The onset mechanisms of ventricular tachycardia

Clinical and electrophysiological features of different initiation patterns of ventricular tachycardia (VT) have been widely studied. At least two different onset patterns of VT have been defined in the studies. Tachycardias, which are preceded by either a single or multiple ventricular ectopic activity, including a short-long-short sequence, are defined as nonsudden onset and those, which are not preceded by ventricular ectopy are defined as sudden onset. The knowledge of initiation pattern of VTs may have some clinical importance and can be essential for the selection of treatment strategies. The use of Holter electrocardiograms and analysis of intracardiac electrograms from implantable cardioverter-defibrillators enables to evaluate the initiation patterns of VTs.