SHARP EKG EXAM WITH COMPLETE
SOLUTIONS
What are the two basic kinds of cardiac cells? -ANS1. myocardial muscle cells
2. myocardial pacemaker cells
What are the 4 primary cell characteristics? -ANS1. Automaticity
2. Excitability
3. Conductivity
4. Contractility
What are the two major ions that affect cardiac function? -ANS1. sodium
2. potassium
What are the primary ions inside the cell? -ANSPotassium
What are the primary ions outside the cell? -ANSSodium
Distribution of ions on either side of the membrane is determined by which several
factors? -ANS1. membrane channels
2. concentration gradient
3. electrical gradient
4. sodium-potassium pump
Where is the SA node located? -ANSIn the upper wall of the right atrium/near the inlet
of the superior vena cava
What is the intrinsic rate of the SA node? -ANS60-100 bpm
Pacemaker cells in the AV junction generate electrical impulses at what rate? -ANS40-
60 bpm
What are the 3 functions of the AV node? -ANS1. 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? -ANSTo the bundle of His
What is the function of the bundle of His? -ANSThe 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? -ANS30-40 bpm
What does the P wave represent? -ANSatrial depolarization
When does atrial repolarization occur? -ANSduring the QRS complex
What does the QRS wave represent? -ANSventricular depolarization
What does the ST segment represent? -ANSearly ventricular repolarization
What does the T wave represent? -ANSventricular repolarization
What does the QT interval represent? -ANSthe time of *ventricular activity* including
both depolarization and repolarization
What are the two refectory phases of the cardiac cycle? -ANS1. Absolute refractory
period
2. Relative refractory period
What is "absolute refractory period"? -ANSThe 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"? -ANSThe 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? -ANS0.04
A big square on EKG paper is how long? -ANS0.2
How long is a P wave? -ANS< .10
What is the duration of the PR interval? -ANS0.12-0.20
What is the duration of the QRS? -ANS< .10
What are some causes of a abnormally wide QRS? -ANS1. 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? -ANS1. STEMI
2. Coronary artery spasm (Printzmetal angina)
3. hyperkalemia
4. hypothermia
5. ventricular aneurysm
,What are some causes of ST depression? -ANS1) NSTEMI
2) Digoxin
3) Hypokalemia
4) RBBB or LBBB
5) RVH or LVH
What causes abnormal T waves? (7) -ANS1. 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? -ANSHalf of a R-R interval
What is hard-wire monitoring? -ANSUses a three lead or five lead system
How is a 5-lead placed on the chest? -ANS1. 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? -ANSobservation of a patient's HR and rhythm at a site
distant from the patient
What is a sinus block? -ANSOccasionally absent P wave associated with a loss of QRS
complex for that beat (resume on time after pause)
What is a sinus arrest? -ANSbasic rhythm doesn't resume on time after pause
What are the three basic mechanisms responsible for ectopic beats? -ANS1. altered
automaticity
2. triggered activity
3. reentry
Where do atrial arrhythmias originate from? -ANSEctopic sites in the atria
Ectopic P waves in slower atrial rhythms (name the rhythms and the characteristics of
the P wave) -ANSPAC & WAP
-small, pointed and upright
-small squiggle
, Ectopic P waves in faster atrial rhythms (name the rhythms and the characteristics of
the P wave) -ANSatrial tachycardia and atrial flutter
-P wave is superimposed on the preceding T wave
Where is the ectopic site for WAP? -ANSRight middle
Where is the ectopic site for PAC? -ANSFurthest R side
Where is the ectopic site for Non-conducted premature atrial contraction? -ANSLower R
atria
Where is the ectopic site for PAT? -ANSL upper site
Where is the ectopic site for atrial flutter? -ANSFurthest L side
Where is the ectopic site for atrial fibrillation? -ANSLower L side
What is WAP? -ANSOccurs when the pacemaker site shifts back and forth between the
sinus node and ectopic atrial sites
-P-wave morphology will vary across the rhythm strip as the pacemaker "wanders"
between multiple sites.
What is WAP usually a result of? -ANSIncreased vagal effect on the SA node, slowing
the sinus rate and allowing other pacemaker sites an opportunity to compete for control
of the HR
When WAP is associated with a HR greater than >100, what is the rhythm called? -
ANSMutlifocal atrial tachycardia
(MAT)
What is a PAC? -ANSA premature atrial contraction is an early beat originating from an
ectopic pacemaker site in the atria.
-the premature beat is characterized by a premature, abnormal P wave follows dby a
normal duration QRS and pause
What is a the P-wave morphology for a PAC? -ANS1. If a PAC is near the vicinity of the
SA node - it may resemble a normal sinus P-wave w/ its only distinguishing feature a
prematurity
2. If near the AV junction, the P-wave is a generally upright and pointed/inverted
3. if PAC extremely early, P-wave hidden in T-wave
What does the QRS complex look like in a PAC? -ANSResembles that of the underlying
rhythm because the impulse is conducted normally through the bundle branches into
the ventricles
What is a PAC with a wide QRS called? -ANSPAC with aberrancy
SOLUTIONS
What are the two basic kinds of cardiac cells? -ANS1. myocardial muscle cells
2. myocardial pacemaker cells
What are the 4 primary cell characteristics? -ANS1. Automaticity
2. Excitability
3. Conductivity
4. Contractility
What are the two major ions that affect cardiac function? -ANS1. sodium
2. potassium
What are the primary ions inside the cell? -ANSPotassium
What are the primary ions outside the cell? -ANSSodium
Distribution of ions on either side of the membrane is determined by which several
factors? -ANS1. membrane channels
2. concentration gradient
3. electrical gradient
4. sodium-potassium pump
Where is the SA node located? -ANSIn the upper wall of the right atrium/near the inlet
of the superior vena cava
What is the intrinsic rate of the SA node? -ANS60-100 bpm
Pacemaker cells in the AV junction generate electrical impulses at what rate? -ANS40-
60 bpm
What are the 3 functions of the AV node? -ANS1. 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? -ANSTo the bundle of His
What is the function of the bundle of His? -ANSThe 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? -ANS30-40 bpm
What does the P wave represent? -ANSatrial depolarization
When does atrial repolarization occur? -ANSduring the QRS complex
What does the QRS wave represent? -ANSventricular depolarization
What does the ST segment represent? -ANSearly ventricular repolarization
What does the T wave represent? -ANSventricular repolarization
What does the QT interval represent? -ANSthe time of *ventricular activity* including
both depolarization and repolarization
What are the two refectory phases of the cardiac cycle? -ANS1. Absolute refractory
period
2. Relative refractory period
What is "absolute refractory period"? -ANSThe 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"? -ANSThe 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? -ANS0.04
A big square on EKG paper is how long? -ANS0.2
How long is a P wave? -ANS< .10
What is the duration of the PR interval? -ANS0.12-0.20
What is the duration of the QRS? -ANS< .10
What are some causes of a abnormally wide QRS? -ANS1. 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? -ANS1. STEMI
2. Coronary artery spasm (Printzmetal angina)
3. hyperkalemia
4. hypothermia
5. ventricular aneurysm
,What are some causes of ST depression? -ANS1) NSTEMI
2) Digoxin
3) Hypokalemia
4) RBBB or LBBB
5) RVH or LVH
What causes abnormal T waves? (7) -ANS1. 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? -ANSHalf of a R-R interval
What is hard-wire monitoring? -ANSUses a three lead or five lead system
How is a 5-lead placed on the chest? -ANS1. 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? -ANSobservation of a patient's HR and rhythm at a site
distant from the patient
What is a sinus block? -ANSOccasionally absent P wave associated with a loss of QRS
complex for that beat (resume on time after pause)
What is a sinus arrest? -ANSbasic rhythm doesn't resume on time after pause
What are the three basic mechanisms responsible for ectopic beats? -ANS1. altered
automaticity
2. triggered activity
3. reentry
Where do atrial arrhythmias originate from? -ANSEctopic sites in the atria
Ectopic P waves in slower atrial rhythms (name the rhythms and the characteristics of
the P wave) -ANSPAC & WAP
-small, pointed and upright
-small squiggle
, Ectopic P waves in faster atrial rhythms (name the rhythms and the characteristics of
the P wave) -ANSatrial tachycardia and atrial flutter
-P wave is superimposed on the preceding T wave
Where is the ectopic site for WAP? -ANSRight middle
Where is the ectopic site for PAC? -ANSFurthest R side
Where is the ectopic site for Non-conducted premature atrial contraction? -ANSLower R
atria
Where is the ectopic site for PAT? -ANSL upper site
Where is the ectopic site for atrial flutter? -ANSFurthest L side
Where is the ectopic site for atrial fibrillation? -ANSLower L side
What is WAP? -ANSOccurs when the pacemaker site shifts back and forth between the
sinus node and ectopic atrial sites
-P-wave morphology will vary across the rhythm strip as the pacemaker "wanders"
between multiple sites.
What is WAP usually a result of? -ANSIncreased vagal effect on the SA node, slowing
the sinus rate and allowing other pacemaker sites an opportunity to compete for control
of the HR
When WAP is associated with a HR greater than >100, what is the rhythm called? -
ANSMutlifocal atrial tachycardia
(MAT)
What is a PAC? -ANSA premature atrial contraction is an early beat originating from an
ectopic pacemaker site in the atria.
-the premature beat is characterized by a premature, abnormal P wave follows dby a
normal duration QRS and pause
What is a the P-wave morphology for a PAC? -ANS1. If a PAC is near the vicinity of the
SA node - it may resemble a normal sinus P-wave w/ its only distinguishing feature a
prematurity
2. If near the AV junction, the P-wave is a generally upright and pointed/inverted
3. if PAC extremely early, P-wave hidden in T-wave
What does the QRS complex look like in a PAC? -ANSResembles that of the underlying
rhythm because the impulse is conducted normally through the bundle branches into
the ventricles
What is a PAC with a wide QRS called? -ANSPAC with aberrancy
