Glossary
Introduction
A
A-5
Hemoglobin
The oxygen-bearing, iron-containing conjugated protein in vertebrate red blood
cells, consisting of about 6 per cent heme and 94 per cent globin.
Hertz
A unit of frequency equal to one cycle per second. Used to measure electrical
current and light, especially ultraviolet radiation (as in fluorescent light).
Impedance
A measure of the total opposition to current in a circuit.
Infrared
Of, pertaining to, or being electromagnetic radiation having wavelengths greater
than those of visible light and shorter than those of microwaves.
Joule
A unit of energy, equal to the work done when a current of one ampere is passed
through a resistance of one ohm for one second.
Kilogram
The fundamental unit of mass in the International System, about 2.2046 pounds.
LCD
Liquid crystal display. A digital display consisting of a liquid crystal material
between sheets of glass that becomes readable in the presence of an applied
voltage.
Meter
The fundamental unit of length, equivalent to 39.37 inches, in the metric system.
Millivolt
One-thousandth of a volt.
Missed Beat
A single missing beat, with the heart rate returning to normal. Missed beats, often
present in first-degree heart block, are symptomatic of other conditions as well.
Multifocal PVCS
A sequence that includes a left-focus PVC, followed by two normal beats,
followed by a right-focus PVC, followed by a normal rhythm at 80 BPM. Multifocal
PVCs are premature ventricular contractions that originate in different ectopic-
pacemaker sites throughout the ventricles. These PVCs, which exhibit different
size and shape elements, are characterized by the absence of a P wave (due to
the lack of any atrial-pacemaker activity).
Multiple PVCS: Paired PVCS; Run 5 PVCS; Run 11 PVCS
Three series of multiple PVCs run as one-time (nonrepeating) events. The term
multiple PVCs refers to any condition where two or more PVCs occur in a row.
Standard PVCs of this type include a pair of PVCs (also known as a couplet), a
run of five PVCs in a row, and a run of eleven PVCs in a row.
Myocardium
The thick muscular layer of the heart, located between the endocardium at the
inside and the epicardium at the outside walls of the heart.
To Next Page
Loading...
