What is Conduction Disorder?
In the atrioventricular blocks, the electrical click from the atria cannot arrive at the ventricles or arrives late: it is blocked.
In the 1st degree atrioventricular block: the click is simply slowed down in its path from the atrium to the ventricle. This phenomenon is graphically represented on the electrocardiogram by an elongation of the PR space;
In the atrioventricular block of 2nd degree: the click is slowed down more and more over the contractions until it ends in an electrical disjunction and so on: these are the Luciani-Wenckebach periods.
In the atrioventricular block of 3 ° degree: the click never arrives at the ventricles. The auricles are beating on their own. The ventricles manage by themselves and slowly beat at their own pace. It is the permanent slow pulse disease.
Causes and Risk Factors of Conduction Disorder
The causes of atrioventricular block are numerous:
- Acute phase of myocardial infarction;
- Acute viral myocarditis;
- Cardiac surgery suites;
- Primary sclerotic degeneration of His tissue;
- Congenital atrioventricular blocks;
- Iatrogenic causes: drug combinations, digitalispoisoning …
The branch blocks designate the interruption or deceleration of electrical conduction in one branch of the His bundle. The branch block may be complete or incomplete, left or right depending on which branch of His’s beam is reached. The diagnosis is made on reading the electrocardiogram.
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At auscultation, the duplication of the first cardiac noise reflects the asynchronous closure of the auriculoventricular valves. The causes of the branch block are diverse because these abnormalities can be seen in all acquired or congenital heart disease.
The isolated right branch block can be seen quite often in patients free from any heart disease. This conduction disorder, however, may be the first sign of cardiomyopathy and requires regular monitoring.
Lenègre’s disease is a degenerative disorder of conduction tissue in patients over 60 years of age. The evolution towards a paroxysmal or permanent atrioventricular block is possible with its episodes of syncopes imposing the implantation of a pacemaker.
Permanent slow-pulse disease (or Adams-Stokes syndrome)
This syndrome is characterized by a slow pulse at 40 / min and a series of nervous accidents ranging from vertigo to sudden death through black veil, brief stunning, fleeting pallor of the face, epilepsy attack (Convulsive crisis), and syncope in flash with fall.
CAUSES AND RISK FACTORS
Pulse slowing is the consequence of the atrioventricular block.
If you experience syncope, pallor, absence of pulse and cardiac noise prove circulatory arrest.
Some blows on the anterior surface of the thorax with the palm of the hand often make it possible to interrupt the paroxysm.
A generalized convulsive seizure may occur. The patient returns to him rather quickly. The doctor should be called urgently. Hospitalization in specialized settings is required.
Careful use of Isuprel makes it possible to wait for the implantation of an external pacemaker initially, then internal permanent (electro-systolic drive with lithium batteries or pacemaker).