Author + information
- Received July 26, 1989
- Revision received July 23, 1991
- Accepted August 2, 1991
- Published online March 1, 1992.
- Anthony J. Sanfilippo, MD†,1,
- Pamela Harrigan, RDCS1,
- Aleksandar D. Popovic, MD1,
- Arthur E. Weyman, MD, FACC1 and
- Robert A. Levine, MD, FACC*,‡,1
- ↵*Address for reprints: Robert A. Levine, MD, Cardiac Ultrasound Laboratory, Phillips House 8, Massachusetts General Hospital, Boston, Massachusetts 02114.
Previous angiographic observations in patients with mitral valve prolapse have suggested that superior leaflet displacement results in abnormal superior tension on the papillary muscle tips that causes their superior traction or displacement. It has further been postulated that such tension can potentially affect the mechanical and electrophysiologic function of the left ventricle. The purpose of this study was to confirm and quantitate this phenomenon noninvasively by using two-dimensional echocardiography to determine whether superior displacement of the papillary muscle tips occurs and its relation to the degree of mitral leaflet displacement.
Directed echocardiographic examination of the papillary muscles and mitral anulus was carried out in a series of patients with classic mitral valve prolapse and results were compared with those in a group of normal control subjects. Distance from the anulus to the papillary muscle tip was measured both in early and at peak ventricular systole. In normal subjects, this distance did not change significantly through systole, whereas in the patient group it decreased, corresponding to a superior displacement of the papillary muscle tips toward the anulus in systole (8.5 ± 2.6 vs. 0.8 ± 0.7 mm; p < 0.0001). This superior papillary muscle motion paralleled the superior displacement of the leaflets in individual patients (y = l.0x + 0.8; r = 0.93) and followed a similar time course. The systolic motion of the mitral anulus toward the apex, assessed with respect to a fixed external reference, was not significantly different in the patients and control groups (14.3 ± 4 vs. 15.5 ± 4.4 mm; p = 0.4) and therefore could not explain the superior papillary muscle tip motion relative to the anulus in the patients with mitral valve prolapse.
These results demonstrate that normal mechanisms maintain a relatively constant distance between the papillary muscle tips and the mitral anulus during systole. In classic mitral valve prolapse, superior leaflet displacement is paralleled by superior displacement of the papillary muscles that is consistent with superiorly directed forces causing their traction. Two-dimensional echocardiography can therefore be used to measure these relations and test hypotheses as to their clinical correlates in patients with mitral valve prolapse.
- Received July 26, 1989.
- Revision received July 23, 1991.
- Accepted August 2, 1991.
- American College of Cardiology Foundation