Prognosis in patients with intra-Hisian conduction disturbances.

Intra-Hisian delay is usually associated with fascicular conduction abnormalities. We report our experience in 23 patients who had intra-Hisian delay as their only conduction defect. First-degree intra-Hisian delay (His bundle deflection greater than or equal to 30 msec) was present in 17 patients, 5 of whom also had split His potentials. Three of these patients received permanent pacemakers, all of whom had a history of syncope. Higher degrees of intra-Hisian delay were observed either spontaneously or in response to atrial pacing in 6 patients. Five of these patients were treated with permanent pacing, 4 of whom had symptomatic bradyarrhythmias and/or syncope. No patient has had a recurrence of symptoms following pacemaker insertion during the mean 31-month follow-up. No patient with first-degree intra-Hisian delay not receiving a pacemaker developed symptomatic bradyarrhythmias or syncope during a mean follow-up of 21 months.