What Is Mitral Regurgitation?


Overview of Mitral Regurgitation

Mitral regurgitation (MR) occurs when the leaflets (or flaps) of the heart's mitral valve do not close properly and leak. The mitral valve is a one-way valve that separates the left atrium (a chamber in the heart that collects blood from the lungs) from the left ventricle (a chamber in the heart that pumps blood to the rest of the body). During pumping, the leak in the mitral valve causes blood to flow backwards (MR) into the left atrium, thereby decreasing blood flow to the body. To maintain blood flow to the body and compensate for the MR, the left ventricle must pump harder. Backflow due to MR places an extra burden on the left ventricle and lungs. Eventually, this burden can cause other problems such as:

	Stroke
	Sudden death
	Irregular heartbeat
	Increasing damage to the heart muscle (Progressive myocardial injury)
	Inability to maintain adequate circulation of blood (Congestive heart failure)

Return to top of page.

Causes and Symptoms of Mitral Regurgitation

Mitral regurgitation (MR) is usually caused by conditions that have damaged the mitral valve or weakened the heart muscle. Common causes of MR in adults are:

	Degeneration of the valve.
	Heart attack (also called myocardial infarction) due to coronary artery disease (reduction of blood flow to the heart muscle).
	Damage to the valve from: infective endocarditis (an infection of the heart) or rheumatic fever.

In order to assess the effects of MR, it is important to have regular health exams with your doctor to monitor your condition. The symptoms of MR vary, depending on the severity of a person's disease. Some people may never develop symptoms while other people may develop an enlarged left ventricle (because it is working harder to pump blood out to the body). Patients with severe chronic MR may have symptoms of congestive heart failure such as:

	Fatigue or inability to exercise
	Decrease in appetite
	Dry, hacking cough, often worse when lying down
	Shortness of breath especially at night
	Fainting or blacking out
	Weight gain from fluid retention
	Accumulation of fluid in feet, ankles and lungs (edema)

Patients with sudden development (acute onset) or worsening of MR may experience sudden fluid accumulation in the lungs, low blood pressure and/or a rapid heart rate.

Return to top of page.


Diagnosing Mitral Regurgitation

Mitral regurgitation may go undetected (no obvious symptoms) for a long time. If you have symptoms, they can be caused by other heart-related conditions (see also Causes and Symptoms of Mitral Regurgitation section). Therefore, it is important to have regular health exams with your doctor, in order to monitor your condition.

To diagnose MR, your doctor needs to make several assessments. First, s/he will need to determine whether the MR has been present for a long time (chronic) or has developed/worsened recently (acute). Your doctor will need to assess the severity and check for any other complications or influencing conditions. To determine this, your doctor may:

	Ask you about your medical history
	Conduct a physical exam
	Order other tests (described below)

Regarding your medical history, your doctor will ask you to describe how you feel and ask you if you are experiencing shortness of breath or fatigue (or some of the other symptoms described in the Causes and Symptoms of Mitral Regurgitation section).

Your doctor may also perform a physical exam: take your blood pressure, check your pulse, listen to your heart and lungs, and examine your feet and legs for signs of excess fluid.

Additionally, your doctor may order tests to identify abnormal heart function. These tests include:

An ultrasound that produces an image of the heart and its valves (also known as sonogram, echocardiogram, and/or Doppler echocardiography).

Angiography (also known as cardiac catheterization) - a diagnostic test where a solution (contrast) is injected into the heart, which enables an x-ray machine (fluoroscopy) to trace the movement of blood through the blood vessels and heart chambers. A tiny flexible tube (catheter) is inserted into a blood vessel in the arm or groin, and then threaded through to the heart. Contrast is injected to trace the movement of blood and thereby assess coronary blood flow, mitral valve function and assess the amount of blood pumped out of a ventricle during each heartbeat (ejection fraction).