# LP 12 T wave abnormalities



## Arovetli (Apr 14, 2012)

My service equips LP12's that have seen a quite a bit of use.

Lately I have noticed a range of differences in the T wave as provided by continuous monitoring/4 lead monitoring of lead 2 vs. the lead 2 T wave as provided by the 12 lead.

For instance I will occasionally see significant ST Elevation or biphasic T's displayed in onscreen and printed out once the 4 lead is applied but the waveforms on the 12 lead will be simultaneously normal.

A previous service used LP12's and I never once noticed this phenomena.

An issue with the cables or the actual monitor?

A different algorithm used to calculate the vectors?

Thanks for any insight.


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## usalsfyre (Apr 14, 2012)

Try new cables. They should ideally be replaced every couple of years. Also remember the filtering software on on a continuous 4 lead will occasionally make some odd calculations.


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## Aidey (Apr 14, 2012)

Where are you attaching the leads to the pt?


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## Arovetli (Apr 14, 2012)

I am no electrophysiologist but I would imagine it is a vector calculation/algorithm issue. I have seen some post ablation T's be quite funky in 4 lead and normal in 12lead. I imagine the software has issues calculating the vectors as they act around the ablated tissue?


To the physio rep: I have read the document on the Glascow algorithm. Do you publish anything specific to the LP12 continuous monitoring algorithm?


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## Arovetli (Apr 14, 2012)

Further: these machines are the ones capable of only etco2/ekg, previous experience with LP12's was with ones equipped with nibp/sp02. Was there a software update in the two models?

The leads are appropriately placed with no wave variation if they are on the thorax or proximal limbs or distal limbs.


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## Medic Tim (Apr 14, 2012)

is there a monitor vs diagnostic setting on them? It has been a while since I have used a lp12


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## Arovetli (Apr 14, 2012)

Medic Tim said:


> is there a monitor vs diagnostic setting on them? It has been a while since I have used a lp12



It has an internal self diagnostic and we charge/discharge at 10J as an external diagnostic.

I know repol phenomena occur post ablation I just haven't noticed the difference between continuous 4 lead and 12 lead before.

And my experience with LP12's is a bit limited, the LP platform I'm most accustomed to is the 11's.

The next time it happens I will try and post strips.


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## Physio Control (Apr 19, 2012)

Arovetli said:


> My service equips LP12's that have seen a quite a bit of use.
> 
> Lately I have noticed a range of differences in the T wave as provided by continuous monitoring/4 lead monitoring of lead 2 vs. the lead 2 T wave as provided by the 12 lead.
> 
> ...



We checked with one of Physio-Control’s principal scientists about this. The effects you are observing on the ST levels and T waves on the monitor and printed rhythm strips is the effect of the filtering done on the monitored ECG to reduce motion artifact. The LIFEPAK 12 operating instructions contain the following: 

WARNING!
Possible misinterpretation of ECG data.

The frequency response of the monitor screen is intended only for basic ECG rhythm identification; it does not provide the resolution required for diagnostic and ST segment interpretation. For diagnostic or ST segment interpretation, or to enhance internal pacemaker pulse visibility, attach the 3-lead or 12-lead ECG cable. Then print the ECG rhythm in diagnostic frequency response (DIAG) or obtain a 12-lead ECG.​Hope this helps.


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## Arovetli (Apr 19, 2012)

Awesome, thanks.

Should have read the instruction manual ;-)


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## Brandon O (May 2, 2012)

This happens on all monitors.


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