oscilloscope
provides a continuous visual image of the electrical activity of the heart on a screen displays rapid changes in a voltage as a moving line on a phosphorescent screen generally displays a single lead
electrocardiograph
instrument used to record the electrical activity of the heart
Holter monitor
a portable electrocardiograph that is worn by an out patient to continuously monitor the heart rates and rhythms over a 24-48 hour period it can also be used to evaluate the effectiveness of anit-arrythmia drugs chest electrodes are connected o the monito
pqrst waves