Synchronized Cardioversion (Ambulatory) - CE

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    Synchronized Cardioversion (Ambulatory) - CE/NCPD


    Do not perform cardioversion as the first-line treatment for stable atrial fibrillation and atrial flutter because there is a risk of a mural thrombus breaking loose and creating emboli.undefined#ref1">1


    The goal of synchronized cardioversion is to deliver an electrical shock with a goal of converting tachyarrhythmia to a normal stable rhythm.5,7 Cardioversion is performed using a defibrillator; some defibrillators deliver monophasic waveforms, whereas others deliver biphasic waveforms. Knowing which type of waveform the defibrillator delivers is important because the recommended joules (J) for cardioversion are different for monophasic and biphasic waveforms.

    The AHA recommends emergent synchronized cardioversion for these conditions:6

    • Unstable supraventricular tachycardia (SVT)
    • Unstable atrial fibrillation
    • Unstable atrial flutter
    • Unstable ventricular tachycardia

    An unstable patient has an acute altered mental status, ischemic chest discomfort, hypotension, or other signs of shock that are likely to be secondary to the arrhythmia.

    If the patient is stable, a 12-lead electrocardiogram (ECG), consultation with a cardiac specialist, and pharmacologic therapy should be considered before synchronized cardioversion. For patients with atrial fibrillation lasting longer than 48 hours, treatment options include rate control with medication or delayed cardioversion after anticoagulation therapy.9

    If the patient’s heart rate is less than 150 beats per minute with a regular rhythm,6 the patient probably has an underlying noncardiac condition, such as sepsis or fever, which is unlikely to respond to synchronized cardioversion. Treatment should instead focus on correcting the causative condition.


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    • Provide developmentally and culturally appropriate education based on the desire for knowledge, readiness to learn, and overall neurologic and psychosocial state.
    • Explain the procedure as the delivery of a small electrical shock to the heart. Advise the patient that multiple attempts may be necessary.
    • Inform the patient that this procedure is performed while the patient is awake (unless general anesthesia is used) but that, in most cases, sedation with medication produces a relaxed and drowsy state.
    • Explain that some patients report a brief, very sharp pain but that the sedative usually causes amnesia regarding the procedure and the pain.
    • Explain that, after the procedure, there may be redness of the skin and minimal soreness of the chest wall.
    • Instruct the patient who is discharged home to seek emergency care promptly if the patient experiences chest pain, shortness of breath, lower extremity swelling, dizziness, weakness, or changes in vision or speech.
    • Encourage questions and answer them as they arise.


    1. Perform hand hygiene and don gloves. Don additional personal protective equipment (PPE) based on the patient’s need for isolation precautions or the risk of exposure to bodily fluids.
    2. Introduce yourself to the patient.
    3. Verify the correct patient using two identifiers.
    4. Explain the procedure and ensure that the patient agrees to treatment.
    5. Ensure that evaluation findings are communicated to the clinical team leader per the organization’s practice.
    6. If time permits, ask the patient about a history of acute myocardial ischemia or infarction, heart failure, pulmonary edema, or tachyarrhythmia.
    7. Obtain the patient’s vital signs and evaluate for signs and symptoms of hemodynamic instability.
      1. Dizziness
      2. Exertional symptoms
      3. Weakness
      4. Hypotension
      5. Abnormal heart rate (tachycardia or bradycardia)
    8. If the patient’s condition permits, perform these steps:
      1. Obtain a standard 12-lead ECG.
      2. Establish IV access.
      3. Obtain electrolyte levels.
      4. Obtain a digoxin level if applicable.
        Rationale: If the patient is stable, transportation to a facility with cardiology specialty evaluation is recommended before synchronized cardioversion.
      5. Ask the patient about the current medication regimen and when the last doses of each medication were taken.
      6. Allow the patient to empty the bladder before the procedure begins.
    9. Assist or ask the patient to remove anything metallic (e.g., keys, jewelry).
      Prevent burns and inappropriate transmission of current by keeping the patient away from metallic objects, which are excellent conductors of electrical current.
    10. Remove any transdermal medication ointment or patches. Ensure that the residual cream or ointment is also wiped off the patient’s skin.
      Rationale: The ointment or patches may result in an alternate path for the electrical current and may cause skin burns.
    11. Assist the patient to a resting, supine position. Ensure that the patient is not touching any siderails.
    12. Expose the patient’s chest for the procedure. Ensure privacy and provide warmth for the rest of the patient’s body.
      Rationale: A lack of privacy may increase the patient’s anxiety level.
    13. Remove any dirt or debris from the skin with soap and water.
      Rationale: Removing skin oils and lotion with soap and water, and then drying the skin completely, improves electrode adherence and maximizes delivery of pacing energy through the chest wall.
    14. Clip (rather than shave) excessive chest hair, if applicable and if time allows.
      Rationale: The use of clippers or scissors rather than shaving prevents microscopic skin tears that may lead to infection.
    15. Ensure that the patient’s chest is dry before applying the electrodes or paddles.
    16. Preoxygenate the patient, as needed, per the practitioner’s order or per the organization’s practice.
    17. Premedicate the patient with sedative and analgesic medications as prescribed.
      Rationale: Cardioversion may be painful and cause anxiety for patients.
    18. Reevaluate the patient’s sedation level and pain status, allowing for sufficient onset of action per the medication, route, and the patient’s condition. Evaluate for adverse reactions to the medication (e.g., respiratory depression).
    19. Continuously observe the patient’s hemodynamic status.
      Rationale: Sudden deterioration of the patient’s condition may warrant rapid synchronized cardioversion or an asynchronous shock if the patient becomes pulseless and converts to ventricular fibrillation or ventricular tachycardia.6
    20. Check the cables and lead wires of the defibrillator for fraying, broken wires, or discoloration. Replace the cable and lead wires per the organization’s practice.
      Rationale: Using frayed, broken, or discolored cables or lead wires could cause harm to the patient or health care team member delivering the shock to the patient.
    21. Turn on the cardioversion-defibrillation function of the defibrillator.
    22. Attach the monitor leads and confirm the patient’s rhythm is displayed properly.
    23. Prepare to position the multifunction electrode pads in an anterior-anterior (sternum-apex), anteroposterior, or alternate position as directed.
      Rationale: The recommendation is to use multifunction electrodes rather than paddles. They are safer for the patient and health care team members and provide better skin contact and conduction.
      For atrial arrhythmias, the clinical team leader may prefer alternate pad locations; place multifunction electrode pads as directed.
      1. Anterior-anterior (sternum-apex) position (Figure 1)Figure 1: The anterior multifunction electrode is placed to the right of the upper third of the sternum below the clavicle; the apex multifunction electrode is placed to the left of the nipple line below the axilla.
      2. Anteroposterior position (Figure 1)Figure 1: The anterior multifunction electrode is placed over the precordium; the posterior multifunction electrode is placed behind the heart at the left scapular line at the inferior angle of the scapula.
    24. Place the multifunction electrode pads.
      Do not place the multifunction electrode pads over wires, drains, dressings, ECG electrodes, or medication patches.
      If a patient has either an internal cardiac defibrillator (ICD) or an implanted pacemaker, ensure that the multifunction electrodes are placed a minimum of 10 cm (4 inches) from the implanted device.7
    25. Activate the synchronization (SYNC) function, per the manufacturer’s instructions for use.
      Observe for whether the defibrillator reverts to synchronization mode after each attempt or whether it needs to be reset each time to deliver a subsequent synchronized shock.
    26. Identify markers on the QRS complex indicating that the defibrillator is in synchronization mode (Figure 2)Figure 2.
    27. Adjust the R wave gain on the monitor to ensure that synchronization markers occur on each QRS complex.
      Rationale: Ensuring that synchronization markers occur on each QRS complex avoids a delay or failure to deliver the shock in synchronization mode and prevents delivery of the shock during the relative refractory period.
    28. If using the multifunction electrodes is not possible, follow these steps for paddle use:
      1. Apply a conductive gel to the paddles and rub them together to spread the gel over their surfaces.
        Rationale: Burns may occur if there is insufficient or excessive conductive medium.
      2. Make sure that the paddles are placed correctly, ensuring that no path of gel is between them.
        Rationale: A path of gel or incomplete paddle contact may cause an energy arc to occur.
      3. Press firmly to ensure full contact between the paddles and the chest wall.
        Rationale: Maximal contact between the chest wall and the paddle decreases transthoracic impedance. Proper pressure applied to the paddles and proper positioning decrease the risk of burns.
      4. If a patient has large breasts, place the paddle at the apex of the heart under the left breast.
    29. Select the energy level based on the specific device’s recommendations.
    30. Perform these safety steps immediately before delivering the shock:
      1. Charge the defibrillator and state “Clear” loudly.
      2. Visually confirm that no health care team members have direct or indirect contact with the patient.
        Rationale: Bystanders in contact with the patient during cardioversion may receive a mild shock or burns.
      3. If oxygen from a face mask or bag mask is blowing directly on the patient’s chest, turn the oxygen device away from the patient’s chest.
      4. Check the cardiac monitor one last time to verify that the patient is still experiencing tachyarrhythmia and that the defibrillator is in synchronization mode (as evidenced by synchronization marks on each R wave).
    31. Deliver a shock by depressing the discharge button until the energy is delivered; this may take several milliseconds as the defibrillator seeks the next R wave. When using paddles, depress both discharge buttons simultaneously and hold them down until discharge occurs.
      Look at the patient when depressing the discharge button(s) to ensure that no one is touching the patient.
    32. Reevaluate the patient and check the rhythm after every shock.
      1. If the tachyarrhythmia persists, increase the energy level in a stepwise manner and deliver another shock.5
        Check that synchronization mode is active after each attempt.
      2. If ventricular fibrillation results, immediately deliver a defibrillation (asynchronous) shock at 360 J or a clinically equivalent biphasic shock (120 to 200 J).6 Ensure that synchronization mode is turned off or there may be a delay in delivering the defibrillation shock.
    33. After the synchronized cardioversion, disconnect the equipment from the patient and wipe off the gel from the patient’s chest (if necessary). Return the patient’s clothing and assist the patient to a comfortable position.
    34. Perform these steps after the synchronized cardioversion procedure:
      1. Record the patient’s vital signs.
      2. Obtain a hard copy of the postshock rhythm.
      3. Repeat the 12-lead ECG.
    35. Clean the defibrillator per the manufacturer’s instructions for use. Return the equipment to its assigned storage location.
    36. Discard supplies, remove PPE, and perform hand hygiene.
    37. Document the procedure in the patient’s record.


    • Restoration of normal sinus rhythm
    • Adequate perfusion as indicated by normal mental status, no shortness of breath or chest pain, resolution of dizziness, and signs of adequate tissue perfusion


    • Burns from insufficient or excessive conductive medium or multiple shocks
    • Pulmonary embolus (rare)
    • Inadvertent injuries to patient or health care team member


    • Vital signs
    • Either an ECG or a rhythm strip (or both) before and after each synchronized cardioversion attempt
    • Time and energy used for each cardioversion attempt and the patient’s response
    • Neurologic and pulmonary status as indicated by the patient’s condition or the organization’s practice, until the patient is transported or discharged home
    • Condition of the skin on the chest wall before and after cardioversion
    • Time-out procedure, including verification of correct patient, correct procedure, and correct site (if performed)
    • Signs and symptoms of cardiac arrhythmias or cardiac problems (e.g., chest pain, syncope, dizziness, palpitations)
    • Evaluation findings communicated to the clinical team leader per the organization’s practice
    • Education
    • Unexpected outcomes and related interventions


    • A pediatric patient with a tachyarrhythmia may present with a history of respiratory distress, poor feeding, irritability, syncope, chest pain, palpitations, and light-headedness.3
    • For pediatric patients, the initial energy level is 0.5 to 1 J/kg; the second dose is delivered at 2 J/kg.4,8
    • SVT is the most common tachyarrhythmia seen in pediatric patients.3 SVT not responsive to medical treatment is more common in infants.4
    • If vascular access is available, consider treating a pediatric patient who has unstable SVT with adenosine before performing cardioversion.8
    • The American Heart Association recommends using the largest electrode pads or paddles possible (that do not touch each other) because the smaller pediatric defibrillation electrodes or paddles increase transthoracic impedance.2,4 The manufacturer’s guidelines regarding pad size should be followed.
    • In infants and children, the multifunction electrodes must not touch each other.2,4
    • Neonates and children may be propped on their side so that an anteroposterior paddle placement can be used.


    1. Clinical Overview. (2023). Atrial fibrillation. Retrieved May 30, 2023, from
    2. Easter, J.S. (2023). Chapter 158: Pediatric resuscitation. In R.M. Walls and others (Eds.), Rosen’s emergency medicine: Concepts and clinical practice (10th ed., pp. 2030-2041). Philadelphia: Elsevier.
    3. Horeczko, T. (2023). Chapter 165: Pediatric cardiac disorders. In R.M. Walls and others (Eds.), Rosen’s emergency medicine: Concepts and clinical practice (10th ed., pp. 2109-2131). Philadelphia: Elsevier.
    4. Lewis, J. and others. (2017). Acute management of refractory and unstable pediatric supraventricular tachycardia. The Journal of Pediatrics, 181, 177-182. doi:10.1016/j.jpeds.2016.10.051 (classic reference)* (Level IV)
    5. Minczak, B.M., Laub, G.W. (2019). Chapter 12: Defibrillation and cardioversion. In J.R. Roberts and others (Eds.), Roberts and Hedges’ clinical procedures in emergency medicine and acute care (7th ed., pp. 238-257). Philadelphia: Elsevier.
    6. Panchal, A.R. and others. (2020). Part 3: Adult basic and advanced life support: 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation, 142(16 Suppl. 2), S366-S468. doi:10.1161/CIR.0000000000000916 Retrieved May 30, 2023, from (Level I)
    7. Tainter, C.R., Wardi, G. (2023). Chapter 66: Implantable cardiac devices. In R.M. Walls and others (Eds.), Rosen’s emergency medicine: Concepts and clinical practice (10th ed., pp. 921-933). Philadelphia: Elsevier.
    8. Topjian, A.A. and others. (2020). Part 4: Pediatric basic and advanced life support: 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation, 142(16 Suppl. 2), S469-S523. doi:10.1161/CIR.0000000000000901 Retrieved May 30, 2023, from (Level I)
    9. Yealy, D.M., Kosowsky, J.M. (2023). Chapter 65: Dysrhythmias. In R.M. Walls and others (Eds.), Rosen’s emergency medicine: Concepts and clinical practice (10th ed., pp. 890-920). Philadelphia: Elsevier.

    *In these skills, a “classic” reference is a widely cited, standard work of established excellence that significantly affects current practice and may also represent the foundational research for practice.

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