1.  Field Of The Invention
The invention relates to a catheter apparatus for use in separating the two leaflets of the mitral valve of the heart during a surgical procedure known as a commissurotomy. 
2.  Description of the Prior Art
In certain types of heart diseases the leaflets of the heart valves fuse together near the valve orifice obstructing the flow of blood.  If the condition is severe the current medical practice is to replace the damaged valve with an artificial valve.  Insertion of an artificial heart valve requires major surgical intervention.  Thereafter, the patient must remain chronically on drugs to prevent complications from hemolysis. 
Heart surgeons have developed another surgical procedure called commissurotomy to correct fused heart valve leaflets or commissures.  This procedure involves opening the chest, stopping the heart and cutting the fused leaflets apart.  Although commissurotomy has been fairly successful it is a major surgical procedure. 
Catheters have long been used for a variety of purposes in the blood vessels and other passageways in the body.  Generally catheters are elongated flexible tubes inserted into a person's body to withdraw or inject fluids.  A special type catheter frequently used to close a passageway is comprised of a lumen with one or more inflatable balloons at one end.  When inflated the balloon presses against the walls of the passageway.  Cannon in U.S. Pat.  No.  3,154,077 discloses a balloon type catheter for post operative use in ano-rectal surgery.  Wallace in U.S. Pat.  No.  3,045,677 uses a similar catheter in the uretha.  A tracheal tube having balloons to occupy the spaces above and below the open larynx is disclosed in U.S. Pat.  No.  4,091,816.  Shihata in U.S. Pat.  No.  4,295,464 discloses a ureteric stone extractor having a dislodger balloon.  Balloon type catheters for opening blood vessels are disclosed in U.S. Pat.  Nos.  4,271,839 and 4,273,128.  Pollack in U.S. Pat.  No.  4,285,341 reveals a balloon type catheter for use during cardiac cannulation.  Banka in U.S. Pat.  No.  4,292,976 uses a catheter having a balloon tip to inject dye into the right ventricle of the heart. 
Despite the wide variety of catheters in the prior art none are suitable for correcting damaged heart valves.