Exercise Physiology Flashcards
When analyzing an EKG - Which lead is used most often and why?
Lead 2 is most commonly used for EKG analysis: Gives best view of P-wave and most upright QRS complex
When analyzing an EKG - Which wave, segment, interval or complex represents the electrical forces generated by ventricular depolarization?
a) Q wave
b) ST segment
c) QRS Complex
d) T wave
c) QRS Complex:
electrical forces generated by ventricular depolarization; depolarization wave travels through interventricular septum via Bundle of His, bundle branches, and reaches ventricular myocardium via Purkinje fibres; left side of septum depolarizes first, and impulse spreads to the right; from endocardium (inside layer of heart) to epicardium (outside layer), in all directions.
When analyzing an EKG - Which wave, segment, interval or complex represents the onset of ventricular depolarization; septal depolarization?
a) Q wave
b) PR Segment
c) QRS Complex
d) S wave
B) PR segment:
the end of P wave, until just before the Q wave represents the onset of ventricular depolarization; septal depolarization
When analyzing an EKG - Which wave, segment, interval or complex represents the time between the onset of atrial depolarization and the onset of ventricular depolarization?
a) Q wave
b) PR segment
c) PR Interval
d) P wave
c) PR Interval:
electrical impulse conducted through AV node to bundle of His, bundle branches, and Purkinje fibres; the PR interval is the time between onset of atrial depolarization and onset of ventricular depolarization
When analyzing an EKG - Which wave, segment, interval or complex represents the total time taken for ventricular depolarization to repolarization?
a) QT interval
b) ST segment
c) T wave
d) P wave
a) QT Interval:
measured from beginning of QRS to end of T wave; total time taken for ventricular depolarization to repolarization.
When analyzing an EKG - What wave represents ventricular repolarization?
a) P wave
b) T wave
c) S wave
d) R wave
e) U wave
f) Q wave
b) T wave
When analyzing an EKG - What wave represents depolarization of the main mass of the ventricles?
a) P wave
b) T wave
c) S wave
d) R wave
e) U wave
f) Q wave
d) R wave:
depolarization of the main mass of the ventricles; left ventricle is larger in muscle mass, so its depolarization overpowers the right ventricle on ECG
When analyzing an EKG - What wave represents atrial depolarization?
a) P wave
b) T wave
c) S wave
d) R wave
e) U wave
f) Q wave
a) P wave:
sinoatrial node in right atrium initiates atrial depolarization, producing P wave.
When analyzing an EKG - Which wave, segment, interval or complex represents septal depolarization?
a) QT interval
b) ST segment
c) T wave
d) Q wave
d) Q wave:
represents septal depolarization (about 25% amplitude of R wave)
When analyzing an EKG - Which wave, segment, interval or complex represents the repolarization of mid-myocardial cells?
a) U wave
b) PR segment
c) T wave
d) Q wave
a) U wave:
represents the repolarization of mid-myocardial cells; between endo and epicardium, and His-Purkinje system.
When analyzing an EKG - Which wave, segment, interval or complex represents the the final depolarization at the base (apex) of the heart?
a) U wave
b) PR segment
c) S wave
d) Q wave
c) S wave
When analyzing an EKG - Which wave, segment, interval or complex represents the period between the end of ventricular depolarization and the beginning of repolarization?
a) ST segment
b) PR segment
c) T wave
d) Q wave
a) ST segment:
from the J point/ST junction to beginning of T wave; period between the end of ventricular depolarization and beginning of repolarization
What do the x- and y-axis represent on an ECG paper?
X-axis = time (s)
Y-axis = amplitude of electric signal (mV)
On an EKG paper, where each small square is 1mm per side and the paper speed = 25 mm/s, how much time does 1 small square represent?
1 small square =0.04s on the x-axis
On an EKG paper, where each small square is 1mm per side and the paper speed = 25 mm/s, how much time does 1 large square represent?
(1 large square = 5 small squares)
1 large square = 0.2s
On an EKG paper, where each small square is 1mm per side and the paper speed = 25 mm/s, how many large squares are counted in 1 second.
5 large squares = 1 sec
How many mV’s are represented by 1 small square on standard EKG paper ( where 1 small square = 1mm)?
1 small square = 1mm = 0.1mV
(1.0mV = 10mm)
On an EKG paper, where each small square is 1mm per side and the paper speed = 25 mm/s, how many large squares equal 1.0mV?
2 large squares = 1.0mV
True or False: The P wave is measured only in seconds
False. the P wave is measured by both time (in seconds) and by amplitude (in mm / mV)
What is the normal range for the PR interval in ms?
PR Interval, normal: 0.12-0.20 seconds = 120-200 ms
What is the normal time range for QRS duration in ms?
0.06-0.10 seconds = 60-100 ms
What is the normal time and amplitude of the P wave? (in seconds and mm)
<0.12s, <2.5mm tall
What heart arrhythmias will P waves be absent?
Atrial Fibrillation and ventricular fibrillation
When someone has atrial fibrillation there HR will be between:
a) 60-100 bpm
b) 130-200 bpm
c) 100-180 bpm
c) 100-180 bpm (slower is possible)
Atrial Fibrillation:
irregular ventricular rhythm
atrial rhythm 300-600 bpm
What heart arrhythmia will have absent P waves, QRS duration and T waves?
Ventricular fibrillation:
chaotic inflections of amplitude
- VERY serious
- ventricles do not perform normal contractions; quiver, weak contractions; could be caused by insufficient venous return, heart damage, overdose, cardiomyopathies
What type of heart arrhythmia would be indicated by prolonged PR interval?
AV Heart Block:
1st Degree: prolonged >0.2s
2nd degree: lengthens progressively
3rd degree: constant, but prolonged
Premature ventricular contraction (PVC) is common and is mostly benign. When would a PVC be more concerning?
When a PVC appears with other arrhythmia(s), it may be concerning.
