#1
Which of the following is a common cause of first-degree atrioventricular (AV) block?
Hypokalemia
ExplanationLow potassium levels can disrupt the conduction system of the heart.
#2
What is Mobitz type I atrioventricular (AV) block commonly referred to as?
Wenckebach phenomenon
ExplanationProgressive prolongation of the PR interval until a beat is dropped.
#3
Which medication is commonly used to treat atrioventricular (AV) blocks by increasing heart rate?
Atropine
ExplanationAtropine blocks the action of the vagus nerve, increasing heart rate.
#4
Which of the following terms is used to describe a temporary cessation of cardiac electrical activity in a patient with atrioventricular (AV) block?
Cardiac arrest
ExplanationComplete stoppage of heart activity due to electrical malfunction.
#5
Which term is used to describe the phenomenon where there is a consistent ratio of P waves to QRS complexes in second-degree Mobitz type II atrioventricular (AV) block?
2:1 block
ExplanationFor every 2 P waves, only 1 is followed by a QRS complex.
#6
In second-degree atrioventricular (AV) block, what happens to the conducted impulses?
They are delayed but all reach the ventricles
ExplanationImpulses are delayed, but some still reach the ventricles.
#7
Which ECG finding is characteristic of third-degree atrioventricular (AV) block?
Complete dissociation between P waves and QRS complexes
ExplanationNo relationship between P waves and QRS complexes, indicating complete conduction block.
#8
Which of the following is a potential cause of high-degree atrioventricular (AV) block in a young, healthy individual?
Lyme disease
ExplanationLyme disease can cause inflammation of the heart's electrical system.
#9
What is the primary concern in a patient with complete heart block (third-degree atrioventricular (AV) block)?
Bradycardia and potential hemodynamic compromise
ExplanationComplete interruption of electrical signals can lead to dangerously slow heart rates and reduced blood flow.
#10
What is the most common cause of acquired third-degree atrioventricular (AV) block?
Ischemic heart disease
ExplanationPoor blood flow to the heart can damage the conduction system, causing third-degree block.
#11
Which term describes the phenomenon where a P wave is not followed by a QRS complex in the electrocardiogram (ECG) due to complete heart block?
Dropped beat
ExplanationFailure of electrical signals to reach the ventricles, resulting in missed heartbeats.
#12
What is the characteristic ECG pattern seen in Mobitz type I atrioventricular (AV) block?
Consistently prolonged PR interval
ExplanationGradual lengthening of time between atrial and ventricular contractions.
#13
Which type of atrioventricular (AV) block is often associated with an increased risk of developing complete heart block?
Second-degree AV block, Mobitz type II
ExplanationIntermittent blockages may progress to complete heart block.
#14
What is the most common cause of congenital complete heart block in infants?
Maternal autoimmune disease (e.g., lupus)
ExplanationAntibodies from the mother can cross the placenta, affecting the baby's heart.
#15
Which medication is often used to manage atrioventricular (AV) blocks associated with hyperkalemia?
Calcium gluconate
ExplanationCalcium can stabilize cell membranes in hyperkalemic states, improving conduction.
#16
What is a potential complication associated with high-degree atrioventricular (AV) block?
Syncope or sudden cardiac arrest
ExplanationSevere blockages can lead to loss of consciousness or sudden cardiac arrest.
#17
Which of the following medications may be used to manage symptomatic bradycardia in patients with atrioventricular (AV) block?
Epinephrine
ExplanationEpinephrine can increase heart rate and improve symptoms in bradycardic patients.
#18
Which electrocardiogram (ECG) finding is characteristic of Mobitz type II atrioventricular (AV) block?
Sudden block of a conducted impulse without PR interval changes
ExplanationIntermittent blocks of conduction without progressive prolongation of the PR interval.
#19
In patients with atrioventricular (AV) block, what is the role of a temporary pacemaker?
To temporarily support the heart's electrical activity
ExplanationTemporary pacemakers provide electrical impulses to maintain heart function until permanent treatment can be initiated.
#20
What is the primary goal of treatment in a patient with symptomatic second-degree Mobitz type II atrioventricular (AV) block?
Insert a permanent pacemaker
ExplanationTo ensure consistent electrical signals to the heart, a permanent pacemaker may be necessary.
#21
Which electrolyte imbalance is commonly associated with atrioventricular (AV) blocks?
Hypomagnesemia
ExplanationLow magnesium levels can disrupt normal heart rhythm and conduction.
#22
In patients with third-degree atrioventricular (AV) block, what is the recommended treatment?
Permanent pacemaker placement
ExplanationTo ensure consistent electrical signals, a permanent pacemaker is necessary.
#23
What is the potential consequence of untreated high-degree atrioventricular (AV) block over time?
Ventricular fibrillation
ExplanationSevere blockages can lead to chaotic heart rhythms and sudden cardiac death.
#24
What is the primary mechanism of action of atropine in the treatment of bradycardia associated with atrioventricular (AV) block?
Parasympathetic blockade
ExplanationAtropine inhibits the parasympathetic nervous system, increasing heart rate.
#25
What is the potential consequence of prolonged atrioventricular (AV) block on cardiac output?
Decreased cardiac output
ExplanationSlow heart rates can reduce the amount of blood pumped by the heart, decreasing overall cardiac output.