Autonomic dysfunction is common in liver cirrhosis and is associated with cardiac dysfunction and mortality: prospective observational study

Abstract

INTRODUCTIONLiver cirrhosis has a wide spectrum of clinical extrahepatic organ manifestations. The heart is affected in the majority of patients, ranging from mild to severe impairment. The latter is more prevalent during end-stage liver disease. 1 Cirrhosis with portal hypertension is characterized by circulatory dysfunction with chronic peripheral vasodilation, leading to insufficient organ perfusion and a compensatory increase in cardiac output. 2 This hyperdynamic circulation requires an increase in heart rate (HR), which is dependent on the autonomic nervous system (ANS). Dysfunction of the ANS leads to an abnormal HR response, especially in situations when peripheral oxygen demand increases, as during hemodynamic stress or exercise. 3,4 QT interval prolongation has been shown to correlate with cirrhotic cardiomyopathy, 1 representing one manifestation of electrophysiological abnormalities and autonomic dysfunction.However, few studies have demonstrated the relationship between these electrocardiographic abnormalities and outcomes in liver cirrhosis. [5][6][7] Another way to access cardiac autonomic function is to measure heart rate variability (HRV), which involves analysis of consecutive normal R-R intervals (also called N-N) during a period of time. HRV reflects the heart's ability to adapt HR to changing circumstances by detecting and quickly responding to unpredictable and variable stimuli. 8 Sympathetic and parasympathetic system impairment leads to improper acceleration or insufficient increase in HR. A number of different measurements are used to analyze HRV during 24-hour Holter monitoring; these parameters