Fluke Biomedical ProSim 6 - Manual (Page 100)

ProSim™ 6/8
Users Manual
A-6
Premature Atrial Contraction (PAC)
A beat that is 25 % premature but otherwise normal. Any part of the heart can depolarize
earlier than it should; the accompanying heartbeat is called extrasystole. This type of
depolarization is called a premature contraction; a premature contraction that originates
in the SA node is referred to as a PAC. An isolated PAC is relatively unimportant.
However, frequent PACs are a concern, because they could be the precursor of more
serious and potentially life-threatening conditions, including atrial flutter, atrial
fibrillation, and atrial tachycardia.
Premature Nodal Contraction (PNC)
A nodal beat that is 25 % premature, followed by a nodal rhythm at 80 BPM. A
premature nodal contraction—also called a premature junctional contraction, a PNC, or a
PJC—is an extra beat that occurs as a result of an electrical impulse sent from the
atrioventricular (junctional) node. The P-R interval is shorter than normal. PNCs, which
may occur in isolation or in groups, can appear sporadically for no obvious reason in an
otherwise-healthy person.
Premature Ventricular Contractions
Six PVC-type selections of focus and timing:
• a left-focus premature ventricular beat with standard timing, 20 % premature;
• a left-focus premature ventricular beat with early timing, 33 % premature;
• a left-focus premature ventricular beat with very early timing, 65 % premature,
which starts during the T wave of the previous beat;
• a right-focus premature ventricular beat with standard timing, 20 % premature;
• a right-focus premature ventricular beat with early timing, 33 % premature; or
• a right-focus premature ventricular beat with very early timing, 65 % premature,
which starts during the T wave of the previous beat.
A premature ventricular contraction or PVC is an extra beat consisting of an abnormally
wide and unusual QRS complex originating in an ectopic pacemaker in the ventricles.
Early ventricular PVCs occur close to the preceding beat. Moreover, R-on-T PVCs,
which are characterized by a beat that falls on the T wave of the preceding QRS-T
complex, are especially inauspicious because of their potential to cause ventricular
tachycardia or ventricular fibrillation.
Pulse
The rhythmical throbbing of arteries produced by regular contractions of the heart.
Pulse Oximeter
A non-invasive, arterial, oxygen-saturation monitor that measures the ratio of two
principle forms of hemoglobin in the blood.
Purkinje Network
The dense collection of Purkinje fibers, which are dispersed throughout the myocardium
and which represent the terminal portion of the heart's electrical conduction system.
PVCS
Premature ventricular contractions.
PVCS: 6, 12, or 24 Per Minute
PVCs scattered among normal beats AT 80 BPM, so that PVCs take place 6, 12, or 24
times every minute. Premature ventricular contractions may occur independently (even
in healthy individuals), as well as in groups and/or for a number of times every minute.