EKG/ ECG Flashcards
Electrocardiogram
Graphic representation of the electrical potentials produced by the heart muscles during different phases of the cardiac cycle
What does ECG read?
The pulses that spread via body fluids from the heart to the surrounding and to the surface of the body
What are voltage variations due to?
Depolarization/ repolarization of cardiac muscle fibers
What measures the membrane potential of a nerve fiber?
Microelectrode
Electrical dipole
A pair of electrical charges separated by a distance (battery)
How do positive ions flow?
Toward the negative end of the dipole and vice versa and this creates voltage difference within the salt solution
Where is the voltage the strongest and the weakest?
Strongest along the line of the positive and negative terminal (A to B)
Weakest deviating from the line, perpendicular to the terminals (C to D-0)
A wave of depolarization moving in the direction of a positive electrode results in a______ deflection
Positive
A wave of depolarization moving away from a positive electrode results in a______ deflection
Negative
A wave of repolarization moving in the direction of a positive electrode results in a______ deflection
Negative
A wave of repolarization moving away from a positive electrode results in a______ deflection
Positive
A wave of depolarization or repolarization moving perpendicular the direction to a positive electrode results in ______ deflection
No (isopotential)
What does the instantaneous amplitude of the measured potentials depend on?
The orientation of the positive electrode relative to the ,ean electrical vector
What is the voltage amplitude directly related to?
Mass of tissue undergoing depolarization or repolarization
