Ventricular tachycardia (VT) is a potentially life-threatening ventricular arrhythmia that presents as a wide QRS complex tachycardia, and is defined as three or more consecutive QRS complexes with a duration longer than 120 milliseconds (ms) and a rate of 100 beats per minute or more, whereby the complexes have a ventricular origin. VT can be subdivided as follows: (i) sustained VT persists for 30 seconds or more; (ii) non-sustained VT lasts less than 30 seconds; (iii) monomorphic VT displays a uniform QRS morphology; and (iv) polymorphic VT displays QRS morphologies that variy from beat to beat. VT is observed most commonly in individuals with structural heart disease or acute myocardial infarction (MI). VT may also be observed in in the setting of drug toxicity or electrolyte abnormalities or in individuals with Mendelian disease. [url:http://purl.obolibrary.org/obo/HP_0004756]