CLINICAL DIFFERENTIATION OF NARROW QRS COMPLEX TACHYCARDIAS

Supraventricular tachycardias (SVTs) generally present with "narrow" (or normal) QRS complexes, unless aberrantly conducted, and are commonly seen in the emergency department (ED). Narrow QRS complex tachycardia is defined as a heart rate faster than 100 bpm with a QRS duration shorter than 0.12 seconds, or 120 msec. Narrow QRS complex tachycardias are common and occur in all age groups. Their clinical presentation is variable; they can be scarcely perceptible or result in syncope or congestive heart failure. The urgency and choice of clinical management is based on the hemodynamic assessment and understanding of the tachycardia mechanism. This article provides a diagnostic approach to the patients presenting with regular narrow QRS complex tachycardias.