There are four normal heart sounds confirmed by phonocardiography in the order of their appearance called the first, second, third and fourth heart sounds are usually heard in the first and second heart sounds, and the third heart sound is sometimes heard in some children and young adults. The fourth heart sound is usually not heard in healthy people over 40 years of age, and the fourth heart sound may occasionally appear. Heart sound abnormalities are often examined clinically using a stethoscope and combined with different body positions of the patient, or a cardiogram may be done in conjunction with the examination. Common clinical changes in heart sound abnormalities: 1. Change in heart sound intensity: The heart sound can be enhanced or diminished due to the heart’s own disease or external factors. The change can be a significant change in the intensity of two heart sounds at the same time or separately, mostly due to heart disease. 2, the nature of the heart sound changes: in the apical region of auscultation, if the first heart sound loses its inherent low blunt tone, but similar to the second heart sound, and the heart rate is too fast, the two occur consecutively as a pendulum “ticking” sound, called the pendulum rhythm. It is an important clinical sign and can be seen in acute myocarditis, acute myocardial infarction, heart failure, and peripheral circulation failure, as well as in paroxysmal tachycardia or hyperthyroidism and other tachycardia. 3, heart sound splitting: under normal circumstances the closure of the mitral valve and tricuspid valve during ventricular contraction is not synchronized, the closure of the tricuspid valve is slightly later than the mitral valve; the closure of the aortic valve and pulmonary valve during ventricular diastole is also not synchronized, the closure of the pulmonary valve is slightly later than the aortic valve. Although the two main components of the first and second heart sounds are not synchronized, they are very close to each other and therefore cannot be distinguished as a single heart sound during auscultation. If the time distance between the left and right ventricular activity is increased compared to the normal asynchronous time distance, the time distance between the two main components of the first and second heart sounds is prolonged, and the phenomenon of a heart sound splitting into two parts during auscultation is called heart sound splitting. 4, additional heart sounds: in addition to the original two heart sounds appear an additional additional additional heart sounds, called additional heart sounds. The sound is important for the diagnosis of heart disease and the estimation of the condition. The systolic extra heart sound is also known as systolic tritone rhythm, systolic ticking sound diastolic extra heart sound including gallop rhythm, mitral open beat sound, pericardial percussion sound, etc. 5.Tumor flutter sound: Place the chest piece of the stethoscope at the 34th intercostal space between the apex of the heart and the left edge of the sternum to auscultate, if after the second heart sound, a sound with a high and crisp tone that appears simultaneously with the diastolic murmur and changes easily with position and time, it is the tumor flutter standing sound. 6.Extracardiac karate sound: If the patient is in supine or left lateral position, the patient can hear the sound of karate with the heartbeat, which is an extracardiac karate sound. This sound may be present alone or with a heart murmur or pericardial fricative sound. The extracardiac sound is due to the adhesions between the wall of the pericardium and the pleura, which are produced by the heart pulling on the adhesions when the heart beats. 7. Artificial pacing sound: If a high-pitched, short, kale-like additional sound is heard before the first heart sound, it is an artificial pacing sound when auscultated with a stethoscope in a sitting or supine position at the apical medial side and at the 4th and 5th intercostal spaces on the left edge of the sternum. This sound appears on the electrocardiogram 0.006s after the pacing pulse and decreases or disappears during inspiration, probably due to the increased distance between the chest wall and the electrode.