All this gives us knowledge on which to base a safe and accurate
operation. At the same time, the difficulties of the operation itself
thought to be so great as to make heart surgery almost impossible
has been the development of the heart- lung bypass machine, which makes
it possible to maintain the patient’s circulation from outside the body. The
heart can now be stopped and disconnected and operated on almost like
other organ. Defects in the chambers of the heart can be repaired and
stitched under direct vision. As a result, thousands of children are
leading perfectly normal lives when at one time they would have been
doomed to a miserable existence as chronic invalids.
The early success with congenital heart disease in children was
accompanied by an equal success in disease of the heart valves in adults.
Now damaged valves can be replaced, either with artificial valves made of
metal or by grafts of human or animal tissue.
There has been a spectacular development in heart surgery for
coronary heart disease where defective arteries in the heart can be replaced
by veins taken from the leg. Many thousands of patients have been relieved
of their angina by this operation. Even more recently the introduction of
angioplasty, in which a small balloon is inserted into the narrowed coronary
which is enlarged by blowing it up, is a new and successful means of
treating some cases of angina.