Anorexia nervosa is a psychological condition that involves an eating disorder.Symptoms include a very low body mass index , a refusal to eat, and attempts to lose weight, even when body mass index is very low.It is thought to be triggered by a combination of biological, environmental, and genetic factors.Treatment can take some time, but with a combination of counseling and other types of therapy, recovery is possible.Several of the main physical effects of anorexia on the heart include: Abnormal and dangerous heart rhythms, including slow rhythms, also known as bradycardia. Reduced blood flow throughout the body. Reduced and dangerously low blood pressure. Shrinking heart muscles due to loss of blood flow and malnutrition.There is no single cause for eating disorders. Although concerns about weight and body shape play a role in all eating disorders, the actual cause of these disorders appear to result from many factors, including those that are genetic and neurobiologic, cultural and social, and behavioral and psychologic. anorexia always affect child and teenagers Anorexia is usually treated with a combination of individual therapy, family therapy, behavior modification, and nutritional rehabilitation.