Conduction Blocks

Question 1 A patient with a known history of second-degree AV block Type II is admitted to the emergency department. Which symptom would be the most concerning? • A. Occasional dizziness • B. Intermittent fatigue • C. Syncope (fainting) • D. Palpitations Answer: C. Syncope (fainting) • Rationale: Syncope can indicate that the heart is not able to maintain adequate output due to the conduction delay in second-degree AV block Type II. This block can progress to complete heart block, so syncope is concerning and requires prompt evaluation and intervention. ________________________________________ Question 2 Which characteristic is typically seen on an ECG of a patient with a first-degree AV block? • A. Irregular PR intervals • B. Progressive lengthening of the PR interval until a QRS complex is dropped • C. Prolonged PR interval with each P wave followed by a QRS complex • D. Two consecutive P waves without a QRS complex Answer: C. Prolonged PR interval with each P wave followed by a QRS complex • Rationale: A first-degree AV block is identified by a consistently prolonged PR interval, but each P wave is still followed by a QRS complex, indicating that conduction is delayed but not blocked. ________________________________________ Question 3 A 68-year-old patient with a third-degree (complete) heart block may exhibit which of the following symptoms? • A. Tachycardia • B. Confusion and fatigue • C. Hypertension • D. Headache Answer: B. Confusion and fatigue • Rationale: In third-degree heart block, there is complete dissociation between atrial and ventricular rhythms, leading to decreased cardiac output. This often results in symptoms such as confusion, fatigue, dizziness, and syncope. ________________________________________ Question 4 In managing a patient with symptomatic bradycardia due to a second-degree AV block Type II, what intervention is most likely to be used? • A. Administering atropine • B. Initiating transcutaneous pacing • C. Increasing the rate of IV fluids • D. Applying an ice pack to the chest Answer: B. Initiating transcutaneous pacing • Rationale: Transcutaneous pacing is often necessary for symptomatic bradycardia in second-degree AV block Type II, as this block can quickly progress to a complete heart block. Atropine may not be effective in this type of block. ________________________________________ Question 5 Which type of AV block is sometimes referred to as “Mobitz I”? • A. First-degree AV block • B. Second-degree AV block, Type I • C. Second-degree AV block, Type II • D. Third-degree AV block Answer: B. Second-degree AV block, Type I • Rationale: Second-degree AV block, Type I, is also called Mobitz I or Wenckebach block. It is characterized by a progressively lengthening PR interval until a QRS complex is eventually dropped. ________________________________________ Question 6 What is the key difference between a second-degree AV block Type I and Type II? • A. Type I has a constant PR interval, whereas Type II has a variable PR interval • B. Type I typically progresses to third-degree AV block, whereas Type II does not • C. Type II has a constant PR interval, whereas Type I shows progressive prolongation of the PR interval • D. Type II is characterized by a consistently narrow QRS complex Answer: C. Type II has a constant PR interval, whereas Type I shows progressive prolongation of the PR interval • Rationale: In second-degree AV block Type I (Mobitz I), the PR interval progressively lengthens until a QRS is dropped. In Type II, the PR interval is constant, but occasional P waves are not followed by QRS complexes. ________________________________________ Question 7 In third-degree (complete) heart block, the ECG reveals: • A. Consistent PR intervals and missed QRS complexes • B. Complete dissociation between P waves and QRS complexes • C. A progressive lengthening of the PR interval • D. A bundle branch block pattern Answer: B. Complete dissociation between P waves and QRS complexes • Rationale: In complete heart block, atria and ventricles beat independently, so there is no predictable relationship between P waves and QRS complexes. ________________________________________ Question 8 A patient with a first-degree AV block is asymptomatic. What is the most appropriate nursing intervention? • A. Administer atropine IV • B. Prepare for immediate pacing • C. Monitor and document the rhythm • D. Place the patient on a beta-blocker Answer: C. Monitor and document the rhythm • Rationale: First-degree AV block typically does not cause symptoms and does not require intervention. Monitoring is usually sufficient unless the block progresses or the patient becomes symptomatic. ________________________________________ Question 9 A 72-year-old patient with known conduction issues reports increased fatigue. The ECG shows a 2:1 AV conduction ratio. Which block type is this? • A. First-degree AV block • B. Second-degree AV block Type II • C. Second-degree AV block Type I • D. Third-degree AV block Answer: B. Second-degree AV block Type II • Rationale: A 2:1 AV conduction block suggests that every other P wave fails to conduct to the ventricles, a characteristic of second-degree AV block Type II, which can lead to decreased cardiac output and fatigue. ________________________________________ Question 10 In a patient with third-degree heart block, what primary treatment should the nurse anticipate? • A. Administration of a diuretic • B. Transcutaneous or transvenous pacing • C. Administration of an anticoagulant • D. Increase in IV fluids Answer: B. Transcutaneous or transvenous pacing • Rationale: Third-degree heart block requires pacing, as the ventricles are not receiving regular impulses from the atria. Temporary pacing is often used until a permanent pacemaker can be implanted if needed.