Functional and structural response of the left atrium and left ventricle to successful cardioversion in atrial fibrillation

Abstract Background Electrical cardioversion (ECV) for atrial fibrillation (AF) restores sinus rhythm (SR), however, the extent and durability of changes in the left atrium (LA) and ventricle (LV) following cardioversion remain unclear. The aim of this study was to assess echocardiographic changes following successful ECV and to identify parameters that may predict the maintenance of SR. Methods Patients undergoing ECV were prospectively enrolled, with detailed echocardiographic data collected at three time points: before ECV, 24 hours and 30 days post-ECV. Statistical analyses included the Friedman test, Wilcoxon signed-rank test, and Mann–Whitney U test with Bonferroni correction. Effect sizes were assessed using Kendall’s W coefficient (W), effect size r, and eta-squared (η²). Results Out of the initial 94 patients (mean age 65.9 ±9.3 years; 69% male; 42.6% obese), SR was maintained in 76 patients at 24 hours and in 49 patients (52%) at 30 days post-ECV. Two patients were lost to 30-day follow-up. The most common comorbidities in the study group were hypertension (79.8%), heart failure (28.7%), and diabetes mellitus (28.7%). In patients with sustained SR, significant and lasting improvements were observed in both the LA and LV. These improvements were reflected in several parameters, including global atrioventricular strain (GAVS), LA reservoir strain (LASr), E/LASr ratio, LA emptying fraction (LAEF), LA stiffness index (LASI), LV ejection fraction (LVEF), LV global longitudinal strain (GLS LV), and LV global work index (GWI) (Table 1). Changes were evident at 24 hours and became more pronounced by day 30. Additionally, parameters assessable only during SR showed significant improvements between the 24-hour and 30-day post-ECV assessments. These included LA contraction strain (LASct), LA contraction strain index (CSI = LASct/LASr), A wave, E/A ratio, and lateral A’ wave (Table 2). In between-group analyses (patients with vs. without maintained SR), only LV parameters, including global wasted work (GWW), global work efficiency (GWE), LV systolic volume (LVESV), LV systolic diameter (LVSd), and GWI, demonstrated moderate effect sizes (η² = 0.05–0.08), indicating limited but potential predictive value for ECV success. Moreover, several of the parameters (such as LASr, E/LASr, GAVS, LASct, CSI, A wave, lateral A’ wave and E/A ratio) that exhibited the most pronounced changes following ECV (W or r ≥ 0.7) may reflect reverse atrioventricular remodeling. Conclusions Successful cardioversion results in significant and sustained improvements in both LA and LV structure and function. Interestingly, only parameters reflecting LV mechanics, but not LA function, were predictive of successful electrical cardioversion. Echocardiographic indices such as GWW, GWE, GWI, LVESV, and LVSd demonstrated notable improvements, and further studies are needed to verify their clinical value as potential predictors of cardioversion success and long-term SR stability.