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Exploring the heart's electrical system: What's the mysterious mechanism behind bundle branch block?
The heart's electrical system is a mysterious and complex network whose function is critical to maintaining proper heart rhythm. However, when part of this system is damaged or disturbed, a bundle branch block (BBB) occurs. This situation may cause changes in heart function, resulting in the heart being unable to effectively supply blood to the entire body. What is the mechanism behind this?
Bundle branch block can occur as a result of heart disease, myocardial infarction, or heart surgery. It occurs when any of the bundle branches or a small part of the bundle is damaged, causing electrical signals to no longer flow normally.
Anatomy and Physiology of the Heart
The heart's electrical activity begins in the sinoatrial node, the heart's natural pacemaker, located in the upper part of the right atrium. The electrical signal is first transmitted to the left and right atria, where it converges at the atrioventricular node (AV node). The signal then travels down the bundle of His and is divided into the right and left bundle branches. Of the two bundle branches, the right bundle branch has only one slice, while the left bundle branch is further divided into two or three slices: the left anterior slice, the left posterior slice, and possibly the left septal slice. section.
These facets eventually divide into millions of Puget Sound fibers, which interweave with the heart's muscle cells and enable rapid and coordinated depolarization of the ventricles.
Mechanisms of bundle branch block
When a bundle branch or a small section of it is damaged, it can no longer transmit electrical signals properly, which can lead to an altered pathway for the ventricles to depolarize. Because the electrical signal cannot follow its preferred pathway across the bundle branch, the signal may instead travel through the muscle fiber, resulting in a slower signal and a change in direction.
Such changes lead to prolonged ventricular depolarization and may cause a decrease in cardiac output. In cases of heart failure, specialized pacemakers may be used to resynchronize the ventricles, which, in theory, could shorten the QRS interval, bringing the left and right ventricles closer together and thus slightly improve ejection fraction.
Diagnosis
Bundle branch block can be diagnosed by electrocardiography (ECG) and is characterized by a QRS complex duration exceeding 120 milliseconds. Right bundle branch block causes the last part of the QRS to be prolonged and may shift the heart's electrical axis slightly to the right, whereas left bundle branch block causes the entire QRS complex to be widened and, in most cases, shift the heart's electrical axis slightly to the right. Move left.
Types of bundle branch blockIn patients with bundle branch block, the ECG will usually show appropriate T wave discordance, meaning that the T wave is deflected in the opposite direction at the end of the QRS complex.
Based on the anatomical location of the lesion, bundle branch blocks can be further classified as:
- Right bundle branch block (including incomplete and complete types)
- Left bundle branch block (including incomplete and complete types)
Left bundle branch block can be further divided into left anterior facet block and left posterior facet block; bifacet block is the block of the right bundle branch and either left A combination of small sections.
Treatment methods
Some people are born with bundle branch block, while others acquire it due to heart disease. Although many people with bundle branch block may remain active and may only have an atypical appearance on the EKG, in more severe cases this may indicate underlying cardiac pathology.
In some cases, a pacemaker may be necessary to restore optimal electrical signaling to the heart, especially when the bundle branch block is complex and accompanied by significant myocardial damage. It is possible that the need is more pressing in this case.
In exploring the fascinating mechanisms of bundle branch block, can we gain a deeper understanding of the complexity of this electrical system that affects the health of countless heart patients?
