CPEN Cardiac Emergencies 4 — Questions and Answers
Question 1: A newborn presents with cyanosis unresponsive to supplemental oxygen, a single S2, and 'egg-on-a-string' cardiac silhouette on CXR. The most likely diagnosis is:
- Tetralogy of Fallot
- Transposition of the great arteries (Correct answer)
- Tricuspid atresia
- Total anomalous pulmonary venous return
Correct answer: Transposition of the great arteries
Transposition of the great arteries (TGA) causes profound cyanosis unresponsive to O2, a narrow mediastinum, and the classic 'egg-on-a-string' X-ray appearance.
Question 2: Which prostaglandin is used to maintain ductal patency in a neonate with a duct-dependent congenital heart defect?
- Prostaglandin E2 (dinoprostone)
- Prostaglandin E1 (alprostadil) (Correct answer)
- Prostaglandin F2α
- Prostaglandin I2 (prostacyclin)
Correct answer: Prostaglandin E1 (alprostadil)
Prostaglandin E1 (PGE1/alprostadil) keeps the ductus arteriosus open in neonates with duct-dependent congenital heart lesions.
Question 3: A 'tet spell' in a child with Tetralogy of Fallot is best initially managed by:
- Placing the child supine and giving supplemental oxygen
- Placing in knee-chest position, giving morphine, and supplemental oxygen (Correct answer)
- Administering IV adenosine and observing
- Immediate synchronized cardioversion
Correct answer: Placing in knee-chest position, giving morphine, and supplemental oxygen
Knee-chest position increases SVR, morphine reduces hyperpnea and infundibular spasm, and oxygen helps — together these abort the hypercyanotic episode.
Question 4: Which ECG finding is characteristic of hyperkalemia that can directly cause cardiac arrest?
- Prolonged QT interval
- Delta waves
- Peaked T waves progressing to sine wave pattern (Correct answer)
- ST-segment elevation in V1–V2
Correct answer: Peaked T waves progressing to sine wave pattern
Hyperkalemia causes peaked T waves → widened QRS → sine wave pattern → asystole/VF as potassium rises.
Question 5: A 5-year-old is found unresponsive after a submersion injury. Initial ECG shows sinus bradycardia at 30 bpm. What is the PRIMARY cause of bradycardia in this setting?
- Hypothermia and hypoxia (Correct answer)
- Digoxin toxicity
- Increased intracranial pressure
- Sick sinus syndrome
Correct answer: Hypothermia and hypoxia
Submersion causes profound hypoxia and often hypothermia, both of which suppress the sinus node and slow conduction throughout the heart.
Question 6: Myocarditis in children most commonly presents with:
- Sudden cardiac death without prodrome
- Fever, chest pain, and new-onset heart failure signs (Correct answer)
- Isolated ST elevation in inferior leads only
- Asymptomatic murmur on routine examination
Correct answer: Fever, chest pain, and new-onset heart failure signs
Pediatric myocarditis classically presents with a viral prodrome followed by fever, chest pain, and signs of cardiomyopathy/heart failure.
Question 7: Which finding on echocardiography is MOST consistent with Kawasaki disease complication requiring immediate intervention?
- Mild mitral valve prolapse
- Small patent foramen ovale
- Giant coronary artery aneurysm (≥8 mm) (Correct answer)
- Trivial tricuspid regurgitation
Correct answer: Giant coronary artery aneurysm (≥8 mm)
Giant coronary aneurysms (≥8 mm) in Kawasaki disease carry high risk of thrombosis and myocardial infarction, requiring anticoagulation.
CPEN Cardiac Emergencies 4
A newborn presents with cyanosis unresponsive to supplemental oxygen, a single S2, and 'egg-on-a-string' cardiac silhouette on CXR.
The most likely diagnosis is: