Clinically significant arrhythmias in ambulatory patients with symptomatic heart failure (HF) without cardiac implantable electronic devices (CIEDs) remain incompletely characterized. An analysis from the ALLEVIATE-HF trial published in Journal of the American College of Cardiology evaluated arrhythmia burden using continuous insertable cardiac monitor (ICM) surveillance and assessed whether device-guided congestion management influenced arrhythmia occurrence.

The randomized study included patients with New York Heart Association (NYHA) functional class II-III HF, any ejection fraction (EF), and a recent HF event without prior CIED implantation. All participants underwent ICM implantation and were randomized to physician-directed, nurse-facilitated congestion management or usual care. Arrhythmia data were accessible to clinicians in both study groups.

Findings

• The analysis included 711 patients with a mean follow-up of 17.3 ± 8.9 months; 67.9% had HF with preserved EF.
• During the 13-month randomized phase, arrhythmia occurrence rates did not differ between the congestion-management and usual-care groups.
• The overall 3-year occurrence of atrial fibrillation (AF) was 66.6%, including 25.4% with new-onset AF.
• Bradyarrhythmias occurred in 47.1% of patients, while ventricular tachycardia or ventricular fibrillation (VT/VF) occurred in 20.1%.
• ICM-detected arrhythmias were associated with higher risk of all-cause hospitalization (hazard ratio [HR] 1.79; P < 0.001) and HF events (HR 1.69; P = 0.003).
• Therapeutic interventions after arrhythmia detection included CIED implantation in 22.7% of patients and catheter ablation in 26.1%.

Continuous ICM surveillance identified a high burden of clinically meaningful arrhythmias in ambulatory patients with symptomatic HF, with detected arrhythmias frequently followed by hospitalization and therapeutic intervention. Device-guided congestion management did not significantly modify arrhythmia occurrence.