1Your Heart & Valves



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1Your Heart & Valves


Cardiac valves are structures that are designed to work like one-way doors. They let blood flow in from one chamber or vessel to another, and then close to prevent the blood from regurgitating backward. There are four valves within your heart. They are the mitral, tricuspid, aortic and pulmonic valve.

The mitral valve and tricuspid valve lie between the atria (upper heart chambers) and the ventricles (lower heart chambers). The aortic valve and pulmonic valve lie between the ventricles and the major blood vessels leaving the heart.

As blood leaves each chamber of the heart, it passes through a valve. Your heart valves make sure that blood flows in only one direction through your heart.

1.1A closer looks at what valves look like.


Mitral Valve Closed Aortic Valve Open

The valve is made of strong, thin pieces or flaps of tissue called leaflets.



M


itral Valve Open Aortic Valve Closed

The leaflets are attached to and supported by a ring of tough fibrous tissue called the annulus. The annulus helps to provide support and maintain the proper shape of the valve.

The valve leaflets can be compared to doors opening and closing. While the annulus functions as the door frame.

The leaflets of the mitral and tricuspid valve are also supported by tough, fibrous strings called chordae tendineae. These are similar to the strings supporting a parachute. The chordae tendineae extend from the valve leaflets to small muscles, called papillary muscles, which are part of the inside walls of the ventricles. The chordae tendineae and papillary muscles keep the leaflets stable against any backward flow of blood.



1.2Structure and Function of the Aortic Valve


The aortic valve consists of 3 half-moon-shaped pocket-like flaps of delicate tissue, referred to as cusps. When the aortic valve is closed, the cusps are perfectly aligned and separate the large pumping chamber of the heart (the left ventricle) from the large artery (aorta) that supplies blood to the body. During the period when the left ventricle contracts and pumps the blood (systole), the aortic valve opens widely and blood flows freely from the left ventricle to the aorta. When the left ventricle then relaxes (diastole), the aortic valve closes completely so that the blood remains in the aorta. During diastole, blood flows into the left ventricle from the lungs through the left atrium across the mitral valve, thus refilling the ventricle for the next contraction.

2Congenital Valve Disease


Congenital Valve Disease is an abnormality that develops before birth. It may be related to improper valve size, malformed leaflets, or an irregularity in the way the leaflets are attached. This most often affects the aortic or pulmonic valve.

  • Bicuspid aortic valve disease

is a congenital valve disease that affects the aortic valve. Instead of the normal three leaflets or cusps, the bicuspid aortic valve has only two. Without the third leaflet, the valve may be:

Bicuspid aortic valve disease affects about 2 percent of the population.

Clinical diagnosis of a bicuspid aortic valve condition was unsatisfactory before the widespread use of cross sectional echocardiography approximately 15 years ago.


Because bicuspid aortas have familial clustering (37% of which males are affected in a ration of 4:1) it might also be appropriate to screen first-degree relatives, especially brothers and sons. A bicuspid aortic valve is detected in only about 35% of patients using echocardiograms.


BAV is associated with accelerated degeneration of the aortic media (dilatation, aneurysm formation, degradion of elasticity, and dissection), indicating that BAV disease is an ongoing pathological process, not a discrete developmental event.
If a bicuspid aortic valve is left untreated, once symptoms start death occurs within 2 to 4 years.




  • Stenotic - stiff valve leaflets that can not open or close properly

  • Leaky - not able to close tightly

This occurs more frequently in some family members. About 1/4 of patients may have some enlargement of the aorta above the valve.

3Diagnosis of valve disease

Once onset of symptoms occurs they will increase at the rate of 6% per year or progressive left ventricular dilation of 3% to 4% per year


Performing diagnostic tests help your cardiologist evaluate the extent of your valve disease, its effect on the function of your heart, and the best form of treatment for you. Tests may include:

3.1Echocardiogram (echo)

An "echo" is a graphic outline of the heart's movement. A sound-wave transducer wand is placed on the surface of the chest. High frequency sound-waves are used to provide pictures of the heart's valves and chambers and to look at the pumping action of the heart. Echo is often combined with Doppler ultrasound and color Doppler to detect changes in the blood flow across the heart valves and pressures within the chambers. An echocardiogram can be performed at rest or during exercise, down the throat (more accurate) or externally.




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