ABC | Volume 114, Nº5, May 2020

Original Article Bianco et al. Ablation of atrial flutter and fibrillation Arq Bras Cardiol. 2020; 114(5):775-782 Mean age was 68±12 years in the group with AF and 66.4±15 years in the group without AF (p=0.59). In both groups, most patients were male (73.2% in the group with AF and 69.2% in the group without AF, p=0.43). Mean BMI was 28.9 ± 4 kg/m 2 in the group with AF and 29.7 ± 4.2 kg/m 2 in the group without AF (p = 0.72). Comorbidities were similar in both groups. History of renal failure and systemic arterial hypertension was more common in the group with AF (24.4% vs. 7.2% [p = 0.03] and 72.1% vs. x 56.4% [p = 0.12]). There was no difference between the groups regarding other comorbidities such as dyslipidemia, congestive heart failure, diabetes mellitus, vascular disease, stroke/transient ischemic attack, use of anticoagulants or antiarrhythmic drugs. Efficacy and safety of procedures Recurrence rate of CTI-dependent atrial flutter was 11.5%. Table 2 summarizes the results of the procedure and the complication rate. There was rupture and embolization of the curved tip of the transseptal sheath used for stabilization of the ablation catheter (complication rate of 1.2%), that was lodged in the distal branch of the left pulmonary artery and was successfully removed without surgical intervention. The Kaplan-Meier curve (Figure 2) illustrates the occurrence rate of AF of 53.6% after ablation of CTI-dependent atrial flutter. The occurrence was more common in the first year after the procedure. Predictors of AF after ablation of CTI-dependent atrial flutter The univariate analysis revealed statistically significant predictors for the occurrence of AF after ablation of CTI- dependent atrial flutter. The variables history of renal failure (OR = 3.88 [95%CI 0.99-15.1] p = 0.05) and systemic arterial hypertension (OR = 2.15 [95%CI 0.86-5.39] p = 0.10) were included in the multivariate models, but did not show statistical significance after adjustment of the model Table 1 – Characteristics of patients undergoing ablation of atrial flutter, categorized according to occurrence of atrial fibrillation during the follow-up period Variables Occurrence of atrial fibrillation (n = 45) Non-occurrence of atrial fibrillation (n = 39) p-value Age (years) 68.0 ± 12 66.4 ± 15 0.59 Sex (male) 33 (73.2) 27 (69.2) 0.43 Body mass index 28.9 ± 4 29.7 ± 4.2 0.72 LVEF (%) 51.7 ± 14 54.8 ± 18 0.62 Left atrial diameter (mm) 41.2 ± 7.8 42.2 ± 7.3 0.97 Comorbidities History of renal failure 11 (24.4) 3 (7.2) 0.03 Dyslipidemia 13 (28.9) 9 (23.1) 0.36 Heart failure 12 (26.7) 12 (30.8) 0.43 Hypertension 32 (72.1) 22 (56.4) 0.12 Diabetes mellitus 8 (17.8) 10 (25.6) 0.27 Vascular disease 16 (35.6) 9 (23.1) 0.15 Previous stroke/TIA 7 (15.6) 4 (10.3) 0.35 Medications OAC 23 (51.1) 21 (53.8) 0.33 AAD 23 (51.1) 14 (35.9) 0.11 Scores HATCH 1 (1-3) 1 (0-3) 0.41 CHA 2 DS 2 -VASC 3 (2-4) 3 (1-4) 0.42 Data expressed as mean ± standard deviation (age, body mass index, LVEF, left atrial diameter); or absolute and relative frequency; LVEF: left ventricular ejection fraction; TIA: transient ischemic attack; OAC: oral anticoagulants; AAD: antiarrhythmic drugs; Student’s t-test for independent samples; *p-value indicates statistically significant differences at a level of 5% Table 2 – Efficacy and safety of ablation of cavotricuspid isthmus- dependent atrial flutter for treatment of common atrial flutter in 84 patients Event n (%) Occurrence of post-ablation AF 45 (53.6) Recurrence of atrial flutter 10 (11.5) Complications 1 (1.2) AF: atrial fibrillation. 777