Abstract
Ann experimental study was performed to evaluate the influences of various annular plication on the mitral annulus. With the aid of extracorporeal circulation, lead markers were sutured on the annulus of 25 adult mongrel dogs. Annular plication was not done for 5 dogs of control group (Group I). Annular plications were performed at the posterior commissural side in 5 dogs (Group II), at the middle part in 5 dogs (Group III), at the anterior commissural side in 5 dogs (Group IV). Entire annulus of posterior leaflet was plicated following the modified technique of De Vega in 5 dogs (Group V). The areas surrounded by radiopaque markers and the distances between markers were measured at the various phases of cardiac cycle. In Group II dogs, changes of annular area in the cardiac cycle were similar to those in control group. Contraction of annular area was well maintained. Contraction of the posterior part of nonplicated annulus of posterior leaflet was prominent at the time of ventricular contraction. In Group III dogs, the posterior part of plicated annulus was drawed to anterior leaflet. In Group IV dogs, annuluar contraction at the time of ventricular contraction was weak. In Group V dogs, reduction of area at the time of atrial contraction was not noticed.
