CCT Electrocardiography Procedures & Interpretation 3

Question 1

Which ECG pattern is associated with hyperkalemia?

Accepted Answer

Tall peaked T waves progressing to widened QRS

Answer

Hyperkalemia first produces tall, narrow, peaked T waves; as potassium rises further, the PR prolongs, QRS widens, and ultimately a sine-wave pattern may develop.

Question 2

On a standard ECG tracing run at 25 mm/sec, how long does each large box (5 mm) represent in time?

Accepted Answer

0.20 seconds

Answer

At the standard paper speed of 25 mm/sec, each large box (5 mm wide) represents 0.20 seconds (200 ms).

Question 3

A patient's ECG shows P waves that change morphology beat to beat with a rate of 105 bpm. What is this rhythm?

Accepted Answer

Multifocal atrial tachycardia

Answer

Multifocal atrial tachycardia (MAT) features at least three distinct P-wave morphologies, irregular rhythm, and a rate >100 bpm, often seen in COPD patients.

Question 4

Which ECG lead is most commonly used as the monitoring lead in continuous cardiac monitoring?

Accepted Answer

Lead II

Answer

Lead II is the standard monitoring lead because it provides the best view of P waves and QRS complexes for rhythm assessment.

Question 5

ST depression in leads V1–V4 during an acute coronary event should raise concern for which condition?

Accepted Answer

Posterior MI (reciprocal changes)

Answer

ST depression in V1–V4 can represent reciprocal changes of a true posterior MI, which would show ST elevation in posterior leads V7–V9.

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CCT Electrocardiography Procedures & Interpretation 3