Physio Ch 11 Flashcards
It is composed of a P wave, a QRS complex and a T waves
Normal electrocardiogram
The normal electrocardiogram is composed of?
P wave, QRS complex and T wave
The QRS complex is often, but not always, three separate waves;
Q wave, R wave, S wave
caused by electrical potentials generated when the atria depolarize before atrial contraction begins
P wave
caused by electrical potentials generated when the ventricles depolarize before contraction, that is, as the depolarization wave spreads through the ventricles
QRS complex
are both depolarization waves
P wave and QRS complex
caused by potentials generated as the ventricles recover from the state of depolarization
T wave
This process normally occurs in ventricular muscle 0. 25 and 0.35 second after depolarization
T wave
T wave is known as?
repolarization wave
The electrocardiograph is composed of?
depolarization and repolarization
Atrial repolarization wave, known as the?
atrial T wave
The ventricular repolarization wave is the ___________ of the normal electrocardiogram
T wave
All recordings of electrocardiograms are made with appropriate ___________ on the recording paper
calibration lines
voltage of the P wave
0.1 and 0.3
voltage of the T wave between?
0.2 and 0.3
the voltage of the QRS complex is usually?
1.0 to 1.5
The time between the beginning of the P wave and the beginning of the QRS complex is the interval between the beginning of electrical excitation of the atria and the beginning of excitation of the ventricles. This period is called?
P-Q interval
The normal P-Q interval
0.16 second
Interval that often because the Q wave is likely to be absent
P-R interval
Contraction of the ventricle lasts almost from the beginning of the Q wave (or R wave, if the Q wave is absent) to the end of the T wave. This interval is called?
Q-T interval
The ordinarily Q-T interval is about?
0.35 second
The normal interval between two successive QRS complexes in the adult person is about?
0.83 second
The rate of heartbeat can be determined easily from an?
electrocardiogram
electrical currents generated by the?
cardiac muscle
electrical connections between the patient’s limbs and the electrocardiograph for recording electrocardiograms from the so called?
standard bipolar limb leads
means that the electrocardiogram is recorded from two electrodes located on different sides of the heart
bipolar
is not a single wire connecting from the body but a combination of two wires connecting and their electrodes to make a complete circuit between the body and the electrocardiograph
lead
the triangle that drawn around the area of the heart. Illustrates that the two arms and the left leg form apices of a triangle surrounding the heart
Einthoven’s triangle
states that if the electrical potentials of any tro of the three bipolar limb electrocardiographic leads are known at any given instant
Einthoven’s law
This electrode is connected to the positive terminal of the electrocardiograph and the negative electrode called the?
indifferent electrode
it is connected through equal electrical resistances to the right arm, left arm and left leg all the same time
indifferent electrode
Six standard chest leads are recorded, one at a time, from the anterior chest wall, the chest electrode being placed sequentially at the six points. The different recordings are known as?
leads V1, V2, V3, V4, V5, V6
what leads that the QRS recordings of the normal heart mainly negative?
V1 and V2
leads of QRS complexes that are mainly positive because the chest electrode in these leads is nearer the heart apex, which is the direction of electropositivity during most of depolarization
Leads V4, V5, V6
type of recording, that the two of the limbs are connected through the electrical resistances to the negative terminal of the electrocardiograph, and the third limb is connected to the positive terminal
Augmented Unipolar Limb Leads
When the positive terminal is on the right arm, the lead is known as?
aVR lead
When the positive terminal is on the left arm, the lead is known as the?
aVL lead
When the positive terminal is on the left leg, the lead is known as the?
aVF lead
