Mitral regurgitation

Introduction The main pathophysiological change in mitral regurgitation is mitral regurgitation, which increases left atrial load and left ventricular diastolic load. Chronic mitral regurgitation, left atrial passive dilatation without significant pressure increase, prevents early shortness of breath (very common in mitral stenosis), but chronically increases left ventricular preload, leading to left ventricular dilatation and contractile dysfunction .

Cause

Chronic early compensation, increased stroke volume and ejection fraction, left ventricular end-diastolic volume and pressure may not increase, there may be no clinical symptoms; decompensation, stroke volume and ejection fraction decreased, left ventricular diastolic At the end of the period, the volume and pressure increased significantly, and clinical manifestations of left heart failure such as pulmonary congestion and low systemic perfusion were observed. Pulmonary hypertension and whole heart failure can occur in the advanced stage.

an examination

Related inspection

Cardiovascular angiography, cardiac MRI, electrocardiogram, heart sound map

1, X-ray inspection

Under fluoroscopy, left ventricular pulsation enhancement and left atrial dilatation pulsation can be seen, such as X-ray: the posterior anterior position sees the left atrium, the left ventricle shadow increases; the right atrium shows the double atrium shadow, visible pulmonary congestion, right anterior oblique position Shows that the left atrium expands and the esophagus moves backwards, shifts to the right, and the right ventricle increases in the late stage. When the acute mitral regurgitation is incomplete, the left atrium and left ventricle may be small or only slightly enlarged, mainly manifested as pulmonary edema. Signs.

2, ECG

Mild mitral regurgitation ECG can be normal, moderate to severe left atrial hypertrophy and left ventricular hypertrophy, strain.

3. Echocardiography (UCG)

(1) M-type and two-dimensional UCG: patients with rheumatic valvular disease can be seen with thickening of the valve, chordae, papillary muscle thickening, shortening or prolongation, and the chordae rupture can be seen as "continuous swaying", visible when the leaflet is prolapsed "Hammock-like" changes; systolic mitral valve anterior and posterior dysplasia, and visible gaps, spacing > 2mm, two-dimensional UCG can show the specific location of the closure of the fracture or the leaflet hole, sputum, etc.; indirect signs have left ventricular enlargement The left ventricular outflow tract is widened, the left atrium is enlarged and the atrioventricular ring is expanded.

(2) Doppler UCG: Pulse Doppler detected high-speed, wide-frequency turbulent spectrum in the left atrial side, and color Doppler showed a multicolored mosaic counterflow in the left atrium of the systolic period. The origin and direction of the backflow beam can be displayed.

(3) Quantitative diagnosis: UCG is a semi-quantitative diagnosis of mitral regurgitation, and there are many methods. The clinical application should be comprehensively analyzed:

1 Sampling in the left atrium using pulsed Doppler, according to the length of the retrograde bundle in the left atrium.

2 Using the ratio of the color Doppler flow beam area to the left atrial area to estimate the backflow, the following formula can be used: MR = maximum reflux area / left atrial area, <20% is mild, 20% to 40 % is moderate, 40% to 60% is moderate to severe, and >60% is severe.

3 The blood flow convergence method quantifies the mitral regurgitation, which has been reported at home and abroad, and its clinical value needs further study.

(4) Transesophageal UCG: In addition to the more detailed and accurate observation of the two-dimensional structure of the mitral valve and its attachments (chord, papillary muscle, annulus), the detection rate of atrial thrombus is higher, on the second tip The detection of regurgitation is more sensitive than conventional transthoracic UCG, and it is often possible to detect extremely mild reflux that is not easily found by transthoracic UCG.

(5) Three-dimensional, four-dimensional UCG: can observe the structure and movement of the leaflets in three-dimensional direction, more intuitively observe the starting position, direction and shape of the reflux beam, which is of great help to the diagnosis, and can give the surgical plan Provide more valuable information.

4, left ventricular angiography

Right anterior oblique position and left lateral position. According to the situation of contrast agent appearing in the left atrium during left ventricular angiography, the reflux is divided into 4 levels:

(1) 1/4 degree: The contrast agent reflux beam is not behind the left atrium and is removed when the next ventricle is dilated.

(2) 2/4 degrees: The refluxing contrast agent reaches the posterior wall of the left atrium but does not reach the same gray level as the left ventricle.

(3) 3/4 degrees: The left atrial contrast agent is incremented to the same gray level as the left ventricle.

(4) 4/4 degrees: The contrast agent of the first systolic reflux has reached the entire left atrium, and a contrast agent is visible in the pulmonary vein.

Differential diagnosis

The clinical diagnosis is mainly based on the typical systolic murmur of the apical region and the left atrium and left ventricle enlargement. Echocardiography can confirm the diagnosis. The murmur of mitral regurgitation should be identified by systolic murmur in the apical region of the following conditions:

(1) Relative mitral regurgitation may occur in hypertensive heart disease, aortic regurgitation or myocarditis caused by various causes, dilated cardiomyopathy, anemia and heart disease. As the left ventricle or mitral annulus is significantly enlarged, the mitral valve is relatively closed and the apical systolic murmur occurs.

(B) functional apical systolic murmur about half of normal children and adolescents can hear systolic murmur in the anterior region, loudness is 1 ~ 2 / 6 level, short, soft, do not cover the first heart sound, no atrium And the expansion of the ventricle. It can also be seen in high-powered circulation states such as fever, anemia, and hyperthyroidism. After the cause is eliminated, the noise disappears.

(C) ventricular septal defect can be heard in the third to fourth intercostal space of the sternal border and rough full systolic murmur, often accompanied by systolic tremor, murmur to the apical region conduction, apical beats are lifted. Electrocardiogram and X-ray examination showed an increase in left and right ventricles. Echocardiography showed a continuous interruption of the ventricular septum, and echocardiography confirmed the presence of left-to-right shunt at the level of the ventricle.

(4) Tricuspid regurgitation The lower left rim of the sternum is scented with a localized squeaky squeaky squeak. When inhaling, the murmur is enhanced by the increase in blood volume, and the exhalation is weakened. When the pulmonary hypertension is high, the second heart sound of the pulmonary valve is hyperthyroidism, and the v-wave of the jugular vein is enlarged. There may be liver pulsation and swelling. Electrocardiogram and X-ray examination showed right ventricular hypertrophy. Echocardiography can confirm the diagnosis.

(5) Aortic valve stenosis The aortic valve area or apical area of the heart can hear loud and rough systolic murmur, which is transmitted to the neck with systolic tremor. There may be an early contraction of the contraction, and the apex of the apex is lifted. Electrocardiogram and X-ray examination showed left ventricular hypertrophy and enlargement. Echocardiography can confirm the diagnosis.

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