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 echocardiography, the authors describe the cardiac anatomy observed in hospitalized patients with MAT. Because MAT closely resembles atrial fibrillation (AF), these echocardiographic data are compared with those from 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 significantly less in the MAT group. The MAT group had normal ventricular and aortic 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 wall-motion abnormalities were significantly less in the MAT group. Severe Doppler and structural abnormalities were not common in the MAT group. Based on these parameters, physiologic and not anatomic factors are probably more important in the genesis of MAT as compared with AF.