81 year old female CC: ICD shocks x6

EMS responds to a 81 year old female who was implanted with “a pacemaker” 2 weeks ago. She complains that the device has shocked her 6 times.

On arrival the patient is found sitting in a chair. She is anxious but alert and oriented to person, place, time and event.

Vital signs:

Resp: 18
Pulse: 164 and irregular
BP: 128/68
SpO2: 98 on RA

The patient is asked if she carries an ID card for her implantable device and she finds this card in her purse.


A 12 lead ECG is captured (I am using the 12-lead that shows the best data quality which was taken en route to the hospital).


Here is a typical looking rhythm strip during the transport.


Why do you think this patient’s ICD is firing?

What would you do about it?

See also:

71 year old male CC: Seizures

Inappropriate or ineffective ICD shocks – Part I

Inappropriate or ineffective ICD shocks – Part II

Inappropriate or ineffective ICD shocks – Part III

20 Comments

  • Tazambo says:

    Anti-Tachy Pacing…

  • Billy says:

    I agree that this is AF + RVR but I don't think the device is trying to overdrive pace. My guess is that prior to EMS arrival the patient's heart rate was over 200 and the device tried to cardiovert her. I would take a history and try to determine if this is some sort of compensatory tachycardia or if it is in fact an acute arrhythmia. Since the patient claims she was shocked six times and is still tachy I am leaning towards heart failure. I don't think trying to convert the rhythm is indicated. I would place the patient on CPAP, start an IV, and take her to the hospital. Furthermore, she is stable so I wouldn't really feel comfortable trying to control this rate, especially since I don't even carry CCB's.

  • SoCal Medic says:

    I would agree that the history leading up to the Device is going to be key. Furthermore, I think Billy is right in that I am guessing it is trying to cardiovert her because of the high heart rate. Treatment wise, I would get two lines (precautionary since I do not have a magnet and not sure what the device will do). Place my combi-pads, oxygen by cannula since her rate and saturations appear to be ok. With that said, the energy is not working, I carry Verapamil and would give that a shot before the device either converts her to a sinus rhythm (run the risk of a clot being displaced) or puts her into something worse.Billy…. curious.. why the CPAP?Christopher

  • Billy says:

    If it is heart failure CPAP increases cardiac output by increasing intrathoracic pressure as it helps the lungs to expand, and it also increases the partial pressure of oxygen available in the blood. You can use CPAP for things other than pulmonary edema.

  • SoCal Medic says:

    Billy, we just got it here and the only way we would be allowed to use it would be diff breathing. Thanks for the info though.

  • Christopher says:

    AF+RVR, my guess is ICD shocked because it thought it was either PSVT or VT. Admittedly I know zilch about AICDs.Rx is IV, O2, continue monitoring. Her BP is good so it'd be nice to have the diltiazem option (but this is possibly chronic AF, PMHx/Meds may dictate if this is an option). Although I'm wondering if she's not tachy now due to the "painful stimulus" of the shocks. Otherwise since she is stable, I'm inclined just to watch her and make it a nice comfortable ride to the hospital.

  • Tom B says:

    @Tazambo – Good thought, but not this time! @Billy – You are correct. The patient states that she has a known history of chronic atrial fibrillation. I don't carry CCBs either (we just got rid of Cardizem) but it might be a consideration if you don't have a ring magnet! @SoCal Medic – You wrote that you don't have a magnet "and you don't know what the device will do." But you do know what the device will do! It's written on the card. Interesting that you carry Verapamil and not Cardizem! C.Watford – As a side note, while the term AICD is still commonly used by medical professionals, all of the "Big 3" device makers now refer to them as ICDs (implantable cardioverter defibrillators). "Watch her and make it a comfortable ride to the hospital" is exactly how we treated this patient! However, we were ready with our finger on the PRINT button to record an ICD shock to confirm it was inappropriate therapy. As soon as it was confirmed the device was responding to AF/RVR (and not VT/VF) we would have placed the magnet. The other option you could consider is sedation.

  • SoCal Medic says:

    Tom,In my old system we carried the cardizem, here locally however, the temperature controls on the drug are to constrictive considering the temperature environment that we work in. Summer months can hit over 100 degrees and the ambulance take quite a while to work on those days.

  • Tony D says:

    The patient is in a rapid Afib, I guess the ICD tried to cardiovert with electricity and it was unable to even after 6 attepms.Since the patient has a decent BP, I would try Cardizem which is a CCB, and have a bag of fluids at hand just in case the BP drops, sometimes electricity fails but chemical cardioversion does work.

  • NinjaMedic says:

    Amio drip would be the best tool I have available.

  • SJMedic says:

    Are all ICD recipients given similar cards to carry? I have never thought to ask.

  • Tom B says:

    @NinjaMedic – That's all I have, too, since we got rid of Cardizem.@SJMedic – Yes! In fact, they need it to get through the metal detector at the airport.Tom

  • Billy says:

    I thought amiodorone was indicated for rhythm conversion in AF, and not rate control? Would that really be a good idea here? It's definitely not in my protocols.

  • Anonymous says:

    i agree that the patient is currently stable and therefore immediate cardioversion would not be indicated. although we do carry diltiazem, I would reserve it unless I knew more of the hx. if the pt has a hx of afib and we cannot determine how long she has been in the rhythm, i think there would be more risk than benefit to converting with diltiazem. if the patient was not anticoagulated, we would be concerned about thrombus. another option available at our service would be to simply bring down the rate a little with 2.5-5.0 mg of lopressor.

  • Chris says:

    I think the device is trying to cardiovert a rapid A fib. It says defibulator on the card, not Pacemaker. Does this make a difference Tom? Can I suspect that this device was placed due to Hx of tachy or Afib that required cardioversion?
    I would also like to know if she is already on for meds to help with some of my decisions.
    I do not feel electrical intervention is indicated at this point. ACLS stable pt, nothing wrong with placing the pads though.
    for meds im thinking this
    First pick with MD discussion would be Diltiazam (In one service i work for it is available. Others not. Discuss dose options)
    Second Pick especially if she is already on it is the lopressor up to 5mg very slow IVP.
    Third and last would maybe be amiodarone but I dont think this is less AFib rate control as much IMHO- PVCs, Wide complex tachycardia. Though ami does work above and below the AV node, its hard to go wrong. I would discuss this with MD also because its not the ideal medication but may work if we need to treat and its all I have.
    -Chris
    I may discuss with the doc depending on transport time about comfort care and not messing around too much. Unfortunatly I average a 20 min lights and siren pucker till youve used everything in your box transports.
    If she is still receiving shocks during my care I would consider sedation. Since Im already going to be messing with BP maybe a benzo or fentanyl.

  • a nurse says:

    The pt is in atrial fibrillation w/ RVR. Her rapid ventricular rate likely met the low rate threshold programmed on the ICD. It is possible that the ICD did try to do anti-tachycardia pacing (this is NOT seen on the ECGs, but could be determined when the device is interrogated). ATP would not have been successful, thus she was then shocked. Since the device still sensed her fast HR she got shocked several times. Since I am not an EMT, don’t know your protocols, but if I was caring for this pt in a setting where she was monitored and had defib paddles available, I would place a magnet over her device to inhibit tachy therapy and continue to monitor her. Ultimately she will need rate control. Multiple ICD shocks are deleterious to the pt’s psychological health, can deplete battery life and can be associated with adverse outcome.

  • nagwa says:

    i think the the 81 female patient has AF that causes recurrent emboli and strokes that she mentioned as shocking attacks th

  • Device Tech Jerry says:

    ICD's have SVT discriminators to help prevent this in the lower VT zones… however, once the rate hits the programmed VF rate (typically 180-210), the discriminators do not apply , and the device err's on the side of caution and will shock regardless. Idea being that regardless of where it's coming from, that rate is not good.  I have had several of my device clinic patients "home cardioverted" due to a-fib/rvr

  • ASeaman says:

    The scary thing is that most older patients don't know if they have a pacemaker or defibrillator. In all the years that I worked with a cardiologist I ran into the problem of them not knowing and the hospital having to call to get the information. I agree that is looks like AFib/RVR, therefore the defib will try to convert the patient! Most units are set to shock if the rhythm is sustained after attempting to pace the patient out of it. Medtronic needs to be contacted and meet the patient at the hospital to interrogate the device! 

  • Ron P. says:

    AF w/ RVR. Narrow complex tachyarrythmia and not an imminently fatal rhythm. Since the pt is seemingly stable, I would place the magnet, monitor, treat other issues as they arise, and transport

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