The impact of right atrial volume on ablation outcomes in patients with pulmonary hypertension and atrial flutter

Catheter ablation has evolved as a safe treatment for atrial flutter (AFL) in patients with pulmonary hypertension (PH), and the recurrence of AFL may accelerate clinical decompensation. The aim of this study was to determine the recurrence rate and risk factors for recurrent AFL in PH patients after ablation. All PH patients who underwent AFL ablation at Fuwai Hospital between May 2015 and December 2020 were followed up. The recurrence rate and risk factors for recurrence were analyzed. A total of 68 PH patients (mean age 44.0 ± 13.0 years, 36.8% male) were enrolled. The majority patients diagnosed PH had congenital heart disease-associated PH (63.2%), and 30.9% had idiopathic pulmonary arterial hypertension. At baseline, most patients (80.9%) had only cavotricuspid isthmus (CTI)-related AFL; the occurrence of non-CTI-related AFL among patients was 8.8%, and 10.3% of the patients had both types of AFL. During a median follow-up of 17.5 months, 22 patients developed at least one recurrent AFL episode (AFL-free survival: 76.5% at 1 year). The immediate success of ablation (HR 0.061, 95% CI 0.009 to 0.438; P = 0.005) and the right atrial volume index (RAVi, per 10 ml/m2; HR 1.064, 95% CI 1.011 to 1.120; P = 0.018) were associated with long-term ablation outcomes in PH patients. With 166.64 ml/m2 as a cutoff value, AFL-free survival was significantly greater in patients whose RAVi was < 166.64 ml/m2 (log-rank P = 0.024). The immediate success of ablation and the RAVi are associated with recurrent AFL. Patients with a RAVi ≥ 166.64 ml/m2 are likely experience recurrence.