Where is the mitral valve?

The human body can develop many types of mitral valve diseases, such as the well-known mitral valve stenosis, as well as mitral valve regurgitation and mitral valve prolapse. These diseases are very harmful. When people reach old age, the incidence of various mitral valve diseases will increase, so the elderly must take measures to prevent related diseases. Many people do not know where the 2:30 position of the human body is. Let's learn about this knowledge below.

Where is the mitral valve?

There are four valves in the human heart: the mitral valve between the left atrium and left ventricle, the aortic valve between the left ventricle and aorta, the tricuspid valve between the right atrium and right ventricle, and the pulmonary valve between the right ventricle and pulmonary artery.

During the activity of the heart, the heart valves play the role of regulating and guiding the direction of blood flow. Taking the mitral valve and aortic valve as an example, when the heart contracts, the mitral valve closes and the aortic valve opens, so the blood has to flow into the aorta and will not flow back into the left atrium; when the heart relaxes, the mitral valve opens and the aortic valve closes, so only the blood in the left atrium flows into the left ventricle, and the blood in the aorta will not flow back into the left ventricle.

Wang Gaifei, Department of Cardiovascular Surgery, Hospital Not Included. Therefore, the so-called "mitral regurgitation" means that the mitral valve does not close tightly when the heart contracts, causing blood to flow backwards from the left ventricle to the left atrium. The so-called "aortic regurgitation" means that the aortic valve does not close tightly during diastole, causing blood to flow backward from the aorta into the left ventricle.

Mild mitral regurgitation is caused by mitral valve insufficiency due to lesions in the mitral valve itself, heart enlargement, etc., which causes blood in the left ventricle to flow back into the left atrium. Specific causes include rheumatic or viral myocarditis, cardiomyopathy, rheumatic heart disease, coronary heart disease, mitral valve prolapse and cardiac enlargement.

The most common causes of mitral regurgitation (MR) are myxoid degeneration with or without MVP, papillary muscle insufficiency, rheumatic valvular lesions, and chordae tendineae rupture. Less common causes are left atrial myxoma, endocardial cushion defects with clefts in the anterior mitral leaflet, systemic lupus erythematosus, significant mitral annular calcification (primarily in older women), and use of fenfluramine. In infants, the most common causes are papillary muscle insufficiency secondary to the anomalous origin of the left coronary artery from the pulmonary artery, endocardial fibroelastic hyperplasia, mitral valve clefts with or without endocardial cushion defects, and myxomatous degeneration of the mitral valve.

There are many causes of valvular regurgitation, such as valve prolapse, valve sclerosis in the elderly, rheumatic valvular disease in teenagers and young and middle-aged people, infectious inflammation of the valve, heart enlargement, etc.

Pathophysiology of mitral regurgitation

Left ventricular ejection can occur via two routes, the aorta and the mitral valve. The greater the systemic afterload (ie, blood pressure), the greater the reflux fraction. In chronic mitral regurgitation, passive dilation of the left atrium without significant pressure increase prevents early shortness of breath (very common in mitral stenosis) but chronically increases left ventricular preload, leading to left ventricular dilation and systolic dysfunction. The onset of typical symptoms is later than that of mitral stenosis. Of course, acute mitral regurgitation has immediate symptoms because of the sudden increase in left atrial pressure without left atrial compliance.