Heart rate variability in the clinical assessment of patients with chronic liver disease.

Autonomic dysfunction (AD) is frequently observed in cirrhotic patients and is associated with poor clinical outcomes and prognoses. Heart rate variability (HRV), a noninvasive tool for assessing autonomic nervous system balance, has been extensively studied in a variety of conditions, including chronic liver disease (CLD); however, no recent reviews have focused on its role in CLD. This article examines the mechanisms of AD in CLD and the foundation for HRV assessment, highlighting its diagnostic, prognostic, and therapeutic applications in CLD, including liver transplantation (LT). Changes in HRV, particularly in patients with cirrhotic complications, and its prognostic significance throughout the natural history of CLD are summarized. We show that HRV is consistently reduced in CLD patients, reflecting AD, and is inversely correlated with liver disease severity. Also, low HRV is associated with complications such as hepatic encephalopathy, ascites, and portal hypertension. Moreover, evidence indicates that reduced HRV is an independent risk factor for mortality and circulatory instability in CLD. Furthermore, treatment with beta-blockers and LT improves HRV, underscoring its potential role in patient management. While further studies are needed, HRV emerges as a promising tool for the comprehensive evaluation and clinical management of patients with CLD, offering insights into disease progression and therapeutic response.