The Electrical Cardioversion Procedure: What You Need to Know by Cardiovascular Group Explained Clearly

Key Takeaways

Electrical cardioversion resets an irregular heartbeat to a normal rhythm.
The procedure is quick, safe, and usually done under light sedation.
Knowing how to prepare and recover helps ensure the best results.

What Is Electrical Cardioversion?

Electrical cardioversion uses controlled electric shocks to restore a normal heart rhythm in people with certain types of arrhythmias.

It helps the heart’s electrical system reset so the sinoatrial node can resume its role as the natural pacemaker.

How Electrical Cardioversion Works

During electrical cardioversion, we deliver a brief, low-energy shock to the heart through adhesive pads placed on the chest and sometimes the back.

The shock momentarily stops abnormal electrical activity, allowing the heart’s normal rhythm to restart.

We perform this procedure under short-acting anesthesia so the patient remains comfortable and unaware of the shock.

Continuous monitoring tracks heart rate, blood pressure, and oxygen levels throughout the process.

The energy level of the shock depends on the type of arrhythmia.

For atrial fibrillation or atrial flutter, we usually start with a lower energy setting and adjust if needed.

Most people need only one or two shocks to restore a steady heartbeat.

After the procedure, we observe the patient for a short period to ensure the rhythm remains stable.

Many return home the same day with instructions for follow-up care and medications that help maintain a normal rhythm.

Electrical vs. Chemical Cardioversion

Cardioversion can be performed using either electrical energy or medications.

Both aim to correct irregular heart rhythms, but they work in different ways.

Type	Method	Typical Use	Onset
Electrical Cardioversion	Delivers an electric shock to the heart	Atrial fibrillation, atrial flutter	Immediate
Chemical Cardioversion	Uses antiarrhythmic drugs to restore rhythm	Mild or short-term arrhythmias	Gradual

We choose electrical cardioversion when a quick, controlled reset is needed or when medications have not worked.

Chemical cardioversion may be preferred for patients who cannot undergo anesthesia or have mild rhythm disturbances.

Both methods require evaluation for blood clots before treatment, as restoring rhythm can increase stroke risk if clots are present.

Defibrillation and Cardioversion: Key Differences

Defibrillation and cardioversion both use electric shocks, but they serve different purposes.

Cardioversion treats organized but abnormal rhythms like atrial fibrillation, while defibrillation treats life-threatening rhythms such as ventricular fibrillation or pulseless ventricular tachycardia.

Cardioversion delivers a synchronized shock timed with the heart’s electrical cycle.

This timing prevents the shock from occurring during a sensitive phase of the heartbeat.

Defibrillation, by contrast, uses an unsynchronized high-energy shock to stop chaotic electrical activity immediately.

Feature	Cardioversion	Defibrillation
Shock Type	Synchronized	Unsynchronized
Energy Level	Low to moderate	High
Patient Condition	Conscious, stable	Unconscious, emergency

We use cardioversion in a controlled setting, often as an outpatient procedure.

Defibrillation is an emergency measure used to save a life when the heart stops beating effectively.

Who Needs Electrical Cardioversion?

We use electrical cardioversion to restore a normal heart rhythm when the heart beats too fast or irregularly.

It helps prevent complications like stroke and heart failure that can result from untreated arrhythmias.

Common Arrhythmias Treated

Electrical cardioversion most often treats atrial fibrillation (AFib) and atrial flutter.

In AFib, the upper chambers of the heart quiver instead of beating effectively, which can cause blood clots and raise the risk of stroke.

Atrial flutter is similar but has a more regular pattern.

We may also use this procedure for supraventricular tachycardia (SVT), which starts in the upper chambers and causes a very fast heart rate.

In some cases, it helps with ventricular tachycardia, a rhythm that begins in the lower chambers and can be life-threatening if not corrected quickly.

Arrhythmia Type	Typical Heart Area	Common Risk
Atrial Fibrillation	Atria (upper chambers)	Stroke, heart failure
Atrial Flutter	Atria	Fatigue, shortness of breath
Supraventricular Tachycardia	Above ventricles	Dizziness, fainting
Ventricular Tachycardia	Ventricles	Cardiac arrest

Symptoms Indicating the Procedure

We consider electrical cardioversion when symptoms interfere with daily life or pose health risks.

Common signs include shortness of breath, fatigue, chest pain, dizziness, and fainting.

These occur because the heart cannot pump blood efficiently when it beats irregularly or too fast.

Patients may also notice a rapid or fluttering heartbeat that does not improve with medication.

If an irregular rhythm continues, it can strain the heart and lead to heart failure or increase the chance of stroke.

In such cases, restoring normal rhythm helps the heart work more effectively and improves how patients feel day to day.

When Cardioversion Is Not Recommended

We avoid electrical cardioversion in certain situations.

If a patient has a blood clot in the heart, the procedure could dislodge it and cause a stroke.

We typically perform imaging tests, such as a transesophageal echocardiogram, to rule this out.

Cardioversion may also be delayed or avoided if the patient has severe electrolyte imbalances, uncontrolled heart failure, or unstable blood pressure.

In these cases, we focus on correcting the underlying issue first.

Patients with chronic or long-standing AFib that has not responded to other treatments may need different approaches, such as medication or ablation, instead of cardioversion.

Preparing for the Electrical Cardioversion Procedure

We take several careful steps before performing an electrical cardioversion to help ensure safety and success.

These steps focus on checking heart health, reviewing medication use, and identifying any risks, such as blood clots that could cause complications.

Pre-Procedure Evaluation

Before the procedure, we review the patient’s medical history and current symptoms.

We discuss any past heart conditions, surgeries, or allergic reactions to medicines.

This helps us plan the safest approach for restoring a normal rhythm.

We often perform an electrocardiogram (ECG) to confirm the type of arrhythmia.

Some patients may also need an echocardiography test to assess heart structure and function.

If there is a concern about blood clots, we may order a transesophageal echocardiography (TEE).

This test uses sound waves to create detailed images of the heart from inside the esophagus.

It allows us to check for clots in the upper chambers of the heart before proceeding.

We also review fasting instructions, transportation plans, and sedation safety to ensure the patient is ready for the day of the procedure.

Medications and Blood Thinners

Managing medicines is a key part of preparation.

We review all current prescriptions, including blood-thinning medicines such as warfarin or newer anticlotting medicines.

These drugs reduce the risk of blood clots moving during or after cardioversion.

If the patient is already on a blood thinner, we confirm the dosage and timing.

Some patients may need to start or adjust medication several weeks before the procedure.

We also discuss whether to continue or stop other drugs, such as those for diabetes or high blood pressure.

Patients should not make any changes without our direction.

After the procedure, we often continue blood thinners for at least four weeks to prevent new clots from forming while the heart rhythm stabilizes.

Blood Tests and Imaging

We use blood tests to check for anemia, kidney function, and electrolyte balance.

These results help us plan anesthesia and identify any hidden issues that could affect the procedure.

If the patient takes warfarin, we measure the INR (international normalized ratio) to confirm the blood is thin enough to prevent clotting but not so thin that it increases bleeding risk.

Imaging tests such as TEE or standard echocardiography may be repeated if new symptoms appear or if the patient’s condition changes.

These tests give us a clear picture of heart function and help prevent complications like stroke or embolism.

Step-by-Step: The Electrical Cardioversion Procedure

We perform electrical cardioversion in a controlled hospital setting to safely restore a normal heart rhythm.

The process includes giving short-acting sedation, placing electrode pads on the chest, and using a cardioversion machine to deliver a carefully timed electric shock.

Sedation and Monitoring

Before starting, we give sedation through an intravenous (IV) line to help patients relax and prevent discomfort.

The sedation is short-acting, so recovery happens quickly.

We also attach monitors to track heart rate, blood pressure, and oxygen levels throughout the procedure.

Our medical team stays at the bedside to adjust the sedation level as needed.

Continuous monitoring allows us to respond right away if any changes occur.

We use oxygen and have emergency equipment ready, though complications are rare.

Once the patient is stable and asleep, we prepare the chest area for electrode placement.

Electrode Pads and Cardioversion Machine

We place electrode pads (also called patches) on the chest, sometimes one on the front and one on the back.

These pads connect to the cardioversion machine, which controls the energy level and timing of the electrical impulse.

Proper pad placement is important to ensure the current travels through the heart effectively.

We often use a small amount of gel or adhesive to improve contact and reduce skin irritation.

The machine synchronizes with the patient’s heartbeat to deliver energy at the safest point in the heart’s electrical cycle.

This synchronization prevents accidental shocks during vulnerable phases of the heartbeat.

Delivering the Electric Shock

Once everything is ready, we press the control on the cardioversion machine to send a high-energy shock through the pads.

The shock lasts less than a second and aims to “reset” the heart’s electrical system, allowing the normal rhythm to resume.

We may need to deliver more than one shock if the first attempt does not restore a regular rhythm.

After each shock, we check the heart’s rhythm on the monitor to see if it has stabilized.

When the rhythm returns to normal, we stop the sedation and continue to observe the patient until they are fully awake and stable.

Risks and Complications of Electrical Cardioversion

Electrical cardioversion is generally safe, but it still carries some risks.

The most common concerns involve changes in heart rhythm, blood clot formation, and mild side effects from the procedure or medications used.

Potential Heart Rhythm Issues

After cardioversion, the heart may return to an abnormal rhythm or develop a slow heart rate (bradycardia).

These rhythm changes happen because the heart’s electrical system can react unpredictably to the shock.

Some patients may experience low blood pressure right after the procedure.

This usually improves within minutes but requires monitoring.

Rarely, cardioversion can cause a more dangerous rhythm, such as ventricular tachycardia.

This is uncommon but serious.

In these cases, our team acts quickly to restore a safe rhythm.

Heart damage from the shock is rare because the energy level is carefully controlled.

The procedure is done under close supervision with continuous heart monitoring to detect and correct any irregularities immediately.

Blood Clot and Stroke Risks

When the heart beats irregularly, such as during atrial fibrillation, blood clots can form inside the atria. If a clot moves to the brain, it can cause a stroke.

To lower this risk, we often prescribe anticoagulant (blood-thinning) medication before and after cardioversion. This helps prevent new clots from forming or existing clots from traveling.

The risk of stroke is highest if cardioversion is done without proper anticoagulation or if the irregular rhythm has lasted more than 48 hours.

In some cases, a transesophageal echocardiogram (TEE) is used before the procedure to check for clots in the heart. This imaging step helps ensure it is safe to proceed with cardioversion.

Other Side Effects

Mild skin damage or redness can occur where the electrodes are placed. This irritation usually fades within a few days.

Some people feel short-term fatigue, muscle soreness, or mild chest discomfort. These effects are temporary and respond well to rest and simple care.

Serious complications like heart attack, heart failure, or sudden cardiac death are very rare. They are more likely in people with severe underlying heart disease.

We monitor patients closely during and after cardioversion to detect any early signs of complications and provide immediate treatment if needed.

Recovery and Follow-Up Care

After an electrical cardioversion, we focus on restoring comfort, monitoring heart rhythm, and preventing another irregular heartbeat.

Immediate Post-Procedure Care

We usually stay in a recovery area for at least an hour while nurses monitor our heart rhythm, blood pressure, and oxygen levels. The sedative may cause fatigue or dizziness, so we should not drive, operate machinery, or make major decisions for the rest of the day.

Mild redness or chest pain can occur where the electrode pads were placed. Applying a cool compress and keeping the skin clean can ease discomfort.

Most of us can return home the same day. However, we should rest for 24 to 48 hours and avoid strenuous activity.

If we notice shortness of breath, chest pain, or fainting, we must contact our healthcare provider right away.

Typical short-term instructions:

Activity	Recommendation
Driving	Avoid for 24–48 hours
Work	Resume after 1–2 days if feeling well
Exercise	Light activity only after clearance
Monitoring	Check pulse daily and report irregularities

Medications After Cardioversion

After cardioversion, we often continue or start blood thinner medicine to reduce the risk of blood clots. This is especially important if we have atrial fibrillation.

The provider decides how long we need anticoagulation based on our heart rhythm and medical history.

We may also take heart rate control or antiarrhythmic drugs to help maintain a normal rhythm. It is important to take these medicines at the same time each day and not skip doses.

Some medications can cause mild side effects such as dizziness, fatigue, or upset stomach. We should report any new or worsening symptoms to our doctor.

Regular blood tests may be needed to check medication levels and kidney or liver function.

Long-Term Heart Rhythm Management

Follow-up care plays a major role in long-term success.

We usually have a checkup within a few weeks to review our heart rhythm, blood pressure, and medication plan.

Doctors may use an electrocardiogram (ECG) or heart monitor to confirm that our rhythm stays normal.

If irregular beats return, another cardioversion or medication adjustment may be needed.

We can reduce recurrence by maintaining a healthy weight and limiting alcohol.

Managing stress and treating conditions like high blood pressure or sleep apnea are also important.

Ongoing communication with our healthcare team ensures that any changes in symptoms—such as chest pain, fatigue, or dizziness—are addressed early.

Conclusion: A Clear Path Toward Restoring a Healthy Heart Rhythm

Electrical cardioversion is a straightforward, effective procedure that helps reset an irregular heartbeat and restore the heart’s natural rhythm. By understanding how the process works, from preparation and sedation to the brief electrical shock and short recovery period, you can approach the experience with greater confidence and peace of mind. For many patients, cardioversion provides rapid symptom relief, enhanced heart function, and a significant reduction in long-term risks associated with arrhythmias, such as atrial fibrillation. With proper preparation, follow-up care, and support from a trusted cardiology team, most individuals recover quickly and return to normal routines feeling stronger and more at ease.

If you’re dealing with an irregular heartbeat or want to understand whether cardioversion is right for you, Cardiovascular Group (CVG Cares) offers expert evaluation and personalized rhythm-restoration care.

Book your appointment with CVG Cares today.