Sudden cardiac death is an asystole or ventricular fibrillation that occurred against the background of the absence of symptoms in the anamnesis indicating coronary pathology. The main manifestations include lack of breathing, blood pressure, pulse on the main vessels, dilation of the pupils, lack of reaction to light and any types of reflex activity, marbling of the skin. After 10-15 minutes, the appearance of a cat’s eye symptom is noted. Pathology is diagnosed on the spot according to clinical signs and electrocardiography data. Specific treatment – cardiopulmonary resuscitation measures.
I46.1 Sudden cardiac death, as described
Sudden coronary death accounts for 40% of all causes of death of people over 50, but under 75 years of age, who do not suffer from diagnosed heart diseases. There are about 38 cases of SCD per 100,000 population annually. With timely initiation of resuscitation measures in the hospital, the survival rate is 18% and 11% for fibrillation and asystole, respectively. In the form of ventricular fibrillation, about 80% of all cases of coronary death occur. Middle-aged men with nicotine addiction, alcoholism, and lipid metabolism disorders are more likely to suffer. Due to physiological reasons, women are less susceptible to sudden death from cardiac causes.
Causes of sudden cardiac death
Risk factors for SCD do not differ from those for ischemic disease. The number of provoking effects includes smoking, eating a large amount of fatty foods, hypertension, insufficient intake of vitamins into the body. Unmodified factors – old age, male gender. Pathology can occur under the influence of external influences: excessive power loads, diving into icy water, insufficient oxygen concentration in the surrounding air, with acute psychological stress. The list of endogenous causes of cardiac arrest includes:
- Atherosclerosis of the coronary arteries. Cardiosclerosis accounts for 35.6% of all SCD. Cardiac death occurs immediately or within an hour after the appearance of specific symptoms of myocardial ischemia. Against the background of atherosclerotic lesions, MI is often formed, which provokes a sharp decrease in contractility, the development of coronary syndrome, flickering.
- Conduction disturbances. Usually there is a sudden asystole. CPR measures are ineffective. Pathology occurs with an organic lesion of the conductive system of the heart, in particular the sinatrial, atrioventricular node or large branches of the Gis bundle. As a percentage, conduction failures account for 23.3% of the total number of cardiac deaths.
- Cardiomyopathy. They are detected in 14.4% of cases. Cardiomyopathies are structural and functional changes of the coronary muscle that do not affect the coronary artery system. They are found in diabetes mellitus, thyrotoxicosis, chronic alcoholism. They may have a primary nature (endomyocardial fibrosis, subaortic stenosis, arrhythmogenic pancreatic dysplasia).
- Other states. The share in the total structure of morbidity is 11.5%. They include congenital anomalies of the heart arteries, aneurysm of the left ventricle, as well as cases of SCD, the cause of which could not be determined. Cardiac death can be observed with pulmonary embolism, which causes acute right ventricular failure, in 7.3% of cases accompanied by sudden cardiac arrest.
The pathogenesis directly depends on the causes that caused the disease. With atherosclerotic lesions of the coronary vessels, a complete occlusion of one of the arteries by a thrombus occurs, the blood supply to the myocardium is disrupted, a focus of necrosis is formed. The contractility of the muscle decreases, which leads to the occurrence of acute coronary syndrome and the cessation of cardiac contractions. Conduction disturbances provoke a sharp weakening of the myocardium. A week of residual contractility causes a decrease in cardiac output, stagnation of blood in the chambers of the heart, the formation of blood clots.
In cardiomyopathies, the pathogenetic mechanism is based on a direct decrease in the efficiency of the myocardium. At the same time, the impulse spreads normally, but the heart for one reason or another reacts weakly to it. The further development of pathology does not differ from the blockade of the conducting system. With PE, the flow of venous blood to the lungs is disrupted. There is an overload of the pancreas and other chambers, blood stagnation is formed in a large circle of blood circulation. A heart overflowing with blood in hypoxia conditions turns out to be unable to continue working, its sudden stop occurs.
Systematization of SCD is possible due to the causes of the disease (MI, blockade, arrhythmia), as well as the presence of previous signs. In the latter case, cardiac death is divided into asymptomatic (the clinic develops suddenly against the background of unchanged health) and having previous signs (short-term loss of consciousness, dizziness, chest pain an hour before the development of the main symptoms). The most important for resuscitation measures is the classification by type of cardiac activity disorder:
- 1 Ventricular fibrillation. It takes place in the absolute majority of cases. Requires chemical or electrical defibrillation. It represents chaotic disorderly contractions of individual fibers of the ventricular myocardium, unable to provide blood flow. The condition is reversible, it is well stopped with the help of resuscitation measures.
- 2 Asystole. Complete cessation of heart contractions, accompanied by a stop of bioelectric activity. More often it becomes a consequence of fibrillation, but it can develop initially, without previous flickering. It occurs as a consequence of severe coronary pathology, resuscitation measures are ineffective.
Symptoms of sudden cardiac death
40-60 minutes before the development of a stop, previous signs may appear, which include fainting lasting 30-60 seconds, severe dizziness, impaired coordination, a decrease or increase in blood pressure. Pain behind the sternum of a compressive nature is characteristic. According to the patient, the heart seems to be squeezed in a fist. Precursor symptoms are not always observed. Often, the patient simply falls while doing some work or exercise. Sudden death in a dream without previous awakening is possible.
Cardiac arrest is characterized by loss of consciousness. The pulse is not detected both on the radial and on the main arteries. Residual respiration may persist for 1-2 minutes from the moment of pathology development, but breaths do not provide the necessary oxygenation, since there is no blood circulation. On examination, the skin is pale, bluish. Cyanosis of lips, earlobes, nails is noted. Pupils are dilated, do not react to light. There is no reaction to external stimuli. With blood pressure tonometry, Korotkov’s tones are not listened to.
Complications include metabolic storm, which is observed after successful resuscitation. Changes in pH caused by prolonged hypoxia lead to disruption of the activity of receptors, hormonal systems. In the absence of the necessary correction, acute renal or multiple organ failure develops. The kidneys can also be affected by microthrombs formed when DIC syndrome appears, myoglobin, the release of which occurs during degenerative processes in the striated musculature.
Poorly performed cardiopulmonary resuscitation causes decortication (brain death). At the same time, the patient’s body continues to function, but the cerebral cortex dies. Restoration of consciousness in such cases is impossible. A relatively mild variant of cerebral changes is posthypoxic encephalopathy. It is characterized by a sharp decrease in the mental abilities of the patient, a violation of social adaptation. Somatic manifestations are possible: paralysis, paresis, dysfunction of internal organs.
Sudden cardiac death is diagnosed by a resuscitator or other specialist with medical education. Trained representatives of emergency response services (rescuers, firefighters, police officers), as well as people who happened to be nearby and have the necessary knowledge, are able to determine the stop of blood circulation outside the hospital. Outside the hospital, the diagnosis is made solely on the basis of clinical signs. Diagnostic methods include:
- Hardware manual. On the heart monitor, to which each patient of the intensive care unit is connected, large-wave or small-wave fibrillation is noted, ventricular complexes are absent. There may be isolation, but this rarely happens. Saturation indicators are rapidly decreasing, blood pressure becomes undetectable. If the patient is on auxiliary ventilation, the ventilator signals the absence of attempts to inhale independently.
- Laboratory diagnostics. It is carried out simultaneously with measures to restore cardiac activity. Of great importance is the blood test for CSF and electrolytes, in which there is a shift in pH to the acidic side (a decrease in the hydrogen index below 7.35). To exclude an acute infarction, a biochemical study may be required, in which the increased activity of CK, CFK MV, LDH is determined, and the concentration of troponin I increases.
Emergency care of sudden cardiac death
Assistance to the victim is provided on the spot, transportation to the ICU is carried out after the restoration of the heart rhythm. Outside the medical facility, resuscitation is carried out by the simplest basic techniques. In a hospital or ambulance, it is possible to use complex specialized techniques of electrical or chemical defibrillation. The following methods are used to revive:
- Basic CPR. It is necessary to lay the patient on a hard, flat surface, clear the airways, tilt the head back, push out the lower jaw. Pinch the victim’s nose, put a cloth napkin on his mouth, wrap his lips with your lips and exhale deeply. Compression should be carried out by the weight of the whole body. The sternum should be pushed by 4-5 centimeters. The ratio of compressions and breaths is 30:2, regardless of the number of resuscitators. If the heart rate and independent breathing have recovered, you need to put the patient on his side and wait for the doctor. Self-transportation is prohibited.
- Specialized assistance. In the conditions of a medical institution, assistance is provided in full. When ventricular flicker is detected on the ECG, defibrillations are performed with discharges of 200 and 360 J. It is possible to introduce antiarrhythmics against the background of basic resuscitation measures. With asystole, adrenaline, atropine, sodium bicarbonate, calcium chloride are injected. The patient is necessarily intubated and transferred to artificial lung ventilation, if this has not been done before. Monitoring is shown to determine the effectiveness of medical actions.
- Help after the rhythm is restored. After the sinus rhythm is restored, the ventilator continues until consciousness is restored or longer, if the situation requires it. According to the results of the analysis of the ABB, the electrolyte balance is corrected, pH. Round-the-clock monitoring of the patient’s vital activity is required, assessment of the degree of damage to the central nervous system. Restorative treatment is prescribed: antiplatelet agents, antioxidants, vascular drugs, dopamine for low blood pressure, soda for metabolic acidosis, nootropic agents.
Prognosis and prevention
The prognosis for any type of SCD is unfavorable. Even with timely CPR, there is a high risk of ischemic changes in the tissues of the central nervous system, skeletal muscles, and internal organs. The probability of successful rhythm restoration is higher with ventricular fibrillation, complete asystole is less favorable prognostically. Prevention consists in timely detection of heart diseases, exclusion of smoking and alcohol consumption, regular moderate aerobic training (running, walking, jumping rope). It is recommended to give up excessive physical exertion (weightlifting).