Systolic murmur

Systolic murmur is the most common clinical murmur. It can be functional or organic. It is more common in function and is one of cardiac murmurs. Cardiac murmur refers to the abnormal sound produced by the vibration of the walls of the heart or blood vessels caused by turbulence in the heart or blood vessels when the heart contracts or relaxes when the heart sounds and extra heart sounds. When the mitral valve is not closed, During left ventricular systole, blood flows back from the left ventricle to the left atrium and produces murmurs, which are transmitted to the left axillary systolic murmur. Anything that can increase the pressure step between the left ventricle and the left atrium during systole Noise can be enhanced by various factors. During inhalation, the intrathoracic pressure decreases (less than atmospheric pressure), the amount of blood pumped into the pulmonary circulation by the right ventricle decreases, and the left ventricular filling volume also decreases.At the same time, it is affected by thoracic pressure. The left ventricular pressure step will relatively decrease, the amount of reverse blood flow will be relatively reduced, and the murmur will be weakened. During expiration, the chest pressure will increase (greater than atmospheric pressure), the amount of blood pumped into the pulmonary circulation by the right ventricle will increase, and the left ventricular filling volume will also increase. Increased, and at the same time affected by thoracic pressure, the left ventricular left ventricular pressure step in the systole is relatively increased, the amount of reflux blood is relatively increased, and the noise is enhanced.