Contents
The human body, all its tissues and organs are made up of cells. Each of them does a complex job, which, in general, allows you to maintain the vital activity of the body. However, in order for a cell to “perform its direct duties,” it needs an energy substrate from which it will draw energy. Various substances act as such “nutritional capacities”: glucose, proteins, fatty acids, etc. However, oxygen can rightly be called the most significant substrate. If the cells do not have enough of it, then a person quickly develops a condition called hypoxia.
Hypoxia can be acute and chronic. It can harm any organ of the human body, but it primarily affects the brain, heart, liver and kidneys. The article will focus specifically on myocardial hypoxia – the muscular middle layer of the heart.
If myocardial hypoxia develops over several days, hours or minutes, then we are talking about an acute lack of oxygen. If hypoxia develops slowly, and the body adapts to it, then in this case the diagnosis will sound like chronic hypoxia.
Acute course of myocardial hypoxia
Causes
Acute myocardial hypoxia is a condition that poses a direct threat to life. If a person is not helped, he may die.
The causes of acute myocardial hypoxia can be as follows:
exogenous reasons. In this case, hypoxia develops under the condition that the heart muscle does not receive enough oxygen from the external environment. This can happen, for example, during a fire.
Violation of the normal patency of the respiratory system. Myocardial hypoxia can develop as a result of a foreign object entering the respiratory tract, either when a person begins to drown, or during asphyxia. In this case, all organs will suffer, and hypoxia of the brain and heart muscle will lead to death. Acute myocardial hypoxia also develops against the background of a severe course of pneumonia. It is a consequence of acute respiratory failure.
Acute myocardial hypoxia may develop due to the fact that there will be too little hemoglobin in the blood. It is he who is responsible for the transport of oxygen to the tissues of the body, including the myocardium. A similar situation can develop when inhaling air with a high content of carbon monoxide, when heavy metals enter the body, with heavy blood loss, against the background of severe anemia.
Myocardial hypoxia may be a consequence of a violation of the coronary circulation. The coronary arteries are vessels that supply the heart muscle with blood containing oxygen and other nutrients. If a person has crossed the line of 40 years, then there is a high probability that his arteries have undergone age-related changes. It is also impossible to exclude the presence of atherosclerotic plaques in its vessels. As the plaques increase in size, the vessel will be completely or partially blocked. In the place where this happens, the blood flow is disturbed. Therefore, a certain area of uXNUMXbuXNUMXbthe myocardium will be subject to hypoxia. If the artery is blocked completely, then the entire left ventricle is exposed to acute hypoxia. Provided that this problem is not eliminated in a timely manner, irreversible consequences will be launched in the body. The tissues of the heart will begin to suffer from ischemia and then undergo death. To distinguish between hypoxia and ischemia, it should be understood that hypoxia precedes myocardial ischemia. Only after these two conditions begins necrosis of the tissues of the heart. It is impossible to restore cells that have undergone necrosis. As a result, a person has a myocardial infarction.
Thus, hypoxia contributes to the development of myocardial ischemia.
Ischemia causes further violations, including:
Failure of metabolic processes in the tissues of the heart muscle. Changes in the structure of heart cells, disturbances in their work.
Deterioration of normal myocardial excitability with the development of tachycardia, atrial fibrillation and asystole.
Violation of the contractility of the heart muscle, dyskinesia or akinesia of the myocardium.
The patient may develop an attack of angina pectoris.
If ischemia is persistent and not eliminated by therapeutic action, then a person experiences necrosis of the heart tissue, followed by myocardial infarction.
Symptoms
The clinical picture of acute myocardial hypoxia is influenced by the causes that provoked the development of this pathological condition. If a person is poisoned by carbon monoxide or poisons, if he develops asphyxia, or if he drowns, then at first he will lose consciousness. Provided that at this time he is not provided with adequate assistance, the person dies. That is, not only respiratory, but also cardiac activity stops.
If the lumen of the coronary artery is blocked by a thrombus or atherosclerotic plaque, then the symptoms of acute hypoxia will be somewhat different. It should be noted that not only a thrombus or atherosclerotic deposits on the vessels can cause myocardial hypoxia. This condition is characteristic of any acute spasm of the artery, which can develop against the background of inhalation of tobacco smoke, with a sharp increase in blood pressure, with an increase in the level of adrenaline in the blood due to stress or physical overload. In this case, the victim will experience acute pain with localization in the chest, in the region of the heart. The pain is burning or pressing, can be given under the left shoulder blade or in the left arm. It is not possible to remove painful sensations by taking Nitroglycerin. Rarely, painless myocardial infarction develops. However, seeking medical help in either case does not require delay.
How to detect acute hypoxia of the heart muscle?
If hypoxia was provoked by the first, second or third group of reasons listed above, then it makes no sense to think specifically about oxygen starvation of the myocardium. It is important, first of all, to save the patient’s life. For example, you need to quickly remove or take him out of a burning building, pull him out of the water, stop acute blood loss, give a blood transfusion, and perform resuscitation. This means that care should be taken to neutralize the consequences caused by hypoxia of the brain and heart muscle.
If hypoxia is a consequence of a violation of the patency of the coronary arteries, then a competent diagnosis of this condition comes to the fore. The most informative methods that are most widely used are ECG and ultrasound of the heart. In the results of the electroencephalogram, acute hypoxia will be expressed in the appearance of negative or biphasic T waves, in the rise or depression of the ST segment. If a deep or widened Q wave appears on the tape, then this is an extremely dangerous signal that requires emergency assistance to a person. The fact is that such a tooth indicates the development of an acute and extensive myocardial infarction, which was provoked by hypoxia.
Ultrasound of the heart makes it possible to detect symptoms of hypoxia in the form of ischemic damage to its tissues. Ultrasound also allows you to determine those areas where impaired contractility is observed.
Treatment
To determine the most effective tactics for managing a patient affected by myocardial hypoxia, it is necessary to establish the cause of the development of this pathological condition.
If hypoxia is a consequence of impaired airway patency, or disorders in the composition of the blood, then it is important to eliminate these factors. This is the only way to stop the further progression of hypoxia. After a person has been taken out of the fire zone, or he has been removed from the water, or the airways have been cleared of foreign objects, or the bleeding has stopped, he must be urgently delivered to a medical facility. In hospital conditions, it is possible to carry out artificial ventilation of the lungs with an increase in oxygen supply, which makes it possible to prevent pathological changes in the brain and other organs responsible for ensuring the life of the victim. If necessary, the patient is prescribed detoxification therapy, for which plasma-substituting solutions are supplied through a vein, blood transfusion is performed.
If, against the background of acute hypoxia, the patient has a myocardial infarction, then the person is urgently placed in the intensive care unit of the cardiology department of the hospital. The patient is injected with thrombolytic drugs, which allows you to dissolve the clot that has formed in the arteries. This may be a drug such as Streptokinase or another enzyme. Also, a person is shown the introduction of Heparin, which is aimed at preventing the further process of thrombosis. If possible, perform coronary angiography with further stenting of the coronary artery, or CABG.
Myocardial hypoxia in chronic nature
Chronic myocardial hypoxia can last long enough, and the person will not know about his diagnosis. The symptoms of such a pathological condition are often erased, and diagnostic methods of examination do not always allow clarifying the presence of this pathology.
Causes
The following factors can provoke chronic hypoxia of the tissues of the heart muscle:
exogenous reasons. They begin to adversely affect the state of the heart, provided that they affect the body for a long time. For example, if a person smokes or works in a hazardous industry, he often dives to a depth or rises to a height. Air that contains a low amount of oxygen can provoke the development of hypoxia.
Diseases of the respiratory system. Often bronchial asthma leads to hypoxia of the heart muscle. Moreover, the more often the attacks of the disease occur, the more the heart suffers. Also, disorders such as cystic fibrosis, chronic bronchitis, bronchiectasis can lead to myocardial hypoxia. If all these diseases are aggravated by occupational hazards, then the risk of developing severe myocardial hypoxia increases. As a result, a person manifests cardiopulmonary insufficiency.
Anemia of chronic course. If the level of hemoglobin in the blood is low, but does not reach critical levels, then this negatively affects the state of the heart muscle. In addition, other organs will suffer from oxygen starvation.
Ischemic heart disease accompanied by atherosclerosis of the coronary arteries.
A combination of various pathological factors.
Symptoms
Although there are no symptoms that would indicate exclusively chronic myocardial hypoxia, there are signs of the disease by which the doctor can still suspect this pathology.
Among those:
Increased fatigue.
Physical weakness.
Shortness of breath that develops against the background of physical exertion.
Violations in the work of the heart, which a person can feel on their own.
Frequent bouts of dizziness. Sometimes even fainting is possible.
Excessive sleepiness.
How is it diagnosed?
To detect pathological changes in the tissues of the heart muscle, the doctor will refer the patient to undergo a comprehensive examination, which includes:
Pulse oximetry. This method provides information about the level of oxygen in the blood. Normally, its content is equal to 95%. If this indicator is underestimated, it is necessary to establish the cause of the violation.
ECG. If a person makes complaints that may indicate abnormalities in the work of the heart, he is necessarily sent to an ECG. In patients with chronic myocardial hypoxia, tachycardia, sinus tachycardia, changes in the shape of the P wave can be diagnosed, it is possible to identify symptoms indicating ischemic myocardial damage.
Ultrasound makes it possible to detect areas of the heart that have low contractility. Also, this method is informative in terms of determining the volume of cardiac output and stroke volume.
A blood test allows you to determine the level of hemoglobin in the blood. This analysis makes it possible to exclude anemia.
X-ray examination of the lungs and the function of external respiration allows you to assess the condition of the organs of the respiratory system.
It will be possible to identify myocardial hypoxia only after a thorough examination of the patient. Knowing the causes that led to the development of a pathological condition makes it possible to prescribe a quality treatment to the patient.
Treatment
The main efforts in terms of the treatment of chronic myocardial hypoxia should be aimed at eliminating the cause that provoked this violation. The patient may be prescribed antioxidants and antihypoxants. Taking these drugs allows you to normalize the processes of oxidative reactions in the body that occur at the cellular level. In addition, they make it possible to enhance the production of enzymes that are directly involved in oxidative processes. Antihypoxants have a positive effect on cell membranes, increasing their ductility. This makes it possible to improve the process of enrichment of cells with oxygen.
Drugs that can be prescribed for the treatment of chronic myocardial hypoxia:
Mexidol. This drug slows down the process of lipid oxidation, which reduces the level of harmful substances in the body that accumulate as a result of these reactions. This drug can be used to treat acute and chronic hypoxia. It is prescribed in the early stages of the patient’s recovery after a heart attack or stroke. The drug is administered intravenously or intramuscularly for 14 days. The daily dosage should not exceed 1200 mg.
Actovegin. This drug allows you to improve the consumption and processing of oxygen by the cells of the body, which is important in developing ischemia. He is prescribed a course for 5-10 days. Actovegin is administered either intravenously as an injection or as an infusion. In the future, for another 14-28 days, the drug should be taken orally.
Mildronate. The composition of this drug contains a substance that is present in the cells of the body. It is called meldonium dihydrate. Its action is similar to that of Actovegin and Mexidol. Mildronate is prescribed for acute myocardial infarction, as well as for chronic myocardial hypoxia. Take the drug for 10 days. While injecting it into a vein. Then for another 1-1,5 months Midronat should be taken orally.
Preductal. This drug affects the transport of ATP into the heart muscle. It is taken for a long time in the form of tablets. The duration of treatment should not be less than a month.
Self-treatment of myocardial hypoxia is unacceptable. The drug must be prescribed by a doctor.