Arrhythmia, << uh RIHTH mee uh, >> is an abnormal heart rhythm. Arrhythmias often are extra heartbeats that cause no serious problems. However, sometimes the heart rhythm can become dangerously slow or fast.
Abnormally slow heart rhythms frequently are a sign of heart block, a condition in which the electrical impulses started by the heart’s natural “pacemaker” fail to be conducted to the ventricles, the heart’s main pumping chambers. The heart rate becomes very slow, which may cause loss of consciousness, heart failure, or death. A doctor can correct the condition by implanting an electronic pacemaker in the body. This device transmits an electric impulse to the heart, stimulating it to beat in a normal rhythm.
Abnormally fast heart rhythms are the chief cause of disabling symptoms or death from heart disease. Such arrhythmias can occur unexpectedly in the months or years after a heart attack. Many can be controlled with medication. In serious emergencies, they can be treated by applying a strong electric shock, but the shock must be administered within minutes to prevent severe heart damage or death. In some cases, doctors implant a device called a defibrillator to detect and treat abnormally fast heart rhythms. The defibrillator monitors the heart and automatically delivers electric shocks before the arrhythmia causes permanent damage.
See also Atrial fibrillation; Defibrillator; Digitalis; Lidocaine.
