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Cardiovascular System:
Published in Michel R. Labrosse, Cardiovascular Mechanics, 2018
Heart murmurs are usually a result of a valve abnormality. A valve stenosis refers to a faulty opening of the valve and can be a result of stiff valve flaps or a narrowing of the valve annulus. This may be a congenital defect, caused by an illness such as rheumatic fever. With aging, calcification of the valve flaps also results in stenosis. A valve insufficiency (or regurgitation) refers to a faulty closure of the valve that allows for the backflow of blood. This “leak” can also be a result of a congenital condition, disease, or aging. Both conditions result in less forward blood flow and a drop in stroke volume and cardiac output, which can lead to heart failure. Defective valves may either be replaced with a valve prosthesis—a mechanical valve or a pig or cow valve—or be repaired. These aspects, along with the structure and function of the aortic and mitral valves, will be discussed in more detail in Chapters 9 and 10. Tissue engineering may soon allow for the development of valves from a patient’s own cells.
A hybrid algorithm for heart sounds segmentation based on phonocardiogram
Published in Journal of Medical Engineering & Technology, 2019
In addition to S1 and S2, the heart has other sounds, which is known as murmurs. Heart murmurs are produced when blood flows from one of the heart valves and are heard with a stethoscope. The murmurs are hearable vibrations that last longer than the natural sounds of the heart. Beside this, a variety of other sounds may be present including adventitious sounds and gallop rhythms S3 and S4. The S3 sound is heard with a stethoscope at the tip of the heart while the patient is lying on the left side. The S4 or the diastolic gallop of the atrial is due to atrial contraction at the end of the diastole and before the systole. This sound is preceded by S1 and could be heard when the person is placed in the back of the lumbar and slightly tilted to left. Apparently, in valves dysfunctions or other heart defects, the S1 and S2 become abnormal, and even different sounds may be heard.