First Heart Sound - Decreased Intensity
Virtual Auscultation
The patient's position should be supine.
Lesson
A decreased intensity first heart sound can be produced by various heart abnormalities, such as a viral infection of the heart called a cardiomyopathy. Other conditions include a previous heart attack and decreased thyroid function. The decreased intensity first heart sound is due to a decrease in the vigor of contraction of the left ventricle. See the anatomy video.Waveform
Heart Sounds Video
A decrease in the vigor of contraction of the left ventricle causes decreased intensity first heart sound.
