Ventricular fibrillation
Ventricular fibrillation is a peculiar condition of the body in which the heart rhythm is disturbed so much that it threatens the life of the patient. At the time of ventricular fibrillation, rapid, uncoordinated and inefficient ventricular contractions are noted, which are formed as a result of multiple chaotic electrical impulses. This pathological condition is characterized simply by their trembling without coordinated contractions, as in atrial fibrillation. During this process, the cardiac output of the blood does not work, so the indiscriminate contraction of the ventricles is practically a stop of the heart, and if it does not stop, then death occurs. Inadequate blood circulation in the myocardium against the background of IHD, especially with myocardial infarction is the main widespread cause of ventricular fibrillation, and among other causes of its occurrence is hypokalemia and shock.
As a rule, this pathological process leads to loss of consciousness, and without appropriate treatment causes seizures, and then an irreversible process of brain death due to non-occurrence of oxygen, which is the cause of death.
Ventricular fibrillation can presumably be diagnosed on the basis of sudden fainting, palpation of the pulse, as well as the absence of cardiac contractions and pressure. Therefore, only ECG results can absolutely confirm this diagnosis.
At the heart of urgent events is resuscitation of the heart and lungs, as well as cardioversion. Further treatment continues with the help of medications to maintain a normal heart rhythm.
In the event of such a pathological condition after myocardial infarction without HF and shock, carrying out urgent cardioversion gives a positive effect with a favorable prognosis in 95% of cases. And in the presence of significant damage to the heart, cardioversion is characterized by success only in 30% of cases.
Ventricular fibrillation causes
Ventricular fibrillation develops as a result of randomly contracting ventricles with a frequency of up to 450 beats per minute. This type of arrhythmia is dangerous and requires immediate assistance in the form of defibrillation to prevent cardiac arrest.
The cause of the development of chaotic heartbeat in many patients is any cardiac pathology, as well as other extracardiac disorders. To such cardiac pathologies, first of all, coronary artery disease is associated with acute pathology of blood circulation in coronary vessels, acute or transferred myocardial infarction. In addition, 46% of men and 34% of women report a sudden fatal outcome in IHD, and this pathological condition is observed mainly in the first twelve hours of acute myocardial infarction. Also, the risk of this pathology is noted in patients who suffered a myocardial infarction with a Q wave as a result of paroxysmal VT.
Hypertrophic cardiomyopathy can lead to ventricular fibrillation, which mainly affects the younger generation after carrying out intensive physical activities. At the time of circulatory arrest in this group of patients, a ventricular tachycardia of the polymorphic form is recorded, which passes into fibrillation. At the same time, one must not forget that a fainting condition and disturbed hemodynamics can cause any form of supraventricular tachycardia, which has a frequent rhythm of the ventricles.
Almost 10% of the reanimated patients are patients with the diagnosis of dilated cardiomyopathy, which contributed to the formation of ventricular fibrillation.
The formation of this condition is also affected by cardiomyopathy of the prostate, Brugada syndrome and prolonged QT.The precursors of ventricular fibrillation with these syndromes is viral pirouette type, and with cardiomyopathy PZ is a monomorphic form of VT.
Among valvular heart defects in the formation of this pathological process, aortic stenosis of congenital and acquired etiology is isolated. But with such cardiac pathology as mitral valve prolapse with a significant frequency of arrhythmias, ventricular fibrillation is observed quite rarely and is mainly due to impaired cardiac muscle properties.
Among the specific cardiomyopathies, which become the causes of chaotic ventricular contraction, primarily distinguish cardiomyopathies against inflammation and sarcoidosis.
most rare causes of this disease can be considered poisoning cardiac glycosides, disorders of the electrolyte metabolism, shock from electrical shock, hypothermia, acidosis and hypoxia, cardioversion, coronary angiography, a side effect when receiving different groups of drugs, such as sympathomimetics, barbiturates, narcotic analgesics, Antiarrhythmic drugs of the first class, derivatives of phenothiazine and drugs for anesthesia.
The development of ventricular fibrillation is affected by several factors that reduce the electrical stability of the heart muscle. These factors include: increased size of the heart, existing foci of degeneration and sclerosis in the myocardium and the conduction system, as well as increased sympathetic activity.
In almost 90% of patients, ventricular fibrillation causes ventricular tachycardia and, much less often, ventricular extrasystoles.
Ventricular fibrillation
symptoms characteristic symptoms of this condition consists of two forms of ventricular fibrillation: the primary and secondary flows flowing. The first form develops when heart disease without specific manifestations of insufficient blood circulation, and the secondary - the terminally ill, which are peculiar pronounced stagnation of insufficient blood flow and symptoms of cardiogenic shock. In the secondary form isolated atonal, which occurs very rarely and is manifested by the lack of breathing and pressure, as well as other disorders in a very serious form.
The precursors of this pathological condition are early-appearing extrasystoles of group and multiple nature, as well as paroxysmal VT.
As a rule, the symptomatic picture of ventricular fibrillation is characterized by a violent onset. In the beginning, determined whirling head and general weakness, then twenty seconds later the patient loses consciousness, and he appeared convulsions and involuntary urination character in forty-five seconds. In this case, no heart sounds, and comes apnea, in which the patient is in a state of shock to the lack of pulse, blood pressure, and sudden appearance of pallor of the skin and mucous membranes. After performing several breaths, a fatal outcome occurs.
In an electrocardiogram, ventricular fibrillation is characterized by randomly arranged waves that have a different amplitude in form and size.
Since chaotic contraction of the ventricles is the symptoms of sudden cessation of blood circulation and death of clinical character, while still observing pupil dilation, which do not react to light. In addition, it is impossible to feel the pulse on such arteries as the carotid and femoral. If it is impossible to restore the activity of the heart rhythm within four minutes, irreversible processes occur in the central nervous system, as well as in other organs.
The whole nature of the complications and the outcome of the indiscriminate contraction of the heart depends on the correct and timely provision of resuscitative measures on the heart and lungs.
Possible complications may be aspiration pneumonia and lung damage during fracture of ribs during resuscitation. And in the period of cardiac arrest, ischemia of the heart muscle develops, and after the coronary circulation is restored - transient myocardial dysfunction. Complications of the neurological nature are characterized by the appearance of convulsions and coma, leading even to decortication. In the case of a comatose state for more than three days, it is almost impossible to guarantee the survival and recovery of brain activity, as a rule, the prognosis is always poor.
Ventricular fibrillation ECG
It is quite difficult to distinguish between cardiac arrest and ventricular fibrillation due to the similarity of symptomatic manifestations. Thus, the diagnosis is based on ECG data.
On an electrocardiogram, ventricular fibrillation is characterized by the disappearance of the outlines of the ventricular complex and the appearance of waves of different widths and heights with pointed or rounded upper and lower ends. Also, waves are characterized by non-differentiating teeth. At the same time, the heart rate reaches three hundred beats per minute. Amplitude of such waves is two definite forms of ventricular fibrillation: large-wave and shallow wave. In addition, there is no isoelectric interval in the form of separate waves, changing into each other with the formation of a fanciful curve.
Thus, the main signs of ventricular fibrillation on the ECG are: a missing typical curve with habitually differentiated teeth T, S, R, Q, P;Registration instead of them of small and different in magnitude with the unequal form of waves of fibrillation;A different distance between the wave peaks;Lack of a clear form of isolines. The causes of their occurrence are pathological, and the prognosis is unfavorable. Defibrillation may occur.
Ventricular fibrillation treatment of
To prevent biological death it is necessary to conduct emergency measures in the first four minutes of ventricular fibrillation. When the pulse is not felt on such major arteries as the carotid or femoral, they begin to carry out a closed cardiac massage with artificial ventilation( artificial ventilation of the lungs) in order to maintain blood circulation at the necessary level, which can provide the heart and brain with oxygen, and restore their work withSpecific therapy.
In the intensive care unit, which allows you to constantly monitor the heart rate with an electrocardiogram, you can immediately determine the shape of the heart stop and begin treatment. The most effective method of treating ventricular fibrillation in the first seconds is the rapid conduct of therapy with electrical impulses. Very often such therapy, especially in the primary form, is one of the most effective resuscitation methods. In addition, with this electropulse therapy during the first minute with ventricular fibrillation, which appeared for the first time, heart rhythm is restored in almost 75% of patients, and in the third or fourth minute, without cardiac massage and artificial ventilation of the lungs, only in someCases.
If this treatment proves to be ineffective, then normalization of metabolic processes in the heart muscle continues, and sometimes only begins to perform closed cardiac and ventilatory massage using oxygen. If two or even three defibrillator discharges are used, the heart rate may not recover, then the patient is intubated with a transfer to an artificial breathing apparatus. After this, the sodium bicarbonate is injected intravenously intravenously with 200 ml or every 10 minutes through 50 ml until the blood circulation is satisfactory with the possibility of controlling the pH of the blood in order to prevent acidosis on the background of clinical death. In addition, it is better to administer all drugs to 5% of the glucose solution, which is filled with the system for drip administration.
To increase the effectiveness of the therapy of ventricular fibrillation by electrical impulses, an urgent injection into the heart of the adrenaline hydrochloride is prescribed, which, when the heart is massage, gets from the ventricular cavities into the arteries. However, one should not forget that such intracardiac injection of the drug can cause the development of pneumothorax, damage to the veins, various extensive hemorrhages in the heart muscle. After this, the epinephrine hydrochloride can be administered intravenously every five minutes. In addition, other drugs such as Mesaton or Noradrenaline may be used as stimulation.
If the therapy of ventricular fibrillation with electrical impulses is ineffective, Ornid, Obsidan, Anadrilin, Lidocaine, Novokainamid or Novocain may be administered. However, with ventricular fibrillation, all this medication is ineffective, in contrast to the use of electrical impulses. But, nevertheless, they continue heart massage and artificial ventilation of the lungs, and after two minutes they repeat the defibrillation. If the heart stops after it, then Calcium Chloride and Sodium Lactate are administered, and the defibrillation is performed before the restoration of the heart or the appearance of signs on which it is possible to diagnose brain death. At a time when there will be a distinct self-pulsation of large arteries, then stop to hold a closed massage on the heart.
An important moment in the therapeutic treatment of ventricular fibrillation is the round-the-clock monitoring of the patient and the carrying out of all necessary measures in order to prevent a recurrence. In some cases, when there is no equipment available for carrying out therapy with electric pulses, it is possible to apply the usual voltage from the mains from 127 V to 220 V. Sometimes even holding a fist to the atrial region restores the heart rhythm. In some cases, indiscriminate contraction of the ventricles is observed very often, therefore it is necessary to resort to defibrillation up to twenty times a day, but this may not bring a positive result, even with the simultaneous administration of antiarrhythmic drugs. Therefore, in this case, recurrent fibrillation of the ventricles is eliminated only after the implantation of an artificial pacemaker driver.
As a rule, ventricular fibrillation is characterized by an unfavorable prognosis in the event that it is impossible to conduct therapy with electrical impulses, since drug treatment is practically ineffective. Electropulse therapy produces a positive result only in the case of a large wave form of the pathological process, and in the case of a shallow wave, the forecast is negative.
Ventricular fibrillation emergency care
This pathological condition is considered the main cause of sudden onset of death and is characterized by frequent, more than three hundred beats per minute, erratic, hemodynamic activity of the ventricles. Symptoms are very similar to asystole. The electrocardiogram shows a chaotic flicker of waves. Ventricular fibrillation is characterized by a condition in which oxygen is absorbed by the heart muscle and the heart resembles a "swarming clam."
Emergency care for ventricular fibrillation consists of urgent resuscitation, which is able to provide adequate ventilation and normalization of blood circulation, until the cause of respiratory arrest and blood circulation is eliminated.
First of all, you can sharply strike your fist at the bottom third of the sternum, that is, apply a precordial blow to twenty centimeters above the chest if there is no defibrillator nearby. Then call the resuscitation team and begin emergency measures for indirect heart massage and artificial ventilation of the lungs in order to prepare the patient for defibrillation, which will be carried out with a discharge of 200 J.
With the preservation of the pathological process in the heart, a repeated defibrillation with an increase in the discharge to three hundred, And in some cases this charge at the following repetitions increases to 360-400 J. It is very important to remember that if you immediately start treatment with electrical impulses from high indiceslei, it can cause complications postkonversionnogo character.
In the future, when this therapy is ineffective, intravenous or intracardiac lidocaine is introduced, which allows a shorter interval between Q and T teeth and a lower defibrillation threshold, or Obsidan, which reduces refractoriness in different parts of the myocardium. Again, repeated defibrillation is performed.
With preservation of indiscriminate contraction of the ventricles, it is now possible to administer intravenously sodium bicarbonate;Intravenously drip Lidocaine at two milligrams per minute or 100 mg in jet every ten minutes;Polarizing mixture, magnesium sulphate in this mixture or separately( with no positive effect, repeat the administration after seven minutes).And again - defibrillation.
In the case of further preservation of this pathological condition, intravenously, Adrenaline or Calcium Chloride is administered. Using these drugs, it is important to remember that they all contribute to the development of hyperkalemia and alkalosis, so you need to be very careful in their introduction to prevent such complications.
When cardiac rhythm is restored, vascular agents are introduced, and then acid and alkaline balance is corrected.
To prevent the recurrence of indiscriminate contraction of the ventricles in the form of fibrillation, preparations of potassium, magnesium sulphate and lidocaine are administered.
