Understanding the Electrocardiogram (EKG/ECG)

What does an electrocardiogram (EKG/ECG) record?

• The blood pressure levels

• The oxygen levels in the blood

• The electrical activity of the heart

• The electrical activity of the brain

Where does the signal for the heart to contract start?

• AV node

• SA node

• Purkinje fibers

• Bundle fibers

What does the P wave represent in an EKG?

• Ventricular depolarization

• Ventricular repolarization

• Atrial repolarization

• Atrial depolarization

What is the QRS complex indicative of?

• Atrial depolarization

• Ventricular repolarization

• Atrial repolarization

• Ventricular depolarization

Why is the QRS complex larger than the P wave?

• The atria are larger than the ventricles

• The ventricles have more muscle and are larger than the atria

• The signal in the atria is weaker

• The electrodes are closer to the ventricles

What does the T wave represent?

• Atrial depolarization

• Atrial repolarization

• Ventricular depolarization

• Ventricular repolarization

Why don't we see atrial repolarization on the EKG?

• It happens after the ventricles repolarize

• It is represented by the T wave

• It is overshadowed by the QRS complex

• It does not produce a detectable signal

How are the electrical activities of the heart recorded in an EKG?

• By measuring the heart's temperature

• By recording the sound of the heart

• By placing skin electrodes on different parts of the body

• By using a stethoscope

What is the sequence of heart signal transmission?

• Purkinje fibers -> Bundle fibers -> SA node -> AV node

• AV node -> SA node -> Purkinje fibers -> Bundle fibers

• SA node -> AV node -> Bundle fibers -> Purkinje fibers

• Bundle fibers -> Purkinje fibers -> AV node -> SA node

What is the purpose of using an EKG?

• To test for irregularities in heart function

• To measure the blood's oxygen level

• To record brain activity

• To check the efficiency of the lungs