A Glossary of Heart Disease Terms
Hemoglobin: A protein in red blood cells that transports oxygen and carbon dioxide and gives blood its red color.
Hibernating Myocardium: After a heart attack, some areas of heart muscle do not pump as they should. Some areas will have permanent damage. Other areas are able to return to their normal function if blood flow is returned to that area by medications or a procedure. Hibernating myocardium is heart muscle that is "resting" and may possibly return to normal function.
High-Density Lipoprotein (HDL): Lipoprotein is a particle in the blood. HDL is known as "good" cholesterol because it deposits cholesterol in the liver, where it is excreted by the body. High HDL is thought to protect against coronary artery disease.
Holter Monitor: A small recorder (monitor) is attached to electrodes on your chest. It records the heart's rhythm continuously for 24-hours as you go about your normal activities. After the monitor is removed the heart's beats are counted and analyzed by a technician with the aid of a computer. Your doctor can learn if you are having irregular heartbeats, what kind they are, how long they last, as well as what may cause them.
Homocysteine: An amino acid in the body. High levels of homocysteine are a risk factor for coronary artery disease.
Hydrogenation: A process used to harden unsaturated liquid vegetable oils into saturated fats.
Hyperlipidemia: High levels of fat in the blood, such as cholesterol and triglycerides.
Hypertension: High blood pressure.
Hypertrophic Obstructive Cardiomyopathy (HOCM): See IHSS below.
Hypertrophy: An abnormal enlargement of an organ or thickening of its tissue. Ventricular hypertrophy is the name given to a thickened ventricle.
Hypotension: Low blood pressure.
Idiopathic: When the cause of a disease or process is not known.
IHSS: Idiopathic Hypertrophic Subaortic Stenosis is another term used synonymously with hypertrophic obstructive cardiomyopathy (HOCM). It is an inherited disease that causes thickening of the heart muscle and other changes to the heart that significantly impair its function. Although the disease is rare, IHSS is the single most common cause of sudden cardiac arrest in seemingly healthy young people.