0362: Atrial fibrillation after radiofrequency ablation of atrial flutter: prevalence and risk factors

Background Radiofrequency ablation (RFA) is the only curative treatment for typical atrial flutter (AFL) and allows stopping antiarrhythmic drugs. However, atrial fibrillation (AF) is frequent during follow-up but predictive factors of AF onset are unknown while it is necessary to diagnose it in order to apply the correct antithrombotic strategy. Aims To determine prevalence and predictors of AF after AFL RFAAFL. Methods From January 2012 to December 2013, patients who underwent RFA of cavotricuspid isthmus for typical atrial flutter in our centre were retrospectively included. Results Of 166 patients (137 men, mean age: 66.7±10 years), 61 (36.7%) had a history of AF. The mean CHA2DS2VASc and HASBLED scores were 2.49 and 1.11. Mean left ventricular ejection fraction was 53±13% and 77 (46.4%) patients had a subsequent cardiomyopathy, whereas 61 (36.7%) had a history of AF. Of 166 RFA, sinus rhythm was obtain in 160 patients and 141 (84.9%) procedures were considered as a complete success (complete isthmus block). During a mean follow up of 489±244 days, there were 7 (5%) and 9 (36%) AFL recurrence in patients with and without isthmus block respectively. New-onset or recurrent AF were experienced by 63 (39%) patients. History of AF was an independent predictive factor of AF (33 (52.4%) vs. 28 (27.2%) patients; p=0.002). The younger patients (64.4 ±11.7 vs. 68.2±9.9 years; p=0.03) and patients with lower CHA2DS2VASc score had more AF post ablation (2.16±1.53 vs. 2.70±1.57; p=0.03). Conclusion After successful RF ablation, AF was frequent in patients especially in patient with AF history before AFL RFA, but also occurred in patient with lone AFL. Age and CHA2DS2VASc score were inversely associated with onset of AF. Identify AF and risk patients is crucial regarding to long-term antithrombotic therapy. Abstract 0362 – Table: predictive factors of AF No FA post ablation(N=103) FA post ablation (N=63) p Men/Women (N/N) 89/14 48/15 0.09 Age (years) 68.2+/–9.9 64.4+/–11.7 0.03* SAS 10 (9.7) 4 (6.3) 0.57 Cardiopathy 53 (51.5) 24 (38.1) 0.11 History of AF (N [%]) 28 (27.2) 33 (52.4) 0.002* Dilated LA (N [%]) 43 (41.7) 32 (50.8) 0.4 Dilated LV (N [%]) 12 (11.7) 12 (19) 0.41 LVEF  29 (28.2) 10 (15.9) 0.09 High blood pressure (N [%]) 63 (61.2) 31 (49.2) 0.14 Age ≥75 years 29 (28.2) 15 (23.8) 0.59 Diabetes mellitus 18 (17.5) 9 (14.3) 0.66 CHA 2 DS 2 VASc 2.7+/–1.57 2.16+/–1.53 0.03* BMI (kg/m 2 ) 27.4+/–5.5 27.9+/–4.9 0.55 Creatinine clearance (Cockroft) 78.1+/–30.8 85.3+/–37.4 0.19 Creatinine clearance (MDRD) 72.8+/–22.4 73.9+/–23.7 0.76 SAS: sleep apnoea syndrome; AF: atrial fibrillation; LA: left atrial; LV: left ventricular LVEF: left ventricular ejection fraction; BMI: body mass index