears to facilitate the procedure over posterior PA.