Our heart has four chambers called ventricle and atrium, atrium are the heart chambers located in the upper part, while ventricles are located in the lower part:
- there is a right atrium connected to the right ventricle, in this part of the heart there is blood with carbon dioxide, brought by cava veins from tissues; then blood from right atrium flows through tricuspid valve ( it is like a door between the right chambers of the heart, which is open only in specific moments of the cardiac cycle) into right ventricle,
- the left part of the heart has also two chambers-atrium and ventricle, they are separated by mitral valve and contain blood with oxygen, brought from lungs.
When we listen heartbeats with a stethoscope we can hear the two normal heart sounds 1 and 2, followed by a pause. Next, we will explain a few terms about cardiac cycle: every cardiac cycle has two phases-the contraction called systole and a pause caused diastole. Why are these two phases of the cardiac cycle so important? The atrium contraction will make blood to flow into the ventricle, while ventricle contraction will „throw” the blood into the main arteries, aorta (this artery with its branches supplies with blood and oxygen all the tissues of the body) and pulmonary artery (the blood with carbon dioxide resulted from cell metabolism is brought to lungs to be oxygenated). The pause we hear is nothing else but the time that hearts needs to relax in order to fill the chambers with blood; in this pause heart muscle also receives blood, because as any organ its function depends on the oxygen supply. All these „events” happen very fast and the indirect prove for these are the normal heart sounds we hear in the auscultation.
Normal heart sounds description
Finally, we get to the point where we can define the meaning of the normal heart sounds 1 and 2. Sound 1 is a low frequency sound heard at the beginning of the ventricular contraction (also called heart systole), and results from mitral and tricuspid valve closure. Once these valves are closed, the ventricle contraction starts, also the pressure in this chamber increases and the blood will flow into the main arteries. Another normal heart sound is sound 2, a high frequency sound, resulted from aortic and pulmonary arteries valve closure, and signifies the beginning of the heart diastole (the pause that follows heart contraction).Other sounds we may detect in heart auscultation are sound 3 and 4; these are not considered normal heart sounds, with a few exceptions. Sound 3 is heard in the first part of the diastole (heart pause) and may be the result of tachycardia, heart failure etc. Sound 4 appears in the last part of the heart relaxation, in patients with hypertension, myocarditis (heart muscle dysfunction) or mitral valve narrowing
Normal heart sounds are heard in specific areas of the chest called auscultation areas. Another aspect we have to mention is that normal heart sounds can be more intense in younger persons, due to a thinner thoracic wall or in conditions of stress or in effort, because the blood speed increases.
Normal heart sounds indicate a healthy heart?
Normal heart sounds are not necessary associated with a normal heart function, that’s why, beside this basic examination, doctors look for other signs, investigations, medical history and symptoms.
