CRAT ECG Interpretation 2

Question 1

On a standard ECG recorded at 25 mm/sec, each large box (5 mm) represents what duration of time?

Accepted Answer

200 ms (0.20 seconds)

Answer

100 ms (0.10 seconds)

Answer

400 ms (0.40 seconds)

Answer

40 ms (0.04 seconds)

Question 2

The large box method for estimating heart rate from a regular rhythm divides 300 by the number of large boxes between consecutive R waves. If there are 4 large boxes between R waves, what is the approximate heart rate?

Accepted Answer

75 bpm

Answer

100 bpm

Answer

60 bpm

Answer

50 bpm

Question 3

In a 12-lead ECG, which leads are considered the inferior leads?

Accepted Answer

II, III, and aVF

Answer

I, aVL, and V5-V6

Answer

V1, V2, and V3

Answer

aVR, V1, and V2

Question 4

Which ECG finding is the classic sign of acute ST-elevation myocardial infarction (STEMI)?

Accepted Answer

ST segment elevation greater than 1 mm in two or more contiguous leads

Answer

ST depression greater than 0.5 mm in multiple leads

Answer

New left bundle branch block only

Answer

T wave inversion in all leads

Question 5

Left bundle branch block (LBBB) on ECG is confirmed by which set of findings?

Accepted Answer

QRS duration ≥ 120 ms, broad notched R in lateral leads (I, aVL, V5-V6), and rS pattern in V1

Answer

QRS duration ≥ 120 ms with RSR' pattern in V1 and wide S waves in I and V6

Answer

Short QRS with delta waves

Answer

Wide QRS with absent R wave in all leads

Question 6

A patient's 12-lead ECG shows ST depression in leads V1 through V4 with tall R waves in V1-V2. Which condition should be suspected?

Accepted Answer

Posterior wall STEMI with reciprocal changes in anterior leads

Answer

Anterior STEMI

Answer

Right bundle branch block

Answer

Hyperkalemia