Bundle Branch Block - Complete And Incomplete (partial) Left / Right Bundle Branch Block

2024 Author: Josephine Shorter | [email protected]. Last modified: 2023-12-16 21:43

Complete and incomplete left and right bundle branch block

Definition of His bundle block

A bundle branch block is a certain hindrance and obstacle to the normal passage of the sinus impulse through the special conducting system of the heart. Such an impulse is formed in the sinus node. It goes beyond its specific limits and easily enters the atrial system, exciting both atria during passage. In this case, this sinus impulse reaches the atrioventricular junction, undergoing a special physiological delay, and then enters the small conducting system of the ventricles.

Serious violations of the normal conductivity of a sinus pulse are often observed along its entire length. Various violations are noted, depending on the specificity of the level. The first type includes dangerous disorders of intra-atrial conduction, which are otherwise called blockade of the sinus impulse in the atria. The second violation is atrioventricular block. The third type can be noted the complete violation of important intraventricular conduction.

The ventricular conduction system is divided into right and left legs. It should be noted that the right leg includes one wide bundle. In the thickness of the musculature, it branches. The typical left bundle branch is subdivided into anterior and standard posterior branches. Both legs form a distinct network of Purkinje fibers. Normally, the sinus impulse always excites the interventricular septum during the passage of the ventricular system. With complete blocks of the bundle of His, the specific pathway and the time of ventricular excitation usually change.

Complete bundle branch block

To identify a complete blockade of the right bundle branch, it is necessary to determine the course of excitation in the ventricles. It should be recalled that excitement initially covers only the interventricular septum, and only then the unblocked left ventricle is involved in this process of excitation. This impulse of excitation often comes to such a left ventricle in its usual way. In this case, typical excitement is often transmitted to the blocked right ventricle through the network of fibers from the left ventricle.

An unusual course of excitation in a standard blocked right ventricle will always lead to an inevitable change in the shape of a particular QRS complex in typical right chest leads, where it will be deformed and split. If the excitement came in an extremely unusual way, then the excitation time for the right ventricle will be longer.

Complete blockade of the left and right bundle branch block manifests itself in a certain way. The course of excitation in the ventricles initially covers only the interventricular septum. Along the unchanged leg on the right, such excitement quickly reaches the right ventricle. Then the excitement covers the blocked left ventricle. In this case, excitement in this case will come through the network of fibers, due to such serious violations. In the left chest leads, the normal internal deviation time is always significantly higher than the norm, due to the excess of the width of the ventricular complex.

Incomplete bundle branch block

The main factors for the dangerous development of an incomplete type of blockade of the right bundle branch block are electrolyte metabolism disorders, drug overdose or various intoxication. The typical conduction of impulses throughout the heart system slows down due to the development of such a blockade. In this case, there is no full-fledged excitation of the right divisions.

The diagnosis of these disorders separately at the level of a specific right leg is always possible to establish by performing an electrocardiographic study. Changes are visible when decoding the ECG. In this case, the duration of the complex itself should be slightly increased. The enlarged tooth in the chest leads will be clearly visible when decoding, and its segment will be omitted.

Treatment and prevention of bundle branch block

The main therapeutic measures for this incomplete version of the blockade are the diagnosis and treatment of the very disease that caused the development of such a blockade. There is no specific therapy for these disorders. If the patient suffers from dangerous heart failure, hypertension or angina pectoris, then it is necessary to carry out therapeutic therapy based on special preparations of cardiac glycosides, as well as antiarrhythmic and antihypertensive drugs.

With congenital defects in modern conditions, as a rule, only surgical intervention is indicated. If blockade is the norm in young people, then no therapy is required. Dynamic observation and regular examinations by a cardiologist will be enough.

In case of incomplete blockade of the left bundle branch block, the necessary impulse is always slowed down, since the width of the complex is greater than normal. This blockage is often only diagnosed by electrocardiography. You can hear a split tone at the apex with auscultation. These disorders contribute not only to the development, but also to a significant progression of chronic heart failure. The use of cardiac glycosides is contraindicated in this case, so that the blockade does not develop into a complete one.

Article author: Mochalov Pavel Alexandrovich | d. m. n. therapist

Education: Moscow Medical Institute. IM Sechenov, specialty - "General Medicine" in 1991, in 1993 "Occupational Diseases", in 1996 "Therapy".