The symptomatic ( determinate ) chronic stage affect the nervous system , digestive system and heart . About two @-@ thirds of people with chronic symptoms have cardiac damage , including dilated cardiomyopathy , which cause heart rhythm abnormalities and may result in sudden death . About one @-@ third of patients go on to develop digestive system damage , resulting in dilation of the digestive tract ( megacolon and megaesophagus ) , accompanied by severe weight loss . Swallowing difficulties ( secondary achalasia ) may be the first symptom of digestive disturbances and may lead to malnutrition .