EKG Basics Flashcards

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

Answer: 0.20 seconds

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

Sinus tachycardia is defined as a heart rate above:

Answer: 100 bpm

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

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

Answer: ST segment elevation ≥1 mm in two contiguous leads

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

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

Answer: The overall direction of ventricular depolarization in the frontal plane

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

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

Answer: Atrial flutter

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

Right bundle branch block (RBBB) on EKG is characterized by a QRS duration of at least:

Answer: 0.12 seconds

RBBB produces a wide QRS complex of 0.12 seconds or greater with an RSR' (rabbit ear) pattern in V1.

Which electrode placement is correct for lead V4?

Answer: 5th intercostal space at the midclavicular line

V4 is placed at the 5th intercostal space at the midclavicular line on the left side.