HOAG ECG EXAM PRACTICE QUESTIONS COMPLETE WITH 100% VERIFIED ANSWERS

HOAG ECG EXAM PRACTICE QUESTIONS COMPLETE WITH 100% VERIFIED ANSWERS Question 1 What is the normal firing rate of the SA node? A) 20-40 bpm B) 40-60 bpm C) 60-100 bpm D) 100-150 bpm Correct Answer: C Rationale: The SA node is the primary pacemaker of the heart with an inherent firing rate of 60-100 beats per minute. If the SA node fails, secondary pacemakers take over with progressively slower rates. ________________________________________ Question 2 How many small boxes are in one large box on EKG grid paper? A) 3 B) 4 C) 5 D) 6 Correct Answer: C Rationale: Each small box represents 0.04 seconds, and each large box contains 5 small boxes, representing 0.20 seconds. This relationship is fundamental for calculating heart rate and interval measurements. ________________________________________ Question 3 An EKG strip shows no P waves, an irregularly irregular rhythm, and a chaotic baseline. The ventricular rate is 140 bpm. What is the rhythm? A) Atrial Flutter B) Ventricular Tachycardia C) Atrial Fibrillation with Rapid Ventricular Response D) Sinus Tachycardia Correct Answer: C Rationale: Atrial Fibrillation is characterized by absence of discernible P waves, an irregularly irregular ventricular response, and a chaotic baseline. With a rate of 140 bpm, this is classified as rapid ventricular response. ________________________________________ Question 4 What is the normal duration of the PR interval? A) 0.04-0.08 seconds B) 0.08-0.12 seconds C) 0.12-0.20 seconds D) 0.20-0.28 seconds Correct Answer: C Rationale: The PR interval represents the time from the beginning of atrial depolarization to the beginning of ventricular depolarization. Normal duration is 0.12-0.20 seconds (3-5 small boxes). ________________________________________ Question 5 Which medication is known to prolong the QT interval? A) Aspirin B) Metoprolol C) Haldol D) Lisinopril Correct Answer: C Rationale: Haldol (haloperidol) is one of several medications that can prolong the QT interval, increasing the risk of torsades de pointes. Other QT-prolonging medications include Tikosyn (dofetilide) and Amiodarone. ________________________________________ Question 6 A pacemaker spike appears just before the QRS complex but no P wave is visible. What type of pacing is this? A) Atrial pacing B) Ventricular pacing C) Dual chamber pacing D) Biventricular pacing Correct Answer: B Rationale: Ventricular pacing is identified by a pacing spike that appears immediately before the QRS complex. The spike triggers depolarization directly in the ventricles, bypassing the normal conduction pathway. ________________________________________ Question 7 What is the normal QRS complex duration? A) 0.02-0.06 seconds B) 0.04-0.12 seconds C) 0.12-0.16 seconds D) 0.16-0.20 seconds Correct Answer: B Rationale: The QRS complex represents ventricular depolarization. Normal duration is 0.04-0.12 seconds (1-3 small boxes). QRS duration greater than 0.12 seconds indicates a bundle branch block or ventricular origin rhythm. ________________________________________ Question 8 A 6-second rhythm strip shows 8 QRS complexes. What is the approximate heart rate? A) 60 bpm B) 70 bpm C) 80 bpm D) 90 bpm Correct Answer: C Rationale: To calculate heart rate from a 6-second strip, count the number of QRS complexes in the strip and multiply by 10. 8 complexes × 10 = 80 beats per minute. ________________________________________ Question 9 The order of the cardiac conduction pathway is: A) AV node → SA node → Bundle of His → Bundle Branches → Purkinje fibers