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