Chapter 9 - The P-wave

Question 1

P-waves are (+) in what leads?

Answer 1

I, II, V4-V6

Question 2

P-waves are negative in what leads?

Answer 2

AVR

Question 3

Criteria for right atria enlargement diagnosis

Answer 3

• p-wave greater than 0.-2 S

- P-wave “notching” with the NOTCH more wide than 0.04s

Question 4

Explain the ECG changes with right atrial enlargement

Answer 4

1) widening of the p-wave occurs due to enlarged right atria
2) More tissue (RAE) requires greater time for the AP to be conducted down intermodal pathways.
3) L atria conduction time remains the same.
4) the increased RA conduction widens the p-wave and adds the “notch”

Question 5

Explain the criteria for diagnosing p-pulmonale.

What does p-pulmonale indicate?

Answer 5

• Found in leads I and II
• p-wave greater than 2.5 mm
• Right atrial enlargement

Question 6

Explain the criteria for diagnosing p-mitrale.

What does p-mitrale indicate?

Answer 6

• p wave longer than 0.12 s (3 boxes)
• a “notched” p-wave with a notch > 0.04 s (1 box)
• Left atrial enlargement

Question 7

Explain the criteria for diagnosing intraatrial conduction delay.

Answer 7

• It indicates a “non-specific delay”

- Any criteria for diagnosing RAE or LAE can be used to determine which specific type of delay it is.