Atrioventricular blockade is the deterioration or absolute cessation of the passage of electrical impulses between the atrium and the ventricle, causing serious defects in hemodynamics and in the heart rhythm. Atrioventricular blockade is often more often diagnosed in people who already have a history of cardiopathology.
The AV node is a significant part of the impulse delivery system, which is responsible for ensuring that the atria and ventricles are correctly, rhythmically and consistently reduced. The advance of the impulses that come from the sinus node slows a little in the AV node, which allows the atrium to contract and the ventricle to be filled with blood. After a short pause along the bundle of the Gisus and the legs, the impulses begin their journey in the direction of the ventricles, bringing them into a state of excitation and contraction. This complex system ensures correct reduction of the main organ departments and hemodynamic processes.
Atrioventricular blockade of the cause
For its own reason, atrioventricular blockade of the heart can hide in violations of a functional and organic nature. Functional atrioventricular blockades occur due to an increase in the tone of the parasympathetic department of the NS.
Atrioventricular blockade, caused by cardiopathology, occurs due to fibrosis or sclerosis of the system for various diseases. Cardiovascular rheumatic changes in the myocardium, heart damage in syphilis , interventricular septal infarction, various cardiomyopathies, collagenoses and myocarditis of any genesis (diphtheria, thyrotoxic or autoimmune), amylo-, sarcoidosis , tumor processes in the heart, cardiosclerosis can cause blockade of cardiac genesis. During an atrioventricular blockade, with an organic defect, at first there can be only a partial block, which, with the progression of the underlying disease, can develop into a third degree.
To trigger the development of AV blockade, some operations and surgical manipulations are possible: the installation of a prosthesis on the arterial valve, the intervention in occasion of the CHD, the insertion of the catheter into the right heart, etc. Sometimes, doctors also register a congenital atrioventricular block (approximately five cases per hundred thousand newborns). If a child's blockade is from birth, then it can be found that some parts of the system are simply missing. At every fourth such child, the atrioventricular blockade is combined with several more anomalies.
Very often blockade is caused by an overdose of certain medications (Digitalis, Diltiazem, Verapamil, Quinidine, beta-blockers, drugs based on lithium salts).
Atrioventricular blockade of symptoms
Manifestations of the blockade and the person's well-being in this pathology directly depend on what was caused by the violation of the conductivity function, what degree of blockade developed, where the damage is (level), what other diseases are the person suffering from.
If there is no reduction in heart rhythm in the atrio-ventricular unit, the patient will not feel anything and will not notice. Manifestations become noticeable only with a sufficiently strong decrease in heart rate. Due to the fact that heart rate and minute volume are rapidly declining, with any load, dyspnea, unmotivated weakness, and pain in the sternum area appear.
When atrioventricular blockade can begin to disturb symptoms such as confusion, dizziness , short-term fainting. With AV blockade of the second degree, the patient feels "interruptions", "fading" of heartbeat, at the third degree Morganyi attacks often occur (sharp growing weakness with severe dizziness, darkness in the eyes, pain in the projection of the heart, confusion, loss of consciousness, convulsions and acrocyanosis, which can pass into cyanosis ).
Incomplete atrioventricular blockade usually does not have any significant, noticeable to human manifestations. Sometimes with this form of blockade the patient may be disturbed by general deterioration of the condition, shortness of breath, fatigue, mild headaches . Usually all these symptoms are written off for fatigue from working days, and no one takes seriously the "alarming calls" of the body.
Complete atrioventricular blockade will make you pay attention to your health even the most indifferent to your health, as it is accompanied by a labored inhalation during exercise and movement (dyspnea), frequent pains, pre-stupor states, and often leads to cardiac asthma . In such people, the risk of developing a dangerous Morgagni-Stokes-Adams syndrome is greatly increased.
Atrioventricular blockade of the degree
Atrioventricular blockade has three degrees of development. The first degree has practically no noticeable manifestations. It can be detected only by ECG. In the study, you can see a significantly slower conduction (atrioventricular), at which the electrical impulses still reach the goal - the ventricles. At this stage, there is no need to prescribe any specific treatment, the patient should treat his organism more closely and be aware that under more severe strains and bad habits, more dangerous conditions may arise.
For the second degree of atrioventricular blockade, it is characteristic to carry out impulses by the ventricles not in full. In this case, the human condition deteriorates in direct proportion to the duration of the pause between pulses. If adequate care and proper treatment are not available, even a complete atrioventricular block can develop. In this case, the impulses do not reach the ventricles at all.
The third degree is the absolute blockade. Atrioventricular conduction in this disease is completely disturbed. Atrial contraction takes control of the sinus node, the ventricles make their contractions at a very slow pace. All these changes entail a total violation of all hemodynamic processes in the body.
Atrioventricular blockade treatment
If the doctor has suspicions that the patient has developed atrioventricular blockade, first of all it is necessary to find out an anamnesis. The patient needs to find out whether he had myocarditis or myocardial infarction , whether he ever took medications that could affect conduction (calcium channel blockers, digitalis, lithium preparations, beta blockers, etc.). When listening to the heart of a person with AV blockade, the right beat rhythm is heard with large interruptions, which indicate that there are no ventricular contractions. There is a bradycardia , cannon can be recorded Strazhesko. Visually, it becomes apparent that the veins of the neck are pulsating more strongly than the carotid and radial arteries.
If the atrioventricular ECG blockade is suspected, it is a necessary research method. At the first degree of blockade, the ECG shows an increase in PQ by 0.20 seconds or more, with a second a sinus rhythm and pauses due to loss of ventricular complexes after the P-wave, the appearance of Wenkebach-Samoilov complexes. At the third degree, the ECG gives information that the number of ventricular complexes is almost three times less than the atrial ones (from twenty to fifty per minute). If the doctor does not have an ECG for diagnosis, daily monitoring is prescribed. During such a study, it becomes possible to detect not only an atrioventricular blockade, but also to trace the association of symptoms with the loads and the use of any medications.
As already mentioned, only the second-third stage is needed in therapy, while the first shows observation in dynamics. Treatment of serious manifestations and conditions associated with atrioventricular blockade depends on the nature of the development of pathology and disturbing symptoms. If the cause of the blockade is covered in medicines, it will be sufficient to simply adjust the dosage (decrease) or completely cancel the drug, replacing it with a safer one. If a person has concomitant cardiopathology, beta-adrenomimetics may be prescribed. Now widely used are Dobutamine and Isadrin, as well as Atropine. With atrioventricular blockade, one-percent Atropine is administered four times (an interval of six hours) one milliliter. Iazdrin is recommended to use under the tongue of the pill at intervals of two to three hours. Usually it takes no more than forty-eight hours, because during this time the rhythm of heartbeat is restored. If the condition is severe, you can start injecting the drug into the vein drip. To do this, one milliliter of the drug solution (0.02%) should be mixed with five hundred milliliters of 5% glucose. The system is adjusted to ten to twenty drops in sixty seconds. In the next one to three days, the drug should be sublingually.
If the atrioventricular blockade accompanies myocarditis or infarction, the treatment tactics have certain characteristics. First, the patient is put a dropper with Iazrin (one milliliter of 0.02% solution per half liter five percent glucose). When the effect is obtained and the heart begins to contract at a rate of fifty to sixty times in one minute, it is necessary to transfer the patient to Alupent tablets. Alupent is given one tablet in four to six hours. The main disadvantage of these drugs is the unstable effect, dryness in the oral cavity.
If a patient has IHD or angina , episodes of pain on the background of taking Isadrin or Alupent can become frequent. During the introduction of Isadrin into the vein, you must enter Prednisolone (up to one hundred and eighty milligrams).
When atrioventricular blockade with myocarditis is effective, treatment with large doses of Prednisolone for a week - ten days. In a day, give up to eighty milligrams of the drug in equal doses in three divided doses. Once the effect is obtained, the dose should be slowly reduced to fifteen to ten milligrams, and within four to eight weeks completely abolish Prednisolone.
If a patient develops a complication of atrioventricular blockade - acute heart failure , you need to inject Glucagon into the vein. First, the agent is injected from the syringe in an amount of five milligrams, and then through a dropper (two to ten mg in sixty minutes).
If the atrioventricular blockade has a chronic course, appoint Corinfar, Theopack, Belloid. Corinfar usually drink three times a day for one or two tablets. Duration of admission is decided by the doctor. In the first couple of days, TeoPek is drunk half the tablets once a day, later - on the whole tablet once. If a person begins to complain about a worsening of sleep, poor appetite, pain in the stomach, head, the amount of the drug should be reduced, and if the symptoms do not go away - cancel altogether. Theopack is not used if the patient has hyperthyroidism, epilepsy or pregnancy . With stomach and duodenal ulcer this drug is used very carefully under monitoring. Belloid is treated for a week, after a three-day break, the course is repeated. Take the medicine one tablet three to six times a day. If drowsiness developed in the afternoon, the dose of Belloid is reduced. The drug is not used if a person is suffering from glaucoma.
If there is congestive heart failure in case of atrioventricular blockade, it is advisable to introduce diuretic drugs, vasodilators into the therapy regimen. Diuretics use hydrochlorothiazide, metholazone, furosemide, spironolactone, etc. Hydrochlorothiazide is taken once a day, the dosage is from twenty-five to one hundred milligrams. A metolazone appoint or nominate on ten milligrammes, one reception in day. Dosage of Furosemide is selected individually, the frequency of administration is one to two times a day, the amount of the drug is from twenty to two hundred milligrams. Spironolactone is taken twice a day for fifty to one hundred milligrams.
If conservative treatment of atrioventricular blockade did not show special results, the patient is prescribed an operation consisting in implantation of a pacemaker. After such an operation, all unpleasant symptoms cease to bother a person. The pacemaker is also put in case the patient has a third degree of blockade, but she does not bother him at all. This is done to prevent the onset of sudden cardiac death.
Atrioventricular blockade is a serious enough disease that can cause a lot of trouble. That is why it is important to undergo regular examinations with a cardiologist in the presence of any cardiopathology. This is especially true of older people. It is also necessary to eat right, eat foods with potassium and magnesium in its composition.