One of two types of fibres that lie parallel to each other; with the influx of calcium into the cell the fibres bind together and

The electrical activities of a cell from depolarization to repolarization; 5 phases (0-4) take place largely involving the sodium, potassium and calcium ions. 1. Six

Phase of depolarization: for myocardial cells the slow sodium channels open, and then, if threshold potential is reached, fast sodium channels open; note that cells

Depolarization has now completed; repolarization begins with the efflux of potassium from the cell. 1. Six Second ECG Guidebook (2012), T Barill, p. 202

Potassium leaves the cell while calcium enters the cell resulting in an electrical plateau; the calcium entering the cell is significant because it initiates the

Potassium leaves the cell resulting in the cell becoming increasingly negative; at 60-70 mV, the cell’s fast sodium channels begin to be receptive to causing

The polarized state of the cell with resting negative potential of approximately –90 mV; early in this phase, the sodium-potassium ATP pump restores the cell

Metabolism that utilizes oxygen is called aerobic metabolism. Energy production through oxygenation (with oxygen) yielding 32 ATP molecules from the interaction of one glucose and

The pressure that the ventricle (right or left) must overcome to eject blood (i.e. the left ventricle pumps against aortic diastolic pressure and systemic vascular

A fatal dysrhythmia with rates usually less than 20/minute and common widening of the QRS; also referred to as the dying heart. Asystole is characterized

The peripheral vasoconstriction that results from circulating catecholamines (epinephrine & norepinephrine). 1. Six Second ECG Guidebook (2012), T Barill, p. 190

The height or depth of waves and complexes of an ECG in millimetres; represents millivolts where 10 mm is 1 millivolt with a properly calibrated

Energy production without oxygen with only 2 ATP produced as well as lactic and pyruvic acid. When energy demands surpass the supply of vital energy