A heart shock, which doctors call electrical cardioversion, may restore the heart’s regular rhythm. A doctor may recommend a heart shock to treat atrial fibrillation (AFib).

If a person’s heart has an atypical rate or rhythm, which doctors call arrhythmia, it may cause uncoordinated and sluggish blood circulation. This can lead to serious problems, such as heart failure and stroke. AFib is a common type of arrhythmia.

This article explores what AFib is in further detail. It also explains what a heart shock is, the potential risks of the procedure, and what it involves. Finally, the article discusses other treatments for AFib.

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In AFib, a person has an irregular, quivering heartbeat. This arrhythmia can occur when electrical abnormalities in the atria, or upper heart chambers, cause the atrial tissue to contract irregularly. This can result in uncoordinated blood flow to the ventricles or lower heart chambers, which causes an irregular heart rhythm.

This atypical heart rhythm may cause changes in a person’s blood pressure and heart function, which can lead to serious conditions, such as stroke.

People with AFib can be asymptomatic, which means they do not experience any symptoms and may be unaware of their condition. However, when symptoms occur, they can include:

Learn more about the types of AFib.

A heart shock, which doctors refer to as electrical cardioversion, is one of two types of cardioversion. Healthcare professionals call the other pharmacological cardioversion, which involves using medication to restore a person’s regular heartbeat.

The electrical signals that control someone’s heartbeat begin in the atria, and people with AFib have fast, irregular electrical impulses moving through these chambers.

In a heart shock procedure, doctors use electrodes, or paddles, to administer a short electrical shock to the heart. This briefly stops the heart, which allows the electrical impulses in the atria to reset into a regular, natural rhythm.

There are some risks involved in electrical cardioversion. These include:

  • skin irritation in the areas where the doctor places the paddles
  • a person’s natural heart rhythm may not return, their AFib may worsen, and they may still require medication or surgery
  • a blood clot may loosen and travel to the brain, where it can cause a stroke

A doctor may give a person blood thinning medication for 3–4 weeks before the procedure to reduce the risk of blood clots. They may also use a transesophageal echocardiogram (TEE) to check for blood clots before the procedure.

A healthcare professional will insert a tube into a person’s mouth and throat to perform a TEE. They will spray the individual’s throat with medication to numb it and suppress the gag reflex. The doctor will also administer sedative medication and attach electrodes to the patient’s chest to record their heartbeat.

Electrical cardioversion involves the following steps:

  • A healthcare professional will sedate a person by administering an anesthetic through an intravenous line going into the vein to make them sleepy and prevent them from feeling pain.
  • They will place a paddle on the patient’s back or chest, or they may place both paddles on the chest.
  • They will then deliver an electric shock to briefly stop and reset a person’s heart rhythm.
  • In some cases, people only require a single shock. The doctor will check a person’s heartbeat to determine whether they need further shocks.

The procedure is typically short and painless, and people can generally go home on the day of their electrical cardioversion.

Various other treatments are available for AFib, including medications, surgery, and lifestyle changes.

Medications for AFib may include:

  • calcium channel blockers, such as diltiazem and verapamil, slow a person’s heart rate
  • sodium channel blockers and potassium channel blockers to help restore a person’s typical heart rhythm
  • beta-blockers, such as metoprolol, bisoprolol, and atenolol, which slow a person’s heart rate
  • anticoagulant medications, such as rivaroxaban or apixaban, to prevent blood clots from forming
  • digoxin, which slows electrical currents in the upper chambers of the heart

Lifestyle changes for AFib may include:

Surgery for AFib may involve a doctor inserting a pacemaker or catheter ablation. The latter involves using radiofrequency energy to destroy areas of heart tissue that are causing the heart to beat with an irregular rhythm.

AFib is an arrhythmia that affects the atria, or upper chambers, of the heart. It occurs when electrical impulses in the atria malfunction and cause an irregular heartbeat. It can lead to severe complications, such as heart failure and stroke.

A heart shock, or electrical cardioversion, involves doctors administering an electrical shock through electrodes on the chest or back. The heart shock briefly stops the electrical impulses in a person’s heart and allows them to reset to a typical, regular rhythm.

There are some risks involved in electrical cardioversion. The most serious risk is a blood clot becoming loose and moving to the brain, where it can cause a stroke. However, doctors may prescribe anticoagulant medication a few weeks before the procedure to lower this risk.

Other treatments for AFib involve various medications to control the rhythm and rate of the heart, surgery, and lifestyle changes.

A person can speak with a doctor to determine which treatment options may be best for them.