Disease overviewHypertrophic obstructive cardiomyopathy has been called muscular subaortic obstruction. Davies reported on 1952 that 5 of th
Hypertrophic obstructive cardiomyopathy has been called muscular subaortic obstruction. Davies reported on 1952 that 5 of the 9 brothers and sisters had the disease, with a total of 3 deaths. In 1958, Teare described a high degree of ventricular septal hypertrophy, which was much more than the free wall of the left ventricle. And the myocardial cells are thick and short, arranged in disorder, and the lateral connections between cells are abundant. After 1960 is considered to be a type of primary cardiomyopathy, in all types of cardiomyopathy accounted for about 20%, so called idiopathic obstructive cardiomyopathy, idiopathic hypertrophic subaortic stenosis or hypertrophic obstructive cardiomyopathy. About 30% of the cases have a family history, may have genetic factors. The time of onset can be from the infant to more than and 60 years old, but the most common is between the ages of 10 and 30. 1960 Goodwin, Kelly, Morrow, Brockenbrough, Braunwald, Wigle and so on to carry out surgical treatment of the disease.
Etiology and pathology
The severity of left ventricular obstruction in hypertrophic obstructive cardiomyopathy. The typical lesions with ventricular septal hypertrophy upper most significantly, lengthwise ventricular septal hypertrophy, myocardial is left and right ventricular cavity bulge. The thickest part of the interventricular septum is located below the free margin of the anterior leaflet of the mitral valve, and the interventricular septum is associated with a localized thickening of the intima. The thickness of the hypertrophic ventricular septal myocardium (aortic valve annulus) was decreased gradually, and the left ventricular outflow tract obstruction was located between the hypertrophic ventricular septal myocardium and the free margin of the anterior leaflet. Heart contraction, hypertrophy of the ventricular septal protruding into the ventricle, mitral valve near the forward anterior leaflet, causing left ventricular outflow tract stenosis, sometimes accompanied by incompetence. Early systolic outflow obstruction to a lesser extent, the ventricular output more.
The left ventricular anterior wall and the apical area of the left ventricular wall were uniformly thickened, and the posterior wall of the left ventricle was less thickened. The ratio of the interventricular septum to the posterior wall thickness of the left ventricle was 3: 1. Ventricular septal thickening of the ventricular cavity was dumbbell shaped. Advanced stage disease, due to myocardial infarction or long-term severe heart failure, left ventricular may expand left atrial chamber is enlarged, atrial wall thickening, mitral valve Ye Zenghou, may be associated with tendon ruptures or congenital malformation. Because the right ventricle into the right ventricular hypertrophy can lead to ventricular septal outflow obstruction. Elderly patients with right ventricular free wall may be thickened due to obstruction or pulmonary circulation pressure. Ventricular septal and ventricular wall of coronary artery branch wall thickening, lumen stenosis, may lead to transmural myocardial obstruction.
Clinical symptoms include shortness of breath, tired after fainting or dizziness and angina pectoris after aortic stenosis, and similar. About 10% of cases are caused by paroxysmal or persistent atrial fibrillation. Advanced cases for congestive heart failure, pulmonary edema and orthopnea.
Common signs of apical impulse enhancement, the lower left shift, common heaving impulse or double impulse. The lower left side of the sternum or the apical region can be heard in the middle of the systolic ejection murmur, conduction to the heart base, often accompanied by tremor. In patients with mitral regurgitation, the apical area presents a systolic murmur and second heart sounds, or the third or the fourth. But not to hear the kind of systolic ejection click. Peripheral arterial strong shock wave, evanescent wave is small, and the water rushed down like.
Chest X-ray examination: increased heart shadow, left ventricular enlargement, but no ascending aortic enlargement or calcification. Advanced cases of left atrium, right ventricle can increase pulmonary vascular congestion.
ECG examination showed left ventricular hypertrophy and strain, sometimes aVL and I lead chest showed abnormal Q wave. Some cases showed complete right bundle branch, left bundle branch or left anterior hemiblock and left atrial hypertrophy.
Cardiac catheterization: right heart catheterization showed increased pulmonary artery pressure and right ventricular outflow tract stenosis. Left heart catheterization showed left ventricular end diastolic pressure increased, systolic pressure gradient between the left ventricle and outflow tract exist. The aortic or peripheral arterial pressure waveform showed a rapid rise of the ascending branch, presenting Shuangfeng, and then slowly decreasing. Premature ventricular contraction after aortic pulse pressure reduction. Taking nitroglycerin, amyl nitrite, isoproterenol, digitalis and physical labor and Valsalva after the action of myocardial contractility strengthening, left ventricular outflow tract obstruction increased, which can lead to murmur loudness strengthen, systolic pressure gradient increases.
Selective left ventriculography can be used to reveal the anterior interventricular septum of the outflow tract and the posterior wall of the outflow tract, the left ventricular cavity is curved, and the left ventricular volume is low and the papillary muscles are large.
Left ventricular angiography can be judged without mitral regurgitation. Adult patients with coronary angiography should be performed in order to understand whether or not the coronary artery lesions.
Echocardiography showed a significant thickening of the left ventricular wall, a more hypertrophic ventricular septum than the posterior wall of the ventricle, a small left ventricular cavity, a narrowing of the outflow tract and a contraction of the mitral valve.
Hypertrophic obstructive cardiomyopathy can present at any age, the most common age of onset is around 20 years of age. The cardiac catheterization diagnosis of cases at the age of 10, only 10% showed serious symptoms, over the age of 50 was increased to 70%. Some cases of illness can be stable or sustained development of more serious. After the occurrence of atrial fibrillation, congestive heart failure or systemic embolism. Approximately 15% of patients presenting with clinical symptoms and arrhythmias without surgical treatment died at the age of 5 years, and died at the age of 25% years after surgery. Most patients died suddenly, and only a few cases died of heart failure or infective endocarditis. The clinical symptoms, medical treatment failed, resting left ventricular outflow tract and systolic pressure exceeds 6.6kPa (50mmHg) should be performed surgical treatment, resection of ventricular septal myocardial hypertrophy to relieve the obstruction.
Commonly used surgical methods are:
(a) through the aorta and left ventricular myocardial resection incision and sternotomy, cardiopulmonary bypass combined with low temperature, in the left atrium in the drainage tube, blocking the aorta, at the root under pressure into the cold cardioplegic solution and reduce the local myocardial temperature, transverse incision of ascending aorta, the right coronary valve forward retractor traction type U ventricular septal myocardial resection from the front with the circular edge knife, cut from below to the left and right coronary valve extends to the right coronary valve and left coronary valve junction below. The ventricular septal incision should not be extended to the right, so as to avoid the injury of the left atrioventricular bundle. The ventricular septal myocardial slice is extended under the direct vision, but not too deep. The governor and the minimum angle in the other branch of flat left ventricular anterior wall of the lower part of the oblique incision for about 4cm, into the left ventricular cavity below the anterior papillary muscle, through the incision of anterior leaflet will be pulled to the left ventricular septum, from the bottom to the top with a knife resection of ventricular septal myocardial hypertrophy, myocardial slices through the aorta connected with then the whole piece removed, cut off the myocardial hypertrophy, the incision depth is about 15 ~ 20mm pruning debris to prevent the occurrence of myocardial embolism. Interrupted suture of myocardial incision, suture aortic incision. Discharge of left ventricular and aortic residual gas, removal of the aortic clamp and increased body temperature, heart strong after the cessation of cardiopulmonary bypass.
(two) through the aortic incision ventricular septal myocardial resection and incision of extracorporeal circulation and take myocardial protection measures, blocking the aortic blood flow through aortic root incision, traction right coronary valve revealed ventricular septal, two parallel incision in the right coronary valve below the ventricular septal upper with a small knife, cut the lower ventricular septal compression the right ventricular free wall, ventricular septal shift to the left ventricular cavity to improve exposure, then removal of hypertrophic myocardium tissue between the two rectangular parallel incision. A finger pressing ventricular septal incision, increase ventricular septal groove depth and width, removing the myocardial fragments of the aortic incision suture, left ventricular cavity and the discharge gas in the aorta, the aortic clamp was removed. Rewarming to body temperature up to 35 degrees Celsius, the heart beat strong, stop cardiopulmonary bypass, such as ventricular septal hypertrophy of myocardial resection is still not satisfied, can also be completely removed by the left ventricular incision approach.