CCT Cardiac Monitoring & Emergency Response 3 — Questions and Answers
Question 1: When applying electrodes for a 5-lead bedside monitoring system, where is the chest (C/V) electrode typically placed for the MCL1 equivalent?
- Left midclavicular line, 5th intercostal space
- Right sternal border, 4th intercostal space (Correct answer)
- Left sternal border, 2nd intercostal space
- Right midaxillary line, 5th intercostal space
Correct answer: Right sternal border, 4th intercostal space
The chest electrode placed at V1 position (right sternal border, 4th ICS) with lead III selected approximates the MCL1 monitoring lead.
Question 2: ST-segment changes are measured from which reference point on the ECG?
- The peak of the T wave
- The J point (end of QRS) (Correct answer)
- The onset of the P wave
- The midpoint of the PR interval
Correct answer: The J point (end of QRS)
ST-segment elevation or depression is measured at the J point (junction between the end of the QRS complex and the beginning of the ST segment).
Question 3: A patient with a known history of long QT syndrome is placed on telemetry. Which rhythm is this patient most at risk of developing?
- Atrial fibrillation
- Torsades de pointes (Correct answer)
- Accelerated junctional rhythm
- Wolff-Parkinson-White syndrome
Correct answer: Torsades de pointes
Long QT syndrome predisposes patients to early afterdepolarizations that can trigger torsades de pointes, a polymorphic ventricular tachycardia.
Question 4: Which of the following best describes the correct action after identifying ventricular fibrillation on the monitor?
- Administer amiodarone and reassess
- Deliver a synchronized shock at 200 J
- Begin CPR and prepare for unsynchronized defibrillation (Correct answer)
- Apply vagal maneuvers to terminate the rhythm
Correct answer: Begin CPR and prepare for unsynchronized defibrillation
VF is a pulseless rhythm requiring immediate CPR and unsynchronized defibrillation; no R wave exists to synchronize a shock.
Question 5: A QRS complex that measures 0.14 seconds is best described as:
- Normal duration
- Borderline prolonged
- Prolonged, indicating bundle branch block (Correct answer)
- Critically shortened
Correct answer: Prolonged, indicating bundle branch block
A QRS duration ≥0.12 seconds (120 ms) indicates intraventricular conduction delay such as bundle branch block; 0.14 s is clearly prolonged.
Question 6: During a code, a patient in pulseless electrical activity (PEA) is being resuscitated. Which reversible cause should be considered related to cardiac tamponade?
- Hyperkalemia
- Tension pneumothorax
- Pericardial effusion compressing the heart (Correct answer)
- Pulmonary embolism
Correct answer: Pericardial effusion compressing the heart
Cardiac tamponade (pericardial fluid accumulation) is one of the 'H's and T's' reversible causes of PEA and requires emergency pericardiocentesis.
Question 7: Wenckebach (Mobitz type I) second-degree AV block is characterized by:
- Constant PR interval with random dropped beats
- Progressive PR prolongation until a QRS is dropped, then reset (Correct answer)
- Alternating narrow and wide QRS complexes
- Complete dissociation between P waves and QRS complexes
Correct answer: Progressive PR prolongation until a QRS is dropped, then reset
Mobitz type I block shows progressive PR interval lengthening with each cycle until one P wave fails to conduct, after which the PR interval resets to its shortest value.
CCT Cardiac Monitoring & Emergency Response 3
When applying electrodes for a 5-lead bedside monitoring system, where is the chest (C/V) electrode typically placed for the MCL1 equivalent?