Choice of cardiac implantable electronic device and age-stratified clinical outcome in patients with known heart failure prior to implant
Authors: Rorsman C , Farouq M , Marinko S , Platonov P G , Chaudhry U , Mortsell D , Wang L , Borgquist R 
Published: November 2023

Abstract

Background
Patients with heart failure (HF) and bradycardia may be eligible for different types of cardiac implantable devices, depending on presence of AV conduction disease, left ventricular ejection fraction, severity of heart failure symptoms, other comorbidities, and age. Once a pacing device is in place, there is a risk that ensuing heart failure progression or worsening of symptoms do not always prompt a device upgrade to resynchronization or conduction system pacing therapy, even if this should be warranted. We therefore aimed to compare prognosis in a national cohort of patients with prior HF diagnosis, who received a pacemaker or defibrillator with or without resynchronization therapy.

Methods
All patients with preexisting HF diagnosis who received a pacemaker with a right ventricular lead during the period 2005-2018 in Sweden were identified via the Pacemaker Registry. Data was crossmatched with the population registry and national disease registries. Primary outcome was 5-year mortality, and secondary was mode of death and hospitalization for heart failure. Cox regression and Kaplan Meier curves with log rank test were used for time dependent outcome analyses. Demography variables were compared with Chi2 test or Mann Whitney U test, as appropriate. Adjustment was done for history of atrial fibrillation, diabetes, hypertension, malignancy, age, gender, ischemic heart disease, renal disease, lung disease and cerebrovascular disease. Separate analyses were made for patients with complete AV block, based on the assumption of 100% ventricular pacing in this group, regardless of choice of implanted device.

Results
37745 patients were included in the study (see figure 1). Demographic data was similar for the different device groups, except that patients with single chamber pacemaker were older, and all those with single chamber devices (pacemaker, ICD) were more likely to have a history of atrial fibrillation. All listed comorbidities, male sex and higher age were associated with lower 5-year survival in multivariable Cox regression analyses. Unadjusted 5-year mortality was 40% (highest for single chamber pacemakers (61%), and lowest for dual chamber ICDs (17%), p=0.001). When stratified by age group, and adjusted for relevant covariables, patients with single-chamber pacemakers still had higher mortality in all age decile groups (ranging from &lt;60 to &gt;90 years old, all p&lt;0.001). Proportion of device upgrades to CRT was very low; 2.9% for dual- and 0.8% for single-chamber pacemakers. 17% of patients with traditional pacemakers died from HF, and 31% were hospitalized for HF.

Conclusions
Survival for patients with prior HF diagnosis who receive traditional pacemakers is poor, risk of HF hospitalization is high, whereas upgrades to CRT are scarce. This highlights the need for choosing correct device type at the primary implant, if ventricular pacing is anticipated.Flowchart of included patientsAge stratified survival per device group