Sinoatrial blockade is a pathological condition that is accompanied by a violation of the natural heart rhythm. Parts of the myocardium contract asynchronously, resulting in a temporary asystole. Naturally, such a violation is dangerous. Many patients are looking for additional information about this pathology. Why is blockade developing? Are there any external symptoms? What treatment methods does modern medicine offer? The answers to these questions will be of interest to many readers.
What is sinoatrial blockade?
In order to explain the essence of the pathology, you first need to pay attention to the anatomical and physiological characteristics of the human myocardium. As you know, the heart is a partially autonomous organ. Its reduction is ensured by the operation of special nerve nodes that conduct nerve impulses.
An important part of heart rate drivers is the sinus node. It is located between the right ear of the atrium and the opening of the superior vena cava, in the wall of the right atrium. The sinoatrial connection has several branches, including a bundle of Torel, Bachmann, Wenckebach - they conduct impulses to the walls of both atria. Violation of the normal conduct of a nerve impulse in this area is called blockade of the sinoatrial node.
Thus, against the background of pathology, disruptions occur in the heart rhythm , which leads to asystole, which, of course, is extremely dangerous. It is worth saying that this is a rather rare pathology - it is diagnosed in 0.16% of patients in the cardiology department. And according to statistical studies, men over fifty are most often affected by the disorder. In women, such a deviation is less common.
Blockade may also develop in childhood, but this usually occurs against a background of congenital organic myocardial lesions.
The main causes of the appearance of pathology
It should be understood that CA-blockade is not an independent disease. This is, rather, a sign of other pathologies. Almost 60% of patients with blockade suffer from coronary heart disease. In addition, pathology often occurs on the background or after myocardial infarction.
In addition, there are other reasons that can lead to a violation of normal heart rhythm. Risk factors include viral and bacterial myocarditis, as well as myocardial cardiosclerosis, calcification of the heart muscle, congenital forms of cardiomegaly. Sometimes SA-blockade develops in people suffering from rheumatism.
Blockade of the sinoatrial node can be caused by the use of too large doses of cardiac glycosides, beta-blockers, quinidines and some other medicines. An excess of potassium in the blood often leads to the development of pathology. Since the work of the heart is regulated by the vagus nerve, an increase in its tone can also lead to rhythm disturbance (a strong blow or chest injury, some reflex tests that increase the activity of nerve endings).
Other illnesses, including heart valve defects, the presence of a tumor in the brain, malfunctioning of the thyroid gland, severe hypertension, meningitis, encephalitis, leukemia, cerebral vascular pathology, are also referred to the causes. As you can see, there are a huge number of risk factors.
Blockade of the first degree and its features
In modern medicine, it is customary to distinguish three degrees of severity of this pathology. Each of them has its own characteristics. The most mild form is considered sinoatrial blockade of the first degree. With a similar pathology, every impulse that occurs in the region of the sinus node reaches the atria. But holding it occurs with some delay.
Such a pathology cannot be seen on the electrocardiogram, and there are no external manifestations - for the most part, patients feel normal. The first degree of blockade can be diagnosed with an intracardiac EFI.
Blockade of the second degree: a brief description
This stage of the development of pathology is usually divided into two types:
- Blockade of the 2nd degree of the first type is accompanied by a gradual decrease in conductivity in the region of the sinus node. Such a violation can already be diagnosed on an ECG. As for external symptoms, patients often complain of periodically occurring dizziness, weakness. As the disease develops, pre-syncope, and sometimes short-term loss of consciousness, provoked by increased physical exertion, severe coughing, sharp turns of the head, etc. become a frequent occurrence in human life.
- Blockade of the 2nd degree of the second type is already accompanied by clear violations of the heart rhythm, which the patient himself can feel. For example, the heartbeat first intensifies (a person may feel contractions), after which it abruptly stops, and after a pause it resumes. During periods of asystole, the patient feels a sharp weakness, often loses consciousness.
What are the signs of a grade 3 blockade?
Pathology of the third degree is a complete sinoatrial block. In this case, the myocardium does not receive impulses from the sinus node at all. Naturally, the pathology is visible on the ECG, because against the background of a complete blockade of conduction, the patient develops asystole. At the same time, an elusive ectopic rhythm appears due to the activity of third-order drivers. During electrocardiography, you may notice that PQRST complexes are absent.
Drug treatment
Immediately it is worth saying that the treatment regimen largely depends on the cause of the pathology. If sinoatrial blockade is partial and is not a threat to the patient’s life, then specific therapy may not be necessary at all - the heart rate can normalize by itself.
Nevertheless, it is necessary to treat the primary disease. For example, if the blockade is provoked by an increase in the tonus of the vagus nerve, then it is important to introduce Atropine to the patient (you can replace it with Ephedrine, Orciprepalin, Isoprenaline). In the event that malfunctions of the heart rhythm occurred against the background of an overdose, the intake of potentially dangerous drugs should be stopped immediately and try to remove the remnants of the medicine from the body.
Unfortunately, quite often, such a rhythm disturbance leads to the development of fibrotic changes in the myocardium. In such cases, a normal contraction of the heart muscle can be achieved only by constant electrical stimulation.
First aid for blockade
As already mentioned, in most cases, the blockade is partial in nature and is not a direct threat to the life of the patient. Nevertheless, in some cases, the complete cessation of the transmission of electrical impulses leads to a sudden cardiac arrest.
If a serious malfunction is observed in the rhythm of the heart up to a stop, then atrial stimulation is performed. As a short-term measure, you can put pressure on the eyeballs (helps change the rhythm of heart contractions). Unfortunately, sometimes the patient requires intensive care, heart massage and connection to a life support device.