Ventricular tachycardia

Ventricular tachycardia is defined as 3 or more consecutive premature ventricular complexes. It is abrupt in onset and termination. The rate is typically 140 to 200 beats per minute, with QRS complexes that are wide (usually greater than 0.14 seconds), different from the sinus QRS complexes, and not preceded by a P wave. AV dissociation is common, although not obvious in our case. The mechanism may be either enhanced automaticity or reentry. Differentiation of these mechanisms is difficult, but the abrupt onset faster wide QRS tachyarrhythmias are typically reentry and the slower ventricular arrhythmias (e.g, accelerated ventricular rhythm) are usually due to enhanced automaticity. Ventricular tachycardia, particularly the more rapid variety is a potentially lethal arrhythmia and can be symptomatic, cause hemodynamic compromise, or deteriorate into ventricular fibrillation. It demands careful clinical evaluation. The following animation illustrates what we have just described.

Animation