lec 1. electrical act of heart

Question 1

What is automaticity?

Answer 1

the spontaneous impulse initiation in the heart

its the reason our heart pumps automatically

Question 2

What lead is most often used for continuous ECG monitoring?

Answer 2

lead II.

electrodes placed:

negative is upper left chest

ground is upper right

positive is lower right

Question 3

Where are the leads placed for a 12 lead ECG?

Answer 3

• V1- 4th intercostal (right)
• V2- 4th intercostal (left)
• V3- between V2 and V4
• V4- midclavicular (mid collarbone)
• V5- 5th intercostal space (anterior axillary line)
• V6- 5th intercostal (midaxillary line)
• AVR- augmented vector right- right shoulder
• AVL- left shoulder
• AVF- left foot
• Ground- right leg

Question 4

What is depolarization?

Answer 4

activating the cell and causing contraction of the heart (systole)

Question 5

What is repolarization?

Answer 5

cell relaxing(diastole)

Question 6

What do the waves represent?

Answer 6

• P-wave: atrial depolarization
• QRS: ventricular depolarization
• T: ventricular repolarization

Question 7

What is the normal amplitude and duration of the P-wave?

Answer 7

<2.5 boxes

Question 8

What is a normal PR interval?

Answer 8

3-5 small boxes

Question 9

What is the normal duration of QRS complex?

Answer 9

3 boxes