The experimental production of mitral insufficiency (MI) has been carried out by numerous investigators, usually for either or both of 2 purposes: (1) creation of a preparation on which to attempt surgical repair and (2) study of the pathophysiology. Acute and chronic preparations have been used for both purposes, but the chronic animal has more often been used for surgical programs, while the acute preparation has more often been utilized in physiologic investigations. The purpose of this communication is to review briefly the methods of producing experimental MI and to present a method which has several advantages.
The methods of producing MI can be classified in several ways. Considering them under the heading of the actual technical procedure carried out, we find that at least 6 methods have been used.
I. Cutting the Chordae Tendineae.
—This has been probably the most popular method. It involves a closed technique, sometimes