Conduction System Pacing to Prevent Pacing-Induced Cardiomyopathy

Eligible participants had an LVEF above 50%, an indication for permanent pacemaker implantation due to atrioventricular block, an anticipated ventricular pacing burden above 85%, and either underlying structural heart disease or a native QRS duration above 120 ms. After written informed consent, participants were randomized to conduction system pacing or right ventricular apical pacing. Clinical, electrocardiographic, echocardiographic, functional, quality-of-life, and biomarker assessments were performed at baseline and at 6 months as specified in the protocol. Subsequent routine pacemaker-clinic follow-up was used to ascertain clinical events.

Inclusion criteria

• Left ventricular ejection fraction greater than 50% by the Simpson four-chamber method before pacemaker implantation.
• Indication for permanent pacemaker implantation due to atrioventricular block.
• Anticipated ventricular pacing burden greater than 85%.
• At least one of the following high-risk features: structural heart disease or native QRS duration greater than 120 ms.
• Structural heart disease was defined as previously diagnosed ischemic heart disease, with or without prior myocardial infarction, and/or at least moderate left-sided valvular stenosis or regurgitation, and/or an aortic or mitral valve prosthesis.
• Provision of written informed consent.

Exclusion criteria

• Failure to meet all inclusion criteria.
• Refusal or inability to provide written informed consent.
• Dementia or significant cognitive impairment.
• Underlying systemic disease associated with a life expectancy of less than 1 year.