This Article Full Text Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Geva, T. Articles by Pignatelli, R. Search for Related Content PubMed PubMed Citation Articles by Geva, T. Articles by Pignatelli, R.

(Circulation. 1995;92:886-892.)
© 1995 American Heart Association, Inc.

Articles

Quantitative Morphometric Analysis of Progressive Infundibular Obstruction in Tetralogy of Fallot

A Prospective Longitudinal Echocardiographic Study

Tal Geva, MD; Nancy A. Ayres, MD; Feyza A. Pac, MD; Ricardo Pignatelli, MD

From the Lillie Frank Abercrombie Section of Cardiology and the Department of Pathology, Texas Children's Hospital, and the Departments of Pediatrics and Pathology, Baylor College of Medicine, Houston, Tex.

Correspondence to Tal Geva, MD, Department of Cardiology, Children's Hospital, 300 Longwood Ave, Boston, MA 02115.

Background The morphological hallmark of tetralogy of Fallot is controversial, with much disagreement as to whether the subpulmonary infundibulum in this lesion is hypoplastic. In addition, few quantitative data are available regarding the morphometry of the subpulmonary infundibulum, what anatomic characteristics are acquired in the postnatal period, and at what rate they progress. We also sought to determine whether echocardiographic morphometric analysis of the infundibulum can predict clinical course in infants with tetralogy of Fallot.

Methods and Results Twenty-one infants with tetralogy of Fallot (median age at initial study, 1.6 months) were prospectively followed with serial echocardiograms until the time of first surgical intervention (median age at surgery, 10 months). Selected video still frames were digitized off-line with a computerized system. Compared with age-matched normal control infants (n=37), the following indexed infundibular dimensions in patients with tetralogy of Fallot were significantly smaller: length (1.86±0.54 versus 2.7±0.56 cm/BSA^0.5, P<.0001), cross-sectional area (1.6±0.49 versus 4.7±1.3 cm²/BSA, P<.0001), and volume (1.24±0.62 versus 7.2±3 mL/BSA^1.5, P<.0001). The following measurements were increased in tetralogy patients: infundibular septal thickness (0.83±0.21 versus 0.54±0.06 cm/BSA^0.5, P=.0002) and infundibular free-wall thickness (0.62±0.13 versus 0.49±0.06 cm/BSA^0.5, P=.006). The angle between infundibular septum and ventricular septum had a greater degree of anterosuperior deviation in tetralogy patients, resulting in a larger infundibuloventricular septal angle (77±8.2° versus 31±6.5°, P<.0001). During follow-up, infundibular volume in tetralogy patients decreased from 1.24±0.62 to 0.81±0.47 mL/BSA^1.5 (P=.002), correlating with infundibular septal thickness (r=-.63, P<.003). The mean rate of decrease of indexed infundibular volume was 0.1±0.13 mL · BSA^-1.5 · mo^-1. Correlation analysis revealed a nonlinear correlation between the degree of infundibular septal malalignment and indexed infundibular volume (r=.93, P<.0001). Tetralogy patients who required early surgical intervention (4.8±0.9 versus 10.7±1.7 months, P<.0001) had a smaller infundibulum at presentation (0.92±0.35 versus 1.41±0.67 mL/BSA^1.5, P=.04) and an accelerated rate of infundibular narrowing (0.17±0.18 versus 0.06±0.08 mL · BSA^-1.5 · mo^-1, P=.04).

Conclusions Compared with normal infants, the subpulmonary infundibulum in tetralogy of Fallot is characterized by a smaller volume, shorter and thicker infundibular septum, and anterosuperior deviation of the infundibular septum. Infundibular obstruction in tetralogy patients is progressive, with an average rate of decrease in indexed infundibular volume of 0.1±0.13 mL · BSA^-1.5 · mo^-1. Infants who are likely to require early therapeutic intervention may be identified on their initial echocardiogram as having an infundibular volume of <0.9 to 1.0 mL/BSA^1.5.

Key Words: tetralogy of Fallot • echocardiography • longitudinal studies • surgery

This article has been cited by other articles:

				J. Kolcz and C. Pizarro Neonatal repair of tetralogy of Fallot results in improved pulmonary artery development without increased need for reintervention Eur. J. Cardiothorac. Surg., September 1, 2005; 28(3): 394 - 399. [Abstract] [Full Text] [PDF]

				U. Dyamenahalli, B. W. McCrindle, G. A. Barker, W. G. Williams, R. M. Freedom, and D. J. Bohn Influence of perioperative factors on outcomes in children younger than 18 months after repair of tetralogy of Fallot Ann. Thorac. Surg., April 1, 2000; 69(4): 1236 - 1242. [Abstract] [Full Text] [PDF]

				M.A. Gatzoulis, S.Y. Ho, and R.H. Anderson A reply Eur. Heart J., November 2, 1999; 20(22): 1682 - 1682. [PDF]

				M.A. Gatzoulis, N. Soukias, S.Y. Ho, M. Josen, and R.H. Anderson Echocardiographic and morphological correlations in tetralogy of Fallot Eur. Heart J., February 1, 1999; 20(3): 221 - 231. [Abstract] [PDF]