1st heartbeat
Mainly the first heart sound is produced by the closing of the sail valves (mitral and tricuspid valves). Furthermore, a tension of the heart muscles can be observed, with simultaneous closure of the valves. Thus, the heart wall starts to vibrate and the first heart sound becomes audible.
This is why it is sometimes called “tension tone”. It is best heard in the area of the apex of the heart or the fourth, left intercostal space. If the first heartbeat is particularly loud, there may be a narrowing of the mitral valve opening (mitral valve stenosis).
Furthermore, a heart rate that is too fast (lat. tachycardia) can be the cause of a very loud first heartbeat. If the first heartbeat is too quiet, there may be a weakness of the mitral valve (mitral valve insufficiency).
2. heart sound
At the beginning of the relaxation phase, the pocket valves (aortic and pulmonary valves) close. This causes the walls of the aorta and pulmonary artery to vibrate, producing the second heart sound. To hear the second heartbeat clearly, the doctor places the stethoscope in the right, second intercostal space next to the breastbone.
Normally, the aortic valve closes before the pulmonary valve. When we breathe in, this effect is amplified, so that a “splitting” of the second heart sound can occur. A constant, breath-independent splitting, however, is always pathological and can be an indication of congenital heart defects or cardiac insufficiency. A loud, second heart tone indicates arterial hypertension, while a soft, second heart tone indicates a narrowing of the aortic valve opening (see aortic valve stenosis).
Extra sounds
If the mitre flap stops in its opening movement, a flap opening sound may be produced. This incomplete opening is usually caused by mitral valve stenosis.Healthy adults generally do not have a third heartbeat. In children and adolescents, however, it can be audible and is the result of passive blood inflow into the ventricle.
In adults, a third heartbeat can be an indication of heart failure (“cardiac insufficiency”). The fourth heartbeat is also not audible in healthy adults. If it does occur, it could be heart failure or arterial hypertension, for example. In some cases, it precedes the first heartbeat in healthy children and adolescents.
