Cardioversion

What is cardioversion?

Cardioversion is a procedure done when you have an abnormal heart rhythm (beat). Abnormal heartbeats are also called arrhythmias. Your heartbeat is controlled by your heart's own electrical system. Problems with your heart's electrical system may cause your heart to beat abnormally, some, or all of the time. Cardioversion delivers a shock of electricity to your heart to help it return to its normal rhythm.

What kinds of arrhythmias can be helped with cardioversion?

• Your heart has four chambers called the atria and ventricles. The atria are at the top of your heart, and the ventricles are the bottom of your heart. Blood enters your atria from your blood vessels, and your atria pump blood to your ventricles. The ventricles then pump the blood out of your heart to the rest of your body. Most arrhythmias that need cardioversion start in the atria of your heart. With an abnormal heart beat, your body may not get the blood and oxygen it needs, and you may become very ill.
  
  
• Ask your caregiver for more information about the following arrhythmias:
  
  
  • Atrial fibrillation: Atrial fibrillation (AF) is the most common heart arrhythmia. With AF, the atria of the heart do not beat as they should in an orderly way with your ventricles. This causes the atria to shake or quiver. With AF, blood may begin to collect in your atria and form clots.
    
    
  • Atrial flutter: This is when the atria beat faster than they should. Normally, there is one atrial contraction (squeeze) for every heartbeat. With atrial flutter, there is more than one atrial contraction for every heartbeat. When you have atrial flutter, your atria may beat as many as 300 times each minute.
    
    
  • Supraventricular tachycardia: This is a rapid heartbeat that starts in the atria of your heart. Your heart beats so fast it cannot rest during beats to fill with enough blood for your body.
    
    
  • Ventricular tachycardia: This is when the ventricles beat too fast. Normally, the atria send electrical impulses (messages) to the ventricles to beat. With ventricular tachycardia, the ventricles beat without the message from the atria.

What symptoms may I have when I need cardioversion?

With an abnormal heart rhythm, you may have no symptoms. When symptoms do occur, you may have the following:

• Chest tightness or pain.
  
  
• Dizziness and feeling faint.
  
  
• Feeling like you heart is jumping in your chest.
  
  
• Weakness and tiredness.
  
  
• Shortness of breath.

What may I need before cardioversion?

• Medicines: You may need the following:
  
  
  • Blood thinners: This medicine helps stop clots from forming in your blood. Blood thinners also may help break down a clot in your atrium. You may need to take blood thinners for up to three weeks before your procedure. You will also need to take blood thinners for at least four weeks after your cardioversion. Blood thinners make it easier for you to bleed or bruise. If you shave, use an electric shaver. Use a soft toothbrush to help keep your gums from bleeding.
    
    
  • Heart medicine: This medicine is used to help make your heart more sensitive to the electrical charge. This helps your heart change back to a normal beat during cardioversion.
  
  
• Blood tests: You may need blood taken to give caregivers information about how your body is working. The blood may be taken from your hand, arm, or IV.
  
  
• Transesophageal echocardiogram:
  
  
  • A transesophageal echocardiogram (TEE) is a type of ultrasound that shows pictures of the size and shape of your heart. It also looks at how your heart moves when it is beating. These pictures are seen on a TV-like screen. If you are unable to take blood thinners before your cardioversion you may need a TEE to check for clots.
    
    
  • You will be given medicine to relax you during a TEE. Caregivers put a tube in your mouth that is moved down into your esophagus (food pipe). The tube has a small ultrasound sensor on the end. Since your esophagus is right next to your heart, your caregiver can see your heart clearly.

What happens during cardioversion?

You will be given medicine that makes you sleepy and relaxed before your procedure. You may also get anesthesia medicine to help you fall, and stay asleep during the procedure. During cardioversion, your caregiver sends an electrical shock to your heart muscle. The shock is given at a certain time during your heartbeat that will best help it return to normal. You may need to be shocked more than once to help your heart return to its normal rhythm. With treatment, your heart rate and rhythm may return to normal, and your symptoms, such as dizziness may resolve. Having cardioversion done may even save your life. You may need one of the following kinds of cardioversion:

• External: During external cardioversion, paddles or gel pads are used to shock your heart. Two pads will be placed on your chest, or one will be on your chest and one on your back. Your caregiver will watch your heart beat on a monitor for the right time to deliver the shock. After the shock is given, your heartbeat will be checked. If your heart continues to beat abnormally, another shock will be given.
  
  
• Internal: During internal cardioversion, catheters (long, thin, bendable tubes) are put into your heart. Your caregiver inserts the catheters through a vein (blood vessel) and up into your heart. The electric shock is then given through the catheters.

What happens after cardioversion?

You will be taken to a room where you can rest until you are fully awake. Do not get out of bed until your caregiver says it is okay. Caregivers will monitor your heart rhythm, and watch you closely for any problems. When caregivers see that you are not having any problems, you may be able to go home. If you are staying in the hospital, you will be taken back to your room.

What are the risks of cardioversion?

• You may have an allergic response to the anesthesia medicine used during your procedure. The electric shock used may cause burns on your skin. If you have internal cardioversion, you may bleed or get an infection. If you have a blood clot in your heart, the procedure may cause the clot to travel out of your heart. If a blood clot travels to your lungs, you may have trouble breathing. Blood clots also may travel to your brain causing a stroke, and you may die. Even with cardioversion, your heart may not return to, or stay in a normal heart rhythm. You also may begin to have other arrhythmias that need treatment.
  
  
• Without treatment, your arrhythmia and symptoms, such as chest pain and tightness, may get worse. Your heart may not be able to pump enough blood and oxygen to the rest of your body. You may have worsening weakness, dizziness, and trouble breathing. Arrhythmias that are left untreated can increase your risk of heart failure or a heart attack. Arrhythmias also increase your risk for blood clots forming in your heart, and you may have a stroke. Choosing not to treat your abnormal heart rhythm may also lead to death. Talk to your caregiver if you have questions or concerns about your condition or procedure.

Where can I find more information?

Contact the following for more information:

• American Heart Association National Center
  7272 Greenville Avenue
  Dallas , TX 75231-4596
  Phone: 1- 800 - 242-8721
  Web Address: http://www.americanheart.org
  

When should I call my caregiver?

Call your caregiver if:

• You have a fever.
  
  
• You have chest pain or trouble breathing that is getting worse over time.

When should I seek immediate help?

• You suddenly feel lightheaded and have trouble breathing.
  
  
• You have new and sudden chest pain. You may have more pain when you take deep breaths or cough. You may cough up blood.
  
  
• Your arm or leg feels warm, tender, and painful. It may look swollen and red.

Seek immediate help or call 911 if:

• Call 911 or an ambulance if you have any signs of a heart attack:
  
  
  • Discomfort in the center of your chest that feels like squeezing, pressure, fullness, or pain, that lasts for more than a few minutes or keeps returning
    
    
  • Discomfort or pain in your back, neck, jaw, stomach, or one or both of your arms
    
    
  • Feeling sick to your stomach
    
    
  • Having trouble breathing
    
    
  • A sudden cold sweat, particularly in combination with chest discomfort or trouble breathing
    
    
  • Feeling very lightheaded or dizzy, particularly in combination with chest discomfort or trouble breathing
  
  
• You have signs of a stroke: The following signs are an emergency. Call 911 immediately if you have any of the following:
  
  
  • Weakness or numbness in your arm, leg, or face (may be on only one side of your body)
    
    
  • Confusion and problems speaking or understanding speech
    
    
  • A very bad headache that may feel like the worst headache of your life
    
    
  • Not being able to see out of one or both of your eyes
    
    
  • Feeling too dizzy to stand

Care Agreement

You have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your caregivers to decide what care you want to receive. You always have the right to refuse treatment.

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The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

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