Increased cardiac output

Introduction Cardiac dysfunction is defined as a cardiac dysfunction caused by different causes, and the development of cardiac output can not meet the needs of systemic metabolism for blood flow when circulating blood volume and vasomotor function are normal, resulting in blood flow. A clinical syndrome characterized by both dysmotility and activation of the neurohormonal system. The high dynamic circulation state mainly occurs in anemia, systemic arteriovenous fistula, hyperthyroidism, beriberi heart disease, etc., due to decreased peripheral vascular resistance, increased cardiac output, can also cause increased ventricular volume load, leading to heart failure.

Cause

1. Heart failure refers to heart failure caused by contraction dysfunction of primary cardiac myofibrils. At this time, the dysfunction of the pump is primary. Heart failure occurs when the myocardium contracts due to various reasons and cannot deliver enough blood to the peripheral blood vessels to be required for systemic tissue metabolism.

2. Heart failure caused by other causes. In the case of valvular heart disease, cardiac hypertrophy and cardiac enlargement occur due to excessive myocardial overload, followed by myocardial contractility due to relatively insufficient myocardial contractility. At this time, the dysfunction of the pump is secondary and is easily reversed when the valve is removed.

3. Heart failure caused by causes other than myocardium, often accompanied by myocardial damage in the late stage.

4. In addition to diseases of the heart itself, such as congenital heart disease, myocarditis, cardiomyopathy, severe arrhythmia, endocarditis, etc., diseases other than the heart, such as acute nephritis, toxic pneumonia, severe anemia, hemolysis, massive veins Rehydration and complications after surgery can also cause heart failure.

an examination

Related inspection

ECG cardiac output (CO)

1. Pay attention to the cause of heart failure and the presence or absence of symptoms and signs of lung or (and) systemic blood stasis, and check according to the general routine of cardiovascular disease.

2. Complete venous pressure, erythrocyte sedimentation rate, liver and kidney function tests within 2 days after admission. Long-term low-salt diet or diuretics should be checked regularly for potassium, sodium, chlorine, and magnesium.

3. It is proposed to distinguish left heart, right heart or whole heart failure according to clinical manifestations and examinations, and determine the level of heart failure.

Differential diagnosis

Reduced heart rate reserve: also known as the reserve of heart pumping function. Refers to the ability of the heart to increase cardiac output under the regulation of neurological and humoral factors, adapting to the needs of the body's metabolism. When healthy adults are quiet, the output is 4.5 to 5 liters, and the maximum cardiac output during vigorous exercise is 25 to 35 liters, that is, the heart rate is 20 to 30 liters. Cardiac stocks include heart rate storage and stroke volume reserve. When you are at rest, your heart rate is 75 beats per minute. The fastest heart rate is 170 to 180 beats per minute. Therefore, your heart rate is about 100 times per minute. The stroke volume is the difference between the ventricular end-diastolic volume and the end-systolic volume, and both have a certain reserve, which is called diastolic storage and systolic storage, and about 15 ml in diastolic storage (quiet at the end of the heart). The volume is 130-145 ml, the maximum cardiac end-stage volume is 145-160 ml), and the storage period is about 50-60 ml during systole (the volume of the end-systolic period is 60-80 ml when quiet, and the volume of the end-systolic period is reduced after the maximum ejection of the ventricle). Up to less than 20 ml), these two stocks together constitute a reserve of stroke volume, about 75-80 ml. During strenuous exercise, sympathetic excitation and adrenaline secretion increase, mainly mobilizing heart rate storage and systolic storage to increase cardiac output. The size of the heart's reserve reflects the ability of the heart's pumping function to adapt to metabolic needs, and is related to heart health. Labor and physical exercise can increase myocardial fiber, increase coronary blood flow, increase myocardial contractility, and increase heart rate storage, thereby improving mental reserve. For example, when athletes exercise vigorously, the heart rate can be 2 to 3 times that of resting. As the myocardial contractility is greatly enhanced, the ejection speed and relaxation rate are significantly accelerated, which increases the cardiac output and accelerates the flow of venous blood back to the heart. At 200 beats/min, the stroke volume is still reduced, and the cardiac output is greatly increased, which is 8 times that at rest.

Decreased cardiac output: In a quiet state, the normal left ventricular end-diastolic volume of normal adults is about 125ml, and the end-systolic volume is about 55ml. The difference between the two is the stroke volume, which is 70ml. It can be seen that the ventricle does not emit all the blood filled in the heart chamber every time the blood is shot. The percentage of stroke volume to the end-diastolic volume of the ventricle is called the ejection fraction. A decrease in cardiac output can lead to shock.

Obstruction of superior vena cava obstruction: Superior vena cava obstruction syndrome is a syndrome in which complete or incomplete superior vena cava obstruction is caused by various causes, which hinders blood flow. The clinical manifestations were mainly upper limb and facial edema and cyanosis, and varicose veins of the chest wall. Most of the causes of obstruction of the superior vena cava are mediastinal or hilar tumors and mediastinal inflammation. A small number is due to superior vena cava thrombophlebitis.

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