NHI Electrocardiography and Cardiac Monitoring

Question 1

What does the P wave on an ECG represent?

Accepted Answer

Atrial depolarization

Answer

The P wave reflects the electrical impulse that spreads through the atria causing atrial depolarization and contraction.

Question 2

The QRS complex on an ECG represents which cardiac event?

Accepted Answer

Ventricular depolarization

Answer

The QRS complex reflects the rapid spread of the electrical impulse through the ventricles, causing ventricular depolarization and contraction.

Question 3

What is the normal range for heart rate in sinus rhythm?

Accepted Answer

60–100 bpm

Answer

Normal sinus rhythm is defined as a regular rhythm originating from the sinoatrial node with a rate between 60 and 100 beats per minute.

Question 4

How many electrodes are placed on a patient for a standard 12-lead ECG?

Accepted Answer

10

Answer

A 12-lead ECG uses 10 electrodes—4 limb electrodes and 6 precordial (chest) electrodes—to produce 12 views of the heart's electrical activity.

Question 5

The T wave on an ECG represents which cardiac event?

Accepted Answer

Ventricular repolarization

Answer

The T wave reflects ventricular repolarization—the recovery phase of the ventricles as they reset for the next contraction.

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