A Glossary of Heart Failure Terms
Leaflets: Thin pieces of tissue or flaps that make up a valve.
Left Ventricular Assist Device (LVAD): A mechanical device placed in people with end-stage heart failure. The device aids in the pumping function of the blood.
Lipid: Fat circulating in the blood.
Lipoprotein: A combination of fat and protein that transports lipids (fats) in the blood.
Loop Recorder (Event monitor): See Event monitor (above)
Low-Density Lipoprotein (LDL): A lipoprotein particle in the blood responsible for depositing cholesterol into the lining of the artery. Known as "bad" cholesterol because high LDL is one of the factors that contribute to coronary artery disease.
Magnetic Resonance Imaging (MRI): A test that produces high-quality still and moving pictures of the heart and large blood vessels. MRI uses large magnets and radio-frequency waves to produce pictures of the body's internal structures. No X-ray exposure is involved. MRI acquires information about the heart as it is beating, creating moving images of the heart throughout its pumping cycle.
Mammary Artery (also called internal thoracic artery): Artery located in the chest wall and used for coronary artery bypass surgery. Most commonly kept intact at its origin, and sewn to the coronary artery beyond the site of blockage. If the surgeon removes the mammary artery from its origin to use as a bypass graft, it is then called a "free" mammary artery bypass graft.
Maze Procedure: A surgical treatment for chronic atrial fibrillation. The surgeon makes multiple incisions in the atrium to block the path of the atrial fibrillation rhythm, thus allowing the normal heart beat to occur.
Mechanical Valve: A mechanical valve replaces a diseased heart valve. It is made of artificial parts and functions similarly to a normal heart valve. People who have a mechanical valve implanted must take blood thinners lifelong to prevent blood clots from forming on the mechanical valve.
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.