His and para-His pacing in AV block: feasibility and electrocardiographic findings

Right ventricular apical pacing induces a dyssynchronous activation of the left ventricle and is associated with adverse clinical outcome. We aimed to establish permanent His-bundle pacing or para-His pacing in patients with high-grade atrioventricular (AV) block. We included patients with pacemaker indication due to second- or third-degree AV block, left ventricular ejection fraction > 0.40, QRS duration < 120 ms, and sinus rhythm. All patients received a pacemaker with one atrial lead, one right ventricular mid-septal lead, and one lead in the His bundle or in the para-His position. Pacing from apex was performed temporarily. Patients were followed for 12 months. Thirty-eight patients were included (mean age, 67 +/- 10 years; 30 (79%) male). Mean implantation time was 85 +/- 31 min, mean fluoroscopy time was 23 +/- 13 min, and mean position attempts of the His bundle lead was 8 +/- 5. In four patients, we established direct His-bundle pacing with a mean QRS of 100 +/- 19 ms, and in 28 patients, para-His pacing was achieved with a mean QRS of 112 +/- 18 ms, and in six patients, neither direct His-bundle pacing or para-His pacing could be achieved. The mean QRS duration was 153 +/- 12 ms with mid-septal pacing and 161 +/- 15 ms with apical pacing. Stable direct His-bundle pacing or para-His pacing is feasible in 85% of patients with narrow QRS and high-grade AV block and leads to a normal or near-normal ventricular activation pattern.