Defining the gap in heart failure treatment in patients with cardiac implantable electronic devices

Background: The use of guideline-directed medical therapy (GDMT) is poorly described in patients with heart failure and reduced ejection fraction (HFrEF) with cardiac resynchronization therapy (CRT) and/or implantable cardioverter defibrillators (ICDs).

Objective: To define the eligibility, uptake, dose, contraindications, and barriers to uptake of contemporary medical therapy in this population.

Methods: Retrospective analysis of consecutive adults with ICD and/or CRT attending two Canadian tertiary centre device clinics between 1 March and 31 May 2021.

Results: From 1005 device clinic consultations, 227 (22.6%) patients with HFrEF and CRT and/or ICD were included. GDMT eligibility was high: beta-blockers (99.6%), mineralocorticoid receptor antagonists (MRA) (89.0%), angiotensin receptor-neprilysin inhibitors (ARNI) (84.6%), and sodium-glucose cotransporter-2 inhibitors (SGLT2I) (87.7%). Contraindications were rare: beta-blockers (0.4%), MRA (11.0%), ARNI (15.4%), and SGLT2I (12.3%). Uptake of GDMT was high for beta-blockers (97.4%) but low for other medications: MRA (63.0%), ARNI (46.7%), SGLT2I (22.9%). Except for SGLT2I (84.6%) and beta-blockers (57.9%), less than one-half of patients were prescribed target-doses of MRA (10.5%), and ARNI (47.7%). Of the visits, GDMT was already optimal in 16%, electrophysiologists acted in 33% (21% prescribed, 7% ordered investigations, 5% referred to heart function services), and in the remaining visits, optimization was either deferred to another cardiologist (20%) or no plan was mentioned (25%), besides other reasons (4%).

Conclusion: Despite broad eligibility for GDMT in patients with HFrEF and ICD/CRT, significant gaps in prescription and titration exist. Our results highlight the need to embed quality assurance initiatives in cardiac device clinics to improve HFrEF care.