HETEROGENEITY AND TIME-COURSE OF IMPROVEMENT IN CARDIAC-FUNCTION AFTER CARDIOVERSION OF CHRONIC ATRIAL-FIBRILLATION - ASSESSMENT OF SERIAL ECHOCARDIOGRAPHIC INDEXES

Objective-To assess the clinical characteristics of patients in whom c ardiac function improved after cardioversion of atrial fibrillation an d the time course of the improvement. Design-A prospective serial stud y of echocardiograms recorded before cardioversion and one day, seven days, one month, and three months after cardioversion.Setting-Echocard iography laboratory of a university hospital. Patients-23 patients wit h chronic atrial fibrillation in whom cardioversion was successful. Ma in outcome measures-M mode indices of the left ventricular wall motion and pulsed Doppler indices of the left ventricular inflow. Results-Th ree months after cardioversion percentage fractional shortening had in creased by more than 5% in 14 patients (improved group) and by less th an 5% in nine patients (non-improved group). Those in whom cardiac fun ction improved had significantly higher heart rates and a greater redu ction in ventricular filling during atrial fibrillation and a more pro minent atrial filling wave three months after cardioversion than those patients in the non-improved group. Over the three months of follow u p the mean (1SD) percentage fractional shortening increased from 22 (3 )% to 30 (4)% in the improved group and in this group heart rate fell one day after cardioversion. A month after cardioversion the percentag e fractional shortening had increased to 35 (5)% and the atrial systol ic contribution to left ventricular filling increased from 30 (9)% on day 1 to 47 (12)%. Conclusions-Cardioversion improved cardiac function in patients with tachycardia and reduced ventricular filling during a trial fibrillation. Because both an immediate reduction of heart rate and a delayed recovery of atrial booster pump function played an impor tant part in the improvement of cardiac function the long-term effects of cardioversion should be assessed at least a month after cardiovers ion.