A Glossary of Heart Failure 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 where small incisions are made on the side of the chest, rather than in the middle of the chest. In addition, the breastbone is left intact, rather than cut open. 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 the mitral valve does not fully close during heart contraction, allowing blood from the left ventricle to leak back into the left atrium.
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.
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.
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 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 to relieve the obstruction to blood flow in the left ventricle during contraction.