SHARP EKG Exam Questions with
Correct Answers
What are the two basic kinds of cardiac cells? - Answer-1. myocardial muscle cells
2. myocardial pacemaker cells
What are the 4 primary cell characteristics? - Answer-1. Automaticity
2. Excitability
3. Conductivity
4. Contractility
What are the two major ions that affect cardiac function? - Answer-1. sodium
2. potassium
What are the primary ions inside the cell? - Answer-Potassium
What are the primary ions outside the cell? - Answer-Sodium
Distribution of ions on either side of the membrane is determined by which several
factors? - Answer-1. membrane channels
2. concentration gradient
3. electrical gradient
4. sodium-potassium pump
Where is the SA node located? - Answer-In the upper wall of the right atrium/near the
inlet of the superior vena cava
What is the intrinsic rate of the SA node? - Answer-60-100 bpm
Pacemaker cells in the AV junction generate electrical impulses at what rate? - Answer-
40-60 bpm
What are the 3 functions of the AV node? - Answer-1. slow conduction of the electrical
impulse through the AV node to allow atria to empty into the ventricles (atrial kick)
2. to serve as a back pack pacemaker
3. protect ventricles from fast rates
After the delay in the AV node, where does the impulse go? - Answer-To the bundle of
His
What is the function of the bundle of His? - Answer-The Bundle of His (AV Bundle) runs
from the AV node through the IV septum, splitting into R. and L. branches and
eventually breaking into Purkinje fibers as it spreads through the ventricular walls
,What is the rate of electrical impulse the Purkinje Fibers have? - Answer-30-40 bpm
What does the P wave represent? - Answer-atrial depolarization
When does atrial repolarization occur? - Answer-during the QRS complex
What does the QRS wave represent? - Answer-ventricular depolarization
What does the ST segment represent? - Answer-early ventricular repolarization
What does the T wave represent? - Answer-ventricular repolarization
What does the QT interval represent? - Answer-the time of *ventricular activity*
including both depolarization and repolarization
What are the two refectory phases of the cardiac cycle? - Answer-1. Absolute refractory
period
2. Relative refractory period
What is "absolute refractory period"? - Answer-The cardiac cells are unable to respond
to an electrical stimulus (from the onset of the QRS to the peak of the T wave)
What is the "relative refractory period"? - Answer-The cardiac cells have depolarized
sufficiently to respond to a strong stimulus (peak of T wave to end of T wave)
A small square on EKG paper is how long? - Answer-0.04
A big square on EKG paper is how long? - Answer-0.2
How long is a P wave? - Answer-< .10
What is the duration of the PR interval? - Answer-0.12-0.20
What is the duration of the QRS? - Answer-< .10
What are some causes of a abnormally wide QRS? - Answer-1. a electrical impulse that
originated in an ectopic site in the ventricles
2. BBB
3. an electrical impulse that went thru a accessory conduction pathway that bypasses
the AV node
What are some causes of a ST elevation? - Answer-1. STEMI
2. Coronary artery spasm (Printzmetal angina)
3. hyperkalemia
4. hypothermia
5. ventricular aneurysm
, What are some causes of ST depression? - Answer-1) NSTEMI
2) Digoxin
3) Hypokalemia
4) RBBB or LBBB
5) RVH or LVH
What causes abnormal T waves? (7) - Answer-1. myocardial ischemia
2. acute MI
3. hyperkalemia
4. pericarditis
5. BBB
6. subarachnoid hemorrhage
7. ventricular enlargement
How long should a normal QT interval be? - Answer-Half of a R-R interval
What is hard-wire monitoring? - Answer-Uses a three lead or five lead system
How is a 5-lead placed on the chest? - Answer-1. one is placed below the right clavicle
at 2nd interspace/right midclavicular line
2. one is place below the left clavicle at 2nd interspace/left midclavicular line
3. one on right lower rib cage (8th interspace/right misclavicular line)
4. one on the left lower rib cage (8th interspace/left midclavicular line)
5. one in the chest lead
What is telemetry monitoring? - Answer-observation of a patient's HR and rhythm at a
site distant from the patient
What is a sinus block? - Answer-Occasionally absent P wave associated with a loss of
QRS complex for that beat (resume on time after pause)
What is a sinus arrest? - Answer-basic rhythm doesn't resume on time after pause
What are the three basic mechanisms responsible for ectopic beats? - Answer-1.
altered automaticity
2. triggered activity
3. reentry
Where do atrial arrhythmias originate from? - Answer-Ectopic sites in the atria
Ectopic P waves in slower atrial rhythms (name the rhythms and the characteristics of
the P wave) - Answer-PAC & WAP
-small, pointed and upright
-small squiggle
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