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Defibrillator vs Cardioversion Understand the Difference

Defibrillator vs Cardioversion: Understand the Difference

Have you ever wondered about the difference between defibrillation and cardioversion? In this context, it’s important to understand “defibrillator vs cardioversion.” These life-saving procedures are vital in treating various heart conditions, but understanding their distinctions is essential for both healthcare professionals and patients. In this blog post, we will dive into the nuances of defibrillator vs cardioversion, discussing their purposes, techniques, and potential complications. Buckle up, and let’s explore the world of heart rhythm management together!

Defibrillation and Cardioversion: A Comparison

Defibrillation and Cardioversion_ A Comparison

Defibrillation and cardioversion are both essential procedures for addressing cardiac arrhythmias, but they serve different purposes and employ distinct techniques. Cardioversion and defibrillation is an urgent, unsynchronized, high-energy shock treatment for life-threatening arrhythmias, such as ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT), when a patient does not have a pulse.

On the other hand, cardioversion is performed as an elective, synchronized, low-energy shock procedure used to re-establish normal cardiac rhythm in individuals with specific types of arrhythmias, such as atrial fibrillation or flutter.

The distinction between defibrillation and cardioversion is primarily based on their synchronization and energy levels. In defibrillation, an unsynchronized, high-energy shock is delivered to the heart to stop life-threatening arrhythmias in pulseless patients. Cardioversion, however, involves administering a synchronized, low-energy shock at a precise moment to restore a normal heart rhythm in patients with certain types of arrhythmias. The shock timing in cardioversion is vital to prevent disruption of the cardiac cycle.


Defibrillation, as previously stated, is a critical procedure for dealing with life-threatening cardiac arrhythmias like ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT) when a patient doesn’t have a pulse. The procedure involves delivering electrical energy to the heart through electrodes, which temporarily stuns the heart and allows it to return to a normal sinus rhythm.

Depending on the particular situation, the suggested energy level for defibrillation may vary. A defibrillation shock of 120 Joules (J) is enough to stop ventricular fibrillation (VF) or pulseless ventricular tachycardia (VT). In a monophasic setup, the amount is increased to 200 J.

In the case of polymorphic VT with a pulse, which may present a rapid ventricular response, defibrillation with energy settings of 120 to 200J biphasic is recommended, as this condition can lead to cardiac arrest if not treated promptly.


By providing a low-energy electrical shock at an exact moment, cardioversion, a medical procedure, aims to restore a normal sinus rhythm in patients with an arrhythmia. This procedure is commonly employed to manage patients with decompensated rapid atrial fibrillation or atrial flutter. The timing of the shock during cardioversion is established by viewing a defibrillator monitor or utilizing a machine that synchronizes the rhythm automatically.

The recommended energy level for synchronized cardioversion varies depending on the patient’s condition. For patients with atrial fibrillation and hemodynamic compromise, cardioversion should be done using a biphasic defibrillator. The energy used for the first shock should be 120 Joules (J), and further shocks should be increased to 200 J. Synchronized cardioversion is recommended for monomorphic VT with a pulse. The energy should begin with a 100 J biphasic (or 100 J monophasic) shock and can be gradually increased to 200 J biphasic (360 J monophasic) if required to attain sinus rhythm.

Monophasic vs Biphasic Waveforms

Monophasic vs Biphasic Waveforms

In the world of defibrillators, there are two types of waveforms: monophasic and biphasic. A monophasic defibrillator utilizes a single waveform to deliver an electrical shock. On the other hand, a biphasic waveform, discovered in the 1980s, is a type of waveform utilized in defibrillators that have been observed to be more effective and cause fewer complications than monophasic shocks in certain cases.

The main distinction between monophasic and biphasic waveforms lies in their effectiveness and potential complications.

Biphasic waveform defibrillators, which utilize biphasic defibrillation:

  • Deliver a more consistent magnitude of current
  • Are typically more effective at terminating arrhythmias at lower energies
  • Are often preferred over monophasic waveforms for their improved success rates and decreased risk of complications.

Indications and Contraindications

Indications and Contraindications

Recognizing the specific scenarios where defibrillation and cardioversion are advisable or discouraged is crucial. For instance, cardioversion is typically utilized to manage patients with:

  • Atrial fibrillation or flutter
  • Supraventricular tachycardia (SVT) is caused by blockages in the heart’s electrical conduction system
  • Premature atrial or ventricular beats
  • Cardiac stimulants
  • Thyroid conditions
  • Valvular and coronary artery disease
  • Digoxin toxicity

However, there are certain contraindications for cardioversion. Dysrhythmias due to enhanced automaticity, such as in digitalis toxicity catecholamine-induced arrhythmias, and multifocal atrial tachycardia are contraindications for cardioversion. Understanding these indications and contraindications is crucial for healthcare professionals in providing the most effective and safe treatment for their patients.

Equipment and Techniques

Having the right equipment and understanding the correct techniques is vital for safely and effectively executing defibrillation and cardioversion procedures. Defibrillators (automated external defibrillators [AEDs], semiautomated AEDs, standard defibrillators with monitors) and paddle or electrode pads are necessary for both procedures.

When using hand-held paddle electrodes for defibrillation, follow these steps:

  1. Activate the defibrillator.
  2. Select the required energy level.
  3. Position the paddles on the patient’s chest.
  4. Apply firm pressure.
  5. Charge the paddles.
  6. Deliver the shock.

For cardioversion, self-adhesive patch electrodes are placed on the patient’s chest and are effective for defibrillation and cardioversion procedures. Proper technique and equipment are essential in ensuring the success and safety of both procedures.

Special Considerations

In unique scenarios such as pediatric patients and pregnant women, defibrillation and cardioversion procedures necessitate special considerations.

When performing defibrillation in pediatric patients, it is crucial to consider factors such as:

  • Pad placement
  • Energy levels
  • Clear airway maintenance
  • Ensuring no one is touching the child during the shock delivery

For pregnant women, cardioversion can be performed, but it is essential to monitor the baby’s heartbeat continuously throughout the procedure to ensure no adverse effects from the treatment.

Understanding and addressing these special considerations is vital for healthcare professionals in providing the most effective and safe treatment for their patients. By taking these factors into account, defibrillation and cardioversion procedures can be tailored to meet the unique needs of each patient, ensuring optimal outcomes and patient safety.

Chemical vs Electrical Cardioversion

In some cases, antiarrhythmic medications, also known as chemical cardioversion, can be used as an alternative to electrical shocks for restoring normal heart rhythm. Chemical cardioversion involves the use of medications to convert an accelerated or irregular heartbeat back to a normal rhythm. Some commonly used medications for chemical cardioversion include:

  • Dofetilide
  • Azimilide
  • Dronedarone
  • Cardizem
  • Metoprolol
  • Ibutilide fumarate
  • Flecainide
  • Amiodarone

These medications are typically employed for this purpose.

Although chemical cardioversion can be effective in some situations, studies have shown that the success rate of electrical cardioversion is typically around 90%, while chemical cardioversion has a slightly lower success rate, ranging between 77% and 81%.

Comprehending the distinctions between chemical and electrical cardioversion allows healthcare professionals to choose the most suitable treatment for their patients’ arrhythmias.

Potential Complications

Potential Complications

Like any medical procedure, defibrillation and cardioversion may come with risks and potential complications. Some risks associated with defibrillation include injury during CPR, with broken ribs being a common occurrence, particularly among elderly individuals.

Cardioversion, on the other hand, may be associated with arrhythmias, thromboembolism, and skin burns, among other potential complications.

Healthcare professionals need to be cognizant of these potential complications and take steps to mitigate the risks. Proper technique, adherence to guidelines, and regular training can help ensure the safety and success of defibrillation and cardioversion procedures while reducing the likelihood of complications.

Preparing for and Recovering from Cardioversion

Preparing for and Recovering from Cardioversion

Patients undergoing cardioversion can expect thorough preparation and a smooth recovery process. Advanced Cardiovascular Life Support (ACLS) measures are implemented before the procedure. These measures include:

  • Obtaining intravenous access
  • Preparing airway management equipment
  • Administering sedative drugs
  • Using a monitoring device

If blood clots are discovered prior to cardioversion, the procedure may be delayed for three to four weeks while the patient is administered blood-thinning medications.

After electric cardioversion, patients should:

  • Be monitored for one to two hours in a recovery bed
  • Have someone accompany them home, as their decision-making abilities might be impaired for a few hours post-treatment
  • Be prescribed blood thinners for several weeks following the procedure to reduce the risk of new clot formation
  • Make lifestyle adjustments to promote heart health and address or prevent arrhythmia-causing conditions such as high blood pressure.

Choosing the Right Defibrillator

Choosing the right defibrillator is vital for ensuring effective and secure patient treatment. Factors such as storage conditions, electromagnetic fields, and accessibility should be taken into account when choosing a defibrillator. Manual defibrillators, while designed for medical professionals and offering advanced capabilities, may require training and have limited accessibility compared to automated external defibrillators (AEDs).

Ultimately, the choice of a defibrillator should be informed by the specific environmental factors and settings in which it will be used. By selecting the right defibrillator, healthcare professionals can ensure its effectiveness and usability, leading to improved outcomes and patient safety.

Enhancing Outcomes and Patient Safety

Regular training, collaborative education, and compliance with guidelines significantly enhance the success and safety of defibrillation and cardioversion procedures. Training programs can provide healthcare professionals with an understanding of the procedures, including the correct timing and technique of defibrillation and cardioversion. Additionally, training can ensure that healthcare professionals are aware of the latest guidelines and advancements in the field, helping to ensure the most effective and safe treatment for patients.

Interprofessional education is essential in improving outcomes and patient safety during defibrillation and cardioversion procedures. It fosters collaboration among the interprofessional team, leading to more effective evaluation and treatment of patients utilizing these procedures. By prioritizing education and collaboration, healthcare professionals can enhance patient outcomes and safety during defibrillation and cardioversion procedures.


In conclusion, understanding the differences between defibrillation and cardioversion is crucial for healthcare professionals and patients alike. By exploring the nuances of these life-saving procedures, we have shed light on their purposes, techniques, and potential complications. Regular training and interprofessional education play a significant role in improving patient outcomes and safety during these procedures. By staying informed and adhering to best practices, healthcare professionals can provide the most effective and safe treatment for their patients, ultimately saving lives and improving overall heart health.

Frequently Asked Questions

What is the difference between cardioversion and defibrillator?

Defibrillation is the asynchronous delivery of a higher energy shock, compared to cardioversion, which involves synchronizing energy to the QRS complex. A defibrillation shock from an AED is more powerful and resets the heart to beat normally.

What is the mortality rate for cardioversion?

The mortality rate for cardioversion is 9.0 per 100 patient-years in the high cardioversion-frequency group and 1.4 in the low-frequency group.

How many times can you shock a heart with a defibrillator?

You can shock a heart with a defibrillator up to three times in succession, as advised by the AED’s programming.

How to do cardioversion?

To do cardioversion, your doctor will attach electrodes to your chest and possibly your back, connected to a defibrillation machine that will record your heartbeat and send a brief electric current to reset your heart’s rhythm. This shock lasts less than one second.

What are the recommended energy levels for defibrillation and cardioversion?

The recommended energy level for defibrillation is typically 120 Joules (J) (200 J monophasic) and depends on the patient’s condition for cardioversion, starting with a biphasic defibrillator at 120 J for patients with atrial fibrillation and hemodynamic compromise.

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