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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.
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 ...
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 ...
A ventricle is one of two large chambers located toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the upper heart that is smaller than a ventricle.
This is the ejection stage of the cardiac cycle; it is depicted (see circular diagram) as the ventricular systole–first phase followed by the ventricular systole–second phase. [2] After ventricular pressures fall below their peak(s) and below those in the trunks of the aorta and pulmonary arteries, the aortic and pulmonary valves close ...
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.
Ventricular arrhythmias include ventricular fibrillation and ventricular tachycardia. [ 46 ] [ 47 ] Arrhythmias are due to problems with the electrical conduction system of the heart . [ 44 ] Arrhythmias may occur in children; however, the normal range for the heart rate is different and depends on age. [ 46 ]
A complication of this is when the atria and ventricles are not in synchrony and the "heart rate" must be specified as atrial or ventricular (e.g., the ventricular rate in ventricular fibrillation is 300–600 bpm, whereas the atrial rate can be normal [60–100] or faster [100–150]). [citation needed]