Clinical and Electrophysiological Characteristics of Patients Developing Macroreentrant Atrial Tachyarrhythmias Following Cardiac Surgery: A Retrospective Cohort Study.

Introduction: Macroreentrant atrial tachycardias (MRAT) predominate the atrial arrhythmias in patients with operated heart disease, and advances in interventional electrophysiology and catheter ablation technology have pioneered a shift in their management. Methods: We retrospectively analyzed clinical, procedural, and outcome data from a cohort of patients who had undergone radiofrequency (RF) ablation for MRAT (utilizing high-density atrial mapping) following cardiac surgery for congenital or acquired heart disease. Results: Forty-one patients underwent ablation for a MRAT from 2016 to 2023. These patients had a mean age of 50.17 ± 11.71 years and had undergone cardiac surgical intervention a median of 18 years prior to first presentation with atrial tachyarrhythmia. The commonest repaired lesion was a surgically corrected atrial septal defect. None of the studied patients had a left-sided macro reentrant circuit. The patients were followed up for a median duration of 2 years following ablation. Twenty-five patients (60.9%) had CTI-dependent atrial flutter (AFl). Using a strategy of high-density activation and voltage mapping and entrainment mapping to define the tachycardia circuit, an acute success rate of 95.1% was noted. Our population continued to do well on medium-term follow-up, with 90.2% of patients tachycardia-free at 2 years. However, seven patients (17.1%) developed sinus bradycardia requiring pacing, and three patients (7.3%) developed incident atrial fibrillation. Conclusions: A meticulous approach to MRAT mapping utilizing a combination of newer high-density mapping catheters with entrainment mapping yields high rates of acute (95.1%) and medium-term success (90.2%) in patients with antecedent cardiac surgery.