Objectives: To determine if restoration of sinus rhythm in patients with atrial fibrillation decreases atrial size, 16 patients undergoing elective cardioversion were prospectively studied. The frequent coexistence of atrial fibrillation and atrial dilation is well recognized. Recent data have demonstrated that atrial enlargement may be the result, rather than the cause, of atrial fibrillation.
Design: Echocardiographic examinations were performed before cardioversion, and at 24 h, three and six months of follow-up. Atrial dimensions were assessed in multiple orthogonal imaging planes and atrial volume was calculated using an ellipsoid formula.
Setting: A tertiary care university teaching hospital.
Patients: All patients admitted to hospital between June 1989 and June 1990 for elective cardioversion were considered for enrollment. Informed consent was obtained in all cases. Patients were excluded if echocardiographic images were technically inadequate or reversion to normal sinus rhythm was not achieved. Twenty-five patients were considered for inclusion. The final study population consisted of 16 patients. Complete follow-up data were obtained in 10 cases.
Main results: Conversion to sinus rhythm resulted in a decrease in mean left atrial volume from 38.5 cm3 to 34.2 cm3 (P < 0.01) at 24 h, 21.7 cm3 (P < 0.02) at three months and 19.6 cm3 (P < 0.02) at six months. Mean right atrial volume decreased from 33.4 cm3 to 29.4 cm3 (P < 0.01) at 24 h, 19.1 cm3 (P < 0.02) at three months and 16.3 cm3 (P < 0.02) at six months of follow-up.
Conclusions: Conversion from atrial fibrillation to sinus rhythm results in a significant decrease in both left and right atrial volumes.