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This Article Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Donald D. Glower Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Glower, D. D. Search for Related Content PubMed Articles by Glower, D. D.

J Thorac Cardiovasc Surg 1996;112:725-766
© 1996 Mosby, Inc.

SURGERY FOR ACQUIRED HEART DISEASE

Commentary

Associate Professor of Surgery
Duke University Medical Center
Durham, NC 27710

Gorman and associates present an elegant study providing information important to the physiology of mitral valve function and of mitral valve repair and replacement. This study, like that of Komeda and associates, ¹ documents the precise spatial relationships of various parts of the mitral valve relative to the left ventricle and to the chest wall throughout the cardiac cycle. Although the study examined anesthetized, normal sheep, their data have several implications for human beings with mitral valve disease:

1. The saddle shape of the normal mitral valve throughout the cardiac cycle is confirmed. The importance of maintaining this shape during mitral valve operations remains highly debated.
   
2. Systolic torsion of the left ventricle is confirmed, as demonstrated by others using magnetic resonance and tantalum radiography. The effects of mitral valve surgery on left ventricular torsion and the significance of these effects are only now being assessed.
   
3. Gorman and associates¹ clearly show that the papillary muscles rotate relative to the mitral valve anulus during the cardiac cycle, and this rotation is greatest for the posterior papillary muscle. This finding suggests that, as viewed from the left atrium, surgically placed artificial chordae or transposed chordae would most optimally be oriented in a counterclockwise direction relative to the anulus to maintain normal left ventricular torsion. While chordal placement during mitral valve repair is more directed by reconstructing normal anatomic relationships, placement of artificial chordae during mitral valve replacement when the native chordae are absent ² is entirely at the discretion of the surgeon, who would be wise to heed the findings of Gorman, and Komeda, and their colleagues. ¹
   
4. Gorman and coworkers graphically demonstrate several geometric aspects of normal mitral function that may be of relevance to the pathophysiology and repair of ischemic mitral regurgitation. These include papillary muscle shortening, mitral valve descent toward the apex in systole, rotation of the posterior papillary muscle relative to the anulus, and narrowing of the ventricular cavity. The relative roles of these factors in ischemic mitral regurgitation are yet to be demonstrated.
   

As Gorman and associates suggest, the technique of sonomicrometry array localization (SAL) has merit as a relatively inexpensive laboratory technique to precisely assess cardiac geometry after mitral valve operation, after myocardial infarction, and in the presence of mitral valve disease. Like any good study, this work demonstrates many areas in which further work is needed to fill gaps in our current knowledge. Future studies using the techniques of Gorman and colleagues may suggest refinements of mitral valve repair and replacement techniques that will improve the applicability of mitral valve repair and improve the functional results of mitral valve operations.

References

1. Komeda M, Glasson JR, Bolger AF, Levitt D, Daughters GT, Niczyporuk MA, et al. Dynamic geometry of normal mitral annulus and papillary muscles. Circulation 1995;92:I515.
   
2. David TE. Papillary-muscle-annular continuity: Is it important? J Card Surg 1994;9(Suppl):252-4
   

This Article Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Donald D. Glower Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Glower, D. D. Search for Related Content PubMed Articles by Glower, D. D.