Ventricular septal defect

Introduction to ventricular septal defect Ventricular septal defect is a common congenital heart malformation, most of which is a single malformation, accounting for about 20% of congenital heart disease; it can also be a component of complex cardiac malformation, as seen in tetralogy of Fallot, completely Sexual atrioventricular access. Ventricular septal defect refers to ventricular septal dysplasia during the embryonic period, which forms abnormal traffic and produces left-to-right shunt at the ventricular level. The defect is usually 0.1 to 3 cm, which is larger in the membranous part and smaller in the muscle part, which is also called Roger disease. If the defect is <0.5cm, the flow rate is small and there are no clinical symptoms. The size of the heart of the defect is normal, and the left ventricle is more obvious than the right ventricle. basic knowledge The proportion of illness: 0.001% Susceptible people: no specific population Mode of infection: non-infectious Complications: Infective endocarditis Aortic valve insufficiency

Causes of ventricular septal defect

Genetic factors (20%):

There is a family history of congenital ventricular septal defect. It is quite uncommon for siblings to get sick at the same time, and parents and children are sick at the same time, and the nature of the disease is very similar. If the first child born to the mother is sick, the probability of the second child is about 2%; if the two consecutive children are ventricular septal defect, the regenerative child may increase to 10%. If the mother has the disease, the risk of the second generation is 10%.

Pregnancy disease factors (18%):

Physical and chemical factors (15%):

Other factors (15%)

For example, during pregnancy, smoking and alcohol in both parents can induce congenital ventricular septal defect.

Ventricular septal defect prevention

The disease is a congenital disease, no effective preventive measures, early detection and early treatment should be achieved.

For patients with ventricular septal defect, the prognosis is good, and its natural life span can reach 70 years old or older; small may even close itself before the age of 10, and heart failure can occur when the defect is large, 1 to 2 years old, there is pulmonary artery High blood pressure has a poor prognosis.

Complications of ventricular septal defect Complications Infective endocarditis Aortic regurgitation

(a) Infective endocarditis

In infants under 1 year of age, it is rare for a group of patients, such as Corone, to have the highest incidence of 15 to 29 years old. Generally speaking, the longer the survival time, the greater the chance of infective endocarditis, according to the literature. Statistics, the incidence rate of 25% to 40%, but since the widespread use of antibiotics and chemotherapy has been greatly reduced, about 5 to 6%, as low as 2 to 3.7%, but the annual incidence of patients is still 0.15% ~ 0.3%.

(two) aortic valve insufficiency

Ventricular septal defect is located in the right ventricular outflow tract and above the superior iliac crest, easily associated with aortic regurgitation, the incidence of Nodas is 4.6%, Tatsuno reported 8.2%, causing regurgitation for two reasons: 1 defect in the aorta Immediately below the annulus, the annulus lacks sufficient support. When the high-speed shunt is sprayed from left to right, the aortic valve leaflet is pulled downward, first extended, and then prolapsed, resulting in incomplete closure, if not repaired in time. Defects, incomplete closure will gradually increase, 2 some defects become thicker at the edge, mechanical contraction, and even form a fibrous band, pulling the aortic valve, resulting in insufficiency.

(3) Conduction block

The endocardial fibrosis at the edge of the membrane defect compresses the adjacent conduction beam, producing a complete or incomplete conduction block.

Symptoms of ventricular septal defect common symptoms purpura right heart failure, gas systolic murmur, heart murmur, ventricular septal defect, tremor, palpitations, dyspnea, edema

Clinical manifestation

Defects with small caliber, less distributing, generally no obvious symptoms, large defects, more sub-flow, may have developmental disorders, post-activity palpitations, shortness of breath, repeated lung infections, severe respiratory distress and Symptoms such as left heart failure, when mild to moderate pulmonary hypertension occurs, and the left-to-right sub-flow is reduced accordingly, pulmonary infections are alleviated, but symptoms such as palpitations, shortness of breath and restricted mobility still exist, or more obvious Severe pulmonary hypertension, when bidirectional or reverse (right to left) shunt occurs, purpura occurs, the so-called Eisenmenger syndrome, physical activity and lung infection, purpura aggravation, and eventually right heart failure.

At the time of physical examination, the defect diameter is relatively large, generally poorly developed, relatively small, advanced cases, visible lips, refers to purpura, severe cases may have clubbing (toe), and liver swelling, lower extremity edema and other right heart failure, In patients with a large flow rate, it can be seen that the pulsation of the anterior region is enhanced, and the chest wall is anterior, and the heart sounding boundary is enlarged at the time of percussion.

Cardiac auscultation: in the 3rd and 4th ribs of the left sternal border (depending on the position of the defect), it can be heard in the III-IV full-systolic jet murmur, the same site can be tremor and tremor, and the pulmonary artery pressure is elevated. In the pulmonary valve area, the second tone can be heard, sometimes due to the defect surface being covered by the chin, the papillary muscle or the abnormal membrane, resulting in weak noise and tremor, but according to the nature of the jet murmur, Can still be judged, the larger the flow rate, in the apex can still hear the diastolic rumbling noise caused by the increase of blood flow through the mitral valve mouth, severe pulmonary hypertension, the left and right ventricular pressure is similar, systolic The murmur is reduced or disappeared, and replaced with a loud heartbeat flap 2nd heart sound or pulmonary regurgitation with diastolic murmur (Graham Steell murmur), high ventricular septal defect with aortic valve prolapse, incomplete closure, except contraction In the period of murmur, the diastolic diastolic murmur transmitted to the apex can be heard. Because the interval between the two murmurs is very short, it is easy to be mistaken for persistent murmur. The blood pressure can be seen to widen the pulse pressure, and there is a femoral artery. "Sound" and other peripheral vascular signs.

In addition to solving the ventricular septal defect itself, it is equally important to know whether there are complicated deformities, especially aortic valve prolapse, left ventricular outflow tract stenosis and patent ductus arteriosus, so as to avoid adverse consequences due to missed diagnosis.

Examination of ventricular septal defect

Electrocardiogram examination: the size of the ventricular septal defect and the disease period are different, the small-diameter defect ECG can be normal, the larger defect, the initial stage shows left ventricular hypertension, left ventricular hypertrophy; with the increase of pulmonary vascular resistance and Pulmonary arterial pressure increased, gradually left and right ventricle with hypertrophy; the final is mainly right ventricular hypertrophy, and may appear incomplete bundle branch block and myocardial strain.

Echocardiography: echo rupture of the ventricular septal defect and ventricular, atrial and pulmonary trunk enlargement, high defect and aortic regurgitation, diastolic valve prolapse, visible color Doppler examination The blood shunt in the defect and the diastolic blood flow in the aortic valve prolapse, the ultrasound examination is helpful to find the clinical malformation of the missed diagnosis, such as left ventricular outflow tract stenosis, power ductus arteriosus, etc. In recent years, two-dimensional Cardiac ultrasound and color Doppler examination have become the main means of diagnosing congenital cardiovascular malformations, and have largely replaced cardiac catheterization and cardiovascular imaging.

Chest X-ray examination: small caliber defect, left to right sub-flow less, often no obvious heart, lung and macrovascular changes, or only the pulmonary artery segment is full or the pulmonary vascular texture is thicker, larger diameter defect When the pulmonary vascular resistance is not increased, a large number of left to right shunts are shown, indicating left ventricular and right ventricle enlargement, such as the left ventricle is particularly enlarged, suggesting that there may be a huge high defect combined with aortic regurgitation; pulmonary artery bulging, lung In the portal and lung, the vascular shadow is thickened, the aortic shadow is relatively small, and in the advanced case, the pulmonary vascular resistance is significantly increased. If the pulmonary hypertension is severe, the heart shadow will become smaller, mainly indicating an increase in the right ventricle, or a merger of the right atrium. The performance is that the pulmonary artery segment is significantly enlarged, the hilar vascular shadow is also enlarged, and the lung field blood vessel shadow is close to normal or relatively small.

Right heart catheterization: Determine and compare the blood oxygen content of the right heart chamber, such as the right ventricle is 1.0% by volume higher than the right atrium, indicating that the ventricular level has left to right shunt; small diameter loss with less flow, or defect caliber Although not small, there is obvious pulmonary hypertension caused by left to right flow reduction, right ventricular / right atrial oxygen is often less than 1.0% by volume, suspected of this situation, should be added for hydrogen absorption test, contrast Observe the time of occurrence of the hydrogen ion curve in the right heart chamber, such as the right ventricle is more advanced than the right ventricle, indicating that the ventricular level has left to right shunt; severe pulmonary hypertension, ventricular level is bidirectional or reverse shunt, right ventricle, There is no edema in the right room, which can be verified by different degrees of decrease in body oxygen saturation measured in the same period. The pressure in the right heart chamber (especially continuous measurement of pulmonary artery and right ventricle) is measured. If the right ventricular pressure is significantly exceeded Pulmonary arterial pressure, according to the characteristics of its pressure curve, can be combined with the right ventricular outflow tract or / and pulmonary stenosis; generally the ratio of pulmonary artery pressure to body arterial pressure to determine the degree of pulmonary hypertension <40% are mild, 40-70% are moderate, and >70% are severe. According to pulmonary artery pressure and cardiac output index, pulmonary vascular resistance is converted, which is helpful for surgical timing and surgical adaptation. The judgment of the card and contraindications, the ratio of pulmonary circulation to systemic blood flow and the ratio of the two are generally measured, with a low flow rate of <1.3, a medium flow of 1.3 to 2.0, and a high flow of >2.0.

Cardiovascular angiography: retrograde intubation to the aortic root, pressurized injection of contrast agent, can be judged whether there is aortic valve prolapse (insufficiency); catheter inserted into the left ventricle for angiography, can identify the location of the ventricular septal defect, caliber And whether to merge the left ventricular outflow tract stenosis and so on.

Diagnosis and diagnosis of ventricular septal defect

According to medical history, signs, radiation and electrocardiogram, combined with cardiac catheterization and cardiovascular angiography, the diagnosis is not difficult, but when the diagnosis is established, it should be identified with the following diseases.

(a) atrial septal defect

1. Primary hole defect and ventricular septal defect are not easy to identify, especially those with pulmonary hypertension. The murmur of primary hole defect is soft, often right ventricular hypertrophy. Left ventricular hypertrophy may occur with mitral valve division. The ECG often has a prolonged PR interval. The QRS of the heart vector map runs counterclockwise, the maximum vector is left, and the main part of the ring moves up to the left. It has discriminative value, but the most reliable is cardiac catheterization. Cardiographic examination is also a differential diagnosis, and the differential diagnosis of left ventricular-right atrial defect should be noted.

2. Secondary hole defect: systolic hairy murmur is soft, the site is in the second intercostal space on the left sternal border, most of which has no tremor, and the electrocardiogram shows incomplete right bundle branch block or right ventricular hypertrophy without left ventricular hypertrophy. The frontal QRS ring is mostly running in the clock direction, and the main body is turned to the right.

(b) Pulmonary artery stenosis: The systolic murmur of the valvular pulmonary stenosis is located in the second intercostal space on the left sternal border, and is generally not confused with the murmur of the ventricular septal defect.

The funnel-shaped pulmonary stenosis is narrow, and the murmur is often heard in the third and fourth intercostal space on the left sternal border. It is easy to be confused with the murmur of the ventricular septal defect, but the former lung X-ray shows that the pulmonary circulation is not congested, the lung texture is scarce, right Cardiac catheterization can detect the systolic pressure gradient between the right ventricle and the pulmonary artery, and no left-to-right shunt performance can establish the diagnosis of the former.

Ventricular septal defect and funnel-shaped pulmonary stenosis can be combined to form a so-called "atypical tetralogy of Fallot", and there is no purpura, so pay attention.

(3) Aortic stenosis: The systolic murmur of the valvular aortic stenosis is located in the second intercostal space of the right sternal border and is transmitted to the carotid artery without confusion with the murmur of the ventricular septal defect, but the aortic stenosis is The location of the murmur is low, and can be heard in the third and fourth intercostals of the left sternal border, and may not be transmitted to the carotid artery, and needs to be differentiated from the murmur of the ventricular septal defect.

(D) hypertrophic obstructive primary cardiomyopathy: hypertrophic obstructive primary cardiomyopathy with left ventricular outflow tract obstruction, can hear systolic murmur in the lower left sternal border, its location and nature similar to the murmur of ventricular septal defect However, this murmur was alleviated during squatting, and half of the patients had reflux systolic murmurs at the apex of the heart, and the pulse was double-peaked.

In addition, X-ray showed no congestion in the lungs, ECG showed left ventricular hypertrophy and strain with abnormally deep Q wave, echocardiography showed obvious thickening of ventricular septum, mitral anterior leaflet systolic advancement, cardiac catheterization There is no left to right shunt, and there is a systolic pressure step between the left ventricle and the outflow tract. Selective left ventricular angiography shows that the left ventricular cavity is small, and the hypertrophic ventricular septum protrudes into the heart chamber to help the hypertrophic obstruction primary. Diagnosis of sexual cardiomyopathy.

(5) ventricular septal defect with aortic regurgitation: need to be identified with patent ductus arteriosus or aortic-pulmonary septal defect, supraventricular supraorbital ventricular septal defect, such as just under the aortic valve, may A leaf of the aortic valve is pulled down, or the lack of tissue support in the lower part of the valve is caused by blood flow impinging into the left ventricle, etc., resulting in aortic regurgitation, and the systolic murmur caused by the ventricular septal defect itself, plus A diastolic murmur caused by aortic regurgitation may produce a continuous murmur between the third and fourth intercostals of the left sternal border, similar to a patent ductus arteriosus or aortic-pulmonary septal defect, but the disease's murmur The lack of typical continuity, ECG and X-ray examination showed significant left ventricular hypertrophy, as well as right heart catheterization and selective indicator dilution curve measurements found that right to ventricular level left to right shunt can be identified.

(6) Patent ductus arteriosus

There are two cases that are not easy to identify. One is that high ventricular septal defect combined with aortic valve prolapse and regurgitation is easily confused with typical patent ductus arteriosus. The former is murmur in two phases, the latter is continuous; the former aortic ganglia Not obvious, the latter increased, the second is the patent ductus arteriosus with pulmonary hypertension, only systolic tremor and murmur, and the identification of high ventricular septal defect is more difficult, the former pulse pressure difference is larger, the murmur position is higher, the main Significant arterial junctions, a more reliable method is left ventricular or retrograde aortic angiography.

(7) Aortic-pulmonary septal defect

Ventricular septal defect with aortic insufficiency murmur is easily confused with high-grade aortic regurgitation in this disease, and retrograde aortic angiography is used to distinguish.

In addition, in patients with advanced cyanosis, it should be differentiated from other congenital malformations such as tetralogy of Fallot, aortic dislocation with ventricular septal defect, mainly by medical history, the second heart sound of pulmonary valve area. , how much lung texture and ECG changes, if necessary, left and right cardiac catheterization and cardiovascular imaging.

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