Dynamic Three-Dimensional Imaging of the Mitral Valve and Left Ventricle Using Rapid Sonomicrometry Array Localization

Joseph H. Gorman II, MD; Krishanu B. Gupta, PhD; James T. Streicher, PhD; Robert C. Gorman, MD; Benjamin M. Jackson, MS; Mark B. Ratcliff, MD; Daniel K. Bogen, MD, PhD; L. Henry Edmunds Jr., MD

Department of Surgery, School of Medicine, and Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA.

J Thorac Cardiovasc Surg 1996;112:712-26

Methods and Results: Sixteen sonomicrometry transducers were placed around the mitral valve annulus, at the tips and bases of both papillary muscles, at the ventricular apex, across the ventricular epicardial short axis, and on the anterior chest wall before and during cardiopulmonary bypass in eight anesthetized sheep. Animals were studied later on 17 occasions. Reproducibility of distance measurements averages 1.6%; Procrustes analysis of three-dimensional arrays of coordinate locations predicts an average error of 2.2 mm. Duration of serial sonomicrometry array localization signals ranges between 60 and 151 days (mean 114 days). Sonomicrometry array localization demonstrates the saddle-shaped mitral annulus, its minimal orifice area immediately before end-diastole, and uneven, apical descent during systole. Papillary muscles shorten only 3.0 to 3.5 mm. Sonomicrometry array localization demonstrates nonuniform torsion of papillary muscle transducers around a longitudinal axis and shows rotation of papillary muscular bases toward each other during systole.

Conclusion: Tagging of ventricular structures in experimental animals by sonomicrometry array localization images is highly reproducible and suitable for serial observations. In sheep the method provides unique, quantitative infomration regarding the interrelationship of mitral vavular and left ventricular structures throughout the cardiac cycle.