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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.
Premature ventricular contraction in an ECG (arrows) of a dog, caused by dilated cardiomyopathy. Premature ventricular contractions occur in healthy persons of any age, but are more prevalent in the elderly and in men. [3] In a very significant proportion of people they occur spontaneously with no known cause. [citation needed]
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.
Ventricular pacemaker with 1:1 retrograde ventriculoatrial (V-A) conduction to the atria (arrows). VA conduction, also named Ventriculoatrial conduction and sometimes referred to as Retrograde conduction, is the conduction backward phenomena in the heart, where the conduction comes from the ventricles or from the AV node into and through the atria.
Further, the left ventricle has thicker walls than the right because it needs to pump blood to most of the body while the right ventricle fills only the lungs. [ citation needed ] [ 1 ] On the inner walls of the ventricles are irregular muscular columns called trabeculae carneae which cover all of the inner ventricular surfaces except that of ...
Ventricular relaxation, or diastole, follows repolarization of the ventricles and is represented by the T wave of the ECG. It too is divided into two distinct phases and lasts approximately 430 ms. [1] During the early phase of ventricular diastole, as the ventricular muscle relaxes, pressure on the remaining blood within the ventricle begins ...
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.