Myocardial infarction: what is it, symptoms of a heart attack, causes, treatment
The content of the article:
- The mechanism of development and stages of the disease
- What are the forms of myocardial infarction?
- Causes and risk factors
- The main clinical signs of myocardial infarction
- Complications of myocardial infarction
- Diagnostics
- Urgent care
- Treatment
- Prevention
- Video
Myocardial infarction is an acute heart disease, in which ischemic necrosis of a portion of the heart muscle develops against the background of relative or absolute insufficiency of blood supply. It is a dangerous complication of coronary heart disease with a high risk of adverse effects. The code of myocardial infarction according to ICD-10 is I21-I22.
The main symptom of a heart attack is anginal pain in the region of the heart.
According to statistics, most often a heart attack is recorded in men at the age of 40-60. In women of the same age, a heart attack is diagnosed about 1.5 times less often. After 60 years, the incidence among women and men is approximately the same.
Heart attack is one of the main causes of disability in adult patients. The mortality rate from it is 10-12%. A significant part of deaths in this pathology is noted in the first day of the disease. The clinical signs of myocardial infarction are manifold, which can make it difficult to quickly diagnose, which is highly desirable.
After the acute period, with properly selected treatment and following all the doctor's prescriptions, the prognosis improves.
The mechanism of development and stages of the disease
In the vast majority of cases, myocardial infarction is preceded by ischemic heart disease (CHD). The development of ischemia is based on a violation of the hemodynamics of the heart muscle. Most often, the narrowing of the lumen of the heart artery by about 70% of its cross-sectional area becomes clinically significant, when the restriction of blood supply to the myocardium can no longer be compensated. Pathological changes during ischemia are usually reversible. With the development of necrosis, damage to the heart muscle becomes irreversible. 1-2 weeks after the transferred heart attack, the area of necrosis begins to be replaced by scar tissue, the scar is finally formed after 1-2 months. The rehabilitation period after myocardial infarction lasts about 6 months.
During an infarction of the heart muscle, four stages are distinguished: ischemia, damage, necrosis, scarring.
What are the forms of myocardial infarction?
By the extent of the lesion, cardiac infarction is divided into large-focal (Q-infarction), small-focal (not Q-infarction).
Depending on the localization of the focus of ischemic necrosis, the disease can take the following forms:
- left ventricular infarction of the heart (posterior, lateral, anterior wall, lower);
- right ventricular infarction;
- interventricular septal infarction (septal);
- isolated apex infarction;
- infarction of combined localization (anterolateral, posterior inferior, etc.).
More often than others, left ventricular infarction is diagnosed.
The course of the disease can be monocyclic, protracted, recurrent myocardial infarction may develop (a new focus of necrosis occurs within two months after the previous one, more often after 3–8 days) and repeated (a new focus of ischemic necrosis develops two months after the previous one). The focus of necrosis in a repeated infarction can be located in the same place as the previous one, or have a different localization.
Depending on the depth of the necrotic lesion, the disease has the following forms:
- transmural - the entire thickness of the muscle wall is damaged;
- intramural - a focus of necrosis in the thickness of the wall;
- subendocardial - myocardial necrosis in the area adjacent to the endocardium;
- subepithelial - myocardial necrosis in the zone adjacent to the epicardium.
Also, a heart attack can be typical and atypical, complicated and uncomplicated.
In some cases, the patient may experience several forms of heart attack simultaneously or sequentially.
There are five main periods of heart attack: preinfarction, acute, acute, subacute, postinfarction.
Causes and risk factors
A heart attack develops as a result of obstruction (blockage) of the lumen of the coronary artery, which provides blood supply to the myocardium. The immediate causes that lead to this are vasospasm, atherosclerosis, embolism, and surgical obstruction. In some cases, the pathology is due to heart disease.
The cause of a heart attack is the cessation of blood flow through the coronary artery
The main risk factors are:
- cardiac ischemia;
- a history of myocardial infarction;
- arterial hypertension;
- rheumatic heart disease;
- bacterial infections (especially staphylococcal, streptococcal);
- diabetes;
- an increase in low density lipoproteins and triglycerides, a decrease in the concentration of high density lipoproteins in the blood;
- lack of physical activity;
- overweight;
- alcohol abuse;
- smoking (including passive smoking);
- age;
- male gender;
- excessive physical activity;
- chronic stress.
The main clinical signs of myocardial infarction
The main symptoms of a heart attack include acute intense compressive, so-called anginal pain behind the sternum, which can radiate to the neck, arm, scapula, jaw. The nature of the pain can be burning, squeezing, pressing, bursting. In some cases, the patient has no pain (for example, with diabetes mellitus), instead there is a feeling of chest discomfort. Usually the pain attack lasts about 15 minutes, but can last an hour or more. The pain is accompanied by shortness of breath, heart rhythm disturbances, unproductive cough, sticky sweat, pallor of the skin, and fever.
In 20-40% of patients with large-focal infarction, clinical signs of heart failure develop.
In some cases, the only symptom of a heart attack is sudden cardiac arrest.
In addition to the typical, manifestations of heart attack can be atypical, which greatly complicates the diagnosis.
The main atypical forms of myocardial infarction:
- abdominal - pain in the upper abdomen, hiccups, nausea, vomiting, bloating (reminiscent of the clinical picture of acute pancreatitis);
- asthmatic - characterized by increasing shortness of breath, resembles the symptoms of an attack of bronchial asthma;
- cerebral - impaired consciousness, dizziness, neurological symptoms;
- collaptoid - vascular collapse develops, blood pressure drops sharply, dizziness appears, darkening of the eyes, cold sweat;
- arrhythmic - manifested by a violation of the heart rhythm;
- peripheral - the pain is localized not behind the sternum, but in the left hand (especially often in the left little finger), throat, lower jaw, cervicothoracic spine;
- edematous - peripheral edema, weakness, shortness of breath, enlarged liver;
- combined - signs of several atypical forms are combined.
Complications of myocardial infarction
Complications of a heart attack are divided into early, arising in the acute period of the disease, and late.
The early ones include:
- acute heart failure;
- ventricular fibrillation;
- cardiogenic shock;
- breathing disorders (with the use of narcotic analgesics);
- cardiac tamponade;
- thromboembolism;
- myocardial rupture;
- arterial hypotension;
- pericarditis.
Late complications include chronic heart failure, postinfarction syndrome, heart aneurysm, neurotrophic disorders, etc.
A heart attack can cause the development of mental changes of a neurosis-like or neurotic nature. Such changes usually occur against a background of increased fatigue, even with minor physical or mental stress, sleep disturbances, and increased excitability.
In about 40% of cases, a cardiophobic reaction occurs, which consists in a panic fear of a second attack and death. Fear is accompanied by weakness, palpitations, tremors throughout the body, increased sweating, and a feeling of lack of air.
A heart attack is dangerous with the development of severe complications
After a heart attack, depression may develop with a rapid heartbeat, sleep disturbances, and movement disorders. In some patients, mainly elderly patients, there is a hypochondriac reaction with an excessive focus on the state of health.
With the development of an anosognosic reaction, the patient, denying the severity of the disease, does not follow medical recommendations, which can lead to the development of adverse consequences.
In some patients, a hysterical reaction is observed, which is characterized by emotional lability, egocentrism, a desire to attract the attention of others and arouse sympathy.
Mental asthenia is more pronounced in elderly patients and in patients with prolonged bed rest.
Psychoses after a heart attack develop in 6-7% of patients and are often accompanied by a significant deterioration in the patient's condition and even death. Usually psychosis occurs during the first week after an attack and lasts 2-5 days. The main causes of psychosis after myocardial infarction include the deterioration of cerebral hemodynamics against the background of impaired cardiac functions, intoxication of the body with the decay products of necrosis from the focus in the heart muscle. This complication is most often observed in patients with extensive cardiac lesions and acute circulatory failure. Risk factors for the development of psychosis are alcohol abuse, a history of traumatic brain injury, arterial hypertension, cerebral atherosclerosis, and old age. Psychosis, as a rule, manifests itself in the evening and at night,it often takes the form of delirium. At the same time, the patients have impaired consciousness, difficulties in orientation in time and space, hallucinations (usually visual), anxiety, motor excitement may occur, delirium may be preceded by euphoria with an overestimation of one's own capabilities and strengths.
In the absence of timely correction, mental changes are aggravated, become persistent, slow down rehabilitation, and lead to disability.
Diagnostics
The primary diagnosis is established when three criteria typical of a heart muscle infarction are met: pain syndrome, characteristic changes in the electrocardiogram, changes in the biochemical blood test.
For clarifying diagnostics, electrocardiography (ECG), echocardiography (EchoCG), blood tests (alanine aminotransferase, aspartate aminotransferase, creatine phosphokinase-MB, troponin) are performed. To confirm the diagnosis, additional research methods may be needed, such as identifying a focus of necrosis of the heart muscle by radioisotope methods, coronary angiography, etc.
Electrocardiography is the main method for diagnosing heart attack, along with a biochemical blood test
Differential diagnosis of heart attack is carried out with intercostal neuralgia. The main difference is the short duration and lower intensity of chest pain, with intercostal neuralgia, but since a heart attack is not excluded, an ECG is required.
Urgent care
A developing heart attack or suspicion of it is an indication for urgent hospitalization of the patient in cardiac intensive care. Before the arrival of the ambulance team, the patient needs to be given first aid. The person should be reassured, given a reclining position with legs bent at the knees. It is necessary to provide access to fresh air: open a window or window, loosen tight clothing (belt, tie, shirt collar, belt). In case of cardiac arrest (loss of consciousness, agonal breathing or lack of it), cardiopulmonary resuscitation should be started immediately, which includes chest compressions, mouth-to-mouth breathing, or mouth-to-nose. Before the arrival of an ambulance, the patient should not be left alone, even if he is conscious.
Treatment
Treatment of a heart attack at the initial stage is to eliminate pain and restore coronary blood flow. To relieve acute pain, narcotic analgesics are prescribed. To eliminate heart failure, inhalation of humidified oxygen is prescribed (supplied through a nasal catheter or mask at a rate of 2–5 liters per minute). In severe heart failure, intra-aortic balloon counterpulsation is used.
In the acute period, surgical methods can be used (angioplasty of the coronary arteries, coronary artery bypass grafting), thrombolytic therapy is carried out, which allows to limit the size of the heart attack, normalize coronary blood flow and reduce mortality. Thrombolytic therapy is prescribed for ST-segment elevation infarction based on the results of electrocardiography.
With high blood pressure, hypotonic drugs, diuretics are prescribed. In the presence of anxiety, fear and excitement after the use of a narcotic analgesic, a tranquilizer is prescribed.
If you suspect a heart attack, you must immediately call an ambulance
In the acute period, the patient is shown bed rest and fractional meals in a sparing regimen with limited calorie content and volume.
Prevention
In persons at risk of heart attack, the use of beta-blockers may be appropriate for prevention. Drugs in this group are prescribed to patients with a history of heart attack, which reduces the risk of re-infarction and mortality. This is also facilitated by antithrombotic therapy, the use of statins, polyunsaturated omega-3 fatty acids, angiotensin-converting enzyme inhibitors.
To prevent the development of a heart attack, a balanced diet, rejection of bad habits, adequate physical activity, avoidance of stress, control of blood pressure and cholesterol levels in the blood, and normalization of body weight are recommended.
Video
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Anna Aksenova Medical journalist About the author
Education: 2004-2007 "First Kiev Medical College" specialty "Laboratory Diagnostics".
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
