Electrocardiogram

Question 1

Q: What are the 3 distinct waveforms in a normal ECG?

Answer 1

A:
1. P wave: Atrial depolarization
2. QRS complex: Ventricular depolarization
3. T wave: Ventricular repolarization

Question 2

Q: What does the PR segment in an ECG represent?

Answer 2

A:
The PR segment represents the AV nodal delay, where the current flowing through the AV node is too small to detect.

Question 3

Q: What is represented by the ST segment in an ECG?

Answer 3

A:
The ST segment represents when the ventricles are completely depolarized and in a plateau phase, waiting to be repolarized. It coincides with ventricular activation, contraction, and emptying.

Question 4

Q: What does the TP interval in an ECG represent?

Answer 4

A:
The TP interval represents when the heart is completely at rest and ventricular filling is taking place.

Question 5

Q: What are the three main phases of the cardiac conduction system?

Answer 5

A:
1. Atrial depolarization
2. Ventricular depolarization
3. Ventricular repolarization

Question 6

Q: What are the 3 uses of the ECG?

Answer 6

A:
1. Diagnose abnormal heart rates
2. Diagnose arrhythmias
3. Assess damage to heart muscle

Question 7

Q: How are electrical currents generated for an ECG?

Answer 7

A:
Electrical currents are generated by cardiac muscle during action potentials, which spread into surrounding tissues and body fluids. A small portion of this electrical activity reaches the body surface and can be detected.

Question 8

Q: What are the 3 key points to keep in mind about ECG?

Answer 8

A:
1. An ECG records the portion of electrical activity induced in the body fluids, not the actual electrical activity of the heart.
2. An ECG represents the overall spread of activity throughout the heart, not a single point in time.
3. An ECG represents a comparison of voltage detected by electrodes at different points on the body, not the actual potential.