When the heart beats out of rhythm, it can leave you feeling tired, dizzy, or short of breath. Electrical cardioversion offers a safe and effective way to bring the heartbeat back to normal.
It uses a quick, controlled electric shock to reset the heart’s rhythm and restore steady, healthy beats.
We often use this procedure to treat conditions like atrial fibrillation or atrial flutter, where the heart’s upper chambers beat irregularly. The process is quick, done under sedation, and helps many people feel better almost immediately.
Knowing when this treatment is needed and what to expect can make the experience less stressful and more predictable.
Understanding how electrical cardioversion works and when it’s recommended helps you make informed choices about heart care.
Let’s explore what happens before, during, and after the procedure and how it supports long-term heart health.
Key Takeaways
- Electrical cardioversion resets an irregular heartbeat using a controlled electric shock.
- It’s often used for atrial fibrillation and other irregular heart rhythms.
- Proper preparation and follow-up care improve safety and recovery.
What Is Electrical Cardioversion?
Electrical cardioversion uses a controlled electric shock to restore a normal heart rhythm in people with certain types of arrhythmias.
It helps treat conditions such as atrial fibrillation and atrial flutter by resetting the heart’s electrical system so it beats regularly again.
How Electrical Cardioversion Works
During electrical cardioversion, we deliver a short, low-energy electric shock to the chest using adhesive pads or paddles. The shock passes through the heart to stop the abnormal rhythm for a brief moment.
This pause allows the heart’s sinoatrial (SA) node, the natural pacemaker, to restart a normal rhythm. The procedure is usually done under light sedation so patients stay comfortable.
We monitor heart rate, blood pressure, and oxygen throughout. The electrical energy level is carefully adjusted to each patient’s needs.
Electrical cardioversion is most often used for atrial fibrillation (AFib) or atrial flutter, where the upper chambers of the heart beat irregularly. When successful, it restores a steady rhythm and can relieve symptoms such as fatigue, shortness of breath, or chest discomfort.
Difference Between Electrical and Chemical Cardioversion
Both electrical and chemical cardioversion aim to correct abnormal heart rhythms, but they use different methods.
| Type | Method | Main Feature |
| Electrical Cardioversion | Uses controlled electric shock | Quick, done in a medical setting |
| Chemical Cardioversion | Uses medications (antiarrhythmic drugs) | May take hours or days to work |
In chemical cardioversion, we give drugs such as amiodarone or flecainide to help restore normal rhythm. This approach avoids an external shock but may be less predictable in timing and success rate.
Electrical cardioversion, by contrast, works almost immediately. We often choose it when medication alone does not correct the rhythm or when a faster result is needed.
Electrical Cardioversion vs. Defibrillation
Electrical cardioversion and defibrillation both use electric shocks, but they serve different purposes.
Cardioversion treats non-life-threatening arrhythmias like AFib, while defibrillation is an emergency procedure for life-threatening rhythms such as ventricular fibrillation.
| Feature | Cardioversion | Defibrillation |
| Timing | Shock synchronized with heartbeat | Shock given immediately |
| Energy Level | Lower (50–200 joules) | Higher (200–360 joules) |
| Use Case | Stable arrhythmia | Cardiac arrest or severe arrhythmia |
In cardioversion, the shock is synchronized with the heart’s electrical cycle to avoid causing dangerous rhythms. Defibrillation, however, delivers a high-energy shock without synchronization because the heart is not beating effectively.
When Is Electrical Cardioversion Used?
We use electrical cardioversion to correct certain abnormal heart rhythms when the heart beats too fast or irregularly. It helps restore a normal rhythm and improve how the heart pumps blood.
The treatment is planned or done urgently, depending on the type and severity of the arrhythmia.
Atrial Fibrillation and Atrial Flutter
Electrical cardioversion is most often used for atrial fibrillation (AFib) and atrial flutter. In these conditions, the heart’s upper chambers, or atria, beat irregularly or too quickly.
This can cause fatigue, shortness of breath, and an increased risk of stroke. We may recommend cardioversion when medicines alone cannot restore a normal rhythm or when symptoms remain bothersome.
Before the procedure, patients usually take blood thinners for several weeks to reduce the risk of blood clots.
Other Arrhythmias Treated
Electrical cardioversion can also treat other types of supraventricular tachycardia (SVT) and ventricular tachycardia (VT) when the rhythm is organized but abnormally fast.
These arrhythmias start in different parts of the heart and can make the heart rate rise suddenly, sometimes above 150 beats per minute.
| Type of Arrhythmia | Area of Origin | Typical Heart Rate | Cardioversion Use |
| Supraventricular Tachycardia | Above the ventricles | 150–250 bpm | Often effective |
| Ventricular Tachycardia | Ventricles | 120–250 bpm | Used if the patient is stable |
We perform cardioversion only when the rhythm is regular enough for a synchronized shock. If the rhythm is chaotic, other treatments like defibrillation are required instead.
Emergency Electrical Cardioversion
Emergency electrical cardioversion is used when a dangerously fast or irregular rhythm causes low blood pressure, chest pain, or loss of consciousness.
In these cases, restoring a normal rhythm quickly can prevent cardiac arrest or organ damage. We deliver a controlled shock while the patient is closely monitored.
This immediate action helps stabilize the heart rate and restore effective blood flow. Afterward, we identify the cause of the arrhythmia to guide further care and prevent recurrence.
Who Is a Candidate for Electrical Cardioversion?
We use electrical cardioversion for people with certain irregular heart rhythms when restoring a normal rhythm can improve heart function and symptoms.
The decision depends on the type of arrhythmia, how long it has lasted, and whether other treatments have worked or are safe.
Symptoms and Severity
We often recommend electrical cardioversion for patients with atrial fibrillation or atrial flutter who experience symptoms such as fatigue, dizziness, shortness of breath, or chest discomfort.
These symptoms usually come from the heart beating too fast or irregularly. When medications or techniques like the Valsalva maneuver fail to control the heart rate or rhythm, cardioversion becomes an option.
It can quickly restore a normal rhythm and improve how well the heart pumps blood. People with new or worsening heart failure or those showing signs of hemodynamic instability—such as low blood pressure or confusion—may need urgent cardioversion.
In some cases, we also use it after a heart attack if the irregular rhythm threatens recovery or blood flow. We carefully assess the duration of the arrhythmia.
If it has lasted longer than 48 hours, we usually check for blood clots before performing the procedure to reduce the risk of stroke.
Contraindications and Alternatives
We avoid electrical cardioversion when the risk outweighs the benefit. Active blood clots in the heart, untreated thyroid problems, or unstable electrolyte levels can make the procedure unsafe.
In these cases, we may use chemical cardioversion, which relies on medications to restore normal rhythm. For patients with mild symptoms or stable heart rates, we may focus on heart rate control instead of rhythm correction.
Some people respond well to noninvasive methods like the Valsalva maneuver or medication adjustments. Others may need long-term rhythm management strategies, such as ablation or lifestyle changes, to prevent recurrence.
Before proceeding, we review each patient’s medical history, rhythm pattern, and overall heart health to choose the safest and most effective approach.
Preparing for the Electrical Cardioversion Procedure
We take several careful steps before electrical cardioversion to ensure the procedure is safe and effective. These steps help lower the risk of blood clots, guide medication use, and prepare our body for sedation and electrical treatment.
Pre-Procedure Tests and Assessments
Before the procedure, we usually have a physical exam, blood tests, and an electrocardiogram (ECG) to check our heart rhythm.
These tests help confirm that cardioversion is the right treatment. If we have atrial fibrillation lasting more than 48 hours, our doctor may order a transesophageal echocardiography (TEE).
This test uses sound waves to look inside the heart and check for blood clots in the atria. Removing or treating these clots before cardioversion helps prevent stroke.
A TEE involves placing a small probe down the throat after we receive mild sedation. The test takes about 15 to 30 minutes.
If no clots are found, cardioversion can often be done the same day. Some patients may need chest X-rays or blood chemistry panels to evaluate heart and lung function.
These tests help confirm that we can safely receive anesthesia and electrical therapy.
Blood Thinners and Medication Management
Blood-thinning medicines play a key role in preventing blood clots before and after cardioversion. We may take warfarin or another anticlotting medicine such as apixaban, dabigatran, or rivaroxaban for at least three weeks before the procedure.
Doctors usually check our INR level if we use warfarin to make sure the blood is thin enough to reduce clot risk. After cardioversion, we often continue blood thinners for at least four weeks, since clots can still form while the heart adjusts to its normal rhythm.
We should review all our medicines with our care team. They may ask us to pause or adjust certain drugs like diuretics or antiarrhythmics.
We should never stop any medicine without medical direction.
Fasting and Day-of-Procedure Instructions
Because we receive sedation, we must fast before the procedure. Most of us are told not to eat or drink anything for 6 to 8 hours beforehand.
A small sip of water with essential medicine is usually allowed if approved by our doctor. We should wear loose, comfortable clothing and remove lotions, powders, or ointments from our chest and back.
These substances can interfere with the electrode pads used to deliver the electrical current. A nurse will place an IV line for sedation and attach monitoring leads to track our heart rhythm, blood pressure, and oxygen levels.
After the procedure, we rest until the sedation wears off and a doctor confirms our heart rhythm is stable.
What to Expect During the Procedure
During electrical cardioversion, we use controlled electrical energy to restore a normal heart rhythm. The process involves careful sedation, continuous monitoring, correct placement of electrode pads, and precise operation of the cardioversion machine.
Sedation and Monitoring
We give light sedation through an intravenous (IV) line to help patients stay relaxed and comfortable. This type of sedation allows them to sleep lightly and not feel the brief electrical shock.
A nurse or anesthesiologist monitors vital signs at all times. We track heart rate, blood pressure, oxygen level, and breathing using an electrocardiogram (ECG) and pulse oximeter.
Before starting, we confirm that emergency and recovery equipment are ready. After the procedure, we continue monitoring until the patient is fully awake and stable.
Placement of Electrode Pads
We attach two large self-adhesive electrode pads to the chest or chest and back. The most common positions are:
| Pad Placement | Description |
| Anterolateral | One pad on the right upper chest and one on the left side below the armpit |
| Anteroposterior | One pad on the front of the chest and one on the back between the shoulder blades |
We make sure the skin is clean, dry, and free of lotion or hair that could reduce contact. Proper placement allows the electrical current to pass evenly through the heart muscle.
We check the pad connection to the machine. We confirm the ECG tracing is clear before delivering the shock.
Cardioversion Machine and Equipment
The cardioversion machine, also called a defibrillator, delivers a short, controlled electrical shock through the electrode pads. We set the energy level based on the type of arrhythmia and the patient’s condition.
The device synchronizes the shock with the heart’s rhythm using the ECG signal. This timing prevents the shock from hitting during a sensitive part of the heartbeat.
We may repeat the shock if the first attempt does not restore normal rhythm. We record the ECG results and disconnect the equipment safely.
Risks and Potential Complications
Electrical cardioversion is generally safe when performed by trained professionals, but it still carries some risks. These include blood clots that can lead to stroke, temporary changes in heart rhythm or blood pressure, and minor skin or heart tissue injury from the electric current.
Blood Clot and Stroke Risk
A major concern is the movement of a blood clot from the heart to another part of the body. In people with atrial fibrillation (AFib), clots can form in the upper chambers of the heart.
When the heart rhythm is restored, these clots may travel to the brain, causing a stroke. We usually lower this risk by giving anticoagulant medication before and after the procedure.
These medicines help prevent new clots from forming and reduce the chance of stroke. In emergency cases, when cardioversion must be done quickly, doctors may use an imaging test called a transesophageal echocardiogram (TEE) to check for clots before treatment.
Heart Rhythm and Blood Pressure Changes
Electrical cardioversion aims to restore a normal rhythm, but sometimes the heart reacts unpredictably. Slow heart rate (bradycardia) or temporary irregular beats may occur after the shock.
In rare cases, more serious rhythms such as ventricular fibrillation can develop, especially if the shock is not properly synchronized with the heart’s natural cycle. We also monitor for low blood pressure, which can happen briefly after the procedure.
This usually resolves on its own or with simple treatment. Continuous heart and blood pressure monitoring during and after cardioversion helps us detect and manage these changes quickly.
Skin and Heart Damage
The electric current used in cardioversion can cause minor skin burns or bruising where the electrodes are placed. These effects are usually mild and heal within a few days.
Using conductive gel and proper pad placement reduces this risk. In rare cases, the heart muscle may experience temporary damage or inflammation.
Very rarely, cardioversion can trigger sudden cardiac death if a severe rhythm disturbance occurs. Careful preparation, correct energy settings, and skilled supervision help prevent these complications.
Recovery and Follow-Up Care
After electrical cardioversion, we focus on restoring a stable heart rhythm and reducing the chance of another arrhythmia. Recovery involves short-term monitoring, medication management, and steps to prevent future rhythm problems.
Immediate Post-Procedure Care
We usually monitor patients for one to two hours after the procedure. During this time, we check heart rhythm, blood pressure, and oxygen levels to make sure the heart stays in normal rhythm.
Mild redness or soreness can appear on the chest where the patches were placed. These spots usually fade within a few days.
Because sedative medicines are used, patients should rest and avoid driving for the rest of the day. If blood thinners were prescribed before the procedure, we continue them afterward to lower stroke risk.
This is important because the heart may not pump blood normally right away, and clots can form. Before discharge, we review symptoms that need medical attention, such as chest pain, dizziness, or irregular heartbeat returning.
We also schedule a follow-up visit to confirm that the heart rhythm remains stable.
Long-Term Management and Prevention
Maintaining a normal heart rhythm often requires ongoing care. We may prescribe antiarrhythmic medications to help prevent the arrhythmia from coming back.
Some patients also continue blood thinners to reduce clot risk, especially if they have atrial fibrillation.
Lifestyle changes support long-term heart health. These include limiting alcohol, avoiding tobacco, managing weight, and treating conditions like high blood pressure or sleep apnea.
Regular follow-up visits help us track heart rhythm and adjust treatment as needed. We may recommend periodic electrocardiograms (ECGs) or heart monitors to detect early rhythm changes.
Conclusion: Restoring Rhythm with a Safe and Proven Approach
Electrical cardioversion is a highly effective and carefully controlled procedure designed to reset an irregular heartbeat and restore the heart’s natural rhythm. Whether used for atrial fibrillation, atrial flutter, or other organized arrhythmias, it offers rapid relief from symptoms like fatigue, shortness of breath, and dizziness. Understanding how the procedure works, from preparation and sedation to delivery of the synchronized shock, helps ease anxiety and ensures patients feel more prepared. With modern monitoring technology, guided energy delivery, and expert oversight, most individuals experience immediate improvement and return to normal activities shortly afterward. Taking the time to understand the process empowers you to make informed decisions and feel confident in your treatment plan.
If you’re experiencing an irregular heartbeat or have been advised to consider cardioversion, Cardiovascular Group (CVG Cares) provides advanced diagnostics and compassionate rhythm-management care. Our cardiologists tailor every treatment plan to your needs, ensuring your heart receives the safest and most effective care available.
