Week 4 Ekg Analysis, Cardiac Cycle, Event Timing

Question 1

What does the P wave represent?

Answer 1

The P wave represents atrial depolarization that leads to an atrial contraction

Question 2

What does the qrs complex represent

Answer 2

Ventricular depolarization leading to ventricular contraction

Question 3

What does T wave represent?

Answer 3

T wave represents ventricular repolarization

Question 4

What are the 2 phases of the cardiac cycle

Answer 4

Systole and diastole

Question 5

What node creates the P wave on ekg

Answer 5

Sinoatrial node

Question 6

What is the duration of the PR interval

Answer 6

• From the onset of the p wave to the onset of the Q/R wave
• Normal duration is < 200 msec

Question 7

What does the PR interval reflect

Answer 7

• Depolarization of the atria through the internodal pathways and buchmann’s bundle
• the spread of the impulse through the av node, av bundle, r and l branches, and purkinje fibers

Question 8

What is the duration of the QRS complex

Answer 8

• onset of Q wave to end of S wave
• Normal qrs duration is < 110 msec

Question 9

What is the ST segment

Answer 9

• early part of ventricular repolarization
• isoelectric unless disease is present

Question 10

What is the QT interval

Answer 10

• onset of Q wave to end of T wave
• reflects ventricular systole
• normal time is 250-460 msec

Question 11

What is the ekg timing for ventricular systole

Answer 11

R wave (closure of AV valves) to the end of the T wave (closure of SL valves)

Question 12

What are the 3 phase of ventricular systole

Answer 12

1) isovolumic contraction time
2) rapid ejection of blood
3) reduced ejection of blood

Question 13

When does isovolumic contraction time occur

Answer 13

• begins at AV valve closure
• ends at SL valve opening

Question 14

What happens during ivct

Answer 14

• Ventricular volume is at its largest
• ventricular pressures rise rapidly in preparation for the SL valve opening

Question 15

What happens during rapid ejection of ventricular systole

Answer 15

• rapid ejection of blood
• ventricular pressure rise rapidly while volume drops rapidly

Question 16

What happens during reduced ejection

Answer 16

• ventricular pressure rapidly decreases

Question 17

What is the ekg timing for ventricular diastole

Answer 17

From the end of the T wave (closure of SL valves) to the R wave (closure of AV valves

Question 18

What are the 4 phases of ventricular diastole

Answer 18

1) isovolumic relaxation timing
2) early rapid filling of the ventricles
3) diastasis
4) late filling

Question 19

When does ivrt occur

Answer 19

Begins at SL valve closure and ends when AV valves open

Question 20

What occurs during ivrt

Answer 20

• heart volume is at its smallest
• volume remains the same because all valves are closed
• pressure decreases rapidly in preparation for av valve opening