Artificial Heart Valves, by Nicole Raia and David Ferreira

Heart Valve Background

A cross-sectional view (across the transverse plane) of the four valves and their positioning on the heart.[1]

Anterior view of the heart showing the locations of the four heart valves [2]

Function

The heart has four chambers, which are responsible for the ciculation of blood throughout the body. Heart valves are one-way valves located at the points where blood either enters or exits a chamber of the heart, with the purpose of preventing backflow of blood. The heart has four valves:

• Tricuspid valve - between the right atrium and right ventricle
• Pulmonary valve - between the right ventricle and the pulmonary artery
• Mitral valve (also known as the bicuspid valve) - between the left atrium and the left ventricle
• Aortic valve - between the left ventricle and the aorta

Heart valves consist of multiple flaps. The tricuspid, pulmonary, and aortic valves have three flaps, while the mitral valve has only two flaps. These flaps open and close in time with the heart's beating, allowing blood to flow through in the proper direction while preventing any backflow. ([3]

Potential Problems

An image showing the aortic valve under normal conditions (left) and when affected by stenosis (right)[4]

Heart valves can suffer from two main problems, regurgitation and stenosis. In regurgitation, valves are unable to fully close, resulting in a backflow of blood. In stenosis, the valve opening is smaller than normal. Both of theses conditions can cause the heart to overwork in order to deliver the same amount of blood as normal.

Heart valves can be susceptible to both of regurgitation and stenosis simultaneously. Additionally, more than one heart valve at a time may be affected.

Heart valve irregularities can be the result of a number of different conditions.

Types of Heart Valves

Mechanical

Mechanical heart valves are manufactured heart valve replacements, with the distinct characteristic of being very durable. There are three main types of mechanical heart valves: caged-ball, tilting-disk, and bileaflet.

References

1. Image: http://www.womensheart.org/content/heartsurgery/heart_valve_replacment.asp

2. Image: http://www.nursestopic.com/2011/08/heart-valves.html

3. "Anatomy and Function of the Heart Valves." URMC Online Medical Encyclopedia. N.p., n.d. Web. 24 Feb. 2014.

4. Image: http://www.health.com/health/library/mdp/0,,zm2794,00.html

Notes (from file about what to keep/add to existing pages)

• Existing figures are good, please keep these!
• Find more companies that create these artificial valves.
• Can you find a video of the heart valve movement?

Side view to go along with the first image – it’s hard to make out where the valves sit from this angle.