ECHOCARDIOGRAPHIC ASSESSMENT OF THE CARDIAC ANATOMY IN PATIENTS WITH MULTIFOCAL ATRIAL TACHYCARDIA - A COMPARISON WITH ATRIAL-FIBRILLATION

Although multifocal atrial tachycardia (MAT) has been recognized since 1968, few data exist on its associated anatomic correlates. Using ech ocardiography, the authors describe the cardiac anatomy observed in ho spitalized patients with MAT. Because MAT closely resembles atrial fib rillation (AF), these echocardiographic data are compared with those f rom an age- and sex-matched population with AF. There were 25 patients in each of the MAT and AF groups. Biatrial enlargement was present in both groups. However, the atrial enlargement was mild and significant ly less in the MAT group. The MAT group had normal ventricular and aor tic dimensions. Right ventricular dysfunction was rare in both groups. Moderate to severe global left ventricular dysfunction was present in 7 of 25 in the MAT group and in 9 of 25 in the AF group. Systolic wal l-motion abnormalities were significantly less in the MAT group. Sever e Doppler and structural abnormalities were not common in the MAT grou p. Based on these parameters, physiologic and not anatomic factors are probably more important in the genesis of MAT as compared with AF.