They couldn't keep my blood pressure up, so they did some tests on my heart and found a little hole . The heart's right upper chamber pumps blood to the right lower chamber, where it goes out to the lungs. The left upper chamber pumps blood to the left lower chamber, and out to the body. If a hole exists between the two upper chambers, some of the blood that's supposed to go out to the body from the left chamber goes to the right side, and a little more blood gets out to the lungs. Over time the blood vessels of the lungs can be damaged.
Doctors often recommend that at some point the hole be closed, but it can go undetected.
Wood's doctors told him his would have to be fixed by the time he was 30 or 40. After consulting with his family and the Cubs, Wood opted not to have surgery immediately. From a surgical point of view, it's a very low-risk thing to fix. Most of the time if people have one, they become symptomatic by the time they're in their 30s, or a lot of times at 2 or 3. They said there is no danger of Wood collapsing on the mound while pitching, even if the hole goes unfixed.