EKG/Cardiology and Resucitation Flashcards
Why is procainamide (Pronestyl) recommended in refractory wide complex tachycardia?
It prolongs QT Interval
Class 1a Antidysrhythmic
inhibits recovery after repolarization and prolongs the refractory period.
It prolongs the QT interval and may be successful in treating refractory SVT after adenosine fails to convert the rhythm.
administered at 20-50 mg/min until dysrhythmia ceases, hypotension occurs, or the QRS duration increases.
It is followed by a maintenance infusion of 1-4 mg/min.
The Bundle of Kent
the accessory pathway responsible for Delta waves in patients with Wolff-Parkinson-White (WPW)
Delta waves appear as the upstroke of the QRS and often have a slur, called the delta wave.
Due to preexcitation syndrome, the conduction of the depolarization impulse from the atria to the ventricles is abnormal in tachycardia.
The bundle of Kent, an extra conduction pathway between the atria and ventricles, effectively bypasses the AV node, shortening the PR interval and prolonging the QRS complex
Resulting in atrioventricular nodal re-entry tachycardia (AVNRT).
Dissections can occur anywhere along the aorta but most commonly begin in which region?
Thoracic aorta
Ascending aorta
Infrarenal abdominal aorta
Aortic root
Correct answer: Ascending aorta
Aortic dissections can begin anywhere in the aorta. The most common region is the ascending aorta, approximately two inches from the aortic valve.
The second most common location is the descending thoracic aorta, right above the left subclavian artery origin.
Dissections of the infrarenal abdominal aorta are rare.
The aortic root is not a common location for an aortic dissection but should still be suspected.
You suspect your patient is experiencing a HIGH lateral wall acute myocardial infarction. Which leads of the EKG are most likely to show evidence of the infarction?
II, III, aVF
I and aVL
V1 and V2
V5 and V6
Correct answer: I and aVL
High lateral MIs are seen in leads I and aVL.
V1 and V2 represent the intraventricular septum.
V5 and V6 show the low lateral wall
II, III, and aVF represent the inferior wall.
You suspect your patient is experiencing a LOW lateral wall acute myocardial infarction. Which leads of the EKG are most likely to show evidence of the infarction?
II, III, aVF
I and aVL
V1 and V2
V5 and V6
Correct answer: V5 and V6
LOW lateral MIs are seen in leads V5 and V6.
V1 and V2 represent the intraventricular septum.
I and aVL show the High lateral wall
II, III, and aVF represent the inferior wall.
Magnesium Sulfate
indicated for polymorhpic VT / Torsades de pointes
administered after an attempt at one unsynchronized shock
the correct dose is 1-2 g over 20 minutes.
Right Heart Failure
Commonly caused by left heart failure.
Right ventricular failure causes a backup of blood and fluid into the peripheral circulation.
Peripheral edema
JVD
Ascites
Enlarged liver
Left Heart Failure
Left ventricular failure is most commonly caused by myocardial infarction.
causes a backup of blood and fluid into the pulmonary circulation leading to pulmonary edema.
Canon A waves
Cannon A waves are produced by the dissociation between the atria and the ventricles.
They commonly occur with atrial contraction against a closed tricuspid valve.
A physical finding that is associated with the Cannon A waves is the depression of the jugular veins.
Which of the following can cause a 60 cycle interference artifact?
A patient using his smartphone
A patient breathing too deeply
A patient shaking uncontrollably
A broken wire
Correct answer: A patient using his smartphone
A 60 cycle interference is caused by electrical interference.
Somatic tremors are caused by patient tremors or anything that shakes the electric wires.
Baseline sways are related to a patient’s breathing pattern.
A broken recording is caused by a frayed or broken wire.
There are three types of EKG leads. Which type of leads are placed on the limbs, and contain only one positive pole?
Electrodes
Bipolar leads
Augmented leads
Precordial leads
Correct answer: Augmented leads
Augmented leads are unipolar leads that are placed on the limbs, while precordial leads are unipolar leads which are placed on the chest.
Bipolar leads contain a positive pole and a negative pole.
Electrodes are sensors that are placed on the patient’s skin.
If the sinus node is firing at a rate of 40 bpm, and the AV node fires at a rate of 60 bpm, what will result?
Escape
Cardiac arrest
Usurpation
Ventricular tachycardia
Correct answer: Escape
Escape occurs when the sinus node fails to fire at a normal rate, allowing the AV node to take over. Should the AV node fail, the ventricles would take over as the pacemaker.
Usurpation occurs when the cells of the lower pacemakers become irritable, taking control from the higher pacemaker. Ventricular tachycardia and cardiac arrest do not initially occur because of escape.
What is the correct way to calculate the heart rate of a regular rhythm with a pause?
Ignore the pause when calculating heart rate
Determine the mean and range of the heart rate
Use only the six-second strip method
Determine the mean only
Correct answer: Determine the mean and range of the heart rate
A pause greatly affects heart rate and cannot be ignored when calculating the rate.
The best way to calculate the rate of these rhythms is to determine the mean heart rate, as well as the range (slowest to fastest).
What occurs when one of the lower pacemakers begins to fire at an accelerated rate, and steals control from the predominate pacemaker?
Escape
Bradycardia
Usurpation
Junctional rhythm
Correct answer: Usurpation
Usurpation occurs when the cells of a lower pacemaker become irritable to take over the electrical impulse from the higher pacemaker.
The result is a higher than normal heart rate.
Escape is when the lower pacemaker takes control of the electrical impulse after the higher pacemaker fails.
Bradycardia is a rate of below 60 beats per minute.
A junctional rhythm is when electrical impulses begin specifically at the AV node and results in a narrow QRS complex.
Baseline sway, a type of artifact, can be caused by:
A patient experiencing tremors
A patient breathing deeply
A broken wire
A patient using their phone
Correct answer: A patient breathing deeply
Baseline sways are related to a patient’s breathing pattern.
Somatic tremors are caused by patient tremors or anything that shakes the electric wires.
A 60 cycle interference is caused by electrical interference.
A broken recording is caused by a frayed or broken wire.
You walk into your patient’s room to check the EKG machine and see that the cord has an exposed wire. The wire is not touching the patient. Which of the following is the correct action for you to take?
Cover the exposed wire with a piece of tape so it does not touch the patient
Call the unit’s biomechanical team to replace the wire
Immediately change the cord
No action is indicated, as the wire is not directly touching the patient’s skin
Correct answer: Immediately change the cord
Macroshocks and microshocks can be fatal; therefore, it is vital to change out any broken or frayed wires immediately to prevent harm to the patient.
Normal Axis Deviation
Positive QRS in both lead I and aVF
+90 to -30
Left Axis Deviation
positive QRS in Lead I & negative in aVF
-30 to -90
Right Axis Deviation
QRS AXIS
Lead I = negative
aVF = positive
+90 to +180
Extreme Axis Deviation
negative QRS in both Lead I and aVF
-90 to +180
What deflection on the P wave of the EKG represents LEFT atrial hypertrophy?
Increased amplitude of the second half of the P wave
Decreased duration of the entire P wave
Increased duration in the first half of the P wave
Increased amplitude of the first half of the P wave
Correct answer: Increased amplitude of the second half of the P wave
The second half of the P wave will increase in amplitude with left atrial hypertrophy.
In right atrial enlargement (or hypertrophy), the first half of the P wave will increase in amplitude.
What deflection on the P wave of the EKG represents RIGHT atrial hypertrophy?
Increased amplitude of the second half of the P wave
Decreased duration of the entire P wave
Increased duration in the first half of the P wave
Increased amplitude of the first half of the P wave
Correct answer: Increased amplitude of the first half of the P wave
With right atrial enlargement (or hypertrophy), the first half of the P wave will increase in amplitude.
The second half of the P wave will increase in amplitude with left atrial hypertrophy.
