[Variations in QRS duration and axis with different sites and intervals of right ventricular pacing]. / Variazioni della durata e dell'asse del QRS con differenti siti ed intervalli di stimolazione in ventricolo destro.

BACKGROUND: The aim of this study was to achieve left ventricular resynchronization by means of right ventricular pacing. METHODS: We studied 12 patients (9 males, 3 females, mean age 61.7 +/- 19.5 years), with syncope, II degree atrioventricular block or ventricular arrhythmias, without intraventricular conduction disturbances. Single and dual site pacing, synchrony or at different delay, was made in the right ventricular, outflow tract from the apex, and midseptal areas. RESULTS: In all patients we obtained the shortest QRS duration with synchrony or delayed bisite pacing (standard ventricular apex pacing 170 +/- 20 ms; bisite pacing 137 +/- 13 ms). CONCLUSIONS: Our data demonstrate that appropriate right ventricular pacing can lead to left ventricular resynchronization.