EKG case: Sudden cardiac arrest after treatment for a seizure

What's your assessment and care for a psychiatric patient who was sedated with haloperidol after a seizure?

Article updated July 26, 2017

EMS providers often have to treat patients who are taking a variety of medications prescribed to address physical and mental health issues. This EKG case looks at the potential effects of medications in a patient suffering from a seizure-like episode, as well as the importance of evaluating the nuances of segments and QT intervals.

The EKG Club experts created this case for these learning objectives:  

  • Basic: Understand the clinical importance of measuring segments and intervals.
  • Intermediate: Identify EKG features that could predispose a patient to impending lethal arrhythmias.
  • Advanced: Recognize potential cardiotoxic effects of commonly encountered prescribed medications

Patient presentation: Patient seizing at nursing home 

You are dispatched at 8:19 p.m. to a psychiatric nursing home for a complaint of a seizure and request for transport to a local medical facility. The nursing staff meets you and your partner at the door and shows you the patient's room.

Upon arrival, you find a 42-year-old male lying in his bed. The nursing staff relates that approximately two hours ago, one of the nurses witnessed a seizure-like episode that lasted less than one minute and quickly resolved on its own. The nursing staff called EMS after contacting the patient's primary physician who requested the patient be transported to his medical facility for further evaluation. 

The patient is conscious, but sedated due to a recent administration of haloperidol by nursing staff. The patient responds to verbal commands . No distress is evident.

Patient's vital signs:

Heart Rate: 64
Respiratory Rate: 14
Blood Pressure: 128/72 mm Hg
SpO2: 99 percent room air

Patient's past medical history:

Type II diabetes
Recent pneumonia


No known drug allergies 



Initial 12-Lead EKG:

You decide to acquire an EKG due to the patient's recent syncope/seizure activity.


Above is the EKG acquired. The computer generated interpretation is not available which makes it important to follow an EKG interpretation checklist.

Answer these questions about the 12-lead EKG and the patient.

  • Is there anything that concerns you about this EKG?
  • What could the reason be, besides the seizure/syncope itself, for the primary physician to be interested in seeing this patient immediately?

Initial patient treatment: Sudden cardiac arrest

You establish IV access and prepare the patient for a short transport of approximately 10 minutes. Shortly before arriving at the receiving facility, the patient loses consciousness. You quickly call your partner for help while assessing airway and breathing. Your partner, who is driving, stops the ambulance on the roadside and climbs into the patient compartment while you inform him that the patient is in cardiac arrest.

While you begin chest compressions, your partner takes a quick look at the patient's monitor, which reveals a polymorphic ventricular tachycardia. A decision is made to immediately defibrillate the patient. The defibrillation pads are placed, a 200J charge is selected and the patient is cleared.

Patient Response to Treatment:

An immediate 200J defibrillation is administered. The following strip was printed by the defibrillator upon shocking the patient.

Second 12-Lead EKG:


Once again, the computer generated interpretation is not available.

You continue CPR immediately after defibrillation and the nurse accompanying the patient offers to assist with the bag-valve ventilations. The other paramedic calls medical command while drawing an ampule of epinephrine from the drug kit. An initial dose of 1mg of epinephrine is administered and CPR is continued.

A non-shockable rhythm persists on the cardiac monitor. The patient is subsequently intubated, the tube position is verified, and the tube is secured with a commercial device. The patient is ventilated while compressions are continued. Medical command orders another dose of epinephrine and to continue transport to the hospital, which is now the closest medical facility with an ETA of approximately 2 minutes.

  • Are there any concerns regarding the patient’s current medications?
  • Is there any other prehospital procedure that is appropriate in this situation prior to arriving to the ER?

Patient follow-up: Prolonged QT

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