LAUSR

Type of funding sources: None. Electrical cardioversion is an effective therapy for the restoration of sinus rhythm. The success of cardioversion has been related to different clinical and echocardiographic variables, although the available evidence is scarce and heterogeneous. Ambispective, observational, single-center registry that consecutively included 271 patients scheduled for elective electrical cardioversion (ECV) on the inpatient ward for atrial fibrilation (AF) or flutter fibrilation (AFL) >48 hours of onset during the years 2018-2021. All patients scheduled for CVE that were ultimately discontinued on the day of the procedure were excluded, finally analyzing 244 patients. The baseline characteristics are shown in Picture 1. No statistically significant differences were observed in the main comorbidities, cardiovascular risk factors, CHAD2S2-VASc scale, the position of the paddles, or days to ECV between patients with successful ECV and those with a failed procedure. Neither were they observed in terms of pharmacological treatment, including the presence of previous antiarrhythmic treatment as part of a facilitated ECV strategy (Picture 2). Moderately-severely depressed systolic function and the presence of moderate-severe mitral regurgitation were associated with a higher rate of cardioversion failure (3% vs 2.6% p= 0.002; 3.3% vs 1.3% p=0.001), higher number of biphasic electric shocks (1.3 vs 1.6 p<0.001; 1.2 vs 1.6 p<0.001) and higher total voltage received (245J vs 310J p=0.32; 229J vs 325J p<0.001). Moderate-severe tricuspid regurgitation was also associated with lower cardioversion success rate (96.7% vs 85% p=0.02) although no differences were seen with respect to the number of shocks or energy received. On the other hand, severe left atrial dilatation, although it had a neutral impact on the success of ECV, was associated with greater immediate recurrence (<5 minutes after ECV) (4.2% vs 50% p<0.001). Patients with moderate-severe systolic dysfunction and significant mitral and tricuspid regurgitation have a lower success rate of ECV. Previous antiarrhythmic therapy presents a neutral effect on sinus rhythm restoration and immediate recurrence.