Ventricular tachycardia

A 69 year old man 2 weeks after an inferior myocardial infarction

A wide QRS tachycardia is VT until proven otherwise (1). Features suggesting VT include:-

• evidence of AV dissociation
  • independent P waves
  • capture or fusion beats
  • beat to beat variability of the QRS morphology (shown here)
• very wide complexes (> 140 ms)
• the same morphology in tachycardia as in ventricular ectopics
• history of ischaemic heart disease
• absence of any rS, RS or Rs complexes in the chest leads (2)
• concordance (chest leads all positive or negative)

1) Griffith MJ, Garrat CJ, Mounsey P, Camm AJ. Ventricular tachycardia as the default diagnosis in broad complex tachycardia. Lancet. 1994;343:386-
2) Brugada P, Brugada J, Mont L, et al. A new approach to the differential diagnosis of a regular tachycardia with a wide QRS complex. Circulation. 1991;83:1649-1659

N.B. The computer-aided diagnosis can often be misleading.