Tachycardia-induced cardiomyopathy in the ovine heart: Mitral annular dynamic three-dimensional geometry

Tomasz A. Timek, Paul Dagum, David T. Lai, David Liang, George T. Daughters, Frederick (Fred) Tibayan, Neil B. Ingels, D. Craig Miller

Research output: Contribution to journalArticle

47 Scopus citations

Abstract

Background: Ring annuloplasty has been used to correct annular dilatation and mitral regurgitation in dilated cardiomyopathy, but little is known about the dynamic precise 3-dimensional geometry of the mitral annulus in this condition. Methods: Nine sheep had radiopaque markers sewn to the mitral annulus, creating 8 distinct segments beginning at the posterior commissure (segments 1-4, septal mitral annulus; segments 5-8, lateral mitral annulus). Biplane videofluoroscopy and transesophageal echocardiography were performed before and after rapid pacing (180-230 min-1 for 15 ± 6 days) sufficient to develop tachycardia-induced cardiomyopathy and mitral regurgitation. Mitral annular segment contraction was defined as the percentage difference between maximum and minimum lengths. Mitral annular area and mitral annular septal-lateral and commissure-commissure diameters and 3-dimensional shape were determined from marker coordinates. Results: With tachycardia-induced cardiomyopathy, end-diastolic mitral annular area, septal-lateral diameter, and commissure-commissure diameter increased by 36% ± 14%, 25% ± 12%, and 9% ± 5%, respectively (P <.01), whereas mitral regurgitation increased from 0.3 ± 0.2 to 2.2 ± 0.9 (P <.0001). All annular segments dilated at end-diastole with tachycardia-induced cardiomyopathy, except the segment between the midseptal annulus and the left fibrous trigone. Annular segment contraction was significantly decreased with tachycardia-induced cardiomyopathy in the lateral, but not in the septal, regions. Three-dimensional reconstruction of annular shape revealed a saddle shape of the annulus at baseline; this shape was also measured with tachycardia-induced cardiomyopathy, but there was some flattening of the septal annulus. Conclusions: With tachycardia-induced cardiomyopathy, the mitral annulus dilated substantially, being more in the septal-lateral than in the commissure-commissure dimension. Greater annular segmental dilatation and decreased contraction occurred in the lateral annulus. The saddle shape of the annulus was retained but flattened.

Original languageEnglish (US)
Pages (from-to)315-324
Number of pages10
JournalJournal of Thoracic and Cardiovascular Surgery
Volume125
Issue number2
DOIs
Publication statusPublished - Feb 1 2003
Externally publishedYes

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ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Surgery

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