(VT) a dangerously fast beating of the heart stemming from an abnormal focus of electrical activity in the ventricles. The electricity does not pass through the heart along the usual channels and as a result the contraction of the heart muscle is often not as efficient as normal, which can result in a sudden drop in blood pressure or even cardiac arrest. Left untreated it will prove ultimately fatal. See also arrhythmia, torsades de pointes.
Subjects: Medicine and Health.