Atrial Function After Ablation Procedure in Patients With Chronic Atrial Fibrillation Using Steady-State Free Precession Magnetic Resonance Imaging

Abstract

Surgical ablation procedures are an established surgical procedure for restoration of sinus rhythm and reestablishment of atrial function in patients with chronic atrial fibrillation. The purpose of this study was to evaluate the feasibility and reproducibility of steady-state free precession magnetic resonance imaging (SSFP MRI) for examination of atrial dimensions and function after ablation procedures. Nineteen patients (mean age, 63.1 +/- 11.7 years) being at least six months after surgical ablation procedure, with stable sinus rhythm, were selected for the study. They underwent cardiac MRI. End-diastolic and end-systolic volumes were measured using Simpson's rule. The presence of visual contraction was visually assessed. In MRI evaluation mean end-diastolic volume of the right atrium and left atrium after an ablation procedure was 127 +/- 45 mL and 163 +/- 50 mL, respectively. Mean stroke volume was 23 +/- 15 mL and 26 +/- 12 mL for the right and left atrium. Mean ejection fraction of the right atrium was 0.19 +/- 0.14 and 0.17 +/- 0.1 for the left atrium. An atrial kick of both atria was observed in 8 of 19 (47%) patients. An atrial kick of only the right atrium was observed in an additional 13 of 19 (68%) patients. The anticipated events after a surgical ablation procedure are the restoration of atrial contractility and the associated atrial kick, thereby enhancing cardiac output and decreasing the risk of thromboembolism. Evaluation of atrial function after an ablation procedure using SSFP MRI is feasible and allows a standardized documentation of postoperative atrial function, thus allowing evaluation of the surgical outcome in a reproducible way. Echocardiographic evaluation seems to underestimate the transport function of the atrium.