What is a Holter monitor A Holter monitor is also called a continuous electrocardiogram (ECG), continuous ECG or ambulatory electrocardiography (ambulatory ECG) that can record

What is hyperventilation Hyperventilation is rapid and deep breathing. Hyperventilation is also called overbreathing, and it may leave you feeling breathless. You breathe in oxygen

What is hypovolemia Hypovolemia is defined as a decrease in the blood volume resulting from loss of blood, plasma and/or plasma water, thereby causing a

What is hydromorphone Hydromorphone (Dilaudid) is used to relieve moderate to severe acute pain, and severe chronic pain ((Abi-Aad KR, Derian A. Hydromorphone. . In: StatPearls

What is hyperemesis gravidarum Hyperemesis gravidarum is severe nausea and vomiting that occurs during pregnancy that may cause severe dehydration (not have enough water in your

What is heterochromia Heterochromia is different colored eyes in the same person. Heterochromia is when a person’s irises (the colored part of the eye) are different

What is hydronephrosis Hydronephrosis is the swelling of one or both kidneys due to a build-up of urine. Hydronephrosis refers to dilation of the pelvis

What is hyperplasia Hyperplasia is an increase in the number of cells in an organ or tissue. These cells appear normal under a microscope. They

What is hydroxyzine Hydroxyzine is a first generation antihistamine (histamine H1 receptor blocker) that is mostly used to help control anxiety and tension caused by

What is HELLP syndrome HELLP syndrome is a group of symptoms that occur in pregnant women who have: H--Hemolysis. This is the breakdown of red