Left Septal Pacing or Left Bundle Branch Pacing to Avoid Left Ventricle Systolic Dysfunction. A Multicenter Randomized Trial From the STAY Investigators
Right ventricular apical pacing (RVAP) can produce left ventricular dysfunction (LVD). Conduction system pacing (CSP) has been used successfully to reverse LVD in patients with left bundle branch block. A recent randomized controlled trial (RCT) has demonstrated that CSP, mostly performed with left bundle branch area pacing (LBBAP), can preserve normal ventricular function and heart failure admissions compared to RVAP in the setting of a high burden of ventricular pacing11 (Stay Trial). Criteria to assess the LBBAP distinguishes those cases in which the LBB is captured (LBBP) from those in which only the muscular septum surrounding the LBB is captured (LVSP). To date, data regarding LVSP to preserve left ventricle ejection fraction (LVEF) is scarce and limited to non-randomized studies.
• Age of 18 years or more.
• Preserved or mild deteriorated LVEF (Simpson \>40%) assessed by a recent (\<1 month before implantation) transthoracic echocardiography.
• Indication for pacing based on the presence of a high degree AVB, and consequently with an anticipated high burden of ventricular pacing (\>80%).
• Life expectancy of more than 12 months and capability to understand the protocol, signing informed consent form, and complying with follow-up.