Search results
Results from the WOW.Com Content Network
The conduction system consists of specialized heart muscle cells, situated within the myocardium. [3] There is a skeleton of fibrous tissue that surrounds the conduction system which can be seen on an ECG. Dysfunction of the conduction system can cause irregular heart rhythms including rhythms that are too fast or too slow.
Sinoventricular conduction is a rare form of cardiac conduction in which the sinoatrial node generates an impulse that is conducted to the atrioventricular node (AV node) in the absence of the right atrium contracting. This is the physiological proof for the presence of the internodal tracts, which have not been clearly demonstrated histologically.
The bundle of His (BH) [1]: 58 or His bundle (HB) [1]: 232 (/ h ɪ s / "hiss" [2]) is a collection of heart muscle cells specialized for electrical conduction.As part of the electrical conduction system of the heart, it transmits the electrical impulses from the atrioventricular node (located between the atria and the ventricles) to the point of the apex of the fascicular branches via the ...
In comparison to second-degree atrioventricular block, in first-degree block there is an absence of non-conduction or "dropped beats." In an electrophysiology study , this corresponds to a prolonged A-H interval that shows the time between atrial depolarization and His bundle depolarization near the AV node.
An important property that is unique to the AV node is decremental conduction, [12] in which the more frequently the node is stimulated the slower it conducts. This is the property of the AV node that prevents rapid conduction to the ventricle in cases of rapid atrial rhythms, such as atrial fibrillation or atrial flutter.
The fibres often conduct slowly and in one direction only - from the atria to the ventricles (antegrade conduction); not from the ventricles to the atria (retrograde conduction). Unlike most atrio-ventricular accessory pathways which conduct electrical impulses at a relatively fixed speed, conduction through a Mahaim pathway varies according to ...
Intraventricular conduction delays (IVCD) are conduction disorders seen in intraventricular propagation of supraventricular impulses resulting in changes in the QRS complex duration or morphology, or both. IVCD can be caused by abnormalities in the structures of bundle of His, Purkinje fibers or ventricular myocardium.
[1] [5] Depending on where the rhythm originates in the AV node, the atria can contract before ventricular contraction due to retrograde conduction, during ventricular contraction, or after ventricular contraction. If there is a blockage between the AV node and the SA node, the atria may not contract at all.