Regular wide-complex tachycardia can be either ventricular tachycardia or supraventricular tachycardia. Ventricular tachycardia originates from the left ventricle, the left ventricular outflow tract, the right ventricle or the right ventricular outflow tract.
A wide complex tachycardia (WCT) is simple enough to define: a cardiac rhythm with a rate >100 beats per minute and a QRS width >120 milliseconds (ms).
If the QRS duration is normal (<0.12 seconds), the arrhythmia is said to be a narrow complex tachycardia (NCT). If the QRS duration is prolonged (≥0.12 seconds), the arrhythmia is a wide complex tachycardia (WCT). This initial distinction will guide the rest of the thinking needed to arrive at a final diagnosis.
ICD-10 | Ventricular tachycardia (I47. 2)
Wide QRS complex tachycardia can be originated by 3 main mechanisms1: Ventricular tachycardia (VT). Supraventricular tachycardia (SVT) with an aberrant conduction attributable to a preexisting bundle-branch block or functional bundle-branch block induced by the fast heart rate.
Wide Complex Tachycardia: Definition of Wide and Narrow. Aberrancy, ventricular tachycardia, supraventricular tachycardia, right-bundle branch block (RBBB), left-bundle branch block (LBBB), intraventricular conduction delay (IVCD), pre-excited tachycardia.
Supraventricular tachycardias are usually narrow-complex tachycardias with a QRS interval of 100 ms or less on an electrocardiogram (ECG). Occasionally, they may show a wide QRS complex in the case of a pre-existing conduction delay, an aberrancy due to rate-related conduction delay or a bundle branch block.
The ECG shows a regular wide complex tachycardia with a left bundle-branch block configuration, northwest axis, and a negative concordance in precordial leads. High in the differential is atrial flutter, an arrhythmia often facilitated by flecainide.
We present a case of a patient presenting with narrow-complex tachycardia that was initially treated as supraventricular tachycardia, but later recognized and treated as ventricular tachycardia (VT).
Wide complex tachycardia is a dysrhythmia with a long list of potential causes that ranges from various arrhythmias, structural heart abnormalities, electrolyte disturbances, toxins, and many more.