ECHOCARDIOGRAPHIC ANALYSIS OF LEFT ATRIAL SIZE BEFORE AND AFTER OPERATION IN MITRAL-VALVE DISEASE

Left atrial dimensions were determined with M mode echocardiography in 39 patients with mitral valve disease before and a mean of 13 months after mitral valve surgery to assess the relations of left atrial size to postoperative clinical course, appearance and refractoriness of atrial fibrillation and the occurrence of systemic emboli. Clinical improvement in 25 patients postoperatively was associated with a decrease in left atrial dimension (mean decrease 19 percent), whereas 14 patients with persistent cardiac decompensation due to either myocardial or postoperative valve dysfunction had no decrease in left atrial dimension (mean increase 2 percent, P < 0.001). Preoperative left atrial dimension was greater in 18 patients with chronic atrial fibrillation (mean 58 mm) than in 15 patients with sinus rhythm (mean 47 mm, P < 0.005). The success or failure of postoperative conversion of atrial fibrillation was related, among other factors, to postoperative left atrial dimension. In eight patients with preoperative systemic emboli (seven with atrial fibrillation), mean left atrial dimension (57 mm) was larger than in patients with sinus rhythm with no emboli (mean 45 mm, P < 0.002). Emboli were not more common in patients with atrial fibrillation and a very large left atrium (60 to 80 mm) than in patients with atrial fibrillation and less left atrial enlargement (45 to 60 mm). Of patients with atrial fibrillation and a cardiac index of less than 2.0 liters/min per m2, 50 percent had emboli compared with only 10 percent of those with a cardiac index greater than or equal to 2.0 liters/min per m2 (P < 0.007). In patients with mitral valve disease, left atrial dilatation predisposes to atrial fibrillation and thus to systemic emboli. In patients with established atrial fibrillation, left atrial size alone fails to predict the likelihood of emboli; however, patients with a low cardiac output and atrial dilatation are particularly at risk for emboli and warrant especially strong consideration for prophylactic anticoagulation. © 1979.