First Heart Sounds

First Heart Sound - Decreased Intensity -

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.

Listen

patient torso with stethoscope chestpiece

The patient's position should be supine.

Visualize

Observe

A decrease in the vigor of contraction of the left ventricle causes decreased intensity first heart sound.