NCLEX RN Practice Question # 888

NCLEX RN Practice Question # 888.

nclex examination

Basics of Electrocardiography

▪ An electrocardiogram (ECG) reflects the electrical activity of cardiac cells and records electrical activity at a speed of 25 mm/second.

▪ An electrocardiographic strip consists of horizontal lines representing seconds and vertical lines representing voltage.

▪ Each small square represents 0.04 second.

▪ Each large square represents 0.20 second.

▪ The P wave represents atrial depolarization.

▪ The PR interval represents the time it takes an impulse to travel from the atria through the atrioventricular node, bundle of His, and bundle branches to the Purkinje fibers.

▪ Normal PR interval duration ranges from 0.12 to 0.2 second.

▪ The PR interval is measured from the beginning of the P wave to the end of the PR segment.

▪ The QRS complex represents ventricular depolarization.

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