Bioimpedance utility in heart failure

Congestion is a central pathophysiological feature of heart failure (HF) and a major contributor to symptoms and prognosis. Despite the substantial mortality benefit of disease-modifying therapies [1], assessing and managing congestion remains challenging. Existing tools such as clinical examination, blood and urinary biomarkers, and cardiac and lung ultrasound are limited by observer variability, logistical constraints and the need for technical expertise [2]. Comorbidities such as chronic kidney disease (CKD), which co-exist in up to 60% of patients with heart failure and may contribute to congestion, further complicate assessments, which can lead to worse outcomes [3, 4]. Consequently, there is growing interest in objective, reproducible and accessible tools that complement conventional approaches to congestion assessment by providing additional information on fluid distribution within body compartments. Bioimpedance analysis (BIA) is a non-invasive technique that measures the electrical properties of biological tissues to estimate body composition and fluid distribution. Since the pioneering work of Nyboer in 1959 and Hoffer et al. in 1969 [5], BIA has evolved from a research tool for body composition into a broader clinical technology used across multiple specialties [6]. Advances in multifrequency, segmental, and spectroscopy-based systems have further expanded its potential for assessing fluid compartments in conditions such as HF and Chronic Kidney Disease (CKD). However, BIA encompasses heterogeneous technologies, parameters and prediction models, and its clinical role remains incompletely defined, with recommendations for further research [7]. This narrative review outlines the physiological principles of bioimpedance, evaluates its applications in HF diagnosis, prognostication, therapeutic guidance and remote monitoring, and explores the methodological and clinical barriers that have restricted its widespread adoption. We discuss its potential as an adjunctive tool for assessing congestion and highlight the key evidence gaps that must be addressed before bioimpedance can be more widely integrated into routine HF care.