Differential Recovery of Regional Atrial Contraction After Restoration of Sinus Rhythm After Intraoperative Linear Radiofrequency Ablation for Atrial Fibrillation

The aim of this study was to quantitate regional atrial contractility in patients with atrial fibrillation (AF) maintained in sinus rhythm after creating lines of block by intraoperative linear radiofrequency ablation for AF. We hypothesized that left atrial regional and global function remains impaired after radiofrequency ablation, despite restoration of sinus rhythm in this cohort. Patients with chronic AF maintained in sinus rhythm ≥6 months after radiofrequency ablation (n = 28) were studied and compared with a chronic AF group who, after standard electrical transthoracic cardioversion, were maintained in sinus rhythm for 6 months (n = 32) and a normal cohort (n = 32). Using color Doppler tissue imaging (CDTI), segmental atrial contraction was measured from annular, mid, and superior locations of the left atrium in both the apical 4- and 2-chamber views and of the right atrium in the apical 4-chamber view. Peak positive strain (SI) and atrial strain rate in early (E-sr) and late diastole (A-sr) were measured from mid and superior segments in both the apical 4- and 2-chamber views of the left atrium. The radiofrequency ablation group had significantly lower CDTI, SI, and A-sr values in all segments compared with both the cardioversion and normal groups. The cardioversion group had lower CDTI velocities than normal subjects. In the radiofrequency ablation group, CDTI velocities, SI, and A-sr values of the inferior and lateral segments were differentially and substantially lower than noted in other segments. In conclusion, patients with chronic AF have significant persistent left atrial dysfunction, despite restoration and maintenance of sinus rhythm. Additive global and regional atrial dysfunction was present in the radiofrequency ablation group suggestive of injury caused by the ablation process. These findings may have implications for selecting the duration of subacute and chronic anticoagulation after anatomic alteration of left atrial endocardium using radiofrequency ablation as a means of restoring sinus rhythm in chronic AF.