The acute effects of external cardioversion of atrial fibrillation on left ventricular performance. A preliminary report using a traditional and a new echocardiographic evaluation tool

Purpose: Atrial fibrillation (AF) is the most frequent arrhythmia met in everyday practice. AF is often associated with the development of signs and symptoms of heart failure. The aim of this study was to evaluate the acute effects on left ventricular (LV) performance of sinus rhythm restoration in patients with persistent AF. Methods: Between January and May 2010, we enrolled all the consecutive patients admitted in a Day-Hospital regimen to undergo external electrical cardioversion (ECV) of AF. A transthoracic echocardiographic evaluation was performed before the induction of general anesthesia (sodium thiopental or propofol), at 9 a.m. (Baseline, B), and 6 hours later (6 h), at 3 p.m., before the discharge from hospital. All echocardiograms were executed with a MyLab30Gold echo machine (Esaote SPA, Florence, Italy). Besides the standard assessment, for each patient we evaluated also the longitudinal strain, a parameter which provides a measure of myocardium total deformation during the contraction process (expressed as %). To this purpose, at least one high-quality bidimensional cine-loop recording of an apical 4-chamber view had to be stored for off-line analysis with a dedicated software (XStrain™ tissue tracking software: Esaote SpA, Florence, Italy). Results: Of the 20 patients who underwent ECV, 3 were excluded from the study (2 for a not adequate acoustic window, 1 for medical reasons). In the 17 remaining patients (mean age: 76±8 years, men: 82.4%, body weight: 76±18 Kg, height: 168±7 cm), a stable sinus rhythm was obtained. After 6 hours from ECV, in front of similar values of heart rate (B: 68±19 vs. 6 h: 63±9 b/min, p=0.248) and of end-diastolic volume (B: 106±38 vs. 6 h: 105±35 mL, p=0.765), it was possible to observe: 1) the re-appearance of an atrial mechanical activity in 15/17 patients (88.2%); 2) a decrease, even if not significant, of end-systolic volume (B: 55±26 vs. 6 h: 48±28 mL, p=0.080); 3) a significant increase of LV ejection fraction (LVEF; B: 50±10 vs. 6 h: 57±10%, p < 0. 001) and of longitudinal strain (B: -13.5±3.5 vs. 6 h: -16.6±4.6%, p=0.001). The improvement of LVEF and of longitudinal strain was present in 14/17 (82.3%) patients. Conclusions: An effective ECV of a persistent AF, with the achievement of a stable sinus rhythm, seems to produce a significant improvement of LV performance after only 6 hours from the procedure. Standard and new echocardiograpic techniques are consistent with these findings and may help to clarify the complex interaction between heart failure and AF.