#1
Which of the following is a characteristic of sinus rhythm?
Regular rhythm with P wave preceding each QRS complex
Irregular rhythm with absence of P waves
Absence of QRS complexes
Wide QRS complexes with peaked T waves
#2
Which ECG lead is commonly used to diagnose inferior wall myocardial infarction?
Lead I
Lead II
Lead III
Lead aVR
#3
Which of the following is NOT a risk factor for the development of atrial fibrillation?
Hypertension
Hyperthyroidism
Bradycardia
Obesity
#4
What is the typical heart rate range in patients with atrial fibrillation?
60-100 bpm
100-150 bpm
150-250 bpm
250-350 bpm
#5
Which arrhythmia is characterized by sudden onset and offset, typically lasting less than 30 seconds?
Atrial flutter
Paroxysmal supraventricular tachycardia
Atrial fibrillation
Ventricular tachycardia
#6
A patient presents with a regular rhythm of 150 bpm, absent P waves, and narrow QRS complexes. What arrhythmia is most likely?
Atrial fibrillation
Ventricular tachycardia
Atrial flutter
Supraventricular tachycardia
#7
What is the mechanism of action of Class III antiarrhythmic drugs?
Blocking sodium channels
Prolonging action potential duration by blocking potassium channels
Blocking beta-adrenergic receptors
Blocking calcium channels
#8
Which electrolyte imbalance is commonly associated with the development of torsades de pointes?
Hypocalcemia
Hyperkalemia
Hypomagnesemia
Hypernatremia
#9
In which type of heart block does the PR interval progressively lengthen until a QRS complex is dropped?
First-degree AV block
Second-degree AV block, type I (Wenckebach)
Second-degree AV block, type II
Third-degree AV block
#10
What is the treatment of choice for a patient with stable monomorphic ventricular tachycardia?
Synchronized cardioversion
Defibrillation
Amiodarone or lidocaine
Adenosine
#11
Which of the following ECG findings is characteristic of ventricular fibrillation?
Absence of P waves
Regular R-R intervals
Sawtooth-shaped waves
Chaotic, irregular rhythm without discernible QRS complexes
#12
Which arrhythmia is characterized by an absence of both P waves and QRS complexes?
Atrial fibrillation
Ventricular fibrillation
Sinus bradycardia
Asystole
#13
What is the hallmark characteristic of Mobitz II (Second-degree AV block, type II)?
Progressively lengthening PR interval until a QRS complex is dropped
Intermittent failure of atrial impulses to conduct to the ventricles
Fixed PR interval with occasional dropped QRS complexes
Consistent PR interval with varying R-R intervals
#14
What is the primary mechanism of action of adenosine in the treatment of supraventricular tachycardia?
Blockade of calcium channels
Prolongation of the action potential duration
Activation of potassium channels
Inhibition of AV node conduction
#15
Which medication is contraindicated in patients with atrial fibrillation and Wolff-Parkinson-White syndrome due to risk of ventricular fibrillation?
Adenosine
Procainamide
Amiodarone
Verapamil