Programmed ventricular stimulation required 1-2 premature beats to initiate arrhythmias in 88% of prior-VT patients, whereas 70% of non-VT patients required 3-4 beats.
Observational (n=102)
Nonsustained polymorphic ventricular tachycardia and ventricular fibrillation induced by aggressive stimulation protocols (3-4 extrastimuli) are nonspecific responses rather than clinically relevant arrhythmias.
Absolute Event Rate: 88% vs 59.6%
An increasing number of premature ventricular stimuli are being used during programmed stimulation of the heart in the investigation of patients with documented or suspected ventricular arrhythmias. To analyze the significance of the different types of ventricular arrhythmias that are initiated, we evaluated in a prospective study the effect of from one to four ventricular premature stimuli in 52 patients without (non-VT group) and 50 patients with (prior-VT group) documented ventricular tachycardia or ventricular fibrillation. More than half of the patients in the prior-VT group had coronary heart disease. In the majority of patients of the non-VT group the heart was normal. In 44 of the 50 patients in the prior-VT group the clinically documented ventricular arrhythmia was initiated by programmed ventricular stimulation of the heart. In 88% of these 44 patients, one or two ventricular premature beats were required to initiate the clinical arrhythmia. A ventricular arrhythmia could be initiated in 31 of the 52 patients in the non-VT group. The ventricular arrhythmias included nonsustained monomorphic ventricular tachycardia (two patients), six to 25 complexes of sustained polymorphic ventricular tachycardia (24 patients), and ventricular fibrillation (five patients). In 70% of patients in the non-VT group three or four ventricular premature beats were required to initiate the ventricular arrhythmia. Our results indicate that not only the number of extrastimuli required to initiate ventricular arrhythmias but also the type of ventricular arrhythmia initiated differed between the two groups of patients. Nonsustained polymorphic ventricular tachycardia and ventricular fibrillation are nonspecific responses to aggressive stimulation protocols.
Brugada et al. (1984) conducted an observational in Ventricular arrhythmias (n=102). Programmed ventricular stimulation vs. Patients without prior ventricular tachycardia or fibrillation was evaluated on Initiation of ventricular arrhythmias. Programmed ventricular stimulation required 1-2 premature beats to initiate arrhythmias in 88% of prior-VT patients, whereas 70% of non-VT patients required 3-4 beats.