My notes from Chapter 2: Basic Electrophysiology Section: Ectrocardiogram Paper ECGs Made Easy 4th Ed., 2011 Barbara Aehlert, RN, BSPA
graphical representation of the heart's electrical activity [p50]
the machine records
the voltage (potential difference) between the electrodes [p50]
needle/pen of the ECGs
moves a specific distance depending on the voltage measured; made on ECG paper [p50]
graph paper made up of small and large boxes measured in millimeters [p52]
horizontal axis of the ECG paper
time; used to measure the interval between or duration of specific cardiac events; stated in seconds [p52]
ECG paper normally records at a constant speed of ___________.
25 mm/sec [p52]
each horizontal 1mm box represents____.
.04 seconds [p52]
large box represents
.20 seconds (5 small boxes) [p52]
vertical axis of the ECG paper measures...
the voltage or amplitude of a waveform [p52]
voltage is measured in ___.
millivolts (mV) [p52]
may be positive or negative
amplitude is measured in ____.
millimeters (mm) [p52]
the ECG machine's sensitivity must be calibrated so that a 1-mV electrical signal will produce a deflection measuring exactly...
10 mm tall [p52]
aka deflection, is a movement away from the baseline in a positive (upward) or negative (downward) direction [p52]
when electrical activity is not detected...
a straight line is recorded [p52]
each waveform on an ECG is related to ...
a specific electrical event in the heart [p52]
baseline or isoelectric line
electrical activity is not detected; a straight line is recorded [p52]
which leads see INFERIOR surface of the heart
II, III, aVF
which leads see SEPTAL surface of the heart
which leads see ANTERIOR surface of the heart
which leads see LATERAL surface of the heart
I, aVL, V5, V6
a line between waveforms; named by the waveform that precedes or follows it [p56]
a waveform and a segment [p56]
several waveforms [p56]
partly positive, partly negative [p56]