After the anesthesia takes effect. The surgical area will be scrubbed with a special disinfectant soap and may also be shaved. The surgeon will then make a 6 to 8 inch incision down the middle of the chest. The breastbone is then separated, the heart sac is carefully pulled back, and the heart is examined. At this point a blood thinning medicine, called Heparin, will be given to make sure that the blood does not clot.
The surgeon will then connect the heart to the heart/lung bypass machine with a plastic tube. Blood from the heart is then sent to the bypass machine through this tube. The machine supplies the blood with oxygen and then pumps it back to the rest of the body through the other tube. While connected the blood simply bypasses the heart and lungs but still reaches the rest of the body.
After the heart/lung bypass is established, the heart will need to be cooled to keep it still. The atrium is gently opened to reveal the mitral valve. The surgeon will then carefully remove the old mitral valve. At this time the doctor will select a mechanical or tissue replacement valve and this will be sown into place with stitches.
Once securely in place the atrium will be closed with stitches. When the heart resumes its normal function and can support the body with its own pumping ability it will be completely free of the machine. Because everyone's heart is different, the time it takes to be removed from the bypass machine varies.
If your heart is slow to return to its normal function several options are available to help it regain strength. These include medication through your IV, or electrical stimulation from small, thin wires, called pacing wires to help your heart beat normally until your own heart's electrical system has recovered. These wires are placed directly onto the surface of your heart and will be left inside your chest during your hospital recovery. Usually these are temporary and should be removed prior to your going home, but in some patients the wires may need to be replaced by a permanent pacemaker.
Several chest tubes will also be placed inside the chest to collect any fluid that drains into the spaces around the heart and lungs. These help to insure that the lungs and heart are working properly.
Lastly, the breastbone is brought back together with thick steel wire. This helps the breastbone to heal and prevents movement. The skin incision is then closed with stitches and a sterile bandage is applied.