Serial evaluation of left atrial dimension after cardioversion for atrial fibrillation and relation to atrial function

The sire of the left atrium is usually increased during atrial fibrillation (AF). The aim of the present study was to evaluate changes in left atrial (LA) dimension after cardioversion for AF, and the relation between LA dime nsion and atrial function. The initial study population included 171 consec utive patients. Patients who had spontaneous cardioversion to sinus rhythm (56 patients) were compared with patients who had random cardioversion with drugs (50 patients) or direct-current (DC) shock (50 patients]. Echocardio graphic evaluations included LA size and volume. LA passive and active empt ying volumes were calculated, and LA function was assessed. Atrial stunning was observed in 18 patients reverted with DC shock and in 7 patients rever ted with drugs. The left atrium was dilated in all patients during AF (48 /- 5 mm). The size of the left atrium decreased after restoration of sinus rhythm in all patients with spontaneous reversion to sinus rhythm, in 73% o f patients reverted with drugs, and in 50% of patients reverted with DC sho ck. The comparison between patients with a normal mechanical atrial functio n and patients with reduced atrial function showed that a higher atrial eje ction force was associated with a more marked reduction in LA sire after re storation of sinus rhythm. A relation between LA volumes and atrial electio n force was observed in the group of patients with depressed atrial mechani cal function [r = -0.78; p <0.001). The active emptying fraction was lower, although not significantly, in this group, whereas the conduit volume was increased. Thus, a depressed atrial mechanical function after cardioversion for AF was associated with a persistence of LA dilation. (C) 2000 by Excer pta Medica, Inc.