Papillary muscle-annular continuity: is it important?

The interactions between the mitral valve and left ventricle are complex and not yet completely understood. However, continuity between the papillary muscles and the mitral annulus is probably the most important factor in this relationship because severance of the chordae tendineae in experimental animals causes a significant drop in left ventricular systolic function as assessed by load independent parameters. This deterioration in ventricular function is even more marked in dilated hearts due to chronic mitral regurgitation. There is strong clinical evidence that maintenance of papillary muscle-annular continuity during mitral valve surgery is beneficial to left ventricular function and clinical outcome. That is one of the reasons why the mitral valve should be repaired rather than replaced in patients who need mitral valve surgery. If replacement is necessary, the chordae tendineae should be preserved. If preservation of chordae tendineae is difficult because of calcification, fibrosis, or for other reasons it is possible to resuspend the papillary muscle with expanded tetrafluoroethylene sutures. Preservation of chordae tendineae during mitral valve replacement is also important because it prevents spontaneous rupture of the posterior wall of the left ventricle, a rare but dreaded complication of this type of surgery.