NRCMA EKG Basics 3

Question 1

On EKG graph paper running at standard speed (25 mm/sec), one large box represents how many seconds?

Accepted Answer

0.20 seconds

Answer

Each large box on standard EKG paper equals 0.20 seconds (5 small boxes × 0.04 seconds each).

Question 2

Sinus tachycardia is defined as a heart rate above:

Accepted Answer

100 bpm

Answer

Sinus tachycardia is defined as a regular rhythm originating from the sinus node with a rate exceeding 100 bpm.

Question 3

Which EKG change is a hallmark of an acute ST-elevation myocardial infarction (STEMI)?

Accepted Answer

ST segment elevation ≥1 mm in two contiguous leads

Answer

STEMI is diagnosed when ST elevation ≥1 mm appears in two or more anatomically contiguous leads.

Question 4

What does the term 'axis deviation' refer to on an EKG?

Accepted Answer

The overall direction of ventricular depolarization in the frontal plane

Answer

Axis deviation describes whether the mean electrical vector of ventricular depolarization is shifted left or right from normal.

Question 5

A medical assistant notices a saw-tooth pattern between QRS complexes at a rate of 300 bpm. This is characteristic of:

Accepted Answer

Atrial flutter

Answer

Atrial flutter produces a distinctive saw-tooth (flutter wave) pattern at approximately 300 atrial beats per minute.

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