SA blockade 1 degree 1 type or other types exist?

author: cardiologist Merter M.V.

One of the frequent violations of the impulse is the so-called sinoatrial, or CA blockade. It should be noted that CA blockade occurs in 0.17 - 2.4% of the population, more often in protection after 55 - 60 years and somewhat more often in women than men.

CA-blockade 1 degree is not of type 1 or any other subtypes. Types differ only in CA 2 degree. So, the sinoatrial blockade occurs due to the inability of the sinus angle to perform atrial stimulation. CA blockade - this phenomenon is the slowing (or periodic termination) of the spreading to the atrium of the pulses produced in the sinoatrial node. In this case, the region in which the locus of disturbance of the excitation impulses is located, is localized between the myocardium of the atria and the sinoatrial node.

At present, there are 3 degrees of sinoatrial blockade, however, only CA of II and III blockade can be reliably recorded on the ECG, where there are episodes of complete stopping of one (or several consecutive) sinus pulses at the atrium.

Etiology of CA blockade of the first degree

·· organic atrial damage:

acute myocardial infarction;

- Chronic ischemic heart disease, especially in the presence of a lesion of the right coronary artery and subsequent posterior myocardial infarction;

- Acute myocarditis of different etiology or myocarditis cardiosclerosis;

- congenital cardiomegaly;

- hypertonic disease;

- defects of MK and AK;

· Overdose with such medicines as:

- cardiac glycosides;

- quinidine;

- beta-blockers;

- calcium antagonists;

· · Pronounced tone of the vagus nerve of peripheral or central origin (inflammatory processes, tumors or pathology of the cerebral vascular genesis);

·· rehabilitation period within 7 to 10 days after electropulse therapy;

· CA of congenital origin, inherited by an autosomal dominant type.

At the moment it is determined that in 25 - 50% of cases of SA blockade of myocardial pathology can not be detected.

Symptoms of CA-blockade of 1 degree

The clinical picture of the disease depends directly on the form of the CA blockade. In the presence of a sinoatrial blockade of the 1st degree, the patient has no complaints, that is, this degree of blockade does not cause any objective changes in the functioning of the cardiovascular system and the general condition of the patient. The clinical picture of conduction disturbance manifests itself in the presence of a sinoatrial block, beginning with the CA of the blockade of the 2nd degree.

ECG

When examining the ECG blockade of degree I (there are no types), the pulses produced by the sinus node pass slowly through the sinoatrial connection. Normally, the duration of the CA is 0.04-0.153 (0.092 ± 0.06) s. Thus, due to the fact that when a routine ECG is recorded, the spread of the impulse originating from the sinus node of the node is not fixed in the sinoatrial connection, then the EC blockade of the 1st degree can not be diagnosed according to the ECG data. It should be noted that this blockade can only be diagnosed if it is combined with a second degree SA blockade. In this case, the interval P - P between the most near sinus pulses that covers the blocking location will not be equal to the interval P - P of 2 normal sinus pulses, but will be shorter than this interval.

Treatment of sinoatrial blockade of 1 degree

The tactics of treatment directly depends on the presence and nature of the patient's disease, as well as the dynamics of the clinical course of the SA blockade of the 1st degree. Partial short-term blockade does not require treatment, but it should be noted that if the cause of its occurrence is the effects of drugs, then stop using them. If the occurrence of a repetitive sinoatrial block is due to the increased tone of the vagus nerve, then atropine or sympathomimetic injections (such as ephedrine, orciprepalin, isoprenaline) can be used for treatment. If a blockade occurs on the background of repeated attacks of loss of consciousness or even, perhaps, episodes of clinical death, electrostimulation of the heart is necessary. In this case, ventricular stimulation of the heart should be used, as often combined cardiac conduction disorders are detected.

Forecast

The prognosis of this pathological process depends on the etiologic factor, duration, degree of CA blockade, functioning of the cardiovascular system of the patient and the presence of a combination of cardiac arrhythmias.
The short-term partial CA of the blockade does not have any noticeable effect on the course and prognosis. The permanent partial CA of the blockade (more often due to fibrotic changes), especially in people over 65 with IHD, can progress to a complete blockade and cause episodes of loss of consciousness and sudden death. Additional information about the SA blockade of the 1st degree by reference in the article of another doctor.