Bradycardia is a slowdown in the work, the most important organ in our body, the heart. It is believed that the heart works in a slow rhythm with a frequency of its cuts less than 55 beats per minute. Different sources give different figures for the lower limit of the normal rhythm. Basically oriented on the figure of 60 beats per minute, tk. this is an indicator of the work of the first-order automatism center, the sinoauricular node. Below 50 beats per minute - the slowing down of the heart is already approaching the critical figure of 40 beats per minute, after which the bradycardia is considered pronounced. The most correct to stop at the figure 55 bpm. in min. This boundary is oriented not only as an indicator of the lower limit of the norm of the rhythm frequency, but also as the lower limit of the pulse when choosing a dose of antiarrhythmic drugs. It is above this boundary that the frequency of cardiac contractions is able to adequately pump blood and provide vital organs and tissues with oxygen, and the brain in the first place.
Bradycardia of the heart
The bradycardia itself is the tip of the iceberg of its causes. That for some people is normal, then for others it is deadly dangerous. So the athlete, with a well-trained heart muscle, adapted to high loads, which for him, because of their constancy, represent a normal rhythm of life, at rest does not need a large supply of oxygen into the blood - the heart beats slowly. The newborn child experiences enormous loads associated with adaptation to the external world, increased growth of organs and tissues, so the slowing of the rhythm of the heart causes anxiety and panic in his mother. At least it should.
In the day-to-day, we all usually perform this or that load, thus loading the heart with work. Even when it seems that just sitting at the table, physically not moving - to keep the body in a certain position is also a job. Mental, emotional work is sometimes no less stressful than physical. And only at night the body is fully relaxed, the "kingdom of Vagus" comes and the rhythm of the heart slows down. It is possible that it will slow down within 50-55 beats. Bradycardia is not a manifestation or symptom of any disease, it is the norm. Therefore, the bradycardia, depending on the situation, can be both absolute and relative, character.
Considering the most important function of the heart - the ability to contract in a given mode (automatism), namely at the expense of it, the heart works with one or another frequency, it is necessary to briefly recall the conduction system of the heart. A conducting system, or a local power station, is capable of generating pulses at a frequency that is currently needed for adequate functioning of the body. At any serious enterprise there should be a director and his deputies. And here everything also. The first center of automatism, which sets the rhythm and suppresses all others by its pressure, is the sinoauric node (CA-node). It is hidden in the right atrium and triggers its impulses along special tracks. However, there are a lot of theories on this subject. How many ways and whether they or the impulse diffusely spread, the answer, in this case is not so important. What is important is that there are so many impulses that they suppress any activity of the underlying cells. Nature, modeling our heart, has taken care that if one driver of a rhythm fails, others will work, and any muscle cell of the heart can generate an impulse. The CA-node generates pulses with a frequency of 60 per minute. With the increased need for oxygen, the body gives signals, and our "director" starts to work faster. Or on the contrary - external signals provoke it to work not so often. When external regulation is not so perfect - CA-node does not work regularly, often, sometimes slowly (arrhythmically). This is typical for children and adolescents.
When the CA node can no longer perform its function, its role is assumed by the AV node and the bundle of the Hyis. Since they are not so powerful, then the impulses from them will come with a lower frequency, i.e. there will almost always be a bradycardia of the heart. Almost always, because with physical exertion or exposure to drugs, the rhythm may become frequent.
Consider the causes of bradycardia in more detail.
Causes of Bradycardia
Only two main causes of cardiac bradycardia are physiological and pathological. The first include:
- bradycardia, registered with trained people, athletes. The usual, household load is not for them something beyond the bounds, the body begins to signal about the need for a higher frequency only under extreme loads, then the frequency of heart contractions increases;
- here you can include sinus bradyarrhythmia of children and adolescents;
- congenital complete AV blockade;
- ideopathic bradycardia.
The pulse with a bradycardia, in these cases, will necessarily increase with physical exertion, and with sinus bradyarrhythmia, it will also become correct.
To the pathological form of bradycardia include the states that have arisen because of:
- CCCU (syndrome of weakness of the sinouauric node);
- Sinoauric blockade;
- Arrest of the sinoauric node;
- Blockade at the AV node level;
- complete transverse blockade;
- rhythm disturbances according to the type of atrial fibrillation (bradyform) or Frederick syndrome (combination of atrial fibrillation and complete AV blockade);
- an overdose of various drugs, mainly antiarrhythmic;
- poisoning with various cardiotropic poisons and substances;
- lesions of the brain and / or peripheral nervous system;
- disruption of the endocrine glands (eg, in hypothyroidism );
- trauma (the case of a bullet wound of the heart with a lesion of the bundle of His is described);
- HIBS (chronic ischemic heart disease );
heart muscle infarction;
- terminal form of renal, hepatic insufficiency;
- Electrolyte disorders (excess of potassium and / or calcium in the blood).
Bradycardia can be reflex, when exposed to or stimulated, for example, carotid sinus (when cupping an attack of a tachycardia or when you unintentionally tighten a necktie, or put on a tight collar, etc.), when pressing on the eyeballs (also used to stop an attack tachycardia).
Bradycardia can be one of the side effects of therapy, for example, with the appointment of Beta-blockers to patients with HIBS or with various rhythm disorders, the pulse may drop to 55 beats per minute. By the level of the frequency of cardiac contractions, the dose of the drug is selected, not allowing a decrease in heart rate below 55 beats. in a minute.
Analyzing the reasons, they can be divided into three groups:
- the impulse can not be produced at the right frequency and cause cells to contract;
- the impulse itself is produced with a good frequency, but in carrying it to the cells there are obstacles;
- external influences on the heart do not give a full and often generate momentum.
Why does the heart need to contract at a certain frequency? The goal is to deliver nutrients and oxygen to the organs. This is possible only with the blood that the heart pumps. If the supply is not enough, the organs stop performing their tasks or go into a protective, economical mode of operation. First of all, the lack of nutrition affects the cells of the brain.
A person, not knowing about the existence of a rhythm problem, will feel an increased fatigue, weakness, drowsiness. There may be episodes of loss of consciousness, from fleeting to serious in duration. Such a long episode of loss of consciousness can end fatal. And can only disturb dizziness , from expressed, to insignificant. Such episodes of dizziness or loss of consciousness are included in the Morgagni-Edams-Stokes syndrome (Adams can also be read as Adams).
Sudden loss of consciousness may be the only and last in human life manifestation of the clinic of pronounced bradycardia.
Bradycardia can be transient in nature - one single episode and it can cause death.
Loss of consciousness most often does not precede anything, in contrast to an attack of epilepsy, for example. Although with the other and possible cramps. After the restoration of consciousness, there is no period of deafness, again, unlike the epileptiform seizure. A person can blush or pale before the attack of a bradycardia, become covered with sweat, and so on. And such attacks can be several a day, and maybe one per year, but it must be taken into account. The number of seizures of MES does not indicate the severity of bradycardia. The presence of MES syndrome is necessarily indicated in the diagnosis of the patient.
People, by their nature, are arranged in such a way that if the problem that worries them is long enough and not expressed, then they begin to adapt to this situation. Drowsiness and fatigue are written off to the large amount of work performed, episodic dizziness - to age and lack of sleep and so on. This can lead to severe, irreparable consequences. Impossibility of the heart at the right time to accelerate to the required frequency leads most often to death.
Imperfection of the regulation of the peripheral nervous system, its sympathetic and parasympathetic divisions (in the fetus the sympathetic influence predominates), the intensive growth of tissues and organs, which requires a huge amount of energy, forces the heart to work in an accelerated mode. What for an adult will be considered an intensified palpitation (tachycardia), for the fetus will be the norm.
The heart rate in a growing organism is 110-160 per minute. Anything less than 110 per minute is considered a bradycardia.
This is a very dangerous condition, because, as mentioned above, there is active growth and maturation. The slightest inhibition in this process can lead to serious problems in the formation of organs and tissues, especially the brain.
The causes of bradycardia of the fetus may be:
- Non-compliance with the mother of the future baby simple rules - do not smoke, do not drink alcohol, walk more, do not eat food rich in chemical additives and dyes. In a word, the future mother forgot what a healthy way of life is;
- Taking a pregnant woman with drugs toxic to the fetus (always read the instructions carefully);
- The presence of a woman with chronic diseases of the lungs, heart, anemia. The appearance of anemia during pregnancy. Exacerbations of chronic diseases, especially infectious, during pregnancy in a future mother;
- The presence of stressful situations or great stress in a pregnant woman can lead to severe fetal suffering;
- Congenital malformations of the fetus. It can be formed malformations of the heart, brain and other internal organs, rhesus conflict;
- Multiple pregnancy , many or little water;
- Severe, long-term toxicosis;
- Such a complication as premature detachment of the placenta;
- Urgent situation of fetal suffering, for example, cord injury by the umbilical cord.
The reasons can be different, but the outcome is one - the emergence of bradycardia entails the suffering of the fetus, the development of hypoxia. As chronically current hypoxia, and sharply arisen threatens directly the life of an unborn little man. If you do not take time to treat, there can be irreversible consequences - the development of vices, both organs and systems and / or fetal death.
Treatment of bradycardia of the fetus is the following:
- First of all, treatment should be preventive in nature and be directed to the condition of the mother. The organization of her day regimen, rejection of bad habits, normalization of nutrition and frequent walks in the fresh air will help not only to restore mother's strength, but also to avoid the aggravation of hypoxia. A future mother needs to be made clear about the benefits of taking iron supplements, if she has anemia, it is also necessary to compensate for her other chronic diseases, especially infectious diseases, if any;
- Dynamic observation of the fetus. The easiest way to do it is to count the frequency of contractions of the fetal heart during CTG (cardiotocography), the stethoscope the doctor conducts listening to the heartbeats in the fetus through the abdominal wall of the woman, starting from the second half of pregnancy or by ultrasound (conducted from 12 weeks of pregnancy , ultrasound examination). These methods of research are performed a certain number of times during pregnancy to assess the development of the fetus at different times of pregnancy and in time to identify the bradycardia, if any.
- If the fetus is viable and the gestation period is long, and the fetal suffering is significant, it is possible to make a decision about abortion by caesarean section. Such decisions are made most often in a maternity home, collegially.
Hypoxia of the fetus can also occur during the period of delivery itself and may be manifested by a decrease in the frequency of cardiac contractions. Therefore, this indicator must be followed by obstetricians during the whole process of childbirth. The suffering of the fetus in this difficult period for him can be caused by both the compression of his pelvic bones, and the possible swallowing of amniotic fluid and ingression into the respiratory tract.
In any case, in the presence of hypoxia, bradycardia in the fetus during pregnancy and childbirth indicates the need to monitor it by neonatologists and pediatricians.
Bradycardia in children
Children, unlike adults, have not yet fully formed organism. Rather, the body they are in the formative stage. Therefore, what is an abnormality for an adult is the age norm for a child. This applies to heart rate and cardiac imaging (ECG). The older the child becomes, the closer his indicators to the indicators of an adult.
So it is believed that bradycardia in children will take place if:
- for a newborn, this is a reduction in the number of heartbeats less than 100 per minute;
- after a year and up to about six years, this figure is less than 70 beats. in a minute;
- in adolescence - less than 60 ud. in a minute.
Because of the imperfect yet conductive system of the heart, not fully formed sinoauric node, the child on the ECG can see a pronounced respiratory arrhythmia, migration of the pacemaker, etc. Simple exercises - squatting or deep breathing, walking can "lead" the ECG back to normal. This also speaks of the great influence of the autonomic nervous system. When a child sleeps or is greatly frightened, it is possible to fix a bradycardia - all this is not pathology, but functional changes and they will pass with the growing up of the baby.
Do not forget that a child actively involved in sports, as well as an adult will have a bradycardia athlete.
Unfortunately, not all the cardiac arrhythmia can be attributed to functional states. The causes of pathological bradycardia in children are about the same as in adults. It is in childhood that the following are diagnosed for the first time:
congenital conduction and rhythm disturbances;
- the effects of hypoxia during pregnancy and / or childbirth can be seen in young children, especially if the brain was suffering;
If the immune system is weakened, frequent catarrhal diseases, meningitis , pneumonia, myocarditis and endocarditis can lead to disruption of the function of internal organs, endocrine glands, brain, heart, including the formation of acquired heart defects. In this case, the development of bradycardia will be secondary.
The clinic of bradycardia in children may not be as pronounced as in adults. Mom of a baby or a teenager must carefully watch the suddenly changed general well-being of the child. The appearance of unmotivated weakness, fatigue, drowsiness, the appearance of incomprehensible dizziness and fainting states - these are all the reasons to see a doctor and take a survey.
Treatment of bradycardia in childhood is based, above all, on preventive measures. This includes the prevention of fetal hypoxia, the prevention of fetal hypoxia in childbirth, the prevention of colds. This can be achieved only at regular check-ups at first for a pregnant woman, and then for a baby. Timely vaccination and strengthening of immunity will prevent the development of serious diseases, one of the complications of which can be the development of bradycardia.
Medical methods of treatment, indications for the formulation of ECS - exactly the same as in adults.
At the slightest suspicion of changes in the general state of health, it is very important to undergo the necessary examinations. The examination is quite simple - graphical recording of the heart, at least for one minute (ECG, II tapping 1-2 minutes at the speed of the tape 12,5 - 25 mm per minute), better within 1-2 days (Holter monitoring, better with a record of breathing to exclude or confirm attacks of nocturnal sleep apnea, accompanied by episodes of severe bradycardia). Recording in the usual mode of life, with physical exertion (Treadmill test or bicycle ergometric test), when carrying out samples with medications (for example, ECG recording after atropine administration).
Then you can deepen the examination and supplement it with ultrasound diagnostic methods and biochemical blood tests. This will help to establish the cause of the organic pathology of the heart muscle.
Conducting PPEFI allows, in the case of an organic cause of bradycardia, to identify the localization of the lesion in the heart and to delineate it from the reflex and physiological forms.
If the bradycardia occurs in an acute condition (stroke, heart attack , ie acute damage to brain tissue or heart), then an emergency diagnosis is required. It includes all the listed activities, but it is necessary to hold them as early as possible.
It should be noted that with an ideopathic form or congenital forms of bradycardias, no one will feel any discomfort. Since the body has adapted to this condition and even expressed, a persistent bradycardia will only give anxiety to the treating physician of such a patient. Of course, the presence of bradycardia in such people will serve as a limitation for them when choosing a profession or certain sports.
Bradycardia is a symptom, a symptom of a disease or a physiological condition of the body that does not need to be treated. Therefore, before the beginning of bradycardia treatment, a thorough examination and careful collection of the history of the disease is necessary. It is necessary to clarify whether there were attacks of MES (seizures Morganyi-Edams-Stokes) and how many minutes they last and with what frequency arise.
Just before the beginning of bradycardia treatment, it is necessary to find out what preparations the patient takes or took earlier. Clarify the results of the examinations, and with what diagnoses the patient is observed with his doctor. Also among the surveys, special attention should be paid to the electrographic methods of examinations. They are fixed on them or not pauses with a length of more than 2 seconds and how many of these pauses during the day and night, the patient marks any change in state of health during them or not.
Sometimes the treatment of bradycardia is reduced to elementary actions to select the dose of the drug that causes a decrease in the rhythm. The group of such drugs include antiarrhythmic drugs. They require special attention at primary appointment and at appointment to elderly patients and, certainly at appointment in a complex with other preparations (one preparation can strengthen action of another and on the contrary). Decreasing the dose, such as a drug from the Beta-blockers group, calcium channel blockers, Sotolex, Quinidine or potassium preparations can save a person from feeling weak and dizzy.
With bradycardia, as a symptom of somatic diseases (hypothyroidism, chronic renal failure, etc.), treatment of these diseases already eliminates bradycardia. The same happens when a person is being detoxified in poisoning. In this case, a separate treatment does not require a bradycardia.
In more severe cases, when changes are irreversible, for example, in strokes or when a person is in a coma and it is necessary to increase the number of heartbeats, drugs that accelerate the pulse are used, but with strict control of hemodynamics.
Since the main focus of bradycardia treatment is to maintain blood pressure, then only at a pulse of less than 40 per minute, that is, only with pronounced bradycardia, drugs such as Adrenaline or Atropine are administered. The same drugs with bradycardia are administered in emergency cases, with an attack of Morgagni-Edams-Stokes, with severe bradycardia (less than 40 per minute heart rate), accompanied by a sharp weakness without loss of consciousness. Drugs are administered subcutaneously, intravenously, intraosseously, rarely by intramuscular injection, since it is important to rapidly absorb and inject the drug into the blood.
Atropine is administered if there is no deep hypotension , that is, blood pressure is maintained. Atropine sulfate (Atropini sulfas) is usually administered at a dose of 0.1% 0.25-0.5-1.0 ml. (0.5 mg most often). The drug is administered without dilution, it can be divided in 3-5 minutes. The effect is usually immediate. Side effects of the drug are dry mouth and dilated pupils, it may be difficult to urinate. When there are signs of an overdose (the appearance of side effects), the drug is stopped. Mandatory control of heart rate, blood pressure and ECG.
Adrenaline with bradycardia must be diluted with saline solution. It is available in ampoules of one milliliter of 0.1%. You can also enter repeatedly, fractional, at a dose of 0.01 mg / kg or 0.1 mg / kg, if the drug is administered endotracheally.
In childhood, the use of drugs is the same, since the dose is calculated per kilogram. It is important that assistance in this case is carried out as close as possible to the resuscitation or directly in it. The possibility to carry out artificial ventilation of lungs (ALV) and oxygen therapy in these cases is extremely important, since bradycardia is a formidable harbinger of cardiac arrest.
If ineffective bradycardia is eliminated by the above methods, when ECG is recorded for frequent pauses lasting more than two seconds and / or the presence of clinically significant MES attacks, the patient will be offered to install an electrocardiostimulator (ECS). In emergency cases, with cardiac arrest, the EKS is placed according to vital indications, without the consent of the patient. The setting of an EKS can also be temporary, under conditions of a cardio-recovery department, for example.
Naturally, seeing how a person fell unconscious on the street, no one will immediately introduce atropine. It is necessary, remembering that the brain "disconnects" first because of lack of oxygen. In this case, you should put a person on the ground, on the asphalt, on the sidewalk, unbutton the collar, loosen the tie, scarf, unfasten the tight clothes. So you can ensure a greater supply of oxygen. It is necessary to turn the patient's head on its side so that in case of vomiting, it does not choke with vomit. Possessing the method of breathing mouth to mouth, mouth to nose, take advantage of this knowledge, combining breathing with an indirect heart massage. Any loss of consciousness is a sharp drop in hemodynamics. The person in this case is better to put so that the head was below a trunk or legs or foots it is possible to lift upwards. By this we provide the best blood flow to the head. If the help is provided by at least two people, it will be much more effective. While one begins to provide first aid, the second calls an ambulance or calls for help from a doctor.
On the Internet, you can find some recipes for treating bradycardia with folk remedies. Broths of herbs and various types of tincture will help, perhaps, to disperse the pulse, but they will not eliminate the cause of the bradycardia. Bradycardia is dangerous, as it was written above, by the fact that you can "get used to it," but it can lead to cardiac arrest. Therefore, with all due respect to traditional medicine, it is safer to treat bradycardia by traditional methods.