The electrical activities of a cell from 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... More to repolarizationFollows depolarization, involving the return to a pre-depolarization state; the myocardial cell’s electrical potential returns from +30 mV to its polarized state of –90 mV; the ions potassium, calcium and sodium are largely involved; note that contraction of the myocardial... More; 5 phases (0-4) take place largely involving the sodium, potassium and calcium ions.
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... More (2012), T Barill, p. 189