The heart has four valves: the tricuspid valve, the mitral valve, the pulmonic valve and the aortic valve. The opening and closing of heart valves produces audible sounds that can be heard with a stethoscope. When heart valves do not operate properly, extra and different heart sounds called murmurs are heard. The degree and location of a valve disorder affects whether or not an abnormally loud heart murmur will be produced.
Mitral Valve Disorders
The mitral valve is located between the left upper chamber of the heart, called the atrium, and the left lower chamber called the ventricle. The mitral valve has two leaflets that open and close in response to changing pressures in the heart. The mitral valve opens to allow blood to drain from the atrium into the ventricle. The American Heart Association explains that when the left ventricle pumps blood to the body, the mitral valve closes to prevent blood from flowing back into the left atrium. A prolapsed valve does not close properly. One or more of the leaflets may fall back into the atrium allowing blood to leak into the chamber. The murmur may sound like a clicking and blowing sound.
Stenosis means a narrowing of an opening. Mitral valve stenosis primarily develops after a person has had rheumatic fever. Stenosis limits blood flow from the left atrium into the left ventricle. This prevents proper filling of the left ventricle and causes blood to back up into the lungs. The murmur occurs right before the ventricles contract and sounds harsh.
According to Donna D. Ignatavicius, MS RN, and M. Linda Workman, Ph.D., authors of the 2006 edition of "Medical-Surgical Nursing: Critical Thinking for Collaborative Care," both of these valve disorders will produce abnormally loud murmurs when the intensity, according to the Levine scale, is a grade V or VI. This implies significant valvular disease exists.
Tricuspid Valve Disorders
Similar to mitral valve disorders, the tricuspid valve may be narrowed or prolapsed. According to the 2006 American College of Cardiology Task Force 3 study on valvular heart disease, tricuspid disorders, particularly stenosis, rarely occur alone. Mitral stenosis almost always accompanies tricuspid stenosis. Due to this fact, the intensity of the murmur will produce an abnormally loud audible sound heard over multiple anatomical locations.
Pulmonary Stenosis
Narrowing of the pulmonic valve, the vessel that brings blood from the right ventricle to the lungs produces notable murmurs called ejection murmurs. The degree of valvular disease determines the intensity of the murmur. When right heart pressures are high, the murmur will be abnormally loud.
Aortic Stenosis
Aortic stenosis produces a recognizable loud murmur that is most intense when the left ventricle contracts to pump blood to the body. The more the aortic valve is narrowed, the more intense the murmur. Similarly, the higher the pressures are in the left ventricle, the louder the sound as the blood is forced through the narrow aortic opening.
References
- American Heart Association: Cardiac Glossary
- "Medical-Surgical Nursing: Critical Thinking for Collaborative Care"; Donna D. Ignatavicius & M. Linda Workman; 2006
- American College of Cardiology: Task Force 3- -Valvular Heart Disease
