NCIt definition : A disorder characterized by an electrocardiographic finding of a rapid grossly irregular
ventricular rhythm with marked variability in QRS cycle length, morphology, and amplitude.
The rate is typically greater than 300 bpm. (CDISC);
Alternative definition : NICHD: An irregular heart rhythm, usually associated with a rapid rate, that is caused
by abnormal electrical activity within the ventricles.; FDA: Arrhythmia characterized by chaotic contractions of the ventricular muscle.; CDISC: Ventricular Fibrillation is characterized by rapid, usually more than 300 bpm
(cycle length: 180 ms or less), grossly irregular ventricular rhythm with marked variability
in QRS cycle length, morphology, and amplitude.; CTCAE: A disorder characterized by a dysrhythmia without discernible QRS complexes
due to rapid repetitive excitation of myocardial fibers without coordinated contraction
of the ventricles.;