Evaluation of volume depletion in patients with heart failure using intrathoracic impedance monitoring

摘要

The incidence of heart failure (HF) is increasing worldwide and despite significant progression in pharmacological therapy, HF-related hospital admissions have also not decreased. The acute decompensation of HF induces irreversible disease progression and predicts poor prognosis. Although the mechanism of developing acute decompensation in HF remains to be unveiled, hypervolemia and altered left ventricular loading volume are thought to be important contributing factors. However, fluid accumulation often arises prior to the onset of symptoms. Conceptually, continuous monitoring of volume status in HF patients may help in the detection of subclinical hemodynamic deterioration (Figure 1), but early detection of volume retention in the clinical setting is often challenging.1 Conventional workups such as weight monitoring, chest X-ray, and echocardiography are useful but of limited use in validating each patient's volume status. However, the recent progression of implantable cardioverter defibrilla-tors (ICD) and cardiac resynchronization therapy/defibrillator device (CRT-D) suggest their potential use as methods for estimating fluid accumulation in the chest cavity by measuring intrathoracic impedance and providing additional insight into the difficult problem of managing HF patients.