The impulses continue through a conductive pathway into the ventricles and cause their contraction, resulting in the pumping of blood through the arteries to the body and lungs. Aside from speeding up in situations such as physical activity and slowing during rest or sleep, the normal heart typically completes 72 of these cycles a minute. But the main predisposing factor, according to the American Heart Association, is acquired heart disease. Some arrhythmias aren't serious enough to warrant treatment. To treat serious arrhythmias, doctors can turn to a permanently implanted artificial pacemaker or defibrillator.
Alternative treatments are drug therapy and surgical correction.
The pulse generator of the artificial pacemaker corrects for a defective sinus node or conduction pathway by emitting rhythmic electrical impulses similar to those of the sinus node. Usually, it's made with a titanium metal case and other materials compatible with the body and powered by a lithium battery system. The doctor implants the generator under the skin in the upper left part of the chest, attaching it to lead wires threaded to the heart. The first pacemaker was implanted in 1958. These early devices had only one wire and paced the ventricles at regular intervals.