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 temporary asystole. Naturally, such a violation is dangerous. Many patients seek additional information about this pathology. Why is the blockade developing? Are there any outward symptoms? What methods of treatment does modern medicine offer? The answers to these questions will be of interest to many readers.
What is sinoatrial block?
In order to explain the essence of the pathology, you first need to pay attention to the anatomical and physiological features of the human myocardium. As you know, the heart is a partially autonomous organ. Its contraction is provided by the work of special nerve nodes that conduct nerve impulses.
An important part of the pacemakers is the sinus node. It is located between the right auricleand opening of the superior vena cava, in the wall of the right atrium. The sinoatrial connection has several branches, including the bundle of Torel, Bachmann, Wenckebach - they conduct impulses to the walls of both atria. Violation of the normal conduction of a nerve impulse in this area is called the blockade of the sinoatrial node.
Thus, against the background of pathology in the rhythm of the heart, failures occur, 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 years of age most often suffer from the disorder. In female representatives, such a deviation is less common.
It is possible to develop blockade in childhood, but this usually occurs against the background of congenital organic lesions of the myocardium.
Main causes of pathology
It should be understood that SA-blockade is not an independent disease. It is rather a sign of other pathologies. Almost 60% of blockade patients suffer from coronary heart disease. In addition, pathology often occurs against the background of or after myocardial infarction.
Besides this, there are other reasons that can lead to disruption of the normal heart rhythm. Risk factors include viral and bacterial myocarditis, as well as myocardial cardiosclerosis, calcification of the heart muscle, and congenital forms of cardiomegaly. Sometimes SA block develops in people suffering from rheumatism.
Blockadesinoatrial 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).
The reasons include other ailments, including heart valve defects, the presence of a tumor in the brain, malfunctions of the thyroid gland, severe hypertension, meningitis, encephalitis, leukemia, pathology of cerebral vessels. As you can see, there are a huge number of risk factors.
First degree blockade 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 mildest form is considered to be first-degree sinoatrial block. With such a pathology, each impulse that occurs in the region of the sinus node reaches the atria. But its implementation takes place with some delay.
This pathology cannot be seen on an electrocardiogram, and there are no external manifestations - for the most part, patients feel normal. You can diagnose the first degree of blockade during intracardiac EPS.
Second degree blockade: a brief description
This stage of development of pathology is accepteddivided into two types:
- Blockade of the 2nd degree of the first type is accompanied by a gradual decrease in conductivity in the area of the sinus node. Such a violation can already be diagnosed on the ECG. With regard to external symptoms, patients often complain of recurrent dizziness, weakness. As the disease develops, pre-syncope states, 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 a person’s life.
- 2nd degree blockade of the second type is already accompanied by clear cardiac arrhythmias that the patient himself can feel. For example, the heartbeat first increases (a person can feel contractions), after which it stops abruptly, and after a pause it resumes. During periods of asystole, the patient feels a sharp weakness, often loses consciousness.
What are the symptoms of a 3rd degree block?
Third degree pathology 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 there are no PQRST complexes.
Medicated treatment
It should be said right away that the treatment regimen largely depends oncauses of pathology. If the sinoatrial blockade is partial and is not a threat to the patient's life, then specific therapy may not be required at all - the heart rhythm can normalize on its own.
Still need to treat the primary disease. For example, if the blockade is provoked by an increase in the tone of the vagus nerve, then it is important to administer Atropine to the patient (can be replaced with Ephedrine, Orciprepalin, Isoprenaline). In the event that heart rhythm failures occur against the background of an overdose, the use of potentially dangerous drugs should be stopped immediately and an attempt should be made to remove the remnants of medications from the body.
Unfortunately, quite often such rhythm disturbance leads to the development of fibrotic changes in the myocardium. In such cases, normal contraction of the heart muscle can only be ensured by constant electrical stimulation.
First aid for blockade
As already mentioned, in most cases the blockade is partial and does not pose a direct threat to the patient's life. However, in some cases, the complete cessation of the transmission of electrical impulses leads to sudden cardiac arrest.
If there is a serious failure 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 heart rate). Unfortunately, sometimes the patient needs intensive care, cardiac massage and connection to a life support machine.
