Decreased heart reserve

Introduction Also known as the reserve of the 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. The cardiac reserve can be expressed as the difference between the maximum cardiac output and the cardiac output at rest. 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.

Cause

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.

an examination

Related inspection

Dynamic electrocardiogram (Holter monitoring) ECG Doppler echocardiography

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.

Differential diagnosis

Heart failure: Heart failure is not an independent disease, it is a serious stage of heart disease caused by various causes. The incidence is high and the five-year survival rate is similar to that of malignant tumors. Heart failure is due to initial myocardial damage and stress: including systolic or diastolic ventricular overload and/or changes in the number and quality of cardiomyocytes (segmental myocardial infarction, diffuse such as myocarditis), causing ventricles and (or Buxinfang hypertrophy and enlargement (ventricular remodeling, remodel-ing people followed by ventricular systolic and diminished function, gradually developed.

Cardiac decompensation: When heart disease becomes worse and heart function declines beyond its compensatory function, cardiac decompensation occurs.

1, respiratory failure: the symptoms of this chronic pulmonary heart disease are mostly lung infection or improper use of sedatives as incentives, palpitations, shortness of breath, difficulty breathing, cyanosis, conjunctival congestion and edema, headache, head swelling, irritability, spirit Hemorrhoids, hallucinations, disorientation, lethargy, severe cases can appear madness, convulsions or tremors, and even coma, also known as pulmonary encephalopathy.

2, heart failure: mainly due to right heart failure. It is characterized by shortness of breath, increased purpura, jugular vein engorgement, hypertrophy of the liver, edema of both lower extremities or ascites, increased venous pressure, oliguria, loss of appetite, abdominal distension, nausea and vomiting, increased heart rate, severe shock or even shock death.

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.

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