Impact of sinus rhythm restoration and maintenance on left ventricular function and exercise tolerance in patients with persistent atrial fibrillation.

BACKGROUND: Although early improvement of haemodynamic parameters following successful cardioversion of atrial fibrillation (AF) has been well documented, the long-term benefits of sinus rhythm (SR) restoration are less obvious, mainly due to a high rate of AF relapses.

AIM: To determine the impact of SR restoration and maintenance on exercise tolerance and heart failure progression in patients with persistent non-valvular AF during a one year follow-up period.

METHODS AND RESULTS: We studied 104 patients (33 females, 71 males, mean age 60.4+/-7.4 years) with mild to moderate stable heart failure and persistent AF with well-controlled ventricular rate who were scheduled for cardioversion. They underwent submaximal exercise testing 24 hours before cardioversion, as well as 1 and 12 months afterwards. Exercise capacity was determined during symptom-limited exercise testing, according to a modified Bruce protocol. Heart failure symptoms were assessed at the same time-points of follow-up.

RESULTS: SR was presented in 66 (63.5%) patients one year after cardioversion. In patients with SR, a significant improvement in left ventricular (LV) performance, exercise capacity and heart failure symptoms was noted. There was an increase in LV fractional shortening (29.9+/-7.6% vs 35.6+/-9.3%; p<0.001), maximal workload (4.7+/-2.3 vs 8.5+/-3.0 MET; p<0.001), exercise duration (125.3+/-115.3 vs 294.7+/-216.7 sec.; p<0.001), and improvement in the NYHA functional class (p<0.001). No such changes were observed in patients who had AF relapse during follow-up or in those who had unsuccessful cardioversion.

CONCLUSIONS: Successful cardioversion of persistent AF resulted in a significant improvement of exercise capacity and a decrease in heart failure symptoms during one year follow-up period only in patients who maintained SR.