What is the cause of hypertrophic non-obstructive cardiomyopathy

Many people do not understand the cause of hypertrophic non-obstructive cardiomyopathy. In fact, this disease is partly caused by genetic factors, and if there is an endocrine disorder, it can also lead to this disease. Common symptoms include difficulty breathing, fatigue, dizziness, heart failure, etc.

1. Causes

The cause of this disease is not clear, but possible factors include:

1. Genetics

Multiple people in a family may be affected, suggesting that it is related to genetics. Matsumori found that the detection rate of HLADRW4 in this disease was as high as 73.3%, while the detection rate in the control group was extremely low. The HLADR system is one of the genetic genes that regulates the immune response, indicating that this disease is related to genetics.

2. Endocrine disorders

Many patients with pheochromocytoma have coexisting hypertrophic cardiomyopathy. Intravenous infusion of large amounts of norepinephrine in humans can cause myocardial necrosis. Animal experiments have shown that intravenous infusion of catecholamines can cause myocardial hypertrophy. Therefore, some people believe that hypertrophic cardiomyopathy is caused by endocrine disorders.

2. Clinical manifestations

Onset is usually slow. About 1/3 has a family history. Symptoms usually begin before the age of 30. Men and women are equally affected.

1. Symptoms

(1) Dyspnea often occurs after exertion. It is caused by decreased left ventricular compliance, increased end-diastolic pressure, and subsequent increased pulmonary venous pressure, resulting in pulmonary congestion. Mitral regurgitation associated with ventricular septal hypertrophy can aggravate pulmonary congestion.

(2) Precordial pain often occurs after exertion and is similar to angina pectoris, but may be atypical. It is caused by increased oxygen demand from the hypertrophic myocardium and relatively insufficient blood supply from the coronary arteries.

(3) Fatigue, dizziness and fainting often occur during activities. This is because the increased heart rate further shortens the diastolic period of the left ventricle, which already has poor diastolic filling, aggravating the insufficient filling and reducing cardiac output. When active or emotionally excited, the sympathetic nerves increase the contraction of the hypertrophic myocardium, aggravate the outflow tract obstruction, and cause a sudden drop in cardiac output, resulting in symptoms.

(4) Palpitations are caused by decreased heart function or arrhythmia.

(5) Heart failure is more common in late-stage patients. Due to decreased myocardial compliance, ventricular end-diastolic pressure increases significantly, followed by increased atrial pressure, and is often accompanied by atrial fibrillation. In late-stage patients, myocardial fibrosis is extensive and ventricular contractile function is weakened, making them prone to heart failure and sudden death.