When the heart no longer works properly, a person may be lucky enough to receive a heart transplant. Doctors replace the diseased heart with a normal organ from a donor who has died. The donor organ is removed, cooled and kept in a special solution as it is transported to the patient.
For the operation, the patient is hooked up to a heart-lung machine that pumps blood through the body, bypassing the heart and lungs. The breastbone is split in half and the patient's heart is removed, except for the back walls of the atria, the heart's upper chambers. These are connected to the backs of the atria on the new heart, which is then sewn in place. Once the blood vessels are re-connected, the heart may start beating on its own as it warms up, but sometimes an electric shock is needed to start it.
Once the transplant is complete, the patient must take several medications, usually for the rest of his or her life. The most vital to survival are called immunosuppressants: These keep the body's immune system from rejecting the new organ as foreign tissue. But the drugs have side effects: hypertension, fluid retention, tremors, and possible kidney damage. The weakened immune system may also be less able to fight off genuinely threatening invaders, leading to infection. So additional drugs may also be prescribed.
Transplants are risky procedures. The most common causes of death following a transplant are infection and organ rejection, but survival rates continue to improve. Today, survival rates are 84 percent after one year, 77 percent after three years, and about 50 percent after 10 years following the transplant surgery. As of 2002, the longest a person has survived after a heart transplant is 24 years.