Closed heart surgery

Surgery on the great vessels was followed by the development of closed heart surgery, where a small incision is made (the chest cavity is not opened) and the surgeon blindly worked on the beating heart. It left a great deal to be desired, but had much to offer for great risk. Palliation of severe mitral valve stenosis, which was common in the past due to rheumatic fever, could be accomplished by poking a finger into the (mitral) valve through an incision in the left atrium. If a finger didn't do, a knife was passed through the incision to cut out tissue. Following successful treatment of mitral stenosis, a special cutter for aortic valve stenosis was developed, that maneuvered through an incision in the left atrium, accomplished much the same thing as the surgeon's finger in a stenosed mitral valve.