What are Pacemakers?

Pacemakers are used when a persons heart is unable to beat on it's own or has an irregular electrical sequence.  The hearts electrical spark begins in specialized heart tissue called the SA node, which is located in the right atrium.  Each time this tissue "fires," an electrical impulse is generated that travels first through the right and left atria, signaling these chambers to contract and pump blood into the ventricles. The impulse then travels down into another small patch of specialized heart tissue called the AV node, which is located between the atria and the ventricles. The electrical impulse is conducted through the AV node and then through specialized wire-like pathways into the ventricles, where it signals the ventricles to contract and to pump blood out into the lungs and throughout the body. This normal sequence of electrical activation of the chambers of the heart is called sinus rhythm. It occurs each time the heart beats, usually about 60 to 80 times every minute.  When this electrical spark or impulse fails or develops a disturbance then Pacemakers are useful to maintain proper heart function. 

Pacemakers are battery-powered implantable devices that function to electrically stimulate the heart to contract and thus to pump blood throughout the body.  Pacemakers are small devices that are only a few inches long.  It contains a battery and a electronic circuitry which is what runs the pacemaker.

How the test is performed:
Implanting a Pacemaker is a procedure that is performed at a hospital.  In general, implantation of a pacemaker takes about an hour.  Pacemakers consist of a pager-sized housing device which contains a battery and the electronic circuitry that runs the pacemaker, and one or two long thin wires that travel through a vein in the chest to the heart.  An incision is made, usually on your left chest or shoulder.  The pacemaker will sit just under the skin.  The two long thin wires that travel through a vein into the chest to the heart are the electrodes.  When the pacemaker detects that the heart has experience a irregular electrical sequence are has failed to beat then the pacemaker will deliver a electrical shock to stimulate the heart via the electrodes.


How to prepare for the test:
Patients are usually instructed not to eat or drink anything beginning at midnight before the procedure. Patients should generally take their morning dose of medications (and can take a couple sips of water to help swallow the medications) unless instructed otherwise by their doctor. Patients who are to undergo pacemaker implantation late in the day may occasionally be permitted to have a very light breakfast, such as juice and Jell-O.

How the test will feel:
After the procedure, patients are usually observed in the hospital for a day or so to make sure no bleeding or infection occurs at the site of pacemaker implantation. Patients will usually be monitored overnight in an intensive care or intermediate care unit where their heart beat can be continuously monitored. Patients who have a pacemaker inserted may be treated for several days with antibiotics to decrease the chances of infection developing.  Recovery will continue for another 7 to 10 days in the hospital during which time activities are be gradually resumed.