His-bundle Pacing vs. Right Ventricular Apical Pacing in Patients With Reduced Ejection Fraction (HIS-PrEF)

The study compares standard right ventricle apical pacing with so called His-bundle pacing, for patients with slightly or moderately reduced ejection fraction and atrioventricular block requiring pacemaker therapy. The primary outcome is left ventricular ejection fraction measured after 6 months.

Patients with reduced systolic ejection fraction (40≤ ejection fraction ≤55%) and pacemaker indication due to high degree AV block are included. The study has a randomized double blinded crossover design. Patients are implanted with a standard right ventricle lead and right atrial lead (if indicated), and in addition a His-bundle lead. Randomization is performed as to which pacing modality is used during the first 6 months. After 6 months the pacing modality is changed. Patients are blinded and endpoint adjudicators, including echocardiography staff, are blinded. Device nurse and physician are not blinded. Primary endpoint is difference in left ventricular ejection fraction after 6 months, paired comparisons are used and each patient is their own control. Secondary endpoints include complications and safety of the device/electrode, and quality of life.

His bundle pacing, Conduction system pacing, Heart failure, systolic, Quality of life, Left ventricular ejection fraction

Patients are allocated to receive His-bundle pacing for a period of 6 months. Then the patients will cross over to traditional right ventricular (RV) apical pacing for 6 months.

Patients are allocated to receive traditional RV apical pacing for a period of 6 months. Then the patients will cross over to His-bundle pacing for 6 months.

A standard pacing electrode (Medtronic 4076) will be placed in RV apex (or RV septum as a secondary option) and in the right atrial appendage (if indicated). A dedicated His-bundle pacemaker electrode (Medtronic 3830) will be placed in the region of His bundle, using a dedicated introducer sheath (Medtronic C304 or Medtronic C315). His-bundle potentials will be identified and His-bundle capture (non-selective or selective) will be ascertained using an electrophysiology recording system. Device programming will focus on providing physiological atrioventricular delay and safety RV pacing as backup.

Percentage of device-related adverse events. Events will be classified as general, associated with His-bundle lead or associated with RV lead

Difference in health related quality of life, measured by the SF-36 questionnaire, calculated as difference in mean from baseline to follow-up (calculated using the official scoring algorithm, where each sub scale is assigned a score between 0-100, higher score represents better health)

Difference in health related quality of life, measured by the mean score of the EQ-5D (version 5L) questionnaire (totalt score ranging from 5-25 points, higher score represents more health related problems/disability)

Inclusion Criteria: AV block II or III with high expected pacing need Left ventricular ejection fraction between 40% and 55% (inclusive) Willing to participate and sign informed consent Exclusion Criteria: Under 18 years old Pregnant Hypertrophic cardiomyopathy Cardiac sarcoidosis Cardiac amyloidosis Previous myocardial infarction within last 3 months Ventricular septum defect or other other left ventricular corrective surgery Congenital heart disease surgically corrected Atrial fibrillation with uncontrolled rate (if not planned for AV node ablation)