Efficacy of Electrical Cardioversion in Relation to Occurrence and Type of Functional Mitral Regurgitation in Patients with Atrial Fibrillation.

Background: Recent studies have changed the perception of rhythm control in the treatment of atrial fibrillation (AF). Functional mitral regurgitation (fMR) can be both a cause and a consequence of AF and may influence rhythm restoration procedures. Materials and methods: A retrospective analysis included 182 consecutive patients with AF on optimal medical therapy (OMT) undergoing electrical cardioversion (CVE). Based on transthoracic echocardiography, the study group was divided into 20 (11%) patients without mitral regurgitation (MR) and 132 (82%) with fMR 77 (58%) with atrial fMR (afMR; left ventricle ejection fraction (LVEF) ≥ 50%, left atrial (LA) dilatation) and 55 (42%) and with ventricular fMR (vfMR; LVEF < 50%). Patients with severe and organic MR were excluded from the study. Results: vfMR patients had a greater incidence of kidney failure (p = 0.01) and coronary heart disease (p = 0.02); more frequent use of diuretics during hospitalization (p < 0.01); greater LA diameter and area (p < 0.01; p < 0.01) than afMR patients. CVE efficiency was high in all four groups (84−95%). The presence and type of fMR did not affect the efficacy of CVE (p = 0.2; p = 0.9) and did not require the use of more energy (p = 0.4; p = 0.8). The independent predictor of successful CVE was the amount of white blood cells (OR 0.74, p < 0.05). Conclusions: Efficacy of CVE is high among AF patients on OMT regardless of the incidence and type of fMR. Subclinical inflammation should be excluded before elective CVE because it may decrease its efficacy.