Science Insider
HOW DO HEART TRANSPLANTS WORK? When a heart no longer works properly, its owner may be lucky enough to receive a heart transplant. Doctors replace the diseased heart with a healthy 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. 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. The most vital medications for post-operation 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. 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 2009, the longest a person has survived after a heart transplant is 31 years.
HAVE A HEART: The heart pumps 5.6 liters of blood through the entire body in roughly 20 seconds; each day your blood travels some 12,000 miles, and your heart beats about 100,000 times. This delivers oxygen and other essential nutrients to the body's cells and organs. A heart attack occurs when the blood supply to the heart muscle is cut off, either because part of the heart is damaged (such as the valves to the chambers), or because plaque has built up inside the arteries, narrowing them and severely restricting blood flow. Symptoms of a heart attack include a squeezing discomfort in the center of the chest, pain or tingling in the left arm, shortness of breath, and sometimes a cold sweat, nausea, or dizziness.
The Biophysical Society contributed to the information contained in the TV portion of this report.