Asystole
Asystole is a type of circulatory arrest, which is characterized by cessation of contractions of different parts of the heart. Asystole is conditionally instantaneous and comes after the previous violation of the rhythm of the heart. At instant asystole on the background of absolute well-being and without cardiac arrhythmias is a sudden cessation electroexcitability heart, resembling a short circuit, the cause of which is acute ischemia in coronary artery disease.
Asystole, which occurs after a long-term fibrillation of the ventricles, is formed as a result of the exhaustion of phosphate stores in the heart tissues. For the normal passage of blood through the heart tissue requires its periodic excitability, as a result of ventricular fibrillation develop bystrotsirkuliruyuschie, chaotic and disorderly electrical processes in the system of the heart, which causes the instantaneous cessation of perfusion of the coronary vessels. ATF stocks of endogenous origin are exhausted very quickly within a few seconds, and renewal at this point does not function. Therefore, the lack of these phosphates very much removes the work of the heart out of order with a violation of the pacemaker and electrical impulses. Thus, the heart muscle can not perform cutting movements, so atony comes.
most often asystole observed on the background of myocardial infarction, acute forms of heart failure, abuse and overdose of antiarrhythmic agents that affect the activity of the heart. As a rule, asystole appears unexpectedly and requires urgent hospitalization and resuscitation. If these measures are not fulfilled, a fatal outcome may occur, although only 15% of patients can be saved after resuscitation.
Asystole causes
Asystole is characterized by a lack of heartbeats and symptoms of cardiac electrical activity on the ECG, that is, it marks the onset of clinical death. Asystole needs urgent resuscitation character holding events in which injected adrenaline, atropine, conduct pacing, indirect or direct cardiac massage and artificial ventilation. But the probability of a positive outcome with asystole is very low.
Asystole can occur both atrial and ventricular.
Asystole of the ventricles represents a state of the organism in which the electrical and mechanical activity of the ventricles, the heart as a whole and its stoppage ceases. This pathology is characterized by cessation of blood circulation and clinical death.
Typically, the emergence of ventricular asystole, and hemodynamically inefficient electrical activity of the heart largely contribute to severe irreversible damage to the heart and circulatory disturbances progressing. Therefore, the causes of cardiac and non-cardiac origin can cause heart failure.
The root causes of electrical instability of the heart muscle include: IHD in acute form, as well as chronic;Various lesions, postinfarction restoration of the heart against the background of CHF.In addition, the emergence of a primary stop of blood circulation is associated with the electrostability of the heart muscle. Quite often, asystole develops as a result of complications of an acute form of myocardial infarction, significant myocardial lesions with complete transverse blockade against the background of ventricular fibrillation.
But in terms of forecasting the instant form of asystole is considered unfavorable. The cardiac arrest that occurs after VF is characterized by a positive prognosis, especially against the background of a large-wave VF, in contrast to the shallow wave.
Causes of asystole may be cardiac rupture and cardiogenic shock. Significantly increased risk of cardiac arrest with unstable angina. Approximately 12% of these patients develop sudden death and myocardial infarction.
Risk factors for asystole in CHF is considered heart remodeling after myocardial with further education dilatation and hypertrophy of the heart chambers, as well as existing arrhythmias and conduction block, multivessel disease, alcohol abuse, age, smoking, hypertension, atherosclerosis with hereditary predisposition and hypercholesterolemia.
Other cardiac reasons for the development of asystole include: pericarditis of exudative genesis, obstruction of inflow or outflow of blood to the heart( thrombosis within the heart, valve or myxoma dysfunction).And also low blood outflow, myocarditis against influenza or diphtheria, endocarditis of infectious etiology, cardiomyopathy, aortic stenosis, trauma with tamponade formation, open heart pacing, coronary angiography and catheterization are all causes of possible circulatory arrest.
For extracardiac reasons, which are capable of causing asystole, include: circulatory( hypovolemia, shock of different genesis, pneumothorax of a strained nature with pulmonary diseases, chest injuries or on mechanical ventilation, PE, reflex vaso-vagal properties).In addition, respiratory causes( hypercapnia and hypoxemia) and metabolic( hypothermia, acidosis, hyperkalemia);Acute form of hypercalcemia, hyperadrenalinemia, side effects when taking barbiturates, narcotics, cardiac glycosides, etc., trigger the emergence of asystole.
However, there are many other factors that cause heart failure. It can be electric injury as a result of electric shock, lightning;asphyxia;intoxication;sepsis;Complications of cerebrovascular nature;Different diets, based on the reception of protein and a significant amount of fluid.
Asystole symptoms of
Suddenly occurring primary circulatory arrest is the first sign of cardiac ischemia, although it has in most cases certain precursors. For example, when patients were questioned after resuscitation was carried out, 40% of patients had no precursor to asystole, 30% experienced chest pain, 32% complained of head spin or unconsciousness, and 25% had shortness of breath in the form of dyspnea. All other cases are characterized by the development of asystole as a result of the pathological conditions that caused it to form.
As a rule, circulatory arrest occurs in patients who are heavily ill for a long time. In this case, significantly affects the connection of extracardiac and cardiac factors. In this case, patients experience hypotension, tachycardia, chest pain, dyspnoea, and fever. In addition, they become restless, and then all this causes a disturbance of consciousness.
Asystole of the ventricles is characterized by a sudden disappearance of the pulse, heart sounds and pressure. In the very near future there is a loss of consciousness, the patient becomes pale and breathing stops. After the circulation in the brain stops, that is, after forty-five seconds, the pupils widen, which reach a maximum within one minute of forty-five seconds. Asystole on the ECG is confirmed by the lack of electroactivity of the heart, but resuscitation should be started before the results of the ECG study.
Typically, asystole is seen as a clinical death of the patient, which is a reversible stage of dying. In this case, the symptomatology is manifested by the absence of cardiac contractions, independent breathing and reflexes to external influences. However, there is the possibility of potential recovery of the body functions by resuscitation methods.
Against the background of asystole, in the absence of blood circulation, inhalations of agonal properties continue, characterized by rare, short, deep convulsive respiratory movements with the participation of skeletal musculature. This amplitude of movements can be weak and low, that is, external breathing is somewhat reduced.
When examined on an electrocardiogram, asystole is noted with an undulating isoline, there is no pulsation of the main arteries, atrial activity may be retained in contrast to the ventricles. This asystole with a P-tooth may be a response to electrocardiostimulation.
Asystole treatment
Specialized treatment for asystole is the optimal ventilation of the lungs by intubating the trachea and providing access to the central or peripheral veins through which the adrenaline hydrochloride and Atropine bolus are administered. This is due to the fact that supraventricular and ventricular rhythm drivers are very rarely suppressed as a result of increased parasympathetic tone.
In case of adrenaline inefficiencies in normal doses, inject it every 5 minutes, then increase the dose to five milligrams with the introduction every three minutes. Basically, all medications should be administered intravenously and quickly. If the drugs are injected into the veins at the periphery, then they are diluted with saline. In cases where there is no access to the veins, Adrenaline, Lidocaine, Atropine are injected into the trachea in a dose that is doubled. But the introduction of injections into the heart is permissible only if ineffectiveness or impossibility of other ways of administration.
The available minimal contractile activity of the heart is subjected to cardiac pacing of the endocardial, percutaneous or transesophageal type.
Cardiostimulation is performed in acute forms of myocardium, bradycardia, tachyarrhythmias, overdoses of digitalis preparations and inadequate blood circulation. In addition, both ventilator and indirect heart massage are being performed simultaneously, while trying to eliminate the causes of asystole: hypoxia, hyperkalemia, acidosis, hypothermia, drug overdose, cardiac tamponade and PE.
If hypovolemia develops, then rapidly recover BCC( the volume of blood that participates in circulation).With pneumothorax, a catheter is inserted, left open, and then replaced by drainage. In the presence of cardiac tamponade, pericardiocentesis is performed, and further - catheter drainage or pericardiotomy. In the case of intracardiac thrombosis and myxoma, an emergency operation is prescribed.
For the treatment of hypoxia, ventilation is used, and if the asystole occurs as a result of an overdose of drugs, an etiological method of therapy is prescribed. Hyperkalemia is treated with the introduction of calcium chloride and sodium hydrogen carbonate( must be injected into different veins) and mixtures of glucose with insulin. For the treatment of acidosis, intensive ventilation is carried out and sodium hydrogencarbonate is administered intravenously at the same dosages.
All resuscitation measures are terminated if in half an hour there is no effectiveness from their conduct. In this case, there will be no consciousness, breathing is arbitrary, the heart is inactive, and the pupils are very much enlarged and do not respond to light.
Further treatment measures are performed in the intensive care unit, where the electrocardiogram, respiration, bcc, hemodynamics, electrolytes are monitored. With the help of medications, they are kept closer to the norm of blood pressure, they inject Reopoliglyukin to improve the rheological properties of the blood and carry out intensive treatment of the underlying pathology. But to prevent damage to the brain around the head and neck, put ice bubbles and maintain the temperature in the auditory meatus from the outside within 34 degrees.
Asystole emergency care
Asystole is considered a complete cessation of the mechanical and electrical work of the heart. It is the second reason for the sudden onset of death. Very often VF leads to asystole. The symptomatic picture of a pathological condition consists of symptoms that characterize clinical death. The prognosis for cardiac arrest is somewhat worse, in contrast to fibrillation, since asystole is considered secondary to chronic cardiac pathologies.
Emergency resuscitation measures for the emergence of asystole consist of indirect heart massage and artificial respiration. Then, adrenaline hydrochloride and calcium chloride are injected intravenously. If necessary, you can enter these drugs intracardiacally.
In the future, electrotransvenous or transthoracic pacing is performed. And then low-molecular liquids are injected into the subclavian central large vein, as well as sodium bicarbonate, glucose, panangin, insulin.
