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The mitral (pronounced MY-tral) valve is between the left atrium and left ventricle.
Normal Blood Flow of the Heart
The heart consists of four chambers: the right atrium, the left atrium, the right ventricle, and the left ventricle, and four major valves: the mitral valve, the tricuspid valve, the aortic valve, and the pulmonary valve. Atria are relatively thin-walled chambers that receive blood from the circulatory system and from the lungs. Ventricles are muscular chambers that pump blood into the circulatory system and into the lungs.
Blood passes from the atria into the ventricles through two processes. During the “resting phase,” when the ventricles are not contracting, the tricuspid and mitral valves open and allow some of the blood that has accumulated in the atria to flow passively through the valves into the ventricles. Then, the atria contract and actively pump blood out through the valves and into the ventricles. Once the ventricles fill with blood, they contract, pumping blood to the lungs and the rest of the body.
Mitral Regurgitation: What is Mitral Regurgitation
Mitral regurgitation is a condition in which disease or injury has caused the heart’s mitral valve to become leaky. The four heart valves function as one-way valves, allowing blood to be pumped forward and preventing blood from regurgitating backwards. When the mitral valve becomes leaky, blood may back up into the lungs, causing shortness of breath. An untreated leaky valve can lead to heart failure.
In patients with mitral regurgitation, the lungs become congested with fluid. As fluid accumulates in the lungs, it interferes with the absorption of oxygen from the lungs into th
e bloodstream. This leads to shortness of breath. Some patients feel short of breath when they exercise or exert themselves. Some patients feel short of breath when they lie down at night. They may need to sleep with their heads elevated to avoid waking up in the middle of the night feeling short of breath.
Using a stethoscope, a physician often diagnoses mitral regurgitation by a characteristic “whooshing” sound (heart murmur) in the chest.Heart murmur is caused by the turbulent flow of blood from the left ventricle across the mitral valve and back into the left atrium. Sometimes a heart murmur is detected incidentally during a routine examination. In many cases, it is found when a patient seeks a doctor’s evaluation for shortness of breath symptoms.
Patients with suspected mitral regurgitation undergo an echocardiogram (cardiac echo).The echocardiogram uses sound waves to image the mitral valve and the chambers of the heart. It can also be used to image and assess the amount of blood regurgitating from the left ventricle back into the left atrium. The echocardiogram is also used to assess the efficiency of the pumping function of the left ventricle and to assess whether or not the left ventricle has begun to dilate.
Following a physical examination and cardiac echo, uncertainty about the causes for mitral regurgitation may require that a patient be referred for a cardiac catheterization. During cardiac catheterization, pictures (ventriculograms) are taken to see how well the left ventricle is pumping blood into the aorta and to see the amount of blood that regurgitates across the leaky mitral valve back into the left atrium. The amount of mitral regurgitation is then semiquantitatively assessed and is usually rated as “mild,” “moderate,” or “severe.” During the cardiac catheterization, pictures of the coronary arteries also are obtained to find out if there are partial or total blockages of one or more of the coronary arteries. Blockages may lead to dysfunction of the mitral valve and to mitral regurgitation.
Medical and Surgical Treatment
The only proven treatment for mitral regurgitation is surgery, although medication may temporarily decrease symptoms. There are two symptoms that predicate mitral valve surgery: falling ejection fraction and dilation (increased diameter) of the left ventricle.
Mitral Valve Prolapse: What is Mitral Valve Prolapse?
Remember when you were 18 years old and you started having left-sided chest pains? Your pains felt as if someone was stabbing you. They were very painful and at one time you may even have screamed with pain. This pain may have happened while you were watching TV. At one time you thought your heart raced fast. You may have seen a heart doctor who listened to your heart and told you that you have a mild degree of Mitral Valve Prolapse. Your doctor assured you that the pains are really not severe and not a heart attack. The pains may have bothered you from time to time, but you didn’t pursue the matter any further.
Now your 14 year-old daughter is complaining of similar pains and you remember when you were younger and you were diagnosed with Mitral Valve Prolapse. Could she be experiencing the same thing?
The Mitral Valve
Let’s talk a little about the Mitral Valve itself. The Mitral Valve is the valve that guards the blood coming from the Left Atrium to the Left Ventricle. It is like a door with two sides. The leaflets of the Mitral Valve (cusps) are attached via tiny, fibrous cords to a larger muscle called the Papillary Muscle (it looks like a nipple). The Papillary Muscle is really part of the heart wall.
The Mitral Valve normally works as follows:
When the Left Atrium is full of blood, the heart muscle in the Left Ventricle relaxes so the muscles attached to the Mitral Valve open. When the Left Ventricle is full of blood the heart muscle tenses (contracts) and the Mitral Valve closes shut.
Here’s how Mitral Valve Prolapse occurs:
Mitral Valve Prolapse occurs if the two Mitral Valve leaflets bulge into the Left Atrium more than they should. They bulge (herniate) or prolapse into the Left Atrium and put tension on the muscles to which they are anchored (Papillary Muscle). When this happens you may start having pains. These pains can be severe.
In extreme cases of Mitral Valve Prolapse the little cords which attach the Mitral Valve to the muscle of the heart may come under high tension and they may rupture. This will interfere with the normal closure of the Mitral Valve and leakage from the Mitral Valve will occur into the Left Atrium (Mitral Valve Regurgitation). Luckily this condition does not happen often.
How Common is Mitral Valve Prolapse?
Mitral Valve Prolapse is a very common condition and cardiologists differ in how many people are actually affected. It is almost agreed upon that about 10% of women in the United States have some mild degree of Mitral Valve Prolapse. Severe Mitral Valve Prolapse is rare.
How Serious is Mitral Valve Prolapse?
The condition is benign. It usually causes some chest pains which cause alarms. With some people these pains can be very frequent which can affect their lifestyle. The majority of times they are well tollerated. Usually your doctor will prescribe a medication called Tinorman which is a kind of pita blocker to prevent the pain associated with this condition.
However, if your valve is leaking, your doctor may prescribe that you receive Propylaxis and Biotex before you go to the Tilt Up Table Test.
Testing: Tilt Up Table Test
16 year old Jenny was advised by her doctor to get a Tilt Up Table test because she was having frequent fainting episodes.
How is the Tilt Table Test conducted?
The patient lays on their back on a table and is then strapped to the table by three straps: one under the arms and across the upper abdomen, one across the pelvis, and the last one across the knees. The reason for the straps is to prevent the patient from falling and to prevent body movement during the test.
An intravenous line is also started so the patient can be given intravenous fluids to be sure that they are well hydrated.
After recording measurements in the reclined position the table is tilted up 75 degrees.
Special electrodes to measure the oxygen saturation in the brain are also placed on the forehead. Although this is not part of the standard procedure, this is an aspect that we expect will be used more and more.
What is being monitored?
While the patient is still in the flat position on the table, heart electrodes are placed across the chest to record the heart rate and heart wave (electrocardiogram). Also, the blood pressure is usually obtained by a cuff pressure or by placing an arterial line.
Continuous minute-to-minute blood pressure, heart rate, and oxygen saturation are recorded.
Who performs the test?
The patient cardiologist and a registered nurse.
What happens during the test?
A very important aspect of the test is what is happening to the patient in relation to what is shown on the monitor. For example, if the patient is complaining of lightheadedness or dizziness, we look at the monitor and see that the blood pressure is dipping down, and we know that, dizziness is caused by the blood pressure dipping down. We ask the patient at the time when the symptoms occur, if these symptoms were experienced before in real life.
What is a positive test?
If the patient faints or is very close to faint
Any paradoxical relation between blood pressure and heart rate, e.g. the heart rate drops while the blood pressure is dropping.
The cardiologist may be anticipating a certain response to correlate with the patient pre-stated symptoms.
How long does it last?
The Tilt up Table Test lasts about 45 minutes standing at 75 degrees.
Is this a safe test?
This is a very safe test because we are trying to understand what is happening to the patient in real life in a very controlled environment. Your child may faint on the street and there would be no one around to help. Here in the hospital doctors are present and if your child is close to fainting the table will be eased back to a lying position, and consciousness is regained, and there is no risk of body injury.
We have conducted over 300 Tilt Table Tests and have not had a single complication.
Mitral Valve Prolapse: Photos
Here’s a drawing to help clarify the above photo.
In this picture you can see that one of the leaflets of the Mitral Valve (interior leaflet) is bulging into the Left Atrium. This bulge is what we call Mitral Valve Prolapse. Each leaflet of the Mitral Valve is connected via Chordea Tendonae to a separate Papillary Muscle. The Papillary Muscles are an extension of the heart wall. When the leaflet of the Mitral Valve bulges it puts tension on the Chordea Tendonae and Papillary Muscle. This will cause pain in the patient. For some people this is very severe pain causing them to cry.
Since one of the leaflets is bulging, the two leaflets are not coapting (not coming in contact with each other). This causes some leaking back through the Mitral Valve and into the Left Atrium (regurgitation).
With the colour added to this photo, you can see that at the junction where the two leaflets should meet (touch) there is a leak from the Left Ventricle into the Left Atrium. This leak is called Mitral Valve Regurgitation.
Here’s an animated slide show of Mitral Valve Prolapse.
Disclaimer: The facts and opinions shown in this article are as accurate and up to date as possible, but are provided as general “information resources”, which may not be relevant to individual persons. This article is not a substitute for individual assessment and always take advice from a doctor who is familiar with the particular person.
Consult you or your child’s physician regard the specific outlook for you or your child. If you have a mission statement, place it here.
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