PCP Cardiac Care and ECG 2 — Questions and Answers
Question 1: Atrial fibrillation on an ECG is characterized by:
- Regular RR intervals with saw-tooth baseline
- Irregularly irregular RR intervals with fibrillatory baseline and no distinct P waves (Correct answer)
- Regular P waves with constant PR interval
- Wide QRS complexes at a rate of 300 bpm
Correct answer: Irregularly irregular RR intervals with fibrillatory baseline and no distinct P waves
Atrial fibrillation shows an irregularly irregular ventricular response with fibrillatory (chaotic) baseline replacing distinct P waves.
Question 2: The classic ECG finding in hyperkalemia is:
- Prolonged QT interval and U waves
- Peaked (tent-shaped) T waves and widened QRS (Correct answer)
- ST elevation in all leads
- Short PR interval and delta waves
Correct answer: Peaked (tent-shaped) T waves and widened QRS
Hyperkalemia progressively causes peaked T waves, PR prolongation, widened QRS, and can degrade to sine-wave pattern and cardiac arrest.
Question 3: A delta wave on an ECG is associated with which condition?
- Brugada syndrome
- Wolff-Parkinson-White (WPW) syndrome (Correct answer)
- Hypertrophic cardiomyopathy
- Long QT syndrome
Correct answer: Wolff-Parkinson-White (WPW) syndrome
A delta wave (slurred QRS upstroke) indicates ventricular pre-excitation via an accessory pathway, characteristic of WPW syndrome.
Question 4: The energy used for defibrillation of ventricular fibrillation with a biphasic defibrillator is:
- 50 J
- 100 J
- 200 J (Correct answer)
- 360 J (monophasic equivalent)
Correct answer: 200 J
Biphasic defibrillation for VF/pulseless VT typically starts at 200 J (or manufacturer's recommendation).
Question 5: Pulseless electrical activity (PEA) is defined as:
- Ventricular fibrillation without a palpable pulse
- Organized ECG activity without a palpable pulse (Correct answer)
- Complete cardiac asystole
- Ventricular tachycardia with a BP of 70 mmHg
Correct answer: Organized ECG activity without a palpable pulse
PEA is organized (or semi-organized) electrical activity on the monitor in the absence of a palpable pulse.
Question 6: Which reversible cause of PEA is indicated by distended neck veins, absent breath sounds, and tracheal deviation?
- Hypovolemia
- Hypothermia
- Tension pneumothorax (Correct answer)
- Tamponade
Correct answer: Tension pneumothorax
Tension pneumothorax causes PEA with distended neck veins, absent unilateral breath sounds, and tracheal deviation away from the affected side.
PCP Cardiac Care and ECG 2
Atrial fibrillation on an ECG is characterized by: