Marfan's Syndrome

Marfan's syndrome is an inherited disease characterized by aneurysms in the aorta, excessive height, abnormally long fingers and toes, and problems with the eyes. (For more information on Marfan's Syndrome, please see http://www.marfan.org/; http://www.crtelco.com/~ckbryant/marfan.html; or http://www.aorn.org/JOURNAL/1296/HOMESTUD/article.htm)

Microcatheter

A very small catheter used to deliver diagnostic and therapeutic agents such as embolic devices. There are two types of microcatheters: over-the-wire and flow-directed.

Minimally Invasive Surgery

Minimally invasive surgery, also known as beating heart surgery, refers to the last advancement in open heart surgery. Minimally invasive procedures are performed through a small incision in the chest wall to reduce pain and recovery time. (In conventional open heart surgery a full sternotomy is performed -- the full length of the breast bone, 30 cm long on average, is opened. The average length of a minimally invasive incision ranges from 9-12 cm long.) There are three major types of minimally invasive procedures: (1) minimally invasive direct coronary artery bypass, MIDCAB; (2) minimally invasive valve repair and replacement; and (3) minimally invasive port-access. Originally developed in the early 1960s by a Russian surgeon, minimally invasive techniques have been perfected in the last few years with the development of new medical technologies.

Mitral Incompetence

Mitral incompetence is a problem with the mitral valve that connects the left atrium to the left ventricle. The valve does not create a complete seal when closed, permitting some blood to flow back into the left atrium when the ventricle contracts -- normally all blood flows out through the aorta. The damage to the valve can be congenital, a result of scarring from an infection, or caused by a myocardial infarction (death of some heart muscle). Symptoms and signs of mitral incompetence include breathlessness, atrial fibrillation (rapid, irregular, ineffective heartbeats), embolisms, enlargement of the left ventricle, and a murmur (systolic). In severe cases the valve should either be repaired or replaced surgically.

Mitral Stenosis

A stenotic mitral valve has a narrowed valve opening. Mitral stenosis is often caused by rheumatic fever. Symptoms are the same as for mitral incompetence (except that the heart murmur is diastolic instead of systolic). In severe cases the valve should either be repaired or replaced surgically.

Mitral Valve

The mitral valve connects left atrium to the left ventricle. It has two cusps that, when open, lets blood flow in one direction, from the left atrium into the left ventricle.

Monounsaturated Fat

Monounsaturated fat helps to lower blood cholesterol when used in place of saturated fat in the diet. (See also Saturated Fat; Polyunsaturated Fat; and Omega-3 Fatty Acids.)

Mri/Magnetic Resonance Imaging

MRI/Magnetic Resonance Imaging uses magnets and computer technology to take detailed pictures inside the body.

Muga Scan

A MUGA scan uses low dose radioactive material given intravenously to visualize the heart's pumping action (ejection fraction).

Murmur

A murmur is a abnormal sound made by blood that is flowing irregularly, or turbulently in the heart or arteries. It may be caused by a narrowed vessel or valve, a leaking valve, or too much blood flow through a normal vessel. The presence of a murmur may not mean a significant heart problems, but usually requires further evaluation. Systolic murmurs occur when the heart is contracting. Diastolic murmurs occur when the heart is relaxing. Continuous murmurs usually indicate abnormal communications between arteries and veins or between the aorta and other parts of the heart.

Myocardial Infarction (MI)

Permanent damage to the heart tissue and muscle due to the interruption of the blood supply to the area. Commonly referred to as a heart attack.

Myocarditis

Myocarditis is any inflammation of the heart muscle.

Myocardium

The myocardium is the muscular middle layer of the heart, responsible for making the heart contract.