Ventricular fibrillation (VF) is a pathological condition in which myocardial muscle fibers contract asynchronously, at random, more than 500 times per minute. As a result, the pumping function of the heart significantly worsens in the patient, and a fatal outcome is likely.
A lot of energy and oxygen supplied by the blood are spent on unsynchronized contractions of individual muscle bundles, which increases the likelihood of developing ischemia. The resulting hypoxia (lack of oxygen molecules) dulls the sensitivity of the myocardium to the impulses generated in the sinus node, which significantly reduces the likelihood of an independent resumption of the rhythm.
Fibrillation, ventricular flutter arise due to the pathology of the passage of the pulse through the myocardium. These rhythm disturbances are successive stages in the development of one process. In ICD-10 (international classification of diseases 10 revisions) they are allocated in one heading.
Dysfunction of the pathways of the heart can occur as a result of:
- large scar (a consequence of myocardial infarction);
- focal post-infarction cardiosclerosis;
- ischemic heart disease;
- acute myocardial infarction;
- cardiomyopathies with severe hypertrophy of cardiomyocytes;
- dilatation (wall stretching) of the heart chambers;
- arrhythmogenic cardiomyopathy;
- myocarditis (inflammation of the heart muscle);
- valvular defects;
- severe intoxication (including with alcoholic defects).
VF is a life-threatening condition. It develops suddenly, the patient very quickly manifests a picture of clinical death. However, if he is preceded by ventricular flutter (contraction of muscle fibers with a frequency of more than 200 times per minute), the patient may have time to complain about:
- chest pain;
- a feeling of accelerated heartbeat (2-3 times per second or more);
- dizziness, loss of orientation in space;
- nausea that can turn into vomiting;
- increased sweating;
- disturbed rhythm and shortness of breath;
- general weakness.
These symptoms can last no more than 15-20 seconds. When VF develops, the patient loses the ability to speak coherently. When examining, you must pay attention to:
- pallor of the skin with acrocyanosis (cyanotic color of the earlobes, tip of the nose);
- convulsive muscle contractions (occur 35-45 seconds after the onset of the attack, may be accompanied by involuntary urination or defecation);
- the state of clinical death that occurs 2 minutes after the onset of VF, if no help is provided:
- dilated pupils (normally they become narrower if a person lifts his eyelids in a bright room, and here opening his eyes does not cause a physiological reaction);
- it will not be possible to feel the pulse (both on the radial artery (peripheral, passes on the wrist), and on the main (large: carotid, femoral);
- respiratory movements will stop.
However, to confirm the diagnosis, it is necessary to conduct an instrumental study – electrocardiography.
Ventricular fibrillation on an ECG (electrocardiogram) has several stages of development:
- Ventricular flutter. It lasts a few seconds, myocardial contractions are still coordinated. On the ECG, it manifests itself in the form of high-amplitude (with a large distance between the upper and lower bending points) rhythmic waves (there can be 250-300 such complexes per minute).
- Convulsive stage. High-amplitude waves remain, but now their frequency is about six hundred per minute. This is a manifestation of a chaotic uncoordinated contraction of individual sections of the myocardium lasting 55-65 seconds.
- Ventricular fibrillation. The deterioration of contractility leads to a fragmented contraction of certain groups of cardiomyocytes. On the ECG, small (low-amplitude) waves are recorded with a frequency exceeding 100 per minute.
- Atonic stage. The myocardial energy reserve is almost completely exhausted. There are fading contractions of individual sections of the heart muscle. Waves become even lower and finer, now their frequency does not exceed 400 per minute.
Consider examples of electrocardiographic films and descriptions thereof.
- Ventricular flutter
- ventricular fibrillation;
- Convulsive stage
Since VF is a condition that poses a direct threat to the life of the patient, there is a documented protocol of actions in the event of a similar paroxysm. Since the patient is often assisted after the transition to a state of clinical death, it all starts with resuscitation.
If a person was found during the convulsive period of the VF, then all that is worth doing is to gently hold your head from hitting the underlying surface. You can put folded clothes to mitigate their effects. It is forbidden to open the victim’s mouth, pull out his tongue and hold his limbs.
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Algorithm of actions in order of priority:
- Check the patient’s consciousness: call with his voice, if he doesn’t respond, gently shake his shoulders (so that the head does not come off the surface on which it lies and does not fidget along it; the direction of movement is from top to bottom).
- Assess your heart rate. To do this, it is recommended to clasp the fingers of one hand with the central neck (trachea) in the upper half.
- If there is no pulse, call an ambulance (or instruct someone).
- Check for breathing. It is necessary to bend the cheek to the victim’s mouth and nose, observing the amplitude of the movements of the chest and at the same time feeling the movement of air with the skin (if present). If necessary, clear the airways.
- Perform an indirect heart massage (in this situation, this is the most important) and artificial respiration.
When an ambulance team arrives, they:
- continue resuscitation;
- connect a cardiomonitor and a defibrillator (in modern models, these two devices are combined);
- after recording an electrocardiogram and confirming the presence of VF, defibrillation is performed (discharges are given with increasing intensity every 2 minutes, against the background of indirect heart massage, until the rhythm normalizes);
In the absence of a defibrillator, it was previously recommended that a precardial stroke be performed (with a fist on the lower third of the sternum), but due to injuries and a complicated technique, it is now not recommended for use.
- if necessary, the following medications are administered:
Emergency care for ventricular fibrillation must necessarily include defibrillation. Depolarization waves travel randomly through the myocardium, and therefore, an indirect heart massage or the use of medications are most likely to be ineffective.
|Antiarrhythmic||Lidocaine amiodarone||Prevention of relapse of ventricular fibrillation immediately after an attack|
|Bisoprolol Nebivolol||Long-term support for an adequate heart rate|
|Oral anticoagulants||Warfarin Rivaroxaban||Prevention of blood clots and embolism (blockage) of blood vessels by them|
|Infuzionnaya therapy||Ringer’s Stereofundin Lactate Trisol Sodium Chloride Sodium Bicarbonate||Restoring the water-electrolyte balance of the body (it provides an adequate course of the processes of excitation and contraction in the heart cells)|
- Implantation of a cardioverter-defibrillator. This device is attached not far from the left clavicle, and the electrodes from it are held to the heart. It tracks heart rate uniformity. If VF paroxysm occurs, this device delivers a discharge.
- Coronary angioplasty (coronary stenting).
If VF occurred against the background of coronary heart disease, this surgery will remove the very cause of paroxysm and prevent relapse.
Visits to the cardiologist should be carried out:
- In a planned manner, once every 6 months (if the drug treatment for ventricular fibrillation is selected correctly and the heart rate has stabilized).
- Unscheduled. It is necessary to visit a doctor if:
- recurrence of arrhythmia;
- presyncopal and syncopal conditions (fainting, dizziness);
- worsening of well-being;
- poor tolerance to the prescribed therapy.
If defibrillation was successful (and it is more effective with a large-wave form of VF), the patient survives and the prognosis for future life is relatively favorable.
During ventricular fibrillation, the myocardium is more prone to damage (the occurrence of an extensive heart attack) as a result of a lack of oxygen (hypoxia). This can lead to an increased risk of sudden death, especially if:
- there is atherosclerotic lesion of the coronary arteries;
- chronic inactivity is observed;
- the patient smokes;
- they drink alcohol often and in large quantities;
- overweight or obesity;
- a person suffers from diabetes;
- hypertension is present, and basic drug therapy is not used.
With the right antiarrhythmic therapy, the prognosis for life is favorable.
Irregular contraction of individual muscle bundles in the ventricular myocardium causes their fibrillation. Without immediate cardioversion (rhythm restart), the probability of sudden cardiac death is very high.
The clinic is nonspecific: the patient is found unconscious, pale, often with no pulse, breathing and dilated pupils. The criterion for making a diagnosis is a characteristic electrocardiographic picture (waves of different amplitudes).
Specific therapy is defibrillator discharge. In the future, it makes sense drug and surgical (if necessary) treatment.
Causes of development and risk factors
About 75-80% of sudden deaths caused by heart problems occur in VF. This disease occurs in both young and old people.
The risk group includes those patients who have suffered sudden cardiac arrest. Unexpected death affects 10-30% of such patients.
The chance to face VF in people who suffer from idiopathic dilated cardiomyopathy is 10%. Within 1 year after an extensive heart attack, the disease affects 5% of patients. With hypertrophic cardiomyopathy – 3%.
Fibrillation is characterized by an irregular contraction of the muscle fibers of the heart. The stages of the development of the disease quickly succeed each other: the patient feels weak, faints, his pupils dilate. About 2 minutes elapse from the onset of the attack to clinical death.
In most cases, the cause of primary and other types of gastric fibrillation is a complication of myocardial infarction. Experts highlight the following reasons for the development of VF:
- Ischemic heart disease (acute and transferred heart attack, coronary circulation disorders);
- hypertrophic cardiomyopathy: death occurs in young people with excessive physical exertion;
- dilated idiopathic cardiomyopathy: fibrillation begins with hemodynamic disorders in half of these patients;
- problems with the right ventricle (arrhythmogenic cardiomyopathy);
- different types of heart defects (most often the cause is stenosis of the mouth of the aorta);
- specific cardiomyopathies;
- violation of the electrophysical characteristics of the myocardium.
The disease sometimes develops even in the absence of problems with the heart muscle. Risk factors that in some cases lead to ventricular fibrillation include:
- a sharp decrease in blood volume (this causes a drop in pressure and an increase in heart rate);
- severe poisoning (hypokalemia develops and cardiac excitability increases);
- hormonal imbalance that arose due to pathologies of the thyroid gland;
- chronic stress or excessive nervous strain;
- overdose of drugs: diuretics or cardiac glycosides.
There are cases when the cause of ventricular fibrillation cannot be determined.
Preventive methods, relapse prevention
Heart rhythm disturbance refers to life-threatening conditions. Due to fibrillation, blood flow ceases, the growth of metabolic disorders in the body begins. This is the cause of 80% of deaths with a diagnosis of “sudden death”.
Pathology is more common in men 45–70 years old with cardiac disorders. Arrhythmia can occur anywhere, so it’s important to know first aid measures to save the life of the victim.
Timely methods of resuscitation will help the patient hold out until the ambulance arrives and increase the chances of survival.
Normal contraction of the heart muscle is provided by bioelectric pulses. They are generated by the atrioventricular and sinus nodes. Impulses affect the myocardium, cardiomyocytes of the atria and ventricles, causing the heart to push blood into the vessels.
When the conduction of impulses is disturbed, arrhythmia occurs. Ventricular fibrillation is a condition in which there is a random movement of muscle fibers of the myocardium. They begin to work inefficiently, with a frequency of 300-500 beats per minute.
For this reason, urgent resuscitation of the patient is necessary.
Fibrillation often occurs for reasons of cardiovascular disease. The main ones include:
- Complete blockage of the atrioventricular node.
- Coronary heart disease.
- Complications of myocardial infarction.
- Cardiomyopathies – hypertrophic (thickening of the heart wall), dilated (enlarged heart chambers), idiopathic (violation of the structure of the heart).
- Arrhythmias – ventricular extrasystole, paroxysmal tachycardia.
- Heart defects, valves (aneurysm, mitral valve stenosis).
- Acute coronary insufficiency (narrowing of large vessels).
There are less common causes of ventricular fibrillation. These include:
- Cardiomegaly (increased heart size).
- Cardiosclerosis (scarring of the heart muscle).
- Brugada syndrome (hereditary ventricular arrhythmia).
- Myocarditis (myocardial inflammation).
- A sharp decrease in the volume of blood pushed out by the heart, due to problems of an unclear etiology.
|Violation of electrolyte balance||Lack of potassium leads to myocardial instability|
|Overdose of diuretics or cardiac glycosides||Severe poisoning with thiazide diuretics, narcotic analgesics, barbiturates|
|Medical manipulations||Coronary angiography, cardioversion, coronary angiography, defibrillation|
|Hypoxia||Lack of oxygen|
|Acidosis||Increase in acidity in the body|
There are factors rarely provoking the development of fibrillation. These include:
- Hypo-and hyperthermia – overcooling of the body and its overheating with sharp changes in temperature.
- Dehydration – can cause bleeding and hypovolemic shock (rapid loss of a large amount of fluid).
- Injuries – mechanical to the sternum, electric shock, blunt and penetrating.
- Hormonal imbalance due to thyroid pathologies.
- Chronic stress, excessive nervous tension.
Ventricular fibrillation is usually divided into 3 stages – primary, secondary and late. Primary fibrillation occurs 1-2 days after myocardial infarction.
The electrical instability of cardiomyocytes is explained by acute ischemia.
More than half of cases of primary fibrillation are observed in the first 4 hours, 40% – within 12 hours after a heart attack, which is the main cause of death in patients with this pathology.
Secondary fibrillation develops due to a lack of blood circulation in the left ventricle and is accompanied by cardiogenic shock.
This stage is difficult to eliminate by defibrillation, while the primary phase passes after a single electrical impulse.
Arrhythmia is characterized by symptoms identical to complete cardiac arrest (asystole). Signs of ventricular fibrillation:
- heart rhythm disorder;
- weakness, dizziness;
- sudden loss of consciousness;
- frequent or absent breathing, wheezing;
- pallor of the skin and mucous membranes;
- cyanosis (cyanosis of the tips of the ears, nasolabial triangle);
- heart pain, his stop;
- lack of pulse in large arteries (carotid, femoral);
- dilated pupils;
- complete relaxation or cramps;
- involuntary emptying of the bladder, intestines.
Arrhythmia begins suddenly, its appearance is impossible to predict. Signs of fibrillation determine the state of clinical death, when changes in the body are still reversible and the patient can survive. After 7 minutes of arrhythmia, oxygen starvation leads to irreversible disturbances in the cerebral cortex and the process of cell breakdown begins, i.e. biological death.
The likelihood of fibrillation is indirectly determined by signs of cardiac arrest or sudden death. This condition can only be confirmed using one diagnostic method – ECG (electrocardiography). The advantages of the study are the speed and ability to conduct the procedure anywhere. For this reason, resuscitation teams are equipped with cardiographs.
An electrocardiogram captures the main stages of development of fibrillation. These include:
- Ventricular flutter or short (20 seconds) tachysystole.
- Convulsive stage – takes 30-60 seconds, accompanied by an increase in the frequency of contractions, weakening of the cardiac output, and rhythm disturbance.
- Fibrillation – 2–5 minutes. Large, chaotic frequent flicker waves with no pronounced intervals are observed. The P wave is also absent.
- Atonia – up to 10 minutes. Large waves are replaced by small (low amplitude).
- The complete absence of heart contractions.
Prior to the arrival of the resuscitation team, the victim of fibrillation must be given emergency care. It consists in resuscitation. First stage:
- It is necessary to hit a person in the face if he lost consciousness. This will help bring him to life.
- Determine the presence of pulsation in the carotid or femoral arteries, observe whether there is movement of the chest.
- If pulse and breathing are absent, proceed to first aid.
The second stage consists in performing a closed heart massage and mechanical ventilation. The algorithm is as follows:
- Place the victim on a flat, hard surface.
- Throw back your head, clean your mouth from vomiting, take your tongue if it is sunken.
- Hold the victim’s nose with one hand and blow air through the mouth.
- After blowing, fold the hands crosswise and produce rhythmic pressure on the lower third of the sternum. 2 deep breaths, then 15 pressures.
- After 5-6 cycles of resuscitation, assess the condition of the victim – check for the presence of a pulse, breathing.
Indoor heart massage is performed rhythmically, but without sudden movements, so as not to break the ribs of a person with fibrillation.
Do not try to inflict a precardial beat in the region of the heart if there are no special skills.
Emergency care should be carried out in the first 30 minutes of the onset of arrhythmia and before the arrival of medical specialists, who should be called before resuscitation.
Sudden cardiac arrhythmia is not treatable. Fibrillation can be prevented in some heart diseases by installing a pacemaker or a cardioverter defibrillator. Therapy involves first aid to the victim and the use of special resuscitation equipment:
- Defibrillation – restoration of the heart rhythm with the help of electrical impulses of different strength and frequency.
- Performing artificial lung ventilation – manually using an Ambu bag or through a breathing mask with a ventilator.
- The use of the drug for cardiac resuscitation – Epinifrina, Amiodoron.
Specialized resuscitation of the heart and lungs begins by taking data from a portable cardiograph to determine the type of arrhythmia. If this is not an attack of fibrillation, then the use of an apparatus for electrical stimulation will be ineffective.
Next, you need to strike in the region of the heart, if the pulse and breathing did not appear, a defibrillator should be used.
If doctors tend to diagnose ventricular fibrillation, resuscitation with the help of electric current is carried out immediately.
Using an AC or DC apparatus to normalize heart rate is dangerous without confidence in the diagnosis. Indications for defibrillation are as follows:
- Arrhythmia, when there is a chaotic reduction in cardiomyocytes.
- Ventricular flutter on an ECG while maintaining rhythm. This condition is dangerous because it goes into fibrillation.
Emergency cardiac defibrillation is performed in a specific order. The action algorithm is as follows:
- Release the chest of a lying patient.
- Lubricate the defibrillator electrodes with a special gel or soak gauze in a 7% sodium chloride solution.
- Select the required power and charge the electrodes.
- Place the right electrode on the subclavian area, and the left is just above the heart.
- To give a discharge, firmly pressing the electrodes to the body.
- The result is estimated – waves will appear on the monitor.
- If the fibrillation does not pass, a charge of greater power is supplied.
The first discharge is supplied with a power of 200 J. After it, normalization of the heart rhythm often occurs. If this does not happen, conduct a second impulse of 300 J.
Then antiarrhythmics are administered intravenously or intracardially – Lidocaine 1,5 mg/kg body weight and a third discharge of 360 J. is performed.
The absence of pulse and rhythm on the cardiomonitor after the above steps involves the incubation of the trachea for artificial oxygenation of the respiratory system. Adrenaline is administered to prevent carotid artery collapse and high blood pressure.
|Antiarrhythmics (Lidocaine, Ornid)||Reduce the excitability of cardiomyocytes, improve their conductivity|
|Adrenomimetics (Epinephrine, Adrenaline)||Increase the resistance of myocardial cells, stimulate their rhythmic contraction|
|Regulators of electrolyte and acid-base balance (lactate and sodium bicarbonate)||Restore acidity balance during acidosis, neutralize cell metabolism products|
Specialists distinguish 3 types of VF after heart attacks: primary, secondary and late. Although discussions regarding the classification of this disease are ongoing.
Primary fibrillation occurs 1-2 days after a heart attack. It shows that the myocardium is characterized by electrical instability, which led to acute ischemia.
About 60% of primary VF occurs within 4 hours, 80% – 12 hours after a heart attack. Such fibrillation often leads to sudden death. With left ventricular failure and cardiogenic shock, secondary VF sometimes develops in people who have suffered myocardial infarction.
If fibrillation started 48 hours after a heart attack, then it is called late. About 40-60% of people who have experienced this disease die. In most cases, such fibrillation begins 2-6 weeks after a heart attack. More often it developed in those people whose front wall of the heart was affected.
Doctors distinguish 2 types of fibrillation. If the rhythm of contractions is correct, and their number does not exceed 200-300 per min., Then we are talking about ventricular flutter. With abnormal rhythm and frequency of contractions from 200 to 500 per minute. talking about flickering.
After ventricular fibrillation, the patient is monitored.
His condition is constantly monitored by Holter ECG: done continuously for 1-7 days.
Treatment is aimed at preventing the recurrence of seizures.
If patients have fibrillation due to heart disease, then surgery is performed. Surgeons can install an apparatus that will correct the rhythm of the myocardium.
The method of radiofrequency ablation is also used – this is the introduction of a special device that destroys the pathological focus of irregular heart rhythm.
Medical antiarrhythmic therapy is also carried out. Anticoagulants are prescribed to prevent possible complications. They prevent an increase in blood coagulability and reduce the likelihood of a heart attack. They also recommend drugs that improve metabolism and nourish muscles.
Possible consequences and forecast
When cardiac arrest occurs total myocardial ischemia. After the restoration of blood circulation, dysfunction appears in the work of the heart muscle.
The development of such complications is also possible:
- the appearance of arrhythmia;
- lung problems: aspiration pneumonia, damage to their tissues due to fracture of the ribs;
- neurological problems (occur due to a temporary deterioration in blood circulation in the brain tissue);
- thromboembolism: blockage of blood vessels by blood clots.
During defibrillation in the first 6 minutes and other resuscitation measures in the first 3 minutes, the probability of survival is 70%. If more than 12 minutes have passed since the onset of the attack, less than 20% of patients remain alive.
Preventive methods, relapse prevention
Doctors recommend a review and lifestyle. Necessary:
- give up cigarettes, alcohol, drugs;
- focus on plant foods, dairy products;
- exclude smoked, fried, fatty foods from the diet;
- reduce salt intake;
- lead an active lifestyle, but avoid overload.
After VF, it is advised to adhere to all medical recommendations and take the prescribed drugs.
It is difficult to provide competent timely medical care for ventricular fibrillation. After all, an attack does not always begin in a hospital. Because of this, this disease is considered the main cause of sudden death due to heart problems. You can reduce the likelihood of its development if you observe the condition and adhere to the basics of a correct lifestyle.