Limited left atrial surgical ablation effectively treats atrial fibrillation but decreases left atrial function

Left Atrial Function after Atrial Fibrillation Cryoablation Concomitant to Minimally Invasive Mitral Valve Repair: A Pilot Study on Long-Term Results and Clinical Implications

Background and Objectives: Surgical atrial fibrillation (AF) ablation concomitant to minimally invasive mitral valve repair has been proven to offer improved short- and long-term sinus rhythm (SR) maintenance compared to mitral valve surgery only. The objective of the present study was to explore, by thorough echocardiographic assessment, long-term morphological and functional left atrial (LA) outcomes after this combined surgical procedure. Materials and Methods: From October 2006 to November 2015, 48 patients underwent minimally invasive mitral valve repair and concomitant surgical AF cryoablation. Results: After 3.8 ± 2.2 years, 30 (71.4%) of those completing the follow-up (n = 42, 87.5%) presented SR. During follow-up, four (9.5%) patients suffered from cerebrovascular accidents and two of these subjects had a long-standing persistent AF relapse and were in AF at the time of the event, while the other two were in SR. An echocardiographic study focused on LA characteristics was performed in 29 patients (69.0%). Atrial morphology and function (e.g., maximal LA volume indexed to body surface area and total LA emptying fraction derived from volumes) in patients with stable SR (60.6 ± 13.1 mL/mq and 25.1 ± 7.3%) were significantly better than in those with AF relapses (76.8 ± 16.2 mL/mq and 17.5 ± 7.4%; respectively, p = 0.008 and p = 0.015). At follow-up, patients who suffered from ischemic cerebral events had maximal LA volume indexed to body surface area 61 ± 17.8 mL/mq, with total LA emptying fraction derived from volumes 23.6 ± 13.7%; patients with strokes in SR showed very enlarged LA volume (>70 mL/mq). Conclusions: AF cryoablation concomitant with minimally invasive mitral valve repair provides a high rate of SR maintenance and this relates to improved long-term morphological and functional LA outcomes. Further prospective studies are needed to define the cut-off values determining an increase in the risk for thromboembolic complications in patients with restored stable SR.

Left atrial function after epicardial pulmonary vein isolation in patients with atrial fibrillation

Purpose

Epicardial pulmonary vein isolation has become an increasingly used therapy for medically resistant atrial fibrillation. The purpose of the present study was therefore to evaluate if epicardial pulmonary vein isolation combined with ganglionated plexi ablation affects the size and mechanical function of the left atrium, and whether the effects are dependent on the extensiveness of the ablation applications.

Methods

A total of 42 patients underwent an echocardiographic examination prior to and 6 months after a minimal invasive epicardial pulmonary vein isolation procedure for the assessment of the effects on left atrial size and function. In 27 patients, who had sinus rhythm both at baseline and follow-up, was a comparison of atrial size and function possible at these time intervals. Fractional area changes were obtained from the left atrial end-systolic and end-diastolic areas in the apical four-chamber view. Pulsed-Doppler was used to assess the transmitral flow velocities to evaluate mechanical function.

Results

Left atrial size and function at 6-month follow-up had not changed significantly from those at baseline as indicated by left atrial maximal area (17.1 ± 4.6 vs. 18.7 ± 5.3, p = 0.118), minimal area (12.5 ± 3.8 vs. 13.4 ± 4.7, p = 0.248), fractional area change (27.4 ± 8.2 vs. 28.7 ± 10.6, p = 0.670), and E/A ratio (1.49 ± 0.47 vs. 1.54 ± 0.67, p = 0.855).

Conclusions

Radiofrequency ablation for epicardial pulmonary vein isolation combined with ganglionated plexi ablation has no major effects on atrial function or size. A preserved atrial function for those maintaining sinus rhythm may have important implications for thromboembolic risk after surgery, but warrants confirmation in larger trials.