ECG and Electrical Activities of the Heart

The video tutorial explains the electrical activities of the heart as recorded by an ECG machine. It covers the 12-lead ECG procedure, detailing the placement of electrodes and the different views of the heart. The tutorial describes how voltage is measured using bipolar and unipolar leads, including limb and chest leads. It also explains the principles of depolarization and repolarization, and how they affect the ECG readings.

What does an ECG machine record and display?

• Respiratory rate

• Blood pressure

• Electrical activities of the heart

• Heart rate

How many electrodes are attached to the body in a conventional 12-lead ECG procedure?

• 8

• 10

• 12

• 14

Which electrode serves as the earth electrode in the 12-lead ECG procedure?

• Right arm

• Left arm

• Left leg

• Right leg

Lead I measures the electrical potential between which two electrodes?

• Left arm and left leg

• Right leg and left leg

• Right arm and left arm

• Right arm and left leg

Which lead looks at the heart from the inferior left view?

• aVR

• Lead III

• Lead II

• Lead I

What is the reference value for the augmented limb leads?

• The input from the right leg electrode

• The input from the left leg electrode

• The average of inputs from the chest electrodes

• The average of inputs from the three limb electrodes

Which augmented limb lead looks at the upper right side of the heart?

• aVR

• Lead III

• aVF

• aVL

In which plane do the chest leads view the heart?

• Horizontal

• Oblique

• Diagonal

• Vertical

What happens when depolarization moves toward a lead?

• It produces a negative deflection

• It produces no deflection

• It produces a neutral deflection

• It produces a positive deflection

What is the result of repolarization moving away from a lead?

• Neutral deflection

• No deflection

• Negative deflection

• Positive deflection