The following are the subspecialties: Adolescent medicine. Allergy, Asthma and Immunology, concerned with the diagnosis, treatment and management of allergies, asthma and disorders of the immune system. Cardiology, dealing with disorders of the heart and blood vessels. Clinical cardiac electrophysiology. Critical care medicine. Endocrinology, dealing with disorders of the endocrine system and its specific secretions called hormones Gastroenterology, concerned with the field of digestive disea...