In hepatocyte membrane lesions, elevated serum levels of the enzymes aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are found; cholestatic diseases, due to the impediment or reduction of bile flow, lead to an increase in plasma levels of bilirubin and predominantly alkaline phosphatase (AF) and gamma glutamyl transpeptidase (GGT). Here, GPT is linked to atrial fibrillation.