Question 1

Which structure in the cardiac conduction system is responsible for initiating the fastest rate of electrical firing in the heart?

Accepted Answer

SA node

Question 2

During the rapid upstroke phase of the cardiac action potential, which ion's movement is primarily responsible for the increase in membrane potential?

Accepted Answer

Sodium ions moving into the cell

Question 3

A patient presents with a heart rate of 45 bpm and a normal P wave preceding each QRS complex. Which arrhythmia is most likely present?

Accepted Answer

Sinus bradycardia

Question 4

Which phase of the cardiac action potential is crucial for muscle contraction and is characterized by the influx of calcium ions?

Accepted Answer

Phase 2: plateau

Question 5

A 65-year-old patient is diagnosed with third-degree AV block. Which of the following best describes this condition?

Accepted Answer

No signals reach the ventricles, causing a very slow, irregular rhythm

Question 6

Which of the following is a common cause of disorders of cardiac conduction?

Accepted Answer

Congenital defects or degenerative changes

Question 7

A patient with paroxysmal supraventricular tachycardia (SVT) is most likely to experience which of the following symptoms?

Accepted Answer

Rapid heart rate, dizziness, and palpitations

Question 8

Which diagnostic method provides a continuous live feed of the heart's electrical activity to monitor for rhythm abnormalities?

Accepted Answer

Bedside cardiac monitoring (5-lead system)

Question 9

Which class of antiarrhythmic drugs acts by blocking the fast sodium channels?

Accepted Answer

Class I drugs

Question 10

A patient with ventricular fibrillation is found pulseless and unresponsive. What is the most immediate intervention required?

Accepted Answer

Immediate defibrillation

Question 11

Which of the following best describes the effect of improper lead placement during an ECG?

Accepted Answer

It can significantly change the QRS morphology and lead to misdiagnosis

Question 12

Which arrhythmia is characterized by a sawtooth pattern on ECG and a rapid atrial rate of 240-340 bpm?

Accepted Answer

Atrial flutter

Question 13

A patient with long QT syndrome is at increased risk for which life-threatening arrhythmia?

Accepted Answer

Torsades de Pointes

Question 14

Which of the following interventions is used to restore a regular heart rhythm by delivering an electrical shock to the heart?

Accepted Answer

Cardioversion

Question 15

During phase 3 of the cardiac action potential, which ion movement is primarily responsible for repolarization?

Accepted Answer

Potassium ions moving out of the cell

Question 16

Which of the following is a goal of continuous bedside cardiac monitoring?

Accepted Answer

To provide real-time detection of arrhythmias and ST segment changes

Question 17

A patient with stable ventricular tachycardia and a pulse is best treated initially with which intervention?

Accepted Answer

Antiarrhythmic medications

Question 18

Which of the following best describes the role of the sodium-potassium pump during the diastolic repolarization period?

Accepted Answer

It maintains the membrane potential at a negative value

Question 19

Which class of antiarrhythmic drugs acts by blocking the slow calcium channels, thereby depressing phase 4 and lengthening phases 1 and 2?

Accepted Answer

Class IV drugs

Question 20

A patient with atrial fibrillation is at increased risk for which complication, requiring anticoagulant therapy?

Accepted Answer

Thromboembolism

28 Patho

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