Wearable Cardiac Devices as Windows Into Physiological Decline: A Review of Digital Biomarkers in the Prevention, Detection, and Management of Cardiogeriatric Frailty

In patients with cardiovascular disease (CVD), frailty is a significant problem due to its association with morbidity and mortality, procedural risk, and reduced tolerance to the pharmacological treatment of CVD.However, frailty is a conceptual entity, defined as decreased physiological reserve and increased susceptibility to stressors.Although phenotypic models of frailty have been proposed, they are limited by the variability of detectable clinical features and the subjective nature of clinical frailty assessment.Conversely, the advent of biologically integrated technologies offers new strategies to address the critical challenges of early detection and quantification of frailty.Data obtained from wearable cardiac devices include morphological and dynamic electrocardiography features and assessment of vascular age, which enable insight into the biological signals reflecting early physiological decline, heralding the onset of frailty long before observable sarcopenia or functional decline becomes evident.The inherently chaotic nature of these biological signals provides a strong basis for non-linear data analysis of wearable cardiac device data, allowing for assessment of the loss of physiological complexity associated with frailty.In the context of an ageing population and the growing burden of frailty, the integration of wearable cardiac devices into clinical care provides a technology-based solution for the persistent problem of frailty in patients with CVD.This review examines the technical advances, clinical applications, and current limitations of wearable devices, with the objective of providing an integrated perspective on their future role in the prevention, early detection, and management of cardiogeriatric frailty.