External cardioversion of atrial fibrillation causes an early improvement of cardiac performance: A longitudinal strain analysis study

Introduction: Atrial fibrillation (AF) is often associated with heart failure. Several studies have demonstrated that resumption of sinus rhythm (SR) improves cardiac output in the long-term. Aims of this study were to evaluate the acute variations of left ventricular (LV) performance, following successful external cardioversion (ECV) of persistent AF using longitudinal strain (LSt) analysis, and the influence of inflammation. Materials and Methods: We enrolled 48 patients with AF (age: 73 ± 12 years, men: 83.3%). A standard transthoracic echocardiographic evaluation was performed before the procedure and 6 h later; this included the analysis of LV endocardial peak LSt, a measure of myocardial deformation. In the last 32 patients, plasma concentration of interleukin-6 (IL-6) was also determined. Results: Restoration of SR led to the decrease of heart rate (HR) (74 ± 21 vs 64 ± 10 bpm, P <0.001) and LV end-systolic volume (30 ± 16 vs 27 ± 17 mL/m², P = 0.001), and to the increase of LV end-diastolic volume (LVEDV) (56 ± 20 vs 60 ± 21 mL/m², P = 0.036) and ejection fraction (EF) (48 ± 10 vs 57 ± 11%, P <0.001). Peak LSt improved in 43 (89.6%) patients (-12.9 ± 3.3 vs -18.0 ± 4.7%, P <0.001). Multivariate analysis (R = 0.729, P <0.001) showed that strain changes were directly correlated with basal HR and the appearance of atrial mechanical activity and inversely correlated with corrected thyroid dysfunction, LVEDV and the presence of a permanent pacemaker. Higher levels of IL-6 negatively affected LV performance improvement. Conclusions: Effective ECV of AF determines a significant and fast improvement of LV performance, which is readily captured by LSt analysis. Inflammatory status may impact the response to SR restoration.