A dual-chamber pacemaker is small, electrical device that can be implanted into the chest to regulate the heartbeat. It works by generating electric impulses that are sent to the right atrium and right ventricle of the heart, thereby stimulating contractions and allowing the two chambers to maintain rhythm. Pacemakers can greatly improve symptoms and increase life expectancy in patients who have dangerously slow heart rates, congenital heart defects, or complications from cardiac failure.
When medications and less-invasive procedures are ineffective at correcting heart problems, a cardiologist may consider pacemaker placement. A dual-chamber pacemaker is necessary when the heart is too weak to maintain the timing of the right atrium and ventricle. The first electrical impulse in a series signals the atrium to pump de-oxygenated blood into the ventricle. The second impulse triggers the ventricle to pump blood to the lungs so it can be oxygenated and reintroduced to the heart.
The main body of a dual-chamber pacemaker, called the generator, is usually less than 2 inches (about 5 centimeters) in diameter. The battery-powered generator is equipped with a memory chip that stores information and signals the release of electricity. Two wire leads run from the generator to the heart. The batteries in modern pacemakers usually last for at least 10 years. When a battery does run low, a surgeon can implant a new generator and reconnect the wires that are already in place.
In most cases, a dual-chamber pacemaker surgery can be performed in about one hour in a specialty clinic or general hospital. Before the procedure, a patient is given an injection of localized anesthetic in the chest to numb the area. A small incision is made in the upper-left side of the chest and the dual-chamber pacemaker is secured just underneath the skin. With the aid of real-time x-ray imaging, the surgeon guides two wires into the subclavian vein and directs them to their respective chambers in the heart. The wires are connected to the pacemaker and tested before the surgical scar is closed.
After the procedure, most patients need to stay in the hospital for at least a day so doctors can monitor their conditions and make sure their pacemakers are functioning properly. Frequent follow-up visits in the first six months are important to determine if pacemaker settings need to be adjusted. When patients respond well in the six-month period, they may only need to attend checkups once or twice a year. By making smart lifestyle decisions and attending scheduled doctors' visits, most people who receive pacemakers are able to extend their lives by years or even decades.