#1
Which structure in the heart is responsible for initiating the electrical impulse?
SA node
ExplanationSA node initiates the electrical impulse in the heart's conduction system.
#2
What is the normal resting heart rate (beats per minute) initiated by the SA node?
60-100 bpm
ExplanationSA node typically initiates a resting heart rate of 60-100 beats per minute.
#3
Which part of the heart's conduction system delays the impulse briefly to allow the atria to contract before the ventricles?
AV node
ExplanationAV node delays the impulse to allow atrial contraction before ventricular contraction.
#4
Which ion plays a crucial role in the depolarization phase of the cardiac action potential?
Sodium (Na+)
ExplanationSodium (Na+) plays a crucial role in the depolarization phase of the cardiac action potential.
#5
What is the primary role of the AV node in the cardiac conduction system?
To delay the impulse briefly to allow the atria to contract before the ventricles
ExplanationAV node's primary role is to delay the impulse to allow atrial contraction before ventricular contraction.
#6
Which of the following is NOT a common site for ectopic pacemaker activity?
Bundle of His
ExplanationBundle of His is not a common site for ectopic pacemaker activity.
#7
What ECG characteristic is indicative of atrial fibrillation?
Absence of P waves
ExplanationAtrial fibrillation is indicated by the absence of P waves on the ECG.
#8
In atrial flutter, what is the typical atrial rate?
250-350 bpm
ExplanationIn atrial flutter, the typical atrial rate is 250-350 beats per minute.
#9
Which arrhythmia is characterized by a regular rhythm but with an absent QRS complex?
Asystole
ExplanationAsystole is characterized by a regular rhythm with an absent QRS complex.
#10
Which medication is commonly used for acute termination of supraventricular tachycardias (SVTs) such as AV nodal reentrant tachycardia (AVNRT)?
Adenosine
ExplanationAdenosine is commonly used for acute termination of SVTs like AVNRT.
#11
Which of the following is a potential complication of untreated atrial fibrillation?
Heart failure
ExplanationUntreated atrial fibrillation can lead to the potential complication of heart failure.
#12
What is the most common cause of ventricular tachycardia?
Myocardial infarction
ExplanationMyocardial infarction is the most common cause of ventricular tachycardia.
#13
Which electrolyte imbalance is associated with the development of torsades de pointes?
Hypomagnesemia
ExplanationHypomagnesemia is associated with the development of torsades de pointes.
#14
What is the most common type of supraventricular tachycardia (SVT)?
AV nodal reentrant tachycardia (AVNRT)
ExplanationAVNRT is the most common type of supraventricular tachycardia (SVT).
#15
What is the classic ECG finding in ventricular fibrillation?
Chaotic rhythm with irregular waves
ExplanationVentricular fibrillation is characterized by a chaotic rhythm with irregular waves on the ECG.
#16
What is the primary mechanism of action of beta-blockers in the treatment of arrhythmias?
Antagonism of beta-adrenergic receptors
ExplanationBeta-blockers work by antagonizing beta-adrenergic receptors in the treatment of arrhythmias.
#17
Which of the following is a characteristic feature of long QT syndrome?
Prolonged QT interval on ECG
ExplanationLong QT syndrome is characterized by a prolonged QT interval on the ECG.