Heart Disease Glossary of Terms
Metabolic Exercise Stress Test (also called metabolic stress test): A test used to measure the performance of the heart and lungs while they are under physical stress. The test involves walking on a treadmill or pedaling a stationary bike at increasing levels of difficulty, while being closely monitored.
Minimally Invasive Heart Surgery: Minimally invasive heart surgery is a technique developed to reduce the trauma associated with open heart surgery. The smaller incision that is used may allow the patient to heal more rapidly and decrease the time to recovery and full activity. It also helps to reduce the pain and discomfort associated with heart surgery.
Mitral Insufficiency: A condition where blood in the left ventricle leaks back through the mitral valve into the left atrium and can back up into the lungs. The mitral valve normally opens to allow blood to flow into the left ventricle and then closes, preventing blood from backing up into the atrium during the ventricle's contraction.
Mitral Stenosis: A condition where the mitral valve becomes narrowed or stenotic preventing the easy flow of blood from the left atrium into the left ventricle. This is a consequence of having rheumatic fever.
Mitral Valve: The valve that lies between the left atrium and left ventricle (main pumping chamber of the heart). This valve allows blood to flow from the left atrium into the left ventricle and then prevents the back flow of blood into the left atrium during ventricular contraction.
Morbidity Rate: The percentage of people who have complications from a medical condition or after a procedure or treatment.
Mortality Rate: The percentage of deaths associated with a disease or medical treatment.
Multigated Acquisition Scan (MUGA scan): A nuclear scan that evaluates the pumping function of the ventricles.
Murmur: Turbulent blood flow across a heart valve creating a "swishing" sound heard by a stethoscope.
Myocardial Biopsy (Cardiac biopsy): An invasive procedure to obtain a small piece of heart muscle tissue that is sent to a laboratory for analysis.
Myocardial Infarction (Heart attack): See heart attack (above).
Myocarditis: Inflammation of the myocardium (heart muscle).
Myocardium: Heart muscle.
Myomectomy: A surgical procedure to remove abnormally thickened heart muscle. Used to treat people with idiopathic hypertrophic subaortic stenosis (IHSS) or HOCM thereby relieving the obstruction to blood flow in the left ventricle during contraction.
Nitroglycerin: A medication used to relax and dilate the blood vessels (vasodilator), improving blood flow. Nitroglycerin works very quickly and is the most common vasodilator used to treat angina.
Nuclear Scan: Nuclear imaging is a method of producing images by detecting radiation from different parts of the body after the administration of a radioactive tracer material.
Obesity: Excess fat due to eating more calories than used. It is usually defined having a body mass index (BMI-see above) of 25 or higher.