# LifePak 12 and Pacemakers



## MMiz (May 9, 2012)

In this thread on Bigeminy or paced rhythm, EMTLife user Milla3P shared:



> The fun part of LP12s is that they only recognize Physio pacemakers.  I've seen pacing spikes on Zolls and not my LP with the same guy.



Can you shed any light on the idea that LifePak 12's only recognize Physio Control pacemakers?

Thanks,


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## Aidey (May 9, 2012)

How would the monitor be able to know what pacemaker it is? Electricity is electricity. I bet it has more to do with the interpretation algorithm or lead placement than brand of monitor.


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## Christopher (May 10, 2012)

MMiz said:


> In this thread on Bigeminy or paced rhythm, EMTLife user Milla3P shared:
> 
> Can you shed any light on the idea that LifePak 12's only recognize Physio Control pacemakers?



It has nothing to do with brand and more to do with bipolar versus unipolar pacemaker leads. LP12's are pretty bad at autodetecting bipolar leads due to the low voltages on the surface ECG. Unipolar leads have much higher voltages and trigger the threshold in the detector.

Philips seems to be the best at detecting them. Zoll is a close second.

That being said, I'm not aware of the LP15's differences in this area.


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## Christopher (May 10, 2012)

Christopher said:


> LP12's are pretty bad at autodetecting bipolar leads due to the low voltages on the surface ECG.



I should add that my opinion is based solely on anecdotal evidence. I use all 3 brands of cardiac monitors across the services I work for, and have no financial incentive to support any one of them. I QA every 12-Lead acquired by my department which uses LP12's and frequently find ECG's with evidence of pacing but without monitor detection.

So, if the patient has a pacer-pocket on their chest wall or tells you they have a pacemaker...it's best to take the minute or two and acquire a 12-Lead if the 3-Lead doesn't show an obviously paced rhythm.


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## Physio Control (May 16, 2012)

MMiz said:


> In this thread on Bigeminy or paced rhythm, EMTLife user Milla3P shared:
> 
> 
> 
> ...



The LIFEPAK 12 and 15 are actually both good at detecting pacemaker stimuli if they are set up with internal pacemaker detection turned on. The user can change this in setup.

The 12 and the 15 both use lead V4 for pacemaker spike detection if available, otherwise they use lead II. Detected spikes are marked with a hollow arrow on the screen and printout.

To best see pacemaker spikes, print the ECG at diagnostic bandwidth, 0.05-150 Hz.

Additional information can be found in the LIFEPAK 12 Operating Instructions (page 3-7). Excerpt follows.

Monitoring Patients with Internal Pacemakers
The LIFEPAK 12 defibrillator/monitor typically does not use internal pacemaker pulses to calculate the heart rate. However, when using therapy electrodes or standard paddles to monitor in paddles lead, the monitor may detect internal pacemaker pulses as QRS complexes. This may result in an inaccurate heart rate display.

Smaller amplitude internal pacemaker pulses may not be distinguished clearly in paddles lead. For improved detection and visibility of internal pacemaker pulses, turn on the INTERNAL PACEMAKER detector, and/or connect the ECG cable, select an ECG lead and print the ECG in diagnostic frequency response.

Large amplitude pacemaker pulses may overload the QRS complex detector circuitry so that no paced QRS complexes are counted. To help minimize ECG pickup of large unipolar pacemaker pulses when monitoring patients with internal pacemakers, place ECG electrodes so the line between the positive and negative electrodes is perpendicular to the line between the pacemaker generator and the heart.

The internal pacemaker detection feature can be used to help identify internal pacemaker pulses on the printed ECG. When enabled, this feature uses lead V4 to detect internal pacer pulses. If V4 is not available because it is not attached or is too noisy, lead II is used, if available. If this feature is configured or selected ON, the LIFEPAK 12 defibrillator/monitor annotates a hollow arrow on the printed ECG if internal pacemaker pulses are detected. False annotations of this arrow may occur if ECG artifacts mimic internal pacer pulses. If false annotations occur, you may deactivate the detection feature using the OPTIONS / PACING / INTERNAL PACER menu (see Figure 2-5). Patient history and other ECG waveform data, such as wide QRS complexes, should be used to verify the presence of an internal pacemaker. For information about configuring the internal pacemaker detection, refer to the Pacing Setup menu in Table 9-4.​


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