Hypertrophic cardiomyopathy is characterized by hypertrophy of the myocardium. It can be divided into obstructive and nonobstructive hypertrophic cardiomyopathy according to the presence or absence of obstruction of the left ventricular outflow tract. Asymmetric septal hypertrophy causing subaortic stenosis is called idiopathic hypertrophic subaortic stenosis.
Pathogenic factors
I. Heredity: there can be multiple cases in a family, suggesting a genetic link.
Endocrine disorders: pheochromocytoma patients with coexisting hypertrophic cardiomyopathy are more common, and intravenous injection of large amounts of norepinephrine in humans can cause myocardial necrosis. Animal experiments, intravenous injection of catecholamines can cause myocardial hypertrophy. Thus, it is believed that hypertrophic cardiomyopathy is caused by endocrine disorders.
Clinical manifestations
There is a significant difference between men and women, most of the symptoms appear at the age of 30-40 years old, with age, the symptoms become more obvious, the main symptoms are
1, dyspnea, exertional dyspnea, severe telangiectatic breathing or paroxysmal nocturnal dyspnea.
2, angina pectoris; often have typical angina pectoris, after exertional attacks. Chest pain lasts for a long time, with nitroglycerin containing not only ineffective and can be aggravated.
3, syncope and dizziness; mostly occurs during exertion. It can also cause syncope and dizziness when tachycardia or bradyarrhythmia occurs due to blood pressure drop.
4. Palpitations; the patient feels the heart beating strongly, especially in the left lateral position, which may be due to arrhythmia or altered cardiac function.
In short, through molecular level research, myocardial hypertrophy, in addition to mutations in certain genes, there are also angiotensin receptors, changes in the internal environment of calcium, etc. have an impact But Japanese data in hypertrophic cardiomyopathy apical hypertrophy accounted for 26.5-50%. In Europe, apical hypertrophy is also less common, accounting for about 2-4% of hypertrophic cardiomyopathy. In China, it was rarely reported in the past, but in recent years it has been found to be gradually increasing. In recent years, we have diagnosed dozens of cases of this type of cardiomyopathy, which indicates that this type of cardiomyopathy is quite common in Eastern populations.
The age of onset of this disease can be between 15-80 years old, and it is more common between 30-60 years old, with few clinical symptoms, while patients in the middle and late stages may have chest pain, palpitations, dyspnea, dizziness and fatigue.
The electrocardiogram often has T-wave depression in the thoracic leads, and some T waves are also like coronary T waves, most obvious in leads V3, V4, V5, and V6. The ST segment may also be depressed by 3-4 mm in some cases, which is also obvious in the precordial leads, and is often diagnosed as coronary artery disease or even subendocardial myocardial infarction in the clinical setting, but there are no risk factors for coronary artery disease. The ECG also has left ventricular high voltage, some patients have prolonged Q-T intervals, and mitral P waves may also be present. Various arrhythmias may be present in the mid to late stages. In addition, some patients have dynamic changes in ST segment and T wave, which may be good or bad.
1.Medical treatment
For a long time, the drug treatment of hypertrophic cardiomyopathy is mainly applied
(1) calcium blockers: the application of long-acting slow-release agents such as verapamil, thiodiazepine long-term treatment, can make the disease remission, or slow down the progress. Foreign reports of a group of patients with 14 years of continuous treatment remains effective.
(2) Beta blockers.
(3) Scopolamine class: Tone Micro One (i.e. Clonidine, Coronary Su) also has some effect when taken for a long time. However, it is not used in glaucoma or with severe prostatic hypertrophy. Our institute has used this drug for more than ten years or combined with calcium blockers or alternatively, with good results. Amiodarone can also be used for frequent ventricular arrhythmias, or buried DDD pacemakers have good effect.
2.Surgical treatment
(1)If it is obstructive type, with pressure step difference >30mmHg in the heart chamber, septal hypertrophy myocardial resection can be considered with good efficacy, and the mortality rate is only 2-3% as reported abroad.
(2) If there is significant diastolic closure, prosthetic valve replacement may also be performed.
(3) If there is an adequate donor source, heart transplantation can also be performed in patients with intermediate to advanced stages of this disease.