Obesity cardiomyopathy

Introduction to obesity cardiomyopathy Obesity cardiomyopathy, also known as obese heart syndrome, refers to changes in the pathophysiology of the heart caused by obesity in addition to hypertension, coronary heart disease, valvular heart disease, congenital heart disease, and other causes of heart disease. Smith equaled that in 1933, obese patients were first found to be associated with cardiac insufficiency, and since then, they have been confirmed by autopsy. basic knowledge The proportion of the disease: the incidence of this disease in obese patients is about 0.04% -0.06% Susceptible people: no special people Mode of infection: non-infectious Complications: congestive heart failure, arrhythmia, hypertension

Causes of obesity cardiomyopathy

Causes:

When the body consumes more than the calories consumed, the excess calories can be stored in the body in the form of fat. When it reaches a considerable reserve, it becomes obese. Excessive obesity can cause heart dysfunction and develop into obesity cardiomyopathy.

Pathogenesis:

1. The pathogenesis of obesity cardiomyopathy is not well understood, and may be related to the patient's high blood volume, increased cardiac load, etc. Echocardiographic studies confirm the wall tension of the heart chamber (can be expressed by the following ratio: wall thickness / ventricular diastolic The inner diameter is highly correlated with the systolic function of the heart, such as ventricular shortening fraction, myocardial fiber shortening speed and ejection fraction, etc. When the myocardial contractile function is impaired, this ratio is also low, indicating that the cardiac wall tension is high, and accordingly, obesity can be obtained. The patients were divided into two groups. One group had normal heart function, the ventricular wall was thickened, the ventricular cavity radius was increased, and the ventricular wall tension was normal. The other part of the patient's systolic function was reduced, and the wall thickening was not as obvious as the heart diameter. The ventricular wall tension is high. For obese patients with circulatory congestion, to identify whether they have heart failure, echocardiography, myocardial nucleus or cardiac angiography must be performed to determine the systolic function of the heart.

2. Pathological anatomy The weight of the heart of obese patients is significantly higher than that of the ideal body weight, which is 2 to 3 times higher than that of non-obese people. It is reported that the heart of an obese patient weighs 1100g. The comprehensive report shows that the left ventricular hypertrophy of the patient is 6%. ~56%, characterized by eccentric hypertrophy, left ventricular diameter increased by 8% to 40%, left atrial enlargement by 10% to 40%, some cases (32%) with right ventricular enlargement, 8% to 33% of patients with right ventricle Hypertrophy, some patients (25% to 50%) at the bottom of the heart, a large amount of fat on the atrioventricular sulcus and ventricle surface, but this is not the cause of heart weight gain, it has been reported that myocardial biopsy found that a small number of patients (3%) cardiomyocytes, heart fibers There is fat infiltration around the stent and blood vessels, and the right heart system is easily involved. It is thought to cause ventricular function damage, conduction system involvement and arrhythmia, and there is little fat infiltration in the left ventricle. Studies have reported that right endocardial biopsy found most Obese patients have cardiomyocyte hypertrophy.

3. The pathophysiological hemodynamic changes are obvious in obese people. There is no sufficient data to show that the patients with moderate obesity also have the following changes. The overall blood volume and cardiac output of the patients increase, and the increase in body weight is positive. Related, this is mainly caused by an increase in vascular bed. It is estimated that the blood flow of adipose tissue is 2 to 3 ml/100 g per minute at rest, and the blood flow of the central nervous system and kidneys is not significantly increased due to adipose tissue metabolism. Active, obese people increased oxygen consumption, patients with heart rate and arteriovenous oxygen partial pressure difference is no difference compared with non-obese people, the increase in systemic oxygen consumption mainly depends on the increase in cardiac stroke volume.

5% to 10% of people with excessive obesity have severe hypertension, 50% with mild, moderate hypertension, with or without hypertension, and obese people with resting or active left ventricular diastolic pressure and pulmonary vascular wedge The pressure is increased, and the high blood volume and high cardiac output of the patient cause high blood flow in the lungs, which causes the left ventricular anterior and posterior loads to be aggravated, leading to left ventricular hypertrophy and systemic congestion.

About 5% of obese patients have apnea/hypopnea syndrome, long-term hypoxia, hypercapnia, pulmonary vasoconstriction and thickening of pulmonary arteriolar wall, and high blood flow in obese people Pulmonary hypertension, obesity patients with elevated right ventricular filling pressure, and body mass index is proportional, leading to right ventricular hypertrophy and pulmonary circulatory congestion, single right heart hypertrophy and right heart failure rarely occur, but also with right ventricular hypertrophy Heart damage.

Circulatory congestion: Excessive obesity due to increased circulating blood volume and extracellular fluid, the heart's high blood output is often prone to severe pulmonary circulation and systemic congestion, and these signs are not cardiac dysfunction, and its cardiac output is high, shooting The exact blood flow is normal, and the exact mechanism of this state of circulatory congestion is unclear.

Obesity cardiomyopathy prevention

1. Strengthen publicity and education, raise the level of understanding of the disease, fully understand the harm of obesity to health, and actively act to change bad habits.

2. Establish scientific, civilized living habits, increase proper exercise, and maintain ideal weight.

Obesity cardiomyopathy complications Complications, congestive heart failure, arrhythmia, hypertension

The disease may have complications such as congestive heart failure, arrhythmia, and hypertension.

1. Heart failure The increase in body mass index is associated with the risk of heart failure. The study found that for every 1 increase in body mass index after correction for known risk factors, the risk of heart failure increased by 5% in men and 7% in women, compared with women with normal weight. Overweight women have a 50% higher risk of heart failure, and obese women have a 1% higher heart failure.

2. Arrhythmia In obesity, the whole blood volume increases, the cardiac compensatory output increases, the heart load increases, the stress increases, and the arrhythmia is easily promoted.

3. Hypertension The incidence of hypertension in obese people is 5 times that of non-obese people.

Symptoms of obesity cardiomyopathy Common symptoms Congestive heart failure Ascites diffuse steatosis coma Sit-sit breathing Sudden obesity Obesity Pre-obesity Drug-induced obesity

1. Symptoms are mild, although moderate obesity patients may have ventricular hypertrophy, but generally do not have symptoms of circulatory congestion, obese cardiomyopathy patients may have a longer asymptomatic period, the earliest, the most common symptom is dyspnea after exercise, Sitting on the breathing, these symptoms are paroxysmal, due to impaired diastolic function, increased cardiac output, normal systolic function, and recent weight gain can lead to increased symptoms, if the systolic function is normal during the first episode, these Symptoms can be recurrent within 10 to 15 years, and the heart contraction function can be relatively good for a long time. Conversely, if the heart function is reduced, the prognosis is generally poor, but the course of the disease is not very clear, and some patients have breathing. Suspension/insufficiency syndrome, in addition to the symptoms of systemic circulation and pulmonary circulatory congestion, it may be accompanied by drowsiness, wilting and disorientation. It is caused by central nervous system edema, coma is rare, and sudden death is common. When there is a right heart dysfunction, there may be upper abdominal discomfort, abdominal distension, and the like.

2. Physical examination Heart arrhythmia patients can sometimes hear and systolic fourth heart sounds, third heart sounds and pulmonary heart valve second heart sound hyperthyroidism, although the jugular vein is full, but often difficult to observe, lungs often smell and hairpin Fine wet voice, almost every obese person can have large liver, ascites and non-depression edema of both lower extremities, those with apnea/insufficient syndrome may have cyanosis, common dyspnea, and also There may be conjunctival hyperemia, retinal congestion and optic disc edema.

Patients with severe obesity have progressive shortness of breath, sitting breathing and lower extremity edema, X-ray chest radiograph shows heart enlargement, and pulmonary congestion can be considered obesity cardiomyopathy. The following diagnostic criteria can be referred to.

Examination of obesity cardiomyopathy

Laboratory tests for hypoxemia, often accompanied by respiratory acidosis, but with the improvement of circulating congestion, there may be a certain degree of improvement.

1. The electrocardiogram has a left-biased electric axis, or a right-sided partial P-wave with low voltage. Although the anatomy confirms left ventricular hypertrophy, it is not shown on the electrocardiogram, which may be due to the simultaneous enlargement of the left and right ventricles. Patients with recurrent congestive recurrence may have atrial fibrillation, atrial flutter and various conduction blocks, fat infiltration of the conduction system and enlargement of the left atrium as the pathological basis, and those with apnea/insufficient syndrome may There are sinus node lesions, such as sinus arrest, sinus node block, can have clinical symptoms, the probability of sudden cardiac death is high, the reason is not very clear.

2. X-ray chest X-ray of obesity cardiomyopathy can be normal, the most manifested is heart enlargement, pulmonary congestion.

3. Echocardiography 80% to 98% of patients with obesity cardiomyopathy, can be observed by transthoracic color Doppler echocardiography (TTE), 70% of patients can undergo a complete TTE examination, because the heart is in the chest The position inside is different from normal people, and some are upward. Therefore, the sound window of TTE examination is different from normal. It is not ideal. The ultrasound image under the sword is not ideal. About half of the patients can not observe the ideal endocardium. Surface or measurement of ejection fraction, transesophageal echocardiography (TEE) should be able to compensate for the lack of TTE, but there is no report of TEE in patients with obesity, patients with increased left ventricular filling pressure, some people use Doppler ultrasound study, blood pressure In normal obese patients, the mitral blood flow pressure is reduced by half compared with non-obese hypertensive patients or normal people. The peak rate of left ventricular filling is higher than that of the control group. Some patients have enlarged right ventricular hypertrophy and right ventricular systolic function. There are few studies, and it has been reported that obese patients have reduced right ventricular function and an ejection fraction of 8% to 22%.

Diagnosis and identification of obesity cardiomyopathy

Diagnostic criteria

1 extremely obese patient;

2 significantly increased heart (more obvious left ventricle), may have congestive heart failure;

3 left ventricular end-diastolic pressure is close to the upper limit of normal value at rest, and exercise often rises;

4 The above performance improved with a significant decrease in body weight.

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