Predictors of heart failure hospitalization and cardiovascular mortality in patients with chronic right ventricle pacing
Authors: Lozano J , Escalona R.A , Rodenas-Alesina E , Azpiroz M.J , Badia C , Francisco-Pascual J , Rodriguez-Palomares J.F , Ferreira-Gonzalez I 
Published: October 2021

Abstract

Background
Left ventricle (LV) dysfunction after chronic right ventricle (RV) pacing, also known as pacemaker induced cardiomyopathy (PICM) is a relatively common finding, ranging from 15–20% of patients. It has been associated to a high burden RV pacing, age, male gender and intrinsic and paced QRS duration. However, clinical relevance of LV dysfunction in this population has not been studied.

Purpose
The aim of the study was to identify predictors of heart failure (HF) hospitalization and cardiovascular (CV) mortality in patients with RV pacing.

Methods
Retrospective and unicentric study. We studied 2418 patients undergoing single or dual-chamber pacemaker implantation between 2012–2018. Patients were included if they had an echocardiogram prior to implantation and a repeated echocardiogram &gt;3 months after implantation. Baseline LV ejection fraction (LVEF) had to be &gt;50%. PICM was defined as ≥10% decrease in LVEF, resulting in LVEF &lt;50%. Alternative causes of LV dysfunction were excluded. Primary endpoint was heart failure hospitalization. Secondary endpoint was cardiovascular mortality. Competing-risk regression analysis was performed to identify predictors of HFH and CV mortality.

Results
Of 2418 patients, 495 meeting study criteria and 105 (21.2%) met PICM criteria. Follow-up period was 56.1±28.5months. There were no differences in basal LVEF (60.1±0.5% in non-PICM patients vs 59.5±0.5 in PICM patients, p=0.51). Mean LVEF at follow-up was 37.7±0.9 vs 56.7±0.3, p&lt;0.001. After logistic multivariable analysis, factors associated with PICM were alcohol consumption (OR 3.0, 95% CI 1.1–8.0,p=0.032), right bundle branch block (RBBB) (OR 1.9, 95% CI 1.06–3.51,p=0.031), higher RV pacing burden (OR 1.0, 95% CI 1.0–1.1,p=0.008) and higher basal LV end-diastolic diameter (OR 1.1, 95% CI 1.0–1.1,p=0.016).
HFH occurred in 144 patients (29.1%). Factors associated with HFH after multivariable analysis were any decrease in LVEF (LVEF&gt;55% as reference: LVEF 46–55% (HR 2.1, 95% CI 1.3–3.3,p=0.002); LVEF 36–45% (HR=1.5, 95% CI 0.7–3.0; p=0.306), LVEF≤35% (HR 2.44, 95% CI 1.11–5.37,p=0.027), age (HR 1.0, 95% CI 1.0–1.1,p=0.037), alcohol consumption (HR 3.4, 95% CI 1.9–6.1,p&lt;0.001), presence of atrial fibrillation (HR 1.7, 95% CI 1.06–2.70,p=0.027) and paced QRS duration (HR 1.0, 95% CI 1.0–1.02,p=0.031).
CV mortality occurred in 54 patients (10.9%). Factors associated with CV mortality after multivariable analysis were a decrease in LVEF (LVEF 46–55% (HR 1.6, 95% CI 0.8–3.2,p=0.217); LVEF 36–45% (HR=1.6, 95% CI 0.6–4.2,p=0.33); LVEF≤35% (HR 4.6, 95% CI 2.0–10.7,p&lt;0.001), RBBB (HR 2.1, 95% CI 1.1–3.9,p=0.026) and lower haemoglobin (HR 0.8, 95% CI 0.7–0.99,p=0.033).

Conclusion
In patients with RV pacing, factors associated with PICM were alcohol consumption, RBBB, RV pacing burden and basal LV end-diastolic diameter. HF hospitalization and CV mortality are common (29.1% and 10.9%). Any decrease in LVEF is associated with an increase in CV events.

Funding Acknowledgement
Type of funding sources: None.