Any one of the conductors, composed of two or more electrodes, in the ECG that shows the electrical conduction in the heart.
lead
A fall in blood pressure when changing to an erect position.
orthostatic hypotension
Having one common shape of QRS complex.
monomorphic
The effect on the rate of contraction of the heart.
chronotropic effect
The blood vessels that carry blood to the heart.
veins
Tissue anoxia from diminished blood flow to tissue, usually caused by narrowing or occlusion of the artery.
ischemia
A cardiac dysrhythmia seen just before the heart stops altogether; essentially asystole with occasional QRS complexes that are not associated with cardiac output.
agonal rhythm
A slow heart rate, less than 60 beats/min.
bradycardia
The pressure under which the ventricle fills.
preload
The period from one cardiac contraction to the next. Each cardiac cycle consists of ventricular contraction (systole) and relaxation ( diastole).
cardiac cycle
The baseline of the ECG.
isoelectric line
The effect on the velocity of conduction.
dromotropic effect
The upper left chamber of the heart; receives blood from the pulmonary veins.
left atrium
A system of fibers in the ventricles that conducts the excitation impulse from the bundle branches to the myocardium.
purkinje fibers
The pressure exerted by the pulsatile flow of blood against the arterial walls.
blood pressure
The flow of blood from the right ventricle through the pulmonary arteries and all of their branches and capillaries in the lungs and back to the left atrium through the venules and pulmonary veins; also called the lesser circulation.
pulmonary circulation
The early phase of cardiac repolarization, wherein the heart muscle cannot be stimulated to depolarize.