ECG Cycle
Synopsis
This image shows a section from a roll of recording graph paper with an ECG (electrocardiogram) traced on it. There is a locator dot shown, which will be at the top left of the page when the image is the correct way up.The ink trace starts in the left middle and goes horizontally across ending in the right middle of the page. There are some deviations from the horizontal straight line. The paper strip has gridlines forming a grid four squares high. There is a time scale at the bottom of the image. Near the left middle of the page the trace curves up slightly from the straight line, this is the P wave. The trace curves down to the straight line, then right of this the trace goes down sharply for a little way, this is the Q wave. The trace then immediately goes sharply up to the top third of the paper, the R wave, and immediately comes sharply down about same amount to the S wave. The trace then goes up slightly and returns to the straight line. A little to the right of the S wave, the trace curves up slightly from the straight line, this is the T wave. The T wave is slightly steeper than but not as wide as the P wave. The recording graph paper moves from left to right. A pen which can move up and down the image, but not to the left and right, draws a straight or wavy line as the paper moves under it.