Early detection of worsening HF through insertable cardiac monitor (ICM)-based surveillance remains an area of active clinical investigation. In a randomized trial published in the Journal of the American College of Cardiology, investigators evaluated whether ICM-based high-risk detection combined with centrally coordinated, nurse-facilitated, protocol-driven diuretic management could improve outcomes in patients with HF. 

The study enrolled 711 patients, including 357 assigned to the intervention arm and 354 to the observation arm. The primary efficacy endpoint was a hierarchical composite that included cardiovascular death, HF hospitalization, outpatient HF events within 60 days of high-risk onset, Kansas City Cardiomyopathy Questionnaire Clinical Summary Score (KCCQ-CSS), and 6-minute walk distance. 

Findings

• The primary hierarchical composite outcome did not differ significantly between the intervention and observation groups (win ratio, 0.79; 95% CI, 0.62-1.01; P = 0.06).
• At a mean follow-up of 17.3 ± 8.9 months, the intervention-related serious adverse event rate was 0.32% (95% CI, 0.10%-0.99%), remaining below the prespecified safety threshold of 5%.
• Cumulative cardiovascular death and HF events were numerically higher in the intervention group, although the difference did not reach statistical significance (HR, 1.43; 95% CI, 0.95-2.15; P = 0.091).
• An exploratory sensitivity analysis adjusting for baseline imbalance in KCCQ-CSS showed no significant difference between treatment groups (win ratio, 1.02; 95% CI, 0.80-1.31; P = 0.85).

ICM-based HF risk detection combined with centrally managed diuretic intervention met safety objectives but did not improve the primary clinical outcome under the tested management strategy.