Cardiovascular 9: Electrical Cardioversion Portal
Strongly consider cardioversion early in the treatment of patients whose tachycardia (usually with ventricular rates > 150) is causing serious hemodynamic effects and when administration of medication is either ineffective, contraindicated, or has too slow an onset of action to correct the tachycardia. Signs and symptoms of CHF, decreased LOC, hypotension/shock, or persistent chest pain are some of the patient findings that should prompt a team to consider electrical cardioversion. Determine whether the serious signs and symptoms are due to the tachycardia rather than the tachycardia being a response to another condition, such as hypovolemic shock or pain. This is crucial.
The resuscitation team performs many actions (team action) almost simultaneously in the preparation for synchronized cardioversion. The team must remember that the seriousness of the patient's signs and symptoms determines how quickly the cardioversion must be accomplished to prevent deterioration of the patient's hemodynamic condition.
Pre-Cardioversion Team Actions
- Monitor, O2, IV line
- Attach BP and oxygen saturation monitor.
- Appropriate IV antiarrhythmic therapy may be administered on a trial basis while the patient is being prepared for electrical cardioversion. For example, one team member may give adenosine IV push for PSVT or lidocaine IV push for VT.
- Prepare for airway management by assembling needed equipment/skilled personnel.
- Consider pre-procedure sedation with or without an analgesic agent:
midazolam (Versed) 0.02 - 0.1 mg/kg IV over 1-2 minutes
etomidate 0.1 to 0.3 mg/kg IV over 30 to 60 seconds
propofol 1 to 2 mg/kg IV
For analgesic, consider fentanyl 1 to 5 μg/kg IV or morphine 0.05 to 0.15 mg/kg IV. - Prepare the defibrillator and attach to the patient.
The recommended energy levels to use for synchronized cardioversion have been standardized to facilitate easy recall. (See algorithms for specific energy settings.)
Polymorphic VT/Torsades (irregular QRS form and rate): Treat as ventricular fibrillation. Start electrical treatment at 360 J monophasic or selected energy for biphasic (120 to 200 J) unsynchronized. If unknown, use 200 J with biphasic. PEDS: For pediatric patients, use 2 J/kg unsynchronized.2
Steps of Synchronized Cardioversion
- Pre-medicate as appropriate.
- Manage airway; ventilate as needed.
- Turn on defibrillator.a
- Attach patient to defibrillator using monitor leads; confirm adequate QRS voltage.
- Press the sync button.
- Check that sync marks occur on every QRS complex. (Adjust the gain as needed.)
- Select appropriate energy level.
- Position multi-function pads or paddles on the patients.
- If using paddles, conducting pads or gel is needed.
- Announce "charging defibrillator—stand back."
- Charge defibrillator.
- Loudly announce final clearing chant: "I'm going to shock on three" "One, I'm clear" (clear self)—"Two, you are clear" (check team members)—"Three, we all are clear" (re-check self). Divert or turn off O2.
- If paddles are used, apply 25 pounds of pressure to each paddle and push the discharge buttons simultaneously until current discharged. If using pads, press and hold discharge buttons on defibrillator until current discharged.
- Observe rhythm on the monitor and assess patient.
- Observe and manage airway if the patient is no longer in tachycardia.
- If cardioversion is not successful, reset into sync mode, increase energy to next appropriate level, and proceed with synchronized cardioversion.
- Immediately defibrillate in non-sync mode if the patient has converted into VF.
References
- Hazinski MF, Field JM, Gilmore D, editors. Handbook of Emergency Cardiovascular Care. Dallas, Tx: American Heart Association, 2008.
- ECC Committee, Subcommittees and Task Forces of the American Heart Association. 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2005;112(24 suppl):IV1-203.