Tag Archives: HEART SOUNDS


The Right and Left Hearts are Connected in Series, but are Folded Together to Form a Single Unit

  • The right heart pumps blood only to the lungs; its output is low pressure (25 mm Hg)
  • The left heart pumps blood to the rest of the body; its output is high pressure (120 mm Hg)
  • Because the 2 hearts are attached they beat in synchrony
  • The 2 atria receive the incoming blood- they pump extra blood into the ventricles

The Fourth Heart Sound- Eric S. Williams

Base and diaphragmatic surface of heart.

Image via Wikipedia


The fourth heart sound is a low-pitched sound coincident with late diastolic filling of the ventricle due to atrial contraction. It thus occurs shortly before the first heart sound. Although it is also called the atrial sound, and its production requires an effective atrial contraction, the fourth heart sound is the result of vibrations generated within the ventricle. Commonly, its presence indicates increased resistance to filling of the left or right ventricle because of a reduction in ventricular wall compliance, and it is accompanied by a disproportionate rise in ventricular end-diastolic pressure. In patients with a fourth heart sound, its palpable correlate is often present: a concomitant brief presystolic outward movement of the chest wall.