Differential diagnosis of wide QRS tachycardias.

This article has reviewed the differential diagnosis of wide QRS tachycardia. We have found the stepwise approach suggested by Brugada to be very useful. Of the newer criteria that he proposes, the R to S interval of > 100 ms. appears to be a particularly helpful clue favoring the diagnosis of ventricular tachycardia. Hemodynamic stability, young age, 1:1 AV association, and the absence of structural heart disease do not exclude a diagnosis of ventricular tachycardia. Most wide QRS tachycardias in adults are ventricular, and when all else fails, one will be right more often than not in favoring this as the diagnosis over supraventricular tachycardia with aberrancy. The R to S interval is measured in the precordial (V) leads from the onset of the R wave to the deepest part of the S wave. A value > 100 ms. in any V lead strongly favors ventricular tachycardia. Example is from Case 1 (upper tracing is V1).