When and how does a single ventricular premature beat initiate and terminate supraventricular tachycardia?

Background: The differential diagnosis of a supraventricular tachycardia (SVT) is accomplished using a number of pacing maneuvers. The incidence and mechanism of a single ventricular premature beat (VPB) on initiation and termination of tachycardia were evaluated during programmed electrical stimulation (PES) of the heart in patients with the two most common regular SVTs: atrioventricular re-entrant tachycardia (AVNRT) and orthodromic atrioventricular tachycardia (AVRT).

Methods: Three hundred and thirty-seven consecutive patients aged above 18 years with an inducible sustained AVNRT or AVRT were prospectively enrolled.

[Results of intraventricular resynchronization in patients with severe cardiac failure].

Background: Intraventricular resynchronization with pacemakers is a promising therapy for patients with refractory cardiac failure and intraventricular conductions delay. However its long term effects are not well known.

Aim: To report the results of this therapy in patients with cardiac failure.

[Focal atrial fibrillation. Clinical characteristic and results of radiofrequency ablation].

Background: Atrial fibrillation can originate in arrhythmogenic foci coming from the pulmonary veins. Patients with atrial fibrillation, initiated from triggering foci, can be treated with radiofrequency ablation.

Aim: To report the results of radiofrequency ablation in patients with focal atrial fibrillation.