Subcostal M-mode echocardiography of the right atrial wall for differentiation of supraventricular tachyarrhythmias with aberration from ventricular tachycardia.

Atrial contractions can be reliably detected by subcostal M-mode echocardiography of the right atrial wall. Recognition of various rhythm disturbances, especially tachyarrhythmias, is facilitated in the simultaneously recorded nondiagnostic ECG. Differentiation between supraventricular tachycardias with aberration and ventricular tachycardia with atrioventricular dissociation is alleviated. However, this technique is of limited value in the diagnosis of ventricular tachycardia with retroconduction and is not useful in differentiating supraventricular tachycardias with wide QRS from ventricular tachycardia when atrial fibrillation coexists.