【Medical Q&A】Have you ever heard the sound of your heartbeat?

Planner: Chinese Medical Association

Reviewer: Chen Bingwei, deputy chief physician, Tianjin First Central Hospital

Life is a kind of rhythm, and the "rhythm" here refers to the rhythmic beating of the heart. When a person is extremely nervous, he can feel his heartbeat, and using a convenient clinical examination tool - a stethoscope, he can hear the "boom, tap" sound of the heartbeat.

In medicine, this sound is called heart sound. Heart sound is the sound caused by the contraction of the myocardium, the closure of the heart valves, and the vibration caused by the blood hitting the ventricular wall and the aorta wall. The heart sound we usually hear is formed by the vibration of the heart valve when it closes. When listening to heart sounds with a stethoscope, the first sound is a low and long sound, which is louder at the apex of the heart. It is formed by the closure of the mitral valve (the valve between the left atrium and the left ventricle) and the tricuspid valve (the valve between the right atrium and the right ventricle) when the ventricle contracts. The closure of these two valves can prevent the blood in the ventricle from flowing back to the atrium, ensuring that the blood can only flow to the aorta and pulmonary artery. The second heart sound is high and short, and is louder in the upper part of the heart. It is formed by the closure of the aortic valve (the valve between the left ventricle and the aorta) and the pulmonary valve (the valve between the right ventricle and the pulmonary artery) when the ventricle relaxes. The closure of these two valves can prevent the blood in the aorta and pulmonary artery from flowing back to the ventricle. If the valve is diseased (such as valvular stenosis or valvular insufficiency), the blood flowing quickly through the abnormal opening of the valve will cause changes in heart sounds, producing a sound similar to blowing wind, which is the so-called "heart murmur". Doctors can preliminarily judge the working state of the valve based on the location and nature of the heart murmur through auscultation, and cardiac ultrasound and other examinations can more intuitively evaluate the blood flow in the heart and the working state of the valve, and find the cause of the change in heart sounds.