Electrocardioversion, also known as electrical cardioversion or electric cardioversion, is an effective method of restoring normal sinus rhythm in patients with certain cardiac arrhythmia, such as atrial fibrillation or flutter. During the treatment, two electrodes are placed in the chest area that emit targeted electrical impulses to normalise the heart rhythm. In contrast to defibrillation, which is used mainly in emergency situations for life-threatening arrhythmias, cardioversion is a controlled and planned intervention.

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Cardioversion overview

In medicine, a distinction is made between electric and medicinal cardioversion. Electric cardioversion corrects the heart rhythm by means of targeted electric shock, while medicinal cardioversion aims to restore the normal sinus rhythm with the help of special antiarrhythmics, such as flecainide, propafenone, amiodarone and ibutilide. It is also important to distinguish between electrocardioversion and defibrillation, which is used only in acute emergency situations:

Cardioversion versus defibrillation

Both defibrillation and electric cardioversion use electrical impulses to correct the sinus rhythm. However, they differ significantly in terms of intensity and application situation.

Defibrillation

The defibrillator is used in acute emergency situations for life-threatening arrhythmia, such as ventricular fibrillation or pulseless ventricular tachycardia. Very high energy pulses are emitted without synchronisation with the heart rhythm in order to bring the heart back into a regular rhythm and save the patient’s life. Defibrillation is usually carried out immediately and without anaesthesia, as time is a crucial factor.

Electrocardioversion

Electric cardioversion, on the other hand, is a planned intervention that isusually used to treat persistent but not immediately life-threatening arrhythmia, such as atrial fibrillation or atrial flutter. Low energy electrical impulses are emitted at a certain moment of the cardiac cycle in order to bring the heart gently back into the sinus rhythm.

Treatment goal

The aim of electrocardioversion is to restore normal heart rhythm in order to reduce the risk of complications such as heart failure, blood clots and stroke, and to increase the resilience of those affected. For patients suffering from atrial flutter, atrial fibrillation or a rapid, irregular heartbeat, electrocardioversion may be an effective treatment option.

Cardioversion process

Electrocardioversion is performed on an outpatient basis in specialist hospitals and centres. The patient receives a short anaesthesia of about five minutes, so that the intervention is painless. Similar to defibrillation, but in a controlled environment, two electrodes (paddles) of the cardioverter are attached to the chest. After placement of the paddles, a short, targeted electric shock is delivered synchronously with the heart action in order to normalise the heart rhythm. The severity of the shock depends on the illness and is generally lower than with an emergency defibrillation. Based on the ECG, the attending cardiologist can determine whether the cardioversion was successful and administer further, stronger current shocks if necessary.

After the electric cardioversion, the patient remains in the hospital for a few hours to monitor their heart rhythm and general state of health. As a rule, the patient can leave the hospital on the same day as long as there are no complications.

Preparation and precautions

Before a planned electrical cardioversion, the attending doctor performs an ECG and examines the atrial appendage using a transoesophageal echocardiogram, as this area of the heart is particularly susceptible to the formation of blood clots. It also excludes possible illnesses that could argue against cardioversion, such as digitalis poisoning, existing blood clots (thrombi) or an overactive thyroid (hyperthyroidism). In order to prevent the formation of blood clots, medication is usually administered three to four weeks before cardioversion.

On the treatment day, the patient should fast; i.e. not eat at least six hours before the intervention and not drink at least two hours before.

Aftercare and recovery

After treatment, patients will be monitored for two to three hours to check their heart rate and blood pressure. Due to the short anaesthesia and the sedatives received, it is not permitted to drive or operate machinery on the same day. Regular check-ups in the days and weeks after treatment are important to ensure that the heart rhythm remains stable over a longer period of time and that no complications arise.

Success rate of electrocardioversion

The success rate of a cardioversion is very high at more than 90%. Since the electrical signals emitted during cardioversion do not harm the heart, the therapy can be repeated in the event of a relapse.

If the procedure does not achieve the desired result, cardioversion can be repeated or supplemented with additional methods to treat cardiac arrhythmia, such as the use of a pacemaker or catheter ablation.

Potential complications

Electrocardioversion is a low-risk intervention, but in rare cases side effects can occur:

  • Skin redness: Slight skin redness may occur on the areas where the electrodes have been applied.
  • Aching muscles: Some patients report a temporary feeling in the ribcage that feels like sore muscles.
  • Cardiac arrhythmia: Other cardiac arrhythmia occurs rarely, but it can be remedied with electrical treatment.
  • Blood clot formation: In rare cases, particularly in cases of inadequate prevention of blood clotting, there is an increased risk of blood clots or strokes.