EKG certification Certification ECG Technician Certification Exam 1

Question 1

An ECG strip shows a rhythm where P waves are present but bear no consistent relationship to QRS complexes, and the ventricular rate is slower than the atrial rate. What rhythm does this represent?

Accepted Answer

Third-degree (complete) AV block

Answer

In third-degree (complete) AV block, the atria and ventricles beat independently because no impulses conduct through the AV node. P waves and QRS complexes are dissociated, and the ventricular rate is slower as it is driven by an escape pacemaker below the block.

Question 2

When applying electrodes for a 12-lead ECG, where should the V4 precordial lead be placed?

Accepted Answer

Fifth intercostal space, midclavicular line

Answer

V4 is placed at the fifth intercostal space in the midclavicular line. Correct precordial electrode placement is critical for accurate ECG interpretation, and V4 serves as the anatomical anchor for V5 and V6 placement.

Question 3

On a standard ECG paper running at 25 mm/second, how much time does one large (5 mm) square represent?

Accepted Answer

0.20 seconds

Answer

At 25 mm/second, each small 1 mm square represents 0.04 seconds and each large 5 mm square (containing 5 small squares) represents 0.20 seconds. This is foundational knowledge for measuring intervals and calculating heart rate.

Question 4

A patient's ECG shows saw-tooth flutter waves at a rate of approximately 300 bpm with a ventricular rate of 75 bpm. What is the AV conduction ratio?

Accepted Answer

4:1

Answer

Atrial flutter typically produces atrial rates of 250–350 bpm. With an atrial rate of 300 and a ventricular rate of 75, the ratio is 300:75 = 4:1, meaning only every 4th flutter wave conducts to the ventricles.

Question 5

Which of the following findings on a resting 12-lead ECG is most consistent with left ventricular hypertrophy (LVH)?

Accepted Answer

S wave in V1 plus R wave in V5 or V6 greater than 35 mm

Answer

The Sokolow-Lyon criterion for LVH is S in V1 + R in V5 or V6 ≥ 35 mm. Increased voltage in these leads reflects the greater muscle mass of the hypertrophied left ventricle generating larger electrical forces.

EKG certification Practice Test

EKG certification Practice Test

EKG certification Certification ECG Technician Certification Exam 1