OPTImizing Lead Placement in Patients Requiring Pacemaker After Cardiac Surgery

A high percentage of ventricular pacing increases the risk of pacing‐inducedcardiomyopathy. Pacing‐induced cardiomyopathy is a syndrome defined by left ventriculardysfunction secondary to chronic right ventricular pacing, resulting in impairedoutcomes. Pacing‐induced cardiomyopathy is estimated to affect approximately 10‐20% ofpatients with a high proportion of right ventricular pacing (>20%), a population thatmainly consists of patients with atrioventricular block (AVB). The abnormal activationleads to prolonged electrical and mechanical activation, which results in ventriculardyssynchrony. Other important risk factors for pacing‐induced cardiomyopathy includestructural heart disease and reduced ejection fraction, male sex and wide, paced QRS.Clinical practice guidelines support pacemaker implantation following cardiac surgeryonly for severe and non‐transient bradyarrhythmias, as pacemaker implantation increasesthe risk of severe infections and device‐related long‐term complications. Evidencesuggests that a substantial proportion of patients who receive a pacemaker followingcardiac surgery have limited need for pacing at long‐term follow‐up. Thus, therisk/benefit ratio for patients following cardiac surgery differs from that of thegeneral population, while these patients also form a vulnerable population at high riskfor pacing‐induced cardiomyopathy.Over the last decade, a conduction system pacing strategy called left bundle branch areapacing (LBBAP) has been developed. In LBBAP, the pacemaker lead is inserted deep into theinterventricular septum from the right ventricle to the left ventricular endocardium,targeting the left bundle and its resulting fascicles. As the current understanding ofthe development of pacing‐induced cardiomyopathy suggests that the electricaldyssynchrony introduced by right ventricular pacing plays a crucial role, our hypothesisis that its incidence could be reduced by the favorable electrical activation achievedwith LBBAP.There are ongoing randomized controlled trials of conduction system pacing in the generalpopulation; however, none are investigating cardiac surgery patients. These patientsdiffer substantially from the general population in age, expected long‐term survival, andcardiovascular health. This increases their risk of pacing‐induced cardiomyopathy andcould influence the feasibility of conduction system pacing due to their otherwiseimpaired cardiovascular health. At the same time, their long‐term pacing dependence coulddiffer from that of the general population.Therefore, the aim of the present multicenter randomized controlled trial is to evaluatethe long‐term outcomes of LBBAP versus right ventricular pacing after cardiac surgery inpatients with normal left ventricular ejection fraction. A secondary aim is to assess thefeasibility of LBBAP after cardiac surgery with regard to implantation success andlong‐term electrical parameters. The results of this trial are anticipated to provideclinically meaningful evidence to guide pacing strategy selection in this patient cohort.