I. Case report The patient was diagnosed with hypertrophic obstructive cardiomyopathy at the age of 3 years when he underwent further examination for a heart murmur; at the age of 11 years, in order to relieve the outflow tract obstruction (with pressures as high as 100 mm Hg) and symptoms of heart failure, the patient underwent surgical intervention to remove a portion of hypertrophied interventricular septum (up to 35 mm thick), which relieved the symptoms after the operation; at the age of 19 years when the patient suffered an out-of-hospital sudden cardiac arrest, an ICD was installed. After successful resuscitation, an ICD was fitted, which was then replaced with a new one at the age of 24, 27 (with simultaneous ventricular pacing), and 33. At the age of 26, a wire connector in the superior vena cava tore part of the wall of the superior vena cava, which was surgically repaired and returned to normal. Patient’s full medical history The patient had a family history of hypertrophic cardiomyopathy in his father, who had suffered a cardiac arrest, and asymptomatic hypertrophic cardiomyopathy in his older brother (40 yr. old) The ICD detected ventricular tachycardia and ventricular fibrillation and promptly terminated them when the patient was 25 yr. old (during tennis), 26 yr. old, 32 yr. old (sitting still at the beach), and 34 yr. old. The ICD monitoring records also showed 25 episodes of unidirectional ventricular tachycardia that were terminated, hundreds of episodes of spontaneous ventricular tachycardia, and hundreds of spontaneous episodes of ventricular tachycardia. were terminated, and hundreds of spontaneous short bursts of ventricular tachycardia. At the age of 26, the patient’s heart failure worsened to NYHA class III with left ventricular remodeling: maximal wall thickness of 11 mm; left ventricular end-diastolic internal diameter of 56 mm; and EF of 20%. Progressively worsening symptoms of heart failure persisted for 12 years on a variety of pharmacologic agents, including beta-blockers, verapamil, angiotensin-converting enzyme inhibitors, sotalol, mexiletine, digoxin, and spironolactone. Despite significant deterioration in cardiac function and activity limitations, the patient maintained a sedentary job and performed pedaling and yoga. During this time, the patient’s left ventricular remodeling worsened, with an increased left ventricular end-diastolic internal diameter of 68 mm, an EF of only 15% cardiac index of 2.1 L/min/O,19 peak oxygen consumption of 21 ml/kg/min, a pulmonary capillary wedge pressure of 18 mm Hg, and a BNP of 3,500 pg/mL.The patient underwent a cardiac transplantation at the age of 38 years at the Hospital of the University of Pennsylvania, and recovered well. recovery was good. Genetic testing demonstrated the presence of a pathogenic mutation in the MYBPC3 gene. An autopsy of the patient’s heart showed that the heart weighed 440 g. The interventricular septum was 14 mm thick and the left ventricular wall was 16 mm (Figure 2). The left ventricular cavity was significantly enlarged, and the right ventricle showed no significant abnormalities. Very obvious and extensive scarring of the septum and left ventricular free wall was seen. The endocardium at the septum and the anterior leaflet of the mitral valve were covered with a large amount of fibrous tissue, presumably left over from the surgical removal of the septum 27 years earlier. Anatomy of the patient’s heart A thin-walled ventricular wall tumor was present in the apical portion of the left ventricle. The coronary arteries were free of atherosclerotic plaque, and the right and left main coronary arteries emanated from the aorta in their normal position. There were vacuoles in many cells in the subendocardial area, with hypertrophied, disorganized, and morphologically specific cells (Fig. 3); a large number of myocardial intermural arterioles had thickened walls and narrowed lumens, both of which are pathologic hallmarks of hypertrophic cardiomyopathy. Second, hypertrophic cardiomyopathy introduction 1, definition of hypertrophic cardiomyopathy is characterized by left ventricular hypertrophy, often asymmetric hypertrophy and involvement of the interventricular septum, the left ventricular blood filling is impaired, diastolic compliance decreases as the basic pathology of cardiomyopathy. According to the left ventricular outflow tract obstruction or not can be divided into obstructive and non-obstructive hypertrophic cardiomyopathy, asymmetric septal hypertrophy caused by subaortic stenosis is called idiopathic hypertrophic subaortic stenosis. 2, etiology (1) genetic: a family can have more than one person onset, suggesting that the genetic relationship. At present, it is considered to be an autosomal dominant disease, and myocardial contractile protein gene mutation is a major causative factor. (2) Endocrine disorders: patients with caseophilic cell tumor coexist with hypertrophic cardiomyopathy, intravenous infusion of large amounts of norepinephrine can cause myocardial necrosis. Animal experiments, intravenous catecholamines can cause myocardial hypertrophy. Thus, some people think that hypertrophic cardiomyopathy is caused by endocrine disorders. (3) Abnormal intracellular calcium regulation. (4) Hypertension. (5) High-intensity exercise. 3, clinical manifestations (1) Symptoms: there are significant differences between men and women in this disease, most of the symptoms in the 30-40 years old, with age, the symptoms are more obvious, the main symptoms are: (1) dyspnea: exertional dyspnea, severe sitting respiration or paroxysmal nocturnal dyspnea. ② angina pectoris: often with typical angina pectoris, episodes after exertion. Chest pain lasts for a long time, and taking nitroglycerin is not only ineffective but also aggravating. Fainting and dizziness: mostly occur during exertion. When tachyarrhythmia or bradyarrhythmia occurs, it can also cause fainting and dizziness. (iv) Palpitations: the patient feels that the heart beats strongly, especially more obvious in the left lateral position, which may be due to arrhythmia or changes in cardiac function. (2) Physical signs: physical examination may have mild enlargement of the heart, the fourth heart sound can be heard, and systolic murmur can be heard at the left edge of the sternum in patients with outflow tract obstruction. 4. Diagnostic examination (1) X-ray examination: heart size is normal or enlarged, heart size is proportional to the pressure difference between the heart and the left ventricular outflow tract, and the larger the pressure difference is, the larger the heart is. The left ventricular hypertrophy of the heart is dominant, the aorta is not widened, the pulmonary artery segment is not obviously prominent, pulmonary stasis is mostly mild, and mitral valve calcification is common. (2) Electrocardiogram: due to cardiac ischemia, myocardial repolarization is abnormal, ST-T changes are common, left ventricular hypertrophy and left bundle branch block are also more common, Q waves may appear due to interventricular septal hypertrophy and myocardial fibrosis, and various types of arrhythmia are also common in this disease. (3) Echocardiography: It is an important non-invasive diagnostic method. The main manifestations are ① Abnormal thickening of the interventricular septum, the thickness of the interventricular septum at the end of diastole>15mm. ② Significantly reduced amplitude of the interventricular septal movement, generally ≤5mm. ③ Ratio of interventricular septal thickness / thickness of the posterior wall of the left ventricle up to 1.5-2.5:1, generally considered that the ratio>1.5:1 has diagnostic significance. The end-systolic internal diameter of the left ventricle is smaller than normal. ⑤ The distance between the septum and the anterior leaflet of the mitral valve at the onset of systole is often significantly reduced. ⑥ The mitral valve moves anteriorly during systole toward the ventricular septum and terminates before the second heart sound. (7) Mid-systolic closure of the aorta. The above 7 items should be analyzed comprehensively in order to draw the correct conclusions, it should be noted that hypertension, hypothyroidism, can cause similar performance. (4) Cardiac catheterization and cardiovascular angiography: cardiac catheterization, the left ventricle and the left ventricular outflow tract pressure step difference between the left ventricle, the left ventricular end-diastolic pressure increases, the pressure step difference and the degree of obstruction of the left ventricular outflow tract is positively correlated. Cardiovascular angiography, septal muscle hypertrophy is obvious, the ventricular cavity can be seen as a narrow slit-like change, which is meaningful for diagnosis. 5.Treatment (1)General treatment Provide life guidance to the patients, remind the patients to avoid strenuous exercise, holding weights or exclusion of gas, to reduce the occurrence of sudden death. (2) Internal medicine treatment β-blocker, cardiac glycosides can reduce myocardial contractility, reduce the left ventricular outflow tract obstruction to improve the left ventricular wall compliance and left ventricular filling, but also has the effect of antiarrhythmia. Avoid the use of drugs that enhance myocardial contractility and reduce cardiac volume load, such as digitalis and nitrates, to reduce the aggravation of left ventricular outflow tract obstruction. (3) Surgical treatment Surgical treatment: pressure step difference >60mmHg, drug treatment is ineffective, can be surgical treatment. The hypertrophic muscle resection is feasible. Combined with severe mitral valve insufficiency, can do mitral valve replacement. Heart transplantation is a feasible and effective method, and the survival rate of transplantation is still acceptable, but there is a lack of donors. (4) Interventional therapy Implantation of dual-chamber DDD-type pacemaker; implantation of buried automatic defibrillator to control malignant arrhythmia; chemical ablation for the treatment of intractable myocardial hypertrophy is a kind of hypertrophic obstructive cardiomyopathy interventional therapy carried out in recent years. It is less traumatic, easy to operate, and the prognosis is greatly improved. III.DISCUSSION It is by no means fortunate that the patient survived for such a long time, but adherence to scientific and timely treatment. With the progress of research, the treatment of hypertrophic cardiomyopathy is becoming more and more effective, and we hope that this case can help patients with hypertrophic cardiomyopathy.