ECC Cardiovascular Evaluation & Monitoring 2 — Questions and Answers
Question 1: Which lead configuration is considered the best single lead for detecting ST-segment changes during continuous cardiac monitoring?
- Lead I
- Lead II
- Lead V5 (Correct answer)
- Lead aVR
Correct answer: Lead V5
Lead V5 is the most sensitive single lead for detecting ST-segment changes, particularly myocardial ischemia involving the lateral wall.
Question 2: A patient's arterial blood gas shows pH 7.28, PaCO2 52 mmHg, HCO3 24 mEq/L. What is the primary acid-base disturbance?
- Metabolic acidosis
- Respiratory acidosis (Correct answer)
- Mixed respiratory and metabolic acidosis
- Compensated metabolic alkalosis
Correct answer: Respiratory acidosis
The elevated PaCO2 with normal bicarbonate indicates primary respiratory acidosis without metabolic compensation.
Question 3: During 12-lead ECG acquisition, what is the recommended paper speed for standard recording?
- 10 mm/sec
- 25 mm/sec (Correct answer)
- 50 mm/sec
- 100 mm/sec
Correct answer: 25 mm/sec
The standard ECG paper speed is 25 mm/sec, making each small square represent 0.04 seconds.
Question 4: Which hemodynamic finding is most consistent with cardiac tamponade?
- Elevated pulse pressure
- Pulsus paradoxus >10 mmHg (Correct answer)
- Widened pulse pressure with bradycardia
- Isolated systolic hypertension
Correct answer: Pulsus paradoxus >10 mmHg
Pulsus paradoxus greater than 10 mmHg — an exaggerated fall in systolic BP during inspiration — is a hallmark finding of cardiac tamponade.
Question 5: On a cardiac monitor, artifact mimicking ventricular fibrillation is most commonly caused by which of the following?
- Patient shivering or muscle tremor (Correct answer)
- Electrode gel drying out
- Low battery in the monitor
- Incorrect lead placement
Correct answer: Patient shivering or muscle tremor
Shivering or skeletal muscle tremor produces high-frequency artifact that can closely resemble the chaotic baseline of ventricular fibrillation.
Question 6: What does a prolonged QTc interval (>500 ms) primarily indicate in the context of ECC?
- Increased risk of atrial fibrillation
- Increased risk of torsades de pointes (Correct answer)
- Hyperkalemia
- Complete heart block
Correct answer: Increased risk of torsades de pointes
A QTc greater than 500 ms significantly increases the risk of torsades de pointes, a potentially fatal polymorphic ventricular tachycardia.
Question 7: When auscultating heart sounds, an S3 gallop in an adult patient most commonly suggests:
- Aortic stenosis
- Ventricular volume overload or heart failure (Correct answer)
- Mitral valve prolapse
- Pericardial friction rub
Correct answer: Ventricular volume overload or heart failure
An S3 gallop in adults indicates rapid ventricular filling against a non-compliant ventricle, most commonly associated with heart failure or volume overload.
ECC Cardiovascular Evaluation & Monitoring 2
Which lead configuration is considered the best single lead for detecting ST-segment changes during continuous cardiac monitoring?