A standardized recording of the electrical activity of the heart and may be used to detect heart irregularities, lack of oxygen to parts of the heart, and enlargement of the chambers.
12-lead electrocardiogram (ECG)
Deviations from normal cardiac rhythm
arrhythmias
When a group of cardiac cells have the ability to generate an electrical impulse spontaneously.
automaticity
The imaginary line drawn between two electrodes
axis
The ability of the cardiac cells to transmit an impulse.
conductivity
The capability of muscle fibers to shrink.
contractility
Delivering an electrical shock to the heart so that it completely depolarizes the cardiac cells in an effort to terminate ventricular fibrillation.
defibrillation
Electrical changing in the interior of an excitable cell from negative to positive, which results in an action potential.
depolarization
A disturbance in rhythm
dysrhythmia
Graphic representation of atrial depolarization
P wave
An estimate of the amount of time it takes the impulse to travel from the SA node through the AV node, the bundle of His, and the main part of the left bundle branch.
PR interval
Conductive fibers that help to spread the electrical impulses of throughout the ventricular muscle. They have an inherent rate of 15 to 40 beats per minute.
Purkinje fibers
Graphic representation of ventricular depolarization.
QRS complex
Graphic representation of the amount of time it takes for ventricular depolarization and repolarization.
QT interval
Electrical change in the interior of an excitable cell following depolarization in which the inside of the cell becomes more negatively charged
repolarization
Primary pacemaker of the heart with an inherent rate of 60 to 100 beats per minute
SA node
Delivering an electrical shock to the heart that is synchronized to the patient’s R wave.
synchronized cardioversion
Graphic representation of ventricular repolarization.