American Medical Association Family Medical Guide - American Medical Association [339]
Cardiac arrest is a medical emergency. Call 911 or your local emergency number immediately if someone you know goes into cardiac arrest. If you are alone with the person, call for emergency medical assistance first, and then use a portable defibrillator if one is available. Or begin cardiopulmonary resuscitation (CPR) if you are trained to perform CPR. These techniques can stimulate the heart and keep the brain alive until emergency medical help arrives. It is possible to recover from cardiac arrest if the heartbeat and circulation are restored within a few minutes. The chances of recovering from cardiac arrest are good if emergency treatment is prompt and effective. If emergency treatment is delayed, damage to the heart and brain can be permanent.
Treatment
If cardiac arrest is caused by ventricular fibrillation, the person’s heartbeat can often be restored with a portable defibrillator (see below).
In people who have recurring episodes of ventricular tachycardia that does not respond to treatment with drugs, a device called an implantable defibrillator (see page 584) may be recommended. The device senses the onset of an arrhythmia and automatically provides a potentially lifesaving electrical shock to the heart muscle. Some implantable defibrillators also function as pacemakers (see page 584).
Portable Defibrillators Can Save Lives
An automatic external defibrillator is a portable electronic device that can be used to restore the heartbeat of a person whose heart is beating irregularly (fibrillating) or has stopped beating. With the push of a button, a person who has been trained to use the device can administer an electric shock to another person’s heart through conductive adhesive pads placed directly on his or her chest. The device also analyzes the person’s heart rhythm. Increasing numbers of public facilities, such as airports, shopping malls, hotels, and workplaces, have portable defibrillators available for use in an emergency. These devices come with easy-to-understand instructions, so even people who have not been trained can use them effectively.
Atrial Fibrillation and Flutter
In atrial fibrillation and flutter, the atria (the two upper chambers of the heart) contract (beat) irregularly and are not synchronized with the contractions (beating) of the ventricles (the two lower, pumping chambers of the heart). These uncoordinated heartbeats impair the heart’s ability to pump blood to the tissues.
Atrial flutter is similar to atrial fibrillation, except that in atrial flutter the muscles contract more regularly and at a somewhat slower rate. Both fibrillation and flutter tend to come and go, alternating with periods of normal heart rhythm.
Atrial fibrillation and flutter are usually the result of heart disease (see page 558). The fibrillation or flutter can also be caused by an overactive thyroid gland, high fever, or excessive consumption of alcohol. Any disease that causes heart failure and enlargement of the right or left atrium can cause atrial fibrillation and flutter. In about 10 percent of cases, especially among older people, the condition has no obvious cause. People who have atrial fibrillation or flutter have an increased risk of embolism (see page 601), seizures (see page 686), heart failure (see page 570), or stroke (see page 669).
Symptoms
Atrial fibrillation and flutter often do not cause symptoms. When symptoms occur, they can include palpitations (heartbeats that you’re aware of), weakness, dizziness, angina (chest pain), or fainting. Some people also have symptoms of heart failure such as shortness of breath or fatigue. If you have symptoms of atrial fibrillation or flutter, see your doctor right away.
Diagnosis
To diagnose atrial fibrillation or flutter, your doctor will probably order an electrocardiogram (ECG; see page 559) and an echocardiogram (see page 561) to evaluate the condition of your heart. Because atrial fibrillation or flutter often comes and goes, you may need to wear a portable ECG device called a Holter monitor (see page 580) for 24 hours