Catheter ablation of scar-related atypical atrial flutter

Aims The aim of the study was to assess the impact of isthmus location of atypical atrial flutters/atrial tachycardias (ATs) on outcomes of catheter ablation. Atrial tachycardias are clinically challenging arrhythmias that can occur in the presence of atrial scar—often due to either cardiac surgery or prior ablation for atrial fibrillation. We previously demonstrated a catheter ablation approach employing rapid multielectrode activation mapping with targeted entrainment manoeuvrs. However, the role that AT isthmus location plays in acute and long-term success of ablation remains uncertain. Methods and results Retrospective multicenter analysis of 91 consecutive AT patients undergoing ablation using a systematic four-step approach: (i) high-density activation mapping; (ii) analysis of atrial activation to identify wavefronts of electrical propagation; (iii) targeted entrainment of putative channels; and (iv) irrigated radiofrequency ablation of constrained regions of the circuit. Clinical outcomes, procedural details, and clinical profiles were determined. A total of 171 ATs (1.9 ± 1.0 per patient, 26% septal ATs) were targeted for ablation. The acute success rates were 97 and 77% for patients with either non-septal ATs or septal ATs, respectively ( P = 0.0023). Similarly, the long-term success rates were 82 and 67% for patients with either no septal ATs or at least one septal AT, respectively ( P = 0.1057). The long-term success rates were 75, 88, and 57% for patients with ATs associated with prior catheter ablation, cardiac surgery or MAZE, and idiopathic atrial scar, respectively. Conclusion Catheter ablation of AT can be successfully performed employing a strategy of combined high-density activation and entrainment mapping. Septal ATs are associated with higher rates of acute and long-term recurrences.