Left Ventricular Mechanics Are Associated with Short-Term Sinus Rhythm Maintenance After Electrical Cardioversion in Atrial Fibrillation

(1) Background: Electrical cardioversion (ECV) is effective in restoring sinus rhythm (SR) in atrial fibrillation (AF), but the extent of atrioventricular remodeling and determinants of short-term rhythm maintenance remain unclear. This study evaluated echocardiographic changes following ECV and explored parameters associated with SR persistence. (2) Methods: We prospectively enrolled 94 patients undergoing elective ECV and performed comprehensive echocardiography before, 24 h after, and 30 days after the procedure. Rhythm status was assessed at scheduled follow-up visits. Due to the limited sample size, failure to meet the assumptions required for regression analyses, and non-normal data distributions, the analyses were primarily non-parametric and exploratory. (3) Results: Among 94 patients (mean age 65.9 +/− 9.3 years; 69% male), SR was maintained in 76 patients at 24 h and 49 patients at 30 days. Patients with sustained SR showed progressive improvement in LA reservoir strain, LA emptying fraction, and LA stiffness index, consistent with reverse atrial remodeling. Left ventricular (LV) function also improved, including LV ejection fraction, global longitudinal strain, and myocardial work indices. Between-group analyses identified several baseline LV parameters (including global wasted work, global work efficiency, LV end-systolic volume, LV end-systolic diameter, and global work index) with moderate effect sizes and possible association with short-term SR maintenance. (4) Conclusions: Successful ECV is associated with significant short-term atrioventricular functional improvement. In this exploratory single-center cohort, selected LV mechanical parameters were associated with short-term SR maintenance, while LA functional parameters mainly reflected reverse remodeling after rhythm restoration. Larger studies with longer follow-up and adjusted analyses are needed.