DepolarizationThe rapid influx of positive ions (sodium and/or calcium) into a cell – depolarization is necessary for contraction to occur. A depolarizing wave moves through the myocardium on average along a trajectory or vector. A vector is a force moving... of the ventricle(s) is begun via an accessory pathwayAlternative connecting pathway between the atria and the ventricles (beside the bundle of His); resulting syndrome is called Woolf-Parkinson-White syndrome. 1. Six Second ECG Guidebook (2012), T Barill,p. 189 (other than the AV junctionConducts the impulse through the fibrous plate that separates the atria and the ventricles; consists of the AV node and the bundle of His; functions also to slow the conduction speed to allow for atrial conduction prior to ventricular conduction...) resulting in an early initiation of a QRSThe electrical representation of ventricular depolarization; the atrial repolarization is also a part of the QRS. ECG interpretation relies heavily on the QRS complex. The QRS complex represents the depolarization of the ventricles. The repolarization of the atria is also... and possibly a Delta waveA slurring of the upstroke of the QRS produced by early depolarization (pre-excitation) of a ventricle via an accessory pathway (see Woolf-Parkinson-White Syndrome). Woolf-Parkinson-White Syndrome (WPW): Pre-excitation syndrome characterized by the early depolarization of the ventricle(s) via an accessory pathway...; meanwhile, the junctionConnects the atria to the ventricle and slows the impulse conduction speed sufficiently to allow for atrial kick; the junction consists of the AV node and the bundle of His; the junction is a supraventricular structure. 1. Six Second ECG... and the His-Purkinje network is responsible for depolarizing the remaining unaffected ventriclesThe larger chambers of the heart (3 times the volume and muscle thickness than the atria), responsible for the pumping of blood to the lungs and the rest of the body. and also therefore for the remainder of the QRS.
1. Six Second ECG GuidebookA Practice Guide to Basic and 12 Lead ECG Interpretation, written by Tracy Barill, 2012 Introduction The ability to correctly interpret an electrocardiogram (ECG), be it a simple six second strip or a 12 lead ECG, is a vital skill... (2012), T Barill, p. 202