hypertrophic cardiomyopathy
Introduction
Introduction to hypertrophic cardiomyopathy Hypertrophic cardiomyopathy (HCM) is a kind of myocardium characterized by progressive hypertrophy of the myocardium and progressive reduction of ventricular cavity. It is typical in the left ventricle, with ventricular septum and occasionally concentric hypertrophy. disease. The left ventricular blood filling is blocked, and the diastolic compliance decline is the basic pathological feature of the unexplained myocardial disease. According to the left ventricular outflow tract obstruction, it can be divided into two types: obstructive and non-obstructive. Usually autosomal dominant inheritance. basic knowledge Sickness ratio: 0.0004% Susceptible people: no special people Mode of infection: non-infectious Complications: arrhythmia Infective endocarditis Atrial fibrillation
Cause
Causes of hypertrophic cardiomyopathy
(1) Causes of the disease
1. Hereditary factors Genetic factors are currently considered to be the main cause, based on the obvious familial morbidity of this disease, often combined with other congenital cardiovascular malformations, some patients have this disease at birth, can be seen in patients with this disease The genotype of HLA antigen, familial cases are transmitted in autosomal dominant form, the type of onset is asymptomatic myocardial asymmetry hypertrophy, but also typical obstructive symptoms, about 50% to 55% of hypertrophic myocardium The patient has a family history and is an autosomal dominant genetic disease. The genetic theory of hypertrophic cardiomyopathy has been recognized and is considered to be closely related to the histocompatibility antigen system. HLA-DRW4, Ag, B5 in patients with hypertrophic cardiomyopathy The detection rate of antigens increased significantly. In 1995, the World Health Organization and the International Heart Association's Heart Nomenclature and Classification Committee clearly pointed out that genetic mutations in sarcomeric contractile proteins lead to familial hypertrophic cardiomyopathy. The following assumptions:
1 catecholamine and sympathetic nervous system abnormalities, the evidence is that the disease is easy to be associated with neural crest tissue disease, hyperthyroidism or excessive insulin secretion, high blood pressure, effective with beta blockers,
2 The disproportionate thickening of the interventricular septum was not aligned with the myocardial fibers, and did not retract normally after birth. The three-chamber conduction over-speed caused the ventricular septum and the left ventricular free wall to be synchronized and contracted.
4 abnormal collagen abnormalities cause abnormal cardiac fiber scaffolds, causing disordered myocardial fibers.
5 abnormal myocardial protein synthesis,
6 small coronary artery abnormalities, causing ischemia, fibrosis and compensatory myocardial predecessors,
The 7-compartment interval is convex in the lateral direction to the left and axially convex in the apex of the apex (normally left to the left), and is not equal in length when contracted, causing disorder of myocardial fibers and local hypertrophy.
2. Calcium regulation disorder Clinical studies and experiments have shown that patients with hypertrophic cardiomyopathy have calcium regulation disorder, especially the increase of intracellular calcium concentration is related to ventricular diastolic function. Wagner et al found that intracellular calcium receptors in cardiomyocytes of patients with hypertrophic cardiomyopathy The increase in number reflects the increase in voltage-dependent calcium channel density. This phenomenon exists not only in hypertrophic interventricular septum but also in normal right atrial myocardium, suggesting that the increase in receptor is not a secondary change, but a Primary defects.
(two) pathogenesis
The disease is characterized by cardiac hypertrophy and increased heart weight. It can be expressed as whole heart, ventricular septum, free ventricular wall, apex and papillary muscle hypertrophy. Among them, ventricular septal hypertrophy is the most common, hypertrophic ventricular wall can exceed 3 times normal. Often asymmetrical (non-concentric) hypertrophy, that is, the degree of hypertrophy in the ventricular wall is common in the left ventricle, the right ventricle is rare, the ventricular septal hypertrophy protrudes into the left ventricular cavity, and the left ventricular outflow tract obstruction occurs during contraction. , known as "hypertrophic obstructive cardiomyopathy", formerly known as "esthetic hypertrophic aortic subvalvular stenosis"; ventricular septal hypertrophy is mild, systolic period does not cause obvious obstruction of left ventricular outflow tract, called "hypertrophy Type of non-obstructive cardiomyopathy, the anterior papillary muscles can also be hypertrophic, often displaced and affect normal valve function. When the myocardium is highly hypertrophied, the left ventricular cavity is reduced. Disproportionate cardiac hypertrophy often causes the thickness of the interventricular septum and the left ventricle. The ratio of the thickness of the posterior wall is 1.3, a few can reach 3, there is a variant hypertrophic cardiomyopathy, the cardiac hypertrophy in the apical region is relatively good, this type of pericardial coronary artery is normal, but the ventricular wall The number of arterioles increased and the lumen was narrow. Under the microscope, the arrangement of myocardial cells was disordered, the nucleus was abnormal, the branches of the cells were many, the mitochondria increased, the myocardial cells were extremely hypertrophied, and the intracellular glycogen content increased. In addition, there was interstitial fibrosis, under electron microscope. See the arrangement of myofibrils is also disordered, 2 / 3 patients with mitral leaflets increased, and a fibrous plaque on the left ventricular wall opposite the anterior mitral valve is caused by mitral valve and ventricular septal impact The disease can occur at all ages, but the cardiac hypertrophy is more serious in people under 40 years old than those over 40 years old. The relationship between this type of hypertrophy and age is unknown. As the disease progresses, myocardial fibrosis increases, ventricular wall hypertrophy decreases, and the heart chamber The degree of narrowness is also reduced, showing late performance, hypertrophy can be asymmetry (90%), symmetry (accounting for 5%) and special site hypertrophy, some patients can only show right ventricular hypertrophy, severe cases can form right ventricular outflow The path of the obstruction and systolic pressure, according to the extent and extent of the wall hypertrophy, can be divided into 3 types:
1 asymmetrical ventricular septal hypertrophy;
2 symmetrical left ventricular hypertrophy;
3 special parts are thick.
Pathogenesis
(1) Genetic factors: Hypertrophic cardiomyopathy can be caused by multiple single gene mutations. Seven genes have been found so far, and more than 70 mutations are associated with the disease. The most characteristic is the muscle located on chromosome 14. Globulin heavy chain (MHC) gene mutation, although different gene mutations can produce similar cardiac hypertrophy, but some gene mutations appear to be benign clinical processes, about 50% of patients with hypertrophic cardiomyopathy have a family history, showing autosomal dominant Inheritance, it can also be seen that multiple members of the same family spontaneously undergo the same genetic mutation without a clear family history.
In 1989, Jarcho et al. analyzed a large French-Caucasian family and revealed the first chromosomal locus 14q1 of the disease, confirming the first susceptibility gene of the disease, the -MHC gene. To date, it has been recognized that seven sarcomeric contractile protein gene mutations can cause HCM, which are: -myosin heavy chain (-MHC), cardiac troponin-T (cTn-T), -prosthesis Globulin (-TM), myosin-binding protein-C (MyBP-C), essential myosin light chain (ELC), regulatory myosin light chain (RLC) and troponin-I (cTn) -I), abnormal sarcomere contraction and/or regulatory dysfunction caused by mutations in these genes may be the main cause of HCM.
Further studies have found that the clinical manifestations and prognosis of HCM caused by different gene mutations are different. The clinical manifestations and prognosis of HCM caused by mutations in different coding regions of the same gene are also different, and members of the same family carrying the same pathogenic genes. Not all of them show cardiac hypertrophy. The reason for the above-mentioned HCM genetic heterogeneity is unclear. It is speculated that in addition to genetic factors, it may be affected by factors such as gender, lifestyle, and exercise patterns. In addition, angiotensin-converting The relationship between the enzyme DD genotype and HCM has also attracted people's attention in recent years.
(2) Other pathology:
1 Poison polypeptide theory: This theory believes that abnormal peptides produced by genetic mutations can bind to other myocardial components, causing obstacles to the biosynthesis of normal myocardial fibers.
2 null alleles theory: refers to gene mutations can produce a truncated protein, which reduces the production of normal sarcomeric protein, which affects the structure and function of thick muscle or thin filament, leading to the entire sarcoma Abnormal structure and function, myocardium containing dysfunctional protein can not maintain normal function and lead to the initiation of compensatory mechanism. The expression of proto-oncogenes such as c-myc and c-fos is enhanced, and protein synthesis of cardiomyocytes is promoted, so that myocardial fibers are thickened. , cardiac hypertrophy.
(3) Abnormal calcium channel: Analysis of myocardial fibers of patients with -TM gene Asp175Asn mutation and transgenic mice found that their sensitivity to calcium ions was higher than that of normal myocardial fibers, therefore, at lower calcium ion concentration, myofilament The tension is higher than normal, the contraction ability of muscle fibers is enhanced, and the continuously enhanced contraction state can induce cardiac hypertrophy and myocardial diastolic dysfunction.
(4) Increased activity of catecholamines: Studies have shown that excessive production or increased activity of catecholamines in fetal period can lead to disorder of myocardial cells and asymmetry of interventricular septum hypertrophy; enhanced activity of catecholamines and decreased storage of cyclic adenosine monophosphate in HCM patients Adding norepinephrine to cardiomyocyte culture medium, the transcription level of c-myc gene in cardiomyocytes is increased by 5-10 times. This reaction can be repressed by -blocker and enhanced by protein kinase C activator. , suggesting that norepinephrine may increase the expression of c-myc gene through the alpha receptor-activated phosphoinositide/protein kinase C pathway.
2. Histopathology is characterized by hypertrophy of cardiomyocytes, disordered arrangement, abnormal nuclear nucleus, and spiral destruction of muscle bundle structure; with the development of the disease, myocardial fibrosis components gradually increase, and the coronary artery wall can be thickened and the lumen becomes smaller. .
The hypertrophic ventricular septum swells to the left ventricular outflow tract and the anterior mitral anterior lobes move closer to the ventricular septum, which is the main cause of left ventricular outflow tract stenosis. About 25% of patients have outflow obstruction, leading to left ventricle and There is a pressure gradient between the outflow tracts during systole, which can reach the level of pressure gradient near severe aortic stenosis in the middle of systole. Hemodynamic studies show that the anterior mitral lobes advance when the ventricle contracts. The degree, and the time it is placed on the hypertrophic compartment interval, is the main factor affecting the pressure gradient of the outflow tract and the prolongation of the ejection time of the left ventricle. The systolic anterior mitral anterior leaf is placed on the interventricular septum, the pressure step The greater the difference, the more obvious the ejection time is extended. In addition, any factors that can reduce the left ventricular volume, such as vasodilation, Valsalva movement, sudden standing after squatting, etc., can induce systolic pressure gradients to appear or cause Aggravation; factors that enhance myocardial contractility, such as cardiac impulses immediately after ventricular premature contraction, can also increase the pressure gradient of the outflow tract; while the fist movement increases the peripheral vascular resistance, which can make the pressure gradient Decrease, increase the systolic pressure gradient, reduce cardiac output and increase ventricular filling pressure, stimulate vagus nerve, cause reflex syncope; severe ventricular arrhythmia caused by disorder of myocardial cell arrangement, can also cause syncope.
Cardiac hypertrophy, decreased ventricular diastolic compliance and increased left ventricular filling pressure, can cause shortness of breath, especially after activity, palpitation, shortness of breath; heart rate caused by decreased cardiac output accelerates further shortening left ventricular filling period, thus forming a vicious circle and lowering the heart The reserve function and exercise tolerance, late myocardial contraction and diastolic function are all impaired, but mainly due to diastolic myocardial relaxation abnormality, the increase of coronary blood flow in HCM patients does not adapt to the degree of wall thickening, can not meet the hypertrophic myocardium Oxygenation, which leads to relative myocardial ischemia, is quite common in angina. Long-term ischemia can degenerate hypertrophic myocardium, atrophy and fibrosis, loss of contractility, and ultimately lead to left ventricular enlargement and congestive heart failure.
(3) Pathophysiology
1. Left ventricular outflow obstruction is in systolic phase, hypertrophic myocardium narrows the ventricular outflow tract. In non-obstructive type, this effect is not obvious, and it is prominent in obstructive type. When ventricular contraction, hypertrophic ventricular septal muscle protrudes. The ventricular chamber, in the left ventricle, causes the anterior mitral lobes in the outflow tract to move forward and close to the ventricular septum, causing left ventricular outflow tract stenosis and mitral regurgitation. This effect is evident during contraction and later. In the early stage of left ventricular effusion, the outflow tract obstruction is light, about 30% of the stroke volume is ejected, and the remaining 70% is ejected when the obstruction is obvious. Therefore, the carotid artery wave shows a rapidly rising ascending branch, and then falls again and becomes a trace. Then slowly descend, the outflow obstruction causes a pressure difference between the left ventricular cavity and the outflow tract during systole, and there is no pressure difference between the outflow tract and the aorta. In some patients, the outflow obstruction is not obvious at rest, and becomes obvious after exercise.
2. Diastolic function is abnormally hypertrophic, myocardial compliance is reduced, poor expansion ability, ventricular diastolic filling disorder, end-diastolic pressure can be increased, diastolic cardiac chamber stiffness is increased, left ventricular dilatation is reduced, and thus stroke volume Decreased, increased filling and compression of the coronary artery in the ventricular wall, the rapid filling period is prolonged, and the filling rate and filling volume are reduced.
3. Myocardial ischemia is caused by myocardial oxygenation exceeding coronary blood supply, coronary artery stenosis in the wall, excessive diastolic phase, and increased tension in the ventricular wall.
Prevention
Hypertrophic cardiomyopathy prevention
Among the prognostic factors of hypertrophic cardiomyopathy, reasonable life guidance is a favorable factor. Patients with this disease should avoid strenuous activities, avoid using positive inotropic drugs and dilating vascular drugs, pay attention to bathing time should not be too long, prohibit alcohol and tobacco, To prevent and treat infections, to improve the prognosis, the prevention requirements are as follows:
1. Once the hypertrophic cardiomyopathy is diagnosed, it can not participate in strenuous activities regardless of whether there is left ventricular outflow obstruction.
2. The following are high-risk patients, in addition to restricting participation in strenuous activities, preventive treatment is required:
1 Holter shows persistent or non-sustained ventricular tachycardia;
2 Before the age of 40, the family died of hypertrophic cardiomyopathy;
3 There has been loss of consciousness and syncope;
4 left ventricular outflow tract pressure step >6.67kPa (50mmHg);
5 exercise induced hypotension;
6 severe mitral regurgitation, left atrial diameter 50mm, paroxysmal atrial fibrillation;
7 There is evidence of myocardial perfusion abnormalities, and its prophylactic treatment measures to improve prognosis include beta blockers, calcium antagonists, amiodarone and the like.
3. Patients with this disease may be complicated by infective endocarditis, so prophylactic antibiotics can prevent such complications in the case of tooth extraction and cardiac catheterization may increase the chance of infection.
4. The course of disease is slow, the prognosis is uncertain, and it can be stable for many years. However, once symptoms appear, it can gradually deteriorate. Sudden death and heart failure are the main causes of death. Sudden death is more common in children and young people, and its appearance is related to physical activity. There are asymptomatic or obstructive, ventricular wall muscle thickness is high, there is a family history of sudden death, persistent ventricular tachycardia is a risk factor for sudden death, possible mechanisms of sudden death include rapid ventricular arrhythmia, sinus node Lesions and cardiac conduction disorders, myocardial ischemia, diastolic dysfunction, hypotension, the two most important, the occurrence of atrial fibrillation can promote heart failure, a small number of patients with complications such as infective endocarditis or embolism.
Complication
Hypertrophic cardiomyopathy complications Complications arrhythmia infective endocarditis atrial fibrillation
The disease often has complications such as arrhythmia, sudden cardiac death, arterial embolism, infective endocarditis and heart failure.
1. Arrhythmia Hypertrophic cardiomyopathy is easy to be complicated with arrhythmia. The high incidence of arrhythmia is its prominent feature. Ventricular arrhythmia is the most common arrhythmia. Supraventricular arrhythmia and atrial fibrillation are also common. Serious cases can occur. Ventricular tachycardia, even ventricular fibrillation or arrest, can cause sudden death, of which ventricular arrhythmia and atrial fibrillation are the most important and require treatment.
2. Sudden cardiac death is the main form of death in patients with hypertrophic cardiomyopathy. Sudden death accounts for more than half of the deaths. It is reported that death accounts for 78% of deaths. The cause of sudden death is severe arrhythmia, mainly ventricular tachycardia and ventricular fibrillation. .
3. Arterial embolization is easy to be complicated by arterial embolization, the incidence rate is about 9%. The main part of thrombosis is left atrial appendage, which progresses to the dilated period of hypertrophic cardiomyopathy. It can also form a thrombus in the left ventricle, and the thrombus falls off to form an embolus, causing arterial embolism. It is more common with cerebral embolism.
4. Infective endocarditis usually occurs in obstructive hypertrophic cardiomyopathy, the incidence rate is about 5% to 10%, and the infection occurs in the heart of the mitral valve, aortic valve, and ventricular septal contact injury. Membrane non-obstructive hypertrophic cardiomyopathy, infective endocarditis is rare.
5. Heart block , which can occur in the sinoatrial node and atrioventricular node, often encountered, is also a factor affecting drug treatment.
6. Heart failure due to myocardial hypertrophy, ventricular diastolic compliance decreased, early left ventricular diastolic dysfunction, left ventricular end-diastolic pressure and left atrial pressure increased; with the progression of the disease, may be associated with left ventricular dilatation and Contractile dysfunction, symptoms of severe heart failure, said hypertrophic cardiomyopathy, the incidence of about 14% to 16%.
7. Sudden death : A small number of patients with hypertrophic cardiomyopathy may have sudden death, and there may be no signs before. Systematic evaluation may help identify such high-risk patients.
Symptom
Hypertrophic cardiomyopathy Symptoms Common symptoms Shortness of breath, dizziness, dizziness, tachycardia, palpitation, edema, heart socket, dull pain, difficulty breathing
Symptom
(1) Labor difficulty breathing: About 80% of patients have shortness of breath after exertion, which is related to poor left ventricular compliance, obstructed filling, increased end-diastolic pressure and pulmonary congestion.
(2) nausea in the precordial area: about 2/3 patients have atypical angina pectoris, often induced by fatigue, long duration, poor response to nitroglycerin, may be due to increased blood supply to hypertrophic myocardium, coronary blood supply Relatively insufficient, there is myocardial ischemia.
(3) frequent sporadic syncope: 1/3 of patients occur after sudden standing and exercise after syncope, can be relieved after a while, this symptom can be the only complaint of the patient, the cause of syncope is considered: 1 due to poor left ventricular compliance And outflow obstruction, resulting in decreased cardiac output, resulting in systemic circulation, cerebral arterial insufficiency; 2 physical activity or emotional excitability, increased sympathetic excitability, increased hypertrophic myocardial contractility, resulting in further reduced left ventricular compliance The diastolic blood filling is less, the outflow obstruction is more serious, and the cardiac output is more reduced, so the patient often feels guilty and weak.
(4) fatigue, dizziness and fainting, which occur during activities, is due to the increased heart rate, which further shortens the diastolic phase of the left ventricle, which has been poorly filled during the diastolic period, and further dilate the left ventricular diastolic period. Shortening, aggravation of filling, decreased cardiac output, activity or emotional agitation due to sympathetic nerves to strengthen hypertrophic myocardial contraction, aggravation of outflow obstruction, sudden discharge of cardiac output and symptoms
(5) palpitations, due to cardiac dysfunction or arrhythmia.
(4) Sudden death: Most scholars believe that the following conditions are high risk of death:
1 survivors of cardiac arrest and evidence of ventricular fibrillation; 2
a patient who has experienced persistent tachycardia;
3 family history of sudden death;
4 high-risk gene mutations (such as Arg403Cln mutation);
5 young people;
6 significant cardiac hypertrophy;
7 exercise caused by low blood pressure.
(5) heart failure: in the late stage of the disease, symptoms of left and right heart failure may occur, such as asthma, palpitation, not lying, liver enlargement, lower extremity edema, etc., due to decreased myocardial compliance, ventricular end-diastolic pressure is significantly increased Then, the atrial pressure is elevated, and often combined with atrial fibrillation, advanced patients with extensive myocardial fibrosis, ventricular systolic function is also weakened, prone to heart failure and sudden death.
2. Signs
Common signs are:
1 The heart sounds the voice to the left, the apex beats to the left, there is a lifting impulse, or a apical double beat. This is the beat generated by the atrium to the ventricle with reduced compliance, which is touched before the apex beats.
2 The middle part of the apex of the left sternal rim can be heard in the middle or late stage of systolic murmur, which is transmitted to the apex but not to the bottom of the heart. It may be accompanied by systolic tremor. It is seen in patients with ventricular outflow obstruction, which increases myocardial contractility or reduces the heart. Load measures such as digitalis, isoproterenol (2g / min), isoamyl nitrite, nitroglycerin, Valsalva action, after physical labor or premature beats can make the noise increase; Force or increase in cardiac load, such as vasoconstrictor, beta-blockers, squatting, clenching the palm, can reduce the noise, about half of the patients can hear the murmur of mitral regurgitation,
3 The second sound can be abnormally split, due to obstruction of the left ventricle and delayed closure of the aortic valve. The third sound is common in patients with mitral regurgitation, and systolic murmur is most common in the anterior region. This kind of noise comes from indoor obstruction. The loudness and duration of the noise can vary with different conditions (Table 1). The noise is in the middle of the 3, 4, 5 intercostal or apical area of the left sternal border. Jet murmur, with tremor, systolic reflux murmur with relative mitral regurgitation in half of the patient's apical region, some audible third heart sounds and fourth heart sounds, a small number of patients with apical audible and middle diastolic murmur May be due to poor left ventricular diastolic compliance, diastolic filling is blocked, diastolic blood pressure is increased, and mitral valve opening is blocked. Some patients can hear early diastolic murmur in the aortic valve area, the aortic ring is due to interventricular septal hypertrophy Caused by skew.
In patients with non-obstructive HCM, due to symmetry hypertrophy of the ventricular cavity, there is no indoor pressure difference during rest and excitation, so there is no systolic murmur in the left sternal border and apical region, and the apical area can be heard and mild murmur in the middle of diastole. Obstructed.
For patients with HCM, the intensity of the murmur caused by the pressure difference in the intraventricular pressure is often used clinically to assist in diagnosis.
For obstructive HCM, the main basis for diagnosis is characteristic clinical manifestations and systolic murmur of the left sternal border. Echocardiography is an extremely important non-invasive diagnostic method. In addition, many physical examination techniques also have diagnostic value, the most meaningful of which. The hemodynamic changes from the sudden erect position of the sacral position, the sputum can increase the venous return, the aortic pressure increases and the ventricular volume increases, reducing the pressure gradient between the left ventricle and the outflow tract, thereby reducing the noise, and Sudden erection has the opposite effect, which can cause the outflow obstruction to strengthen and the noise to be enhanced; in addition, the Valsalva action can also enhance the noise.
For patients with asymptomatic or similar symptoms of coronary heart disease, especially young patients, combined with characteristic ECG changes, echocardiography and cardiovascular angiography can make a diagnosis, positive family history is also helpful for diagnosis.
3. Diagnosis
Patients with ventricular outflow tract obstruction have characteristic clinical manifestations and are not difficult to diagnose. Echocardiography is an extremely important non-invasive diagnostic method, which is helpful for both obstructive and non-obstructive patients. 18mm and mitral systolic advancement, enough to distinguish between obstructive and non-obstructive cases, cardiac catheterization showed that the left ventricular outflow tract pressure difference can establish a diagnosis, ventricular angiography is also valuable for diagnosis, clinically on the left sternal left margin The systolic murmur should consider the disease, and it may be helpful to diagnose the hemodynamics by physiological action or drug action.
Examine
Examination of hypertrophic cardiomyopathy
1. ECG performance :
1 The most common abnormalities are left ventricular hypertrophy and ST-T changes. Deep and inverted T waves are sometimes similar to "coronal T". If you are seen in young patients, you should be alert to hypertrophic cardiomyopathy. Most coronary arteries are normal, and a few Patients with localized cardiac hypertrophy in the apical region have large inverted T waves due to abnormal coronary arteries.
2 The signs of left ventricular hypertrophy are found in 60% of patients, and their presence is related to the extent and location of cardiac hypertrophy.
3 The presence of abnormal Q waves, V6, V5, aVL, I lead has deep and not wide Q waves, reflecting asymmetry ventricular septal hypertrophy, no need to mistaken for myocardial infarction, sometimes in II, III, aVF, V1 There may also be Q waves on the V2 lead, which may be caused by irregular and delayed conduction of the myocardium in the subendocardial and interventricular wall after left ventricular hypertrophy.
4 left atrial waveform abnormalities, may be seen in 1/4 of patients.
Five patients had pre-excitation syndrome (Figure 1).
Electrocardiogram of hypertrophic primary cardiomyopathy
I, aVL, V4V5V6 lead have abnormal Q wave due to hypertrophic interventricular septum caused by a large right ventricular depolarization vector, V1V2 is RS wave pattern, R wave is higher, for each lead Corresponding changes in Q wave, this echocardiographic examination showed ventricular septal hypertrophy
2. Echocardiographic performance:
(1) ventricular septal hypertrophy, poor ventricular septal activity, ventricular cavity becomes smaller, left ventricular systolic diameter decreases, the ratio of ventricular septum to left ventricular free wall thickness > 1.3 ~ 1.5.
(2) Left ventricular outflow tract is narrow, generally <20mm.
(3) The anterior mitral lobes often move forward in the systolic phase and are in contact with the hypertrophic ventricular septum. This advancement begins at the end of the first 1/3 of the systolic phase, and 1/3 of the systolic phase is plateau-like and ventricular septal contact. The outflow tract is formed to be narrow, and is returned to the original position at the last 1/3 of the systole.
(4) In the early stage of diastolic mitral valve opening, the anterior lobe again contacts the interventricular septum, and the distance between the anterior mitral lobes and the interventricular septum is smaller than normal in the diastolic phase.
(5) The aortic valve is closed early in the systole, and the isovolumic diastolic time is prolonged, which reflects the decrease in compliance of the ventricular muscle.
(6) left ventricular diastolic dysfunction, including decreased compliance, prolonged rapid filling time, prolonged isovolumic relaxation time, Doppler method can be used to understand the origin of noise and calculate the pressure difference before and after obstruction.
M-mode echocardiography of hypertrophic primary cardiomyopathy
The room interval was markedly thickened, the CD segment was turned upside down, and the left ventricular output channel was significantly narrowed. The diagnosis of this case was confirmed by surgery.
3.X line ordinary chest radiograph
It may be seen that the left ventricle is enlarged, or it may be in the normal range. X-ray or radionuclide angiography may show thickening of the interventricular septum, the left ventricular cavity is reduced, and the radionuclide myocardial scan may show the location and extent of cardiac hypertrophy.
4. Cardiac catheterization
The ventricular end-diastolic pressure is increased, and the left ventricular outflow tract obstruction has a systolic pressure difference between the ventricular chamber and the outflow tract.
5. Left ventricular angiography
The left ventricular cavity is reduced and deformed. The aortic valve is S-shaped stenosis, the ventricular wall is thickened, the interventricular septum is thickened and protruded into the heart chamber, and the left atrium can be simultaneously developed. In addition to the above phenomenon, the heart shadow is acceptable. Show different forms, such as aortic under-hypertrophic, apical hypertrophy, middle hypertrophy and so on.
Diagnosis
Diagnosis and diagnosis of hypertrophic cardiomyopathy
diagnosis
Patients with ventricular outflow obstruction are not difficult to diagnose because of their characteristic clinical manifestations. Echocardiography is an extremely important non-invasive diagnostic method, both for obstructive and non-obstructive patients, ventricular septal thickness 18mm and mitral systolic advancement, enough to distinguish between obstructive and non-obstructive Case. Cardiac catheterization revealed a difference in left ventricular outflow tract pressure to establish a diagnosis. Ventricular angiography is also valuable for diagnosis. Clinically, the systolic murmur in the left sternal segment of the lower sternum should be considered in this disease. It is helpful to diagnose the hemodynamics by physiological action or drug action.
The disease must be diagnosed as follows:
(1) The systolic murmur of the ventricular septal defect is similar, and the systolic murmur of the left sternal border can cause confusion between the two diseases, but it is full systole, and there is no murmur in the apical region. Identification points: 1 Application of drug murmur stimulation test, HCM can To increase or weaken the noise, the ventricular septal defect has no change in noise; 2 ultrasound Doppler can show the continuous interruption of the interventricular septum and the left-to-right shunt blood flow spectrum.
(2) The symptoms and murmurs of aortic stenosis are similar, and the main points of identification are:
1 The systolic murmur position is higher, with the second intercostal space on the right side of the sternum and the left rib of the sternum 2 to 4 intercostal. The murmur is transmitted to the neck, and the noise is changed by the measures of changing the contractility of the heart muscle and the surrounding resistance. Has little effect,
2 the second sound of the aortic valve is weakened;
3 can appear early diastolic blow noise;
4X line shows ascending aorta dilatation, aortic valve may have calcification;
5 echocardiography can be found in aortic valve disease;
6 left heart catheter examination showed no pressure difference between the left ventricle and the outflow tract, and there was a systolic pressure difference between the left ventricle and the aorta.
(C) rheumatic mitral regurgitation murmur is similar, but mostly for the full systolic period, vasoconstrictor or diarrhea to strengthen the murmur, often accompanied by atrial fibrillation, the left atrium is larger, echocardiography does not show ventricular septal defect.
(4) Coronary heart disease angina pectoris, ST-T changes and abnormal Q waves on the electrocardiogram are common to both, but coronary heart disease has no characteristic murmur, aortic multi-widening or calcification, hypertension and hyperlipidemia; echocardiography The interventricular septum is not thickened, but there may be abnormal segmental wall motion. 1 The age of onset of coronary heart disease is mostly in middle age; 2 The left sternal murmur is only caused by ventricular septal perforation caused by myocardial infarction, and the papillary muscle is broken. More with increased blood lipids, especially after middle-aged, although according to the characteristics of the disease and HCM typical ultrasound images can be diagnosed, but about 10% to 15% of patients with HCM are accompanied by coronary atherosclerosis, so sometimes must Coronary angiography can be used to confirm the diagnosis.
