New echocardiographic observations in a patient with dissimilar atrial rhythms.

A patient with an impure flutter was found to have dissimilar atrial rhythms that were confirmed by direct ECG recordings. Echocardiographic studies disclosed that the a waves on the mitral echocardiogram occurred synchronously with the a waves on the esophageal ECG that, in turn, showed atrial flutter at a rate of 300 beats per minute. However, the a waves on the tricuspid echocardiogram coincided closely with the P waves on a surface ECG (lead V) that disclosed a chaotic atrial tachyarrhythmia. These results suggest that echocardiographic study, in conjunction with an esophageal ECG, may be a useful, noninvasive technique for the diagnosis of dissimilar atrial rhythms.