Intraventricular block is a disease characterized by impaired conduction of electrical impulses through the ventricles of the heart, due to the influence of various factors on the heart, but these factors may not exist. This pathology can develop in patients of various ages. In most cases, the disease is diagnosed in old age. Blockages can occur in children, about 5 out of 100,000.
Features of the disease
To understand how and for what reasons intraventricular blockade develops, it is important to understand that in the myocardial system, which provides sequential, continuous and rhythmic electrical excitation of all cardiac structures, there are separate muscle cells called Purkinje fibers and His bundles.
The first formation is represented by cardiomyocytes, which are characterized by increased electroexcitability, while being located in the ventricles. The left and right branches are called legs, the last of which has back and front branches. Decreasing in diameter, they seem to break up into a huge number of small branches, which are Purkinje fibers.
Due to all kinds of organic or functional changes in the heart, obstacles appear on the path of electrical signals. In this case, the impulse does not pass further along the ventricles of the heart (in a specific situation). The sections below, because of this, can not be reduced and excited. This becomes apparent on the cardiogram.
Place of manifestation
Intraventricular block can occur in any part of the ventricles. Therefore, the arising violations are divided into non-specific and blockade of the bundle of His. Each of these subtypes has its own criteria on the ECG.
It is noteworthy that intraventricular blockade can develop even in a completely healthy person, without affecting his well-being. But this is still considered a conduction disorder on the right branch. When registering the left hemiblock, as well as with two or three-beam blockade of the final branches, it is considered that there is some kind of cardiac pathology.
Causes
The causes of intraventricular conduction blockade, as a rule, are manifested already in childhood. The diseases due to which this disorder develops can be either of the right or left hemiblock. In addition, blockades of the final branches can have their effect.
These ailments include: cardiomyopathy, myocarditis, impaired cardiac architectonics due to acquired or congenital malformations, cardiosclerosis, heart tumors. But you should not panic ahead of time, as in both children and adolescents, an incomplete and even complete blockade of the right leg is considered a normal condition, often meeting against a background of a healthy heart.
In adulthood and old age, intraventricular heart block develops for completely different reasons. Almost half of all cases are associated with atherosclerotic lesions of the artery, which feeds the myocardium in the area of the conducting bundle. This causes myocardial ischemia. In addition to chronic ischemia, acute myocardial infarction leads to this problem.
About a third of all cases are due to arterial hypertension. Congenital heart defects and rheumatism can also be a common cause of intraventricular blockade.
Regardless of age, the blockade is provoked by poisoning with alcohol or its surrogates, hyperkalemia, as a rule, with renal failure, chest injuries, excessive use of certain drugs. For example, intraventricular blockade develops in case of poisoning with potassium-containing and some psychotropic drugs.
Symptoms
Often this disease is asymptomatic. If there are any signs of intraventricular blockade, then they are due to the underlying pathology that led to this blockade. For example, with myocardial ischemia, headaches appear, usually in the back of the head, chest pains. Myocarditis is manifested by shortness of breath and discomfort in the chest.
If the patient shows an intraventricular block on ECG, which is accompanied by certain suspicious complaints, then the patient should be urgently examined for cardiac pathologies.
Attention with complete blockade
Particular attention should be paid to complete blockade, if it occurs for the first time, and is also accompanied by pain in the left half of the chest or sternum. The fact is that it is almost impossible to recognize a complete left block on a cardiogram. For this reason, in the event of a complete left blockade, which is accompanied by burning or pressing pains in the chest, the patient must be checked for acute myocardial infarction, hospitalized as quickly as possible in a cardiology hospital.
Nonspecific intraventricular block, as a rule, also does not cause discomfort in the patient, but in most cases is accompanied by symptoms that can be attributed to the causative disease.
Diagnostics
In most cases, a diagnosis of this blockade can only be made by making a cardiogram. An indication of a right intraventricular blockade on an ECG is an expanded and altered M-type complex. At the same time, a jagged and deep tooth is observed along the left branches. Complete blockade from incomplete differs in the duration of the complex. With a complete blockade, the complex will be more than 0.12 s, and with an incomplete blockade, below this indicator.
A sign of a left intraventricular block on an ECG in an adult will be a deformed and enlarged ventricular complex along the left thoracic leads. On the right, a serrated tooth is detected.
Local blocking of final branches
A local block of the final branches, which is also called the local intraventricular block, may also develop. This type is usually caused mainly by acute myocardial infarction. Focal intraventricular block is characterized by an acute “damage block”, which is represented by necrotic cardiomyocytes. They arise in the presence of obstacles in the way of electrical impulses, the absence of R wave growth to the fourth thoracic branch is manifested.
Local intrainfarction intraventricular block is formed directly inside the zone of myocardial necrosis, manifested by splitting of the pathological Q wave. They are observed in the leads that are most characteristic of the affected area. Finally, an adult peri-infarction local intraventricular block on ECG can be determined by the focus of cardiomyocyte necrosis. It is manifested by a jagged and deformed tooth.
It is important to remember that with a local intraventricular block on an ECG, it is impossible to see a Q wave. Its appearance clearly indicates the presence of acute myocardial infarction, which is veiled on the cardiogram just by this block.
Additional examinations
When diagnosing a blockade, the patient, as a rule, requires additional examinations. For accurate and correct diagnosis, cardiologists are advised to use one or all three of these methods.
Ultrasound of the heart or echocardioscopy. This procedure is prescribed if there is a suspicion of myocarditis, heart disease, myocardial infarction. If the patient denies the fact of inpatient treatment, conducting an echo-CS is considered mandatory, since otherwise the patient may suffer a heart attack on his legs, which will fatally affect his health.
Another way is coronaroangiogroafia. It is done in order to evaluate in detail the patency of the coronary arteries, and also to determine if there is a need to perform bypass surgery or stenting.
Finally, daily Holter ECG monitoring is often prescribed. It is especially useful with intermittent blockade. This may be due to tachysensitive blockade, that is, tachycardia, which manifests itself and worsens during physical exertion.
Is blockade necessary?
Given that this disease is often asymptomatic and does not always indicate cardiac pathology, many are wondering if it is worth treating at all.
According to the recommendations of doctors, the treatment of blockades of this type is required only if the patient really reveals a pathology of the cardiovascular system, which leads to this problem.
For example, in acute myocardial infarction, surgery or therapy using conservative methods is recommended. In the latter case, analogues of nitroglycerin, analgesia with narcotic analgesics, massive antiplatelet and anticoagulant therapy are prescribed. If myocarditis is established, anti-inflammatory therapy is carried out, and with cardiosclerosis, cardiac glycosides and diuretics are prescribed, especially if the disease develops against a background of chronic heart failure.
When heart disease becomes the cause of the blockade, surgical correction is necessary.
Danger of blockade
It should be understood that not every intraventricular block represents a real danger. For example, if it is incomplete and single-beam, then you should not pay attention to it at all, especially if it is not provoked by some underlying disease.
Two-beam blockade in most cases transforms into a three-beam block. The latter leads to a complete blockage of the conduct between the ventricles and atria. In this case, attacks, loss of consciousness are possible. In this situation, the patient’s life is at risk. There is a chance of sudden cardiac arrest and death.
Possibility of death
Therefore, most of all, one should fear the two-beam blockade of His, which is combined with the symptoms of a major cardiological ailment. In this case, it is necessary to closely monitor the patient's condition, since there is a likelihood of death.
If signs of AV blockade of the second or third degree on the cardiogram occur, the doctor decides to install a pacemaker. It is important that it be implanted even to those patients who do not experience serious attacks, since the threat to their life still remains.
It should be noted that, in addition to AV blockade, intraventricular problems of this property cause ventricular fibrillation, ventricular tachycardia, which can also lead to a fatal outcome.
Prevention
In this case, the method of preventing sudden death from heart disease due to rhythm disturbance is actively practiced.
In fact, this type of prevention consists of regular visits to a cardiologist, conducting an electrocardiogram, as well as timely and prompt resolution of the issue of implanting a pacemaker if necessary.
As a prophylaxis against this disease, as well as to generally reduce the likelihood of cardiovascular pathologies, it is recommended to avoid unpleasant stressful situations in life, flatly refuse to drink alcohol and smoke, seeks to lead a healthy lifestyle, moderate exercise and sports.
Be sure to take medications, but in no case do not self-medicate, in all respects following the recommendations of your doctor.
Visit to the doctor
After a heart attack or other serious cardiac pathology, it is necessary to regularly see a cardiologist, at least in the first six months. This will fix your condition, identify complications, if any, and quickly eliminate them.
Separately, it is worth noting that any of the types of this blockade at the initial stage requires increased attention, mandatory consultation with your doctor.
First of all, it’s worth going to a therapist or cardiologist who will be able to guide you, is it really worth fearing this disease, what examinations to go through, in what way to build your therapy. After all, as we have already noted in this article, this ailment can be either completely harmless or seriously threaten your life and health. In the latter case, inpatient treatment will be required, possibly surgical intervention.