The first American-made nuclear-powered pacemaker was developed and implanted at Newark Beth Israel Medical Center in Newark, New Jersey.

The first pacemaker implanted into an infant was July 26, 1974 to Jason A. Haines when he was 16 hours old.

Permanent pacemaker placement
Placement of a permanent pacemaker involves placement of one or more pacing wires within the chambers of the heart. One end of each wire is attached to the muscle of the heart. The other end is screwed into the pacemaker generator. The pacemaker generator is a hermetically sealed device containing a power source and the computer logic for the pacemaker.

Most commonly, the generator is placed below the subcutaneous fat of the chest wall, above the muscles and bones of the chest. However, the placement may vary on a case by case basis.

Basic pacemaker function
Modern pacemakers all have two functions. They listen to the heart's native electrical rhythm, and if the device doesn't sense any electrical activity within a certain time period, the device will stimulate the heart with a set amount of energy, measured in joules

Advancements in pacemaker function
When first invented, pacemakers controlled only the rate at which the heart's two largest chambers, the ventricles, beat.

Many advancements have been made to enhance the control of the pacemaker once implanted. Many of these enhancements have been made possible by the transition to microprocessor controlled pacemakers. Pacemakers that control not only the ventricles but the atria as well have become common. Pacemakers that control both the atria and ventricles are called dual-chamber pacemakers. Timing the contractions of the atria to precede that of the ventricles improves the pumping efficiency of the heart and can be useful in congestive heart failure.

Rate responsive pacing allows the device to sense the physical activity of the patient and respond appropriately by increasing or decreasing the base pacing rate via rate response algorithms.

The DAVID trial4 have shown that unnecessary pacing of the right ventricle can lead to heart failure. New devices can minimize the amount of right ventricle pacing to a minimum and thus prevent worsening of the heart disease.

Another advancement in pacemaker technology is left ventricular pacing. A pacemaker wire is placed on the outer surface of the left ventricle, with the goal of more physiological pacing than what is available in standard pacemakers. This extra wire is implanted to improve symptoms in patients with severe heart failure.

Devices with pacemaker function
Sometimes devices resembling pacemakers, called ICDs (implantable cardioverter-defibrillators) are implanted. These devices are often used in the treatment of patients at risk for sudden cardiac death. An ICD has the ability to treat many types of heart rhythm disturbances by means of pacing, cardioversion,or defibrillation.