ECG Practical Content and Preparation 5

Question 1

When applying chest electrodes for a 12-lead ECG, V4 should be placed at:

Accepted Answer

Fifth intercostal space, midclavicular line

Answer

V4 is placed at the fifth intercostal space along the left midclavicular line, and V5/V6 are positioned relative to V4.

Question 2

An ECG technician notes that the patient has a permanent pacemaker. Which expected finding should be documented but does NOT indicate a problem?

Accepted Answer

Pacemaker spikes followed by wide QRS complexes

Answer

Ventricular pacing produces pacemaker spikes followed by wide, aberrant-appearing QRS complexes, which is the expected normal pacemaker pattern.

Question 3

Which rhythm is characterized by a P wave that follows (rather than precedes) the QRS complex?

Accepted Answer

Junctional rhythm

Answer

In junctional rhythms, the AV node fires and activates the ventricles before (or simultaneously with) retrograde atrial activation, placing the P wave after the QRS.

Question 4

During ECG acquisition, the standardization mark (calibration pulse) should show a deflection of:

Accepted Answer

1.0 mV (10 mm tall)

Answer

Standard ECG calibration is 1 mV = 10 mm; the calibration pulse verifies the machine is recording at correct sensitivity.

Question 5

A patient with chest pain has ST elevation in leads V1–V4. Which coronary artery territory is most likely occluded?

Accepted Answer

Left anterior descending artery (LAD)

Answer

The LAD supplies the anterior wall and septum, so anterior STEMI (V1–V4 ST elevation) indicates LAD occlusion.

ECG Certification Practice Test

ECG Certification Practice Test

ECG Practical Content and Preparation 5