Conduction System Pacing to Prevent Pacing-Induced Cardiomyopathy

The purpose of this randomized, open-label trial was to determine whether permanent conduction system pacing preserves left ventricular function and reduces the incidence of pacing-induced cardiomyopathy compared with conventional right ventricular apical pacing in patients with preserved LVEF who required permanent ventricular pacing for atrioventricular block and were considered at increased risk because of structural heart disease and/or a wide native QRS complex.

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.