Ventricular Tachycardia (VT, V Tach)

Ventricular tachycardia is characterized as a wide complex (QRS duration greater than 120 milliseconds) tachyarrhythmia at a heart rate greater than 100 beats per minute. It is classified by duration as non-sustained or sustained. Non-sustained ventricular tachycardia is defined as more than 3 beats of ventricular origin at a rate greater than 100 beats per minute that lasts less than 30 seconds in duration.[1] When the rhythm lasts longer than 30 seconds or hemodynamic instability occurs in less than 30 seconds, it is considered sustained ventricular tachycardia.[1] Further classification is made into monomorphic and polymorphic on the basis of QRS morphology. Monomorphic ventricular tachycardia demonstrates a stable QRS morphology from beat to beat while polymorphic ventricular tachycardia has changing or multiform QRS variance from beat to beat.[1] Torsades de pointes is a polymorphic ventricular tachycardia that occurs in the setting of a long QT interval and appears as waxing and waxing QRS amplitude on ECG.[1] The final form of ventricular tachycardia is bidirectional ventricular tachycardia which has a beat-to-beat alternation in the QRS frontal plane axis.[1] It is associated with digitalis toxicity or catecholaminergic polymorphic VT. The most common cause of VT is ischemic heart disease.