Subcutaneous sensors for monitoring congestion and to reduce heart failure hospitalizations-a viable middle ground between deep implantable intravascular monitoring devices and wearable technologies?

Congestive heart failure (CHF) remains a leading cause of hospitalization and mortality worldwide. Continuous monitoring is crucial for early detection of decompensation, potentially reducing hospital admissions and improving outcomes. Cardiac implantable electronic devices (CIEDs) have been established as useful therapeutic interventions that also support continuous monitoring in order to detect early signs of decompensation. However, prior to CIED implantation, effective continuous monitoring solutions are lacking. They exist at two extremes: deep implantable intravascular solutions such as pulmonary artery pressure sensors, which are effective but costly and complex, and wearables, which are inexpensive but lack evidence of their effectiveness and depend on ongoing active patient adherence. Subcutaneous sensors may represent a promising intermediate solution-offering continuous monitoring with lower invasiveness and cost, while maintaining higher adherence compared to wearables. This review explores the role of subcutaneous sensors in CHF management, comparing existing daily trend data to deep implantable sensors measuring direct filling pressure and CIEDs for multi-parametric risk scoring. We discuss their feasibility, limitations, and future integration into routine clinical practice.