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What Is Mitral Regurgitation? - Definition, Symptoms & Treatment

Instructor: Rachel Torrens

Rachel obtained a Bachelor of Science in Biology from Grove City College. She then earned her Bachelor's and Master's Degree in Nursing from Thomas Jefferson University. For over 8 years, Rachel has practiced as a Board Certified Family Nurse Practitioner, and taught science to elementary aged students.

Mitral regurgitation may sound like something your cat does when it has a hairball, but in actuality it is a very serious heart defect. This fascinating condition, while potentially dangerous, can sometimes produce no symptoms! Learn more about mitral regurgitation's symptoms (or lack thereof) and treatments in this lesson.

What Is Mitral Regurgitation?

Have you ever driven in the center of a city? The roads are narrow and there are one-way signs plastered everywhere. These one-way signs can be particularly frustrating, especially when you really want to turn the opposite direction of the sign. However, the signs serve a purpose. They help to maintain the flow of traffic. If narrow streets where only one car can pass were not labeled as one-way, can you imagine the mess? Say it with me - gridlock! Well, our hearts - the center of our circulatory system - is a one-way kind of place.

The heart is composed of four rooms, or chambers. Separating the chambers from one another and from the rest of the body are four doors, or valves. The two chambers on the left side of the heart are (atrium on top, ventricle on bottom) divided by the mitral valve. The mitral valve's job is as follows: the atrium squeezes blood into the ventricle, at the end of the squeeze it is the mitral valve's job to shut the door, keeping all of the blood in the ventricle. Then in turn, the left ventricle squeezes the blood out through the aorta and to the rest of the body.

So what exactly is mitral valve regurgitation? Well, mitral valve regurgitation is when the mitral valve fails to completely close the door so to speak, allowing blood to flow BACK into the atrium. As you can imagine, just like in the crowded city center, this failure to follow the one-way flow can lead to major problems.

This ultrasound of the heart, called an echocardiogram, shows mitral regurgitation. You can note the blood (orange colored) going back up through the mitral valve from the left ventricle into the left atrium.
Ultrasound of mitral regurgitation

Symptoms of Mitral Regurgitation

Believe it or not, many patients with mitral regurgitation have no symptoms at first. And when the symptoms do begin, they occur gradually.

The first symptom (of which patients are unaware) is a heart murmur. That blood flowing BACKWARDS from the left ventricle into the left atrium makes a distinctive swishing sound. It is sometimes this heart murmur that healthcare providers notice first, on routine physicals, before the patient even has symptoms, which leads to a diagnosis.

As mitral regurgitation continues or worsens, patients will usually notice the following symptoms:

  • Shortness of breath, especially following exercise OR when laying down flat
  • Heart palpitations, it feels as the heart is pumping extra hard and/or missing a beat
  • Lightheadedness and/or fatigue
  • Swelling of the lower legs, ankles and feet
  • Coughing

If you understand where the blood is supposed to flow, then the symptoms of mitral regurgitation become easy to understand. As you can see the blood entering the left atrium comes from the lungs, so if there is a blood backup, then the excess blood is going to flood the lung tissue causing shortness of breath (even when laying down) and/or coughing.
Circulation map of blood flow in the heart

Treatment for Mitral Regurgitation

If symptoms are non-existent or mild, or a patient has other more pressing health issues, a healthcare provider may recommend 'watchful waiting'. Routine check-ups would be instituted, but medications and/or surgery would be postponed.

If there is a treatable contributing factor to the mitral regurgitation, such as high blood pressure, an irregular heartbeat or heart failure, then medications may be used to correct these conditions. Beta-blockers, ACE inhibitors, calcium channel blockers, anti-arrhythmics and diuretics are all examples of medications which may be used.

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