The Egyptian Cardiothoracic Surgeon Corresponding author: Mohamed Elsayegh abdelrahman.zamzam@gmail.com Original Article Left atrial diameter in estimating success rates of radio-frequency ablation treating atrial fibrillation Mohamed Elsayegh, Mohamad Ali El Ghannam, Ayman Mahmoud Ammar, Ahmed Samy Taha, Ahmed Bahig El Kerdany Faculty of Medicine, Ain Shams University, Cairo, Egypt Vol. 1, No. 1, 23 - 31 Abstract Background: In treating atrial fibrillation with radio-frequency ablation, few studies seek to define a cut-off value for left atrial diameter size beyond which the intervention risks outweigh chance of sinus recovery. This study aims to identify a cut-off value for pre-operative left atrial diameter to assess the efficacy of surgical radio-frequency ablation for treatment of chronic atrial fibrillation in patients undergoing mitral valve surgery. Methods: A prospective 6-month follow-up cohort study was conducted, in which 40 patients were recruited during the period from May 2016 till April 2018 at the Academy of Cardiothoracic Surgery, Ain Shams University. All patients had either isolated mitral valve replacements or mitral valve replacements combined with other valve surgeries. A mono-polar saline-irrigated cooled tip Radio-frequency ablation (SICTRA) was performed using the Medtronic Radiofrequency Generator Model 68000 as an energy source. A voltage of 25-30 watts was adjusted according to effectiveness of ablation. Oscillatory and to-and-fro motions were employed on the atrial endocardium using the Cardioblate pen until proper blanching or whitening was achieved. Receiver operator characteristic (ROC) curves were used to calculate the area under the curve and cut-off value for left atrial diameter. The efficacy of the overall survival time was estimated using the Kaplan‐Meier method. Results: Pre-operatively left atrial diameter of 59 mm was significantly associated with decrease in the possibility of reverting to sinus rhythm after surgery (OR 0.292, p-value = 0.001). The cut-off value for left atrial diameter was 59mm (sensitivity = 93.3%, specificity = 96.1%). Kaplan-Meier survival estimates were 175.07 days (156.3 - 193.9) for patients with left atrial diameter < 59mm and 62.64 days (26.6-98.7) for patients with left atrial diameter > 59mm. Conclusion: In patients undergoing mitral valve, we have experienced a significant higher degree of success associated with smaller left atrial diameter (less than 59.0 mm) in terms of conservation of the sinus rhythm post operatively. KEYWORDS Atrial fibrillation; Radio-frequency; Ablation; Left atrial diameter; Mitral valve Article History Submitted: 5 Dec 2018 Revised: 23 Dec 2018 Accepted: 19 Feb 2019 Published: 13 Mar 2019 https://doi.org/10.35810/ects.v1i1.23