Emergency Medical Services (EMS) Agency

CASE OF THE MONTH – MARCH 2020

Case Presentation

Paramedics respond to the home of a 61-year-old male following a syncopal event.  He denies chest pain and SOB, only endorsing lightheadedness prior to fainting then, “everything went white”.  He doesn’t remember much after.  A similar syncopal episode occurred last month.  Subsequently, he was evaluated by a cardiologist.  The patient has a history of diabetes, hypertension, and hypothyroidism.  When paramedics place the patient on the cardiac monitor, they notice a firm “USB drive” sized-device in his anterior chest.  The patient states, “my cardiologist put it there to evaluate my fainting.”

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Picture 1:  Outline of the subcutaneous device implanted in the patient’s chest.

The device implanted in the patient’s chest is a wireless mobile cardiac monitor.  Instead of traditional Holter monitors that are worn in a “fanny pack” at the waist, many patients with suspected cardiac dysrhythmias may have wireless mobile cardiac monitoring devices initiated by their cardiologists.  These devices are typically more convenient for patients, are minimally disruptive, and can allow monitoring for longer periods of time than traditional Holter monitors.

 

A potential underlying cause of syncope is a cardiac dysrhythmia, but the specific cardiac dysrhythmia may not be detected during a patient’s initial evaluation.  In recent years, several wireless devices have entered the market and can monitor and store a patient’s cardiac rhythm over time.  If a subsequent syncopal or other cardiac event occurs, the stored rhythm can be assessed to determine the underlying cardiac rhythm so that appropriate therapy can be initiated.

The wireless mobile cardiac monitoring device in this case is an implanted one that may be left in place for up to 3 years.  Such devices provide minimally invasive but continuous cardiac monitoring.

For patients that only require monitoring for a short period of time, a cardiologist may initiate the use of “wearable” ECG patch devices.  These devices may also be encountered by EMS providers.  Wearable cardiac monitoring devices adhere to a patient’s chest wall and are easily removed for interrogation after a few days to weeks.

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Picture 2.  The Reveal LINQ is one example of an implantable wireless mobile cardiac monitoring device, similar to the one implanted in Picture 1.

 

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Picture 3.  The Zio XT is an example of a “wearable” patch device that adheres (like a sticker) to a patient’s chest wall and can be easily removed when the designated period of cardiac monitoring is completed (typically days to weeks).

The patient’s initial vital signs are BP 130/68 HR 94 RR 18 SPO2 99%.  Cardiac monitors demonstrate a normal sinus rhythm.  The patient is treated as per TP 1233, Syncope/Near-Syncope.  While obtaining a 12-lead ECG, the patient loses consciousness.  His ECG demonstrates the following rhythm.  He is pulseless.

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Figure 1.  LITFL ECG Library1

This patient is in cardiac arrest and should be managed in accordance with TP-1210, Cardiac Arrest.  The patient is in pulseless ventricular tachycardia and should be defibrillated immediately.

Life-saving measures, like defibrillation, always take precedent in patient care.  Instructions for optimizing defibrillation when a wireless mobile cardiac monitoring device is in place vary by manufacturer.  In general, for implanted devices it is advised that:

  1. Defibrillation pads not be placed directly over the device
  2. Defibrillation pads should not be placed such that the device lies between the pads

Most implantable wireless mobile cardiac monitoring devices are designed to withstand exposure to external defibrillation and cardioversion, but direct electricity over the device should be avoided if possible.   In cases of the implanted device, patient safety is the primary objective, and regardless of the location of the device placement the patient should be defibrillated.

If defibrillation or cardioversion is indicated for a patient with a “wearable” patch device, most manufacturers recommend that the patch device be removed prior to defibrillation or cardioversion.  The device can be easily peeled off since it is attached by a sticker like adhesive to the patient’s chest wall.

For this patient, after immediate defibrillation, management should continue in accordance with TP-1210, Cardiac Arrest.

The patient is defibrillated.  ROSC is achieved after a single shock.  Following defibrillation, the patient is awake and alert.  Management is continued as per TP-1210, Cardiac Arrest for Return of Spontaneous Circulation.  The patient’s vital signs after defibrillation are BP 82/46 HR 99 RR 16 SPO2 98%   His blood pressure improves with a 1L Normal Saline bolus.  The patient is transferred to STEMI Center as per Ref No. 516.

As technology advances, EMS professionals must remain aware of medical devices they may encounter when treating patients.  In the case of wireless cardiac monitoring devices, it is most important that EMS providers do not delay or restrict necessary emergent care based on a device’s presence.

 

Emergent defibrillation or cardioversion can still be performed on patients with these devices as per device manufacturer instructions.  Patch devices are simply there to record rhythms and thus they can be removed without consequence in an emergent situation.  Implanted devices cannot be removed in the field, but are designed to withstand defibrillation and cardioversion though direct electricity to the device should be avoided if possible.

The patient sustains ROSC for the duration of transport.  He arrives awake with normal vital signs.  He is admitted and his implanted cardiac monitoring device is interrogated demonstrating that his syncopal episode and his cardiac arrest were due to episodes of sustained ventricular tachycardia.   An implanted cardioverter defibrillator (ICD) is placed during hospital admission. The patient is discharged home a few days later.

  1. Wireless cardiac monitoring devices are more commonly being used and may be encountered by EMS providers.  The most common types are “patch” devices for shorter term use, and implantable devices for longer term monitoring.
  2. Emergent life-saving therapies should be performed when indicated and are not contraindicated by the presence of a wireless cardiac monitoring device.