Right ventricular pacing (RVP) induces ventricular asynchrony in patients with normal QRS and increases the risk of heart failure and atrial fibrillation on long term. His bundle pacing (HBP) is a physiological alternative to RVP. Observational studies have demonstrated the feasibility of this technique. However, it is associated with longer procedure time and higher fluoroscopy exposure compared to standard pacemaker implantation.

We evaluated the possibility to guide the His Bundle (HB) lead placement using HB unipolar mapping only, in an attempt to reduce radiation exposure.

From October 2019 to January 2020, all consecutive patients candidates for HBP in our institution underwent pacemaker implantation using mainly unipolar mapping of the His bundle for lead placement. The pacing lead was delivered through a fixed curve sheath. His bundle electrogram was mapped with the pacing lead and directly recorded on both EP recording system and Medtronic pacing analyser.

Thirty-nine patients were implanted according to this new approach. Sixteen patients (41%) had a dual chamber pacemaker implantation. HBP was successful in all patients. Selective HBP was obtained in 25 patients (64%) while non-selective HBP occurred in 14 patients (36%). His Bundle signal was successfully detected with the pacing lead during all procedures. The overall procedure fluoroscopy duration, including the atrial lead implantation, was 48±54sec and the mean radiation exposure was 0.34±0.57Gy.cm². The mean procedure duration was 48.4±15.6min. The mean His Bundle capture threshold at implant was 1.36±0.71V@0.5ms. There was no pericardial effusion, no pneumothorax and no early lead dislodgment (Fig. 1).

His Bundle lead placement mainly using HB unipolar mapping was feasible and effective and was associated with very limited radiation exposure without compromising procedure duration.