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SHARP EKG/ ECG Exam (Latest 2026/ 2027
Update) 100% Verified Questions & Answers |
Direct Credit A+
What are the two basic kinds of cardiac cells?
1. myocardial muscle cells
2. myocardial pacemaker cells
What are the 4 primary cell characteristics?
1. Automaticity
2. Excitability
3. Conductivity
4. Contractility
What are the two major ions that affect cardiac function?
1. sodium
2. potassium
What are the primary ions inside the cell?
Potassium
What are the primary ions outside the cell?
Sodium
Distribution of ions on either side of the membrane is determined by which several factors?
1. membrane channels
2. concentration gradient
3. electrical gradient
4. sodium-potassium pump
Where is the SA node located?
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?
60-100 bpm
Pacemaker cells in the AV junction generate electrical impulses at what rate?
40-60 bpm
,What are the 3 functions of the AV node?
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?
To the bundle of His
What is the function of the bundle of His?
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?
30-40 bpm
What does the P wave represent?
atrial depolarization
When does atrial repolarization occur?
during the QRS complex
What does the QRS wave represent?
ventricular depolarization
What does the ST segment represent?
early ventricular repolarization
What does the T wave represent?
ventricular repolarization
What does the QT interval represent?
the time of ventricular activity including both depolarization and repolarization
What are the two refectory phases of the cardiac cycle?
1. Absolute refractory period
2. Relative refractory period
What is "absolute refractory period"?
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"?
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?
0.04
A big square on EKG paper is how long?
0.2
How long is a P wave?
< .10
What is the duration of the PR interval?
0.12-0.20
What is the duration of the QRS?
< .10
What are some causes of a abnormally wide QRS?
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?
1. STEMI
2. Coronary artery spasm (Printzmetal angina)
3. hyperkalemia
4. hypothermia
5. ventricular aneurysm
What are some causes of ST depression?
1) NSTEMI
2) Digoxin
3) Hypokalemia
4) RBBB or LBBB
5) RVH or LVH
What causes abnormal T waves? (7)
1. myocardial ischemia
2. acute MI
3. hyperkalemia
SHARP EKG/ ECG Exam (Latest 2026/ 2027
Update) 100% Verified Questions & Answers |
Direct Credit A+
What are the two basic kinds of cardiac cells?
1. myocardial muscle cells
2. myocardial pacemaker cells
What are the 4 primary cell characteristics?
1. Automaticity
2. Excitability
3. Conductivity
4. Contractility
What are the two major ions that affect cardiac function?
1. sodium
2. potassium
What are the primary ions inside the cell?
Potassium
What are the primary ions outside the cell?
Sodium
Distribution of ions on either side of the membrane is determined by which several factors?
1. membrane channels
2. concentration gradient
3. electrical gradient
4. sodium-potassium pump
Where is the SA node located?
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?
60-100 bpm
Pacemaker cells in the AV junction generate electrical impulses at what rate?
40-60 bpm
,What are the 3 functions of the AV node?
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?
To the bundle of His
What is the function of the bundle of His?
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?
30-40 bpm
What does the P wave represent?
atrial depolarization
When does atrial repolarization occur?
during the QRS complex
What does the QRS wave represent?
ventricular depolarization
What does the ST segment represent?
early ventricular repolarization
What does the T wave represent?
ventricular repolarization
What does the QT interval represent?
the time of ventricular activity including both depolarization and repolarization
What are the two refectory phases of the cardiac cycle?
1. Absolute refractory period
2. Relative refractory period
What is "absolute refractory period"?
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"?
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?
0.04
A big square on EKG paper is how long?
0.2
How long is a P wave?
< .10
What is the duration of the PR interval?
0.12-0.20
What is the duration of the QRS?
< .10
What are some causes of a abnormally wide QRS?
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?
1. STEMI
2. Coronary artery spasm (Printzmetal angina)
3. hyperkalemia
4. hypothermia
5. ventricular aneurysm
What are some causes of ST depression?
1) NSTEMI
2) Digoxin
3) Hypokalemia
4) RBBB or LBBB
5) RVH or LVH
What causes abnormal T waves? (7)
1. myocardial ischemia
2. acute MI
3. hyperkalemia
