extra P wave?

HouTx, BSN, MSN, EdD · May 11, 2015

12 lead is best. If that's not available, check PR intervals for defining characteristics of AVB II. Also, see if your "P wave" marches out... if it's occurring at regular intervals, that is another key indicator that will help you identify what's going on.

Happy hunting.

Lev, MSN, RN, NP · May 12, 2015

A u wave comes after the t wave. It can be absent, inverted, or hidden in the t waves at times.

A PAC is a single early beat that comes from a place in the atria other than the SA node. Therefore, the p wave sometimes looks a little different from the other p waves. It can also be hidden in the t wave of the preceding beat if the early beat falls during ventricular repolarization.

There are two types of 2nd degree AV blocks. In all 2nd degree blocks there are more p waves than QRS complexes.

In 2nd degree type I/mobitz I/wenckebach the PR interval gets longer and longer, til a QRS complex is dropped, usually after the 3rd beat.

in 2nd degree type II/mobitz I, there is a regular p to p interval but only some of the p waves are followed by a QRS. The PR interval will be constant for each beat. Sometimes the QRS widens a little.

ninjago · May 13, 2015

Thanks for the reply. Here's the EKG strip from what I can remember. If you can kinda picture it in your mind ;-)

P-QRS-T-->p? or u? wave----->P-QRS-T-->p? or u? wave ---->P-QRS-T --->P-QRS-T

This was only found in V2, V3 and V4 and not in other leads.

Some said it was a U wave, others said it was a PACs. Another said it was a second degree AVB Type II.

If it was a Second degree AVB Type II, wouldn't this show it all the leads?

If it was a PAC, the P wave would have been closer to the next P wave? This was found about 2-3 small boxes from the preceding T wave?

If it was a U wave, wouldn't the interval from P to P waves remains same? The next P wave was a bit more distant from the preceding P wave in this case.

I hope I explain it clearly. I apologize if I make you all the more confused.

Anyways, I will try to see what the doctor said when I go back to work and update you then.

Thanks.

Lev, MSN, RN, NP · May 13, 2015

Was the P-P interval consistently even? If not, then it's not a 2nd degree type II block. They can't be PACs because PACs are not just early p waves, there is a QRS too. Did the PR intervals gradually get longer? From what you are describing it sounds like u waves were present and there may be some actual PACs going on too if the P to P interval is not even.

ninjago · May 13, 2015

PACs are P then P-QRS, correct? It's like two P waves per QRS?

The PR intervals remain the same. This was just another either p or u wave right after the T wave. Definitely not Wenckebach if that is what you're thinking. There was no lengthening PR interval.

I think you are correct, it could be U wave.

Thanks so much!

Lev, MSN, RN, NP · May 13, 2015

PACs are P then P-QRS, correct? It's like two P waves per QRS?
The PR intervals remain the same. This was just another either p or u wave right after the T wave. Definitely not Wenckebach if that is what you're thinking. There was no lengthening PR interval.
I think you are correct, it could be U wave.
Thanks so much!

PAC = Premature Atrial Complex which is a p wave followed by a QRS (unless p wave is hidden). It is an atrial beat therefore it has an upright p wave. P wave comes from the atria. Compared with a PJC or Premature Junctional Complex which is junctional beat that has a QRS with either an inverted or absent p wave. That complex initiates in the "junction" or lower down on the conduction pathway therefore the p wave is not your usual upright wave.

Was it like this?

pqrstu space space space pqrstu space space space pqrstu space space pqrstu space space space space pqrstu space space space pqrstu etc?

The bold was a PAC.

Sometimes the p wave of the PAC can be right after the t wave of the preceding complex and may look like a u wave.

Mully · May 14, 2015

A couple things...

It could in fact be a PAC, termed a "non-conducted PAC". This is when there is a P wave which occurs earlier than its expected time (hence premature), not followed by a QRS (hence non-conducted). These are relatively common and relatively benign.

If the additional P wave is in time with when it is expected with no QRS, this is a second degree type II block. This is a more serious condition, as it often progresses to complete heart block.

The key to differentiating the above is whether or not this additional P wave is premature or not. If it is premature, and there is no QRS, it means the conduction system distal to the AV node is refractory from the previous beat which is why there was no QRS. If it is on time and there is no QRS, this is more serious as there is some sort of block in the conduction pathway.

The best leads for looking at P waves are your inferior leads which are II, III, and aVF. Since this did not appear in any of these leads, it is unlikely that it is any of the above. This makes me think it was the stupid u wave.

U Wave basic ECG patterns

Here's a site that explains more than you'll ever want to know about a u wave. Don't spend too much time on it though, the u wave is pretty low in specificity and doesn't really play a role clinically, at least in my experience.