Understanding left ventricular outflow obstruction: anatomoechocardiographic correlation.

Objective: Echocardiography is a valuable noninvasive technique for identifying the site and type of obstruction in the left ventricular outflow tract. Knowledge of the morphological details of each type of obstruction is the basis for correct interpretation of the diagnostic images and clinical decisions.

Methods: This study was undertaken to provide improved understanding of the anatomy of left ventricular outflow obstruction with corresponding side-by-side echocardiographic images. Specimens were part of the collection of the Department of Embryology of the Instituto Nacional de Cardiología "Ignacio Chávez," Mexico City, Mexico. Twenty-eight patients were studied by echocardiography, and 22 specimens with different types of left ventricular outflow tract obstruction were analyzed.

Results: Echocardiographic characteristics: Eighteen (64.3%) patients were women and 10 (35.7%) men. Three had fibrous rings, 19 with obstructive asymmetric septal hypertrophic cardiomyopathy, 1 with posterior displacement of the infundibular septum, 2 with accessory mitral valve tissue, 2 with anomalous insertion of mitral valve chordae tendineae, and 1 with malposition of the mitral valve and papillary muscles. Anatomic characteristics: Twelve had fibrous ring, 2 asymmetric septal hypertrophic cardiomyopathy, 2 posterior displacement of the infundibular septum, 1 ectopic mitral tissue, 1 anomalous insertion of mitral valve chordae tendineae in the ventricular septum, 3 malposition of the mitral valve and papillary muscles, and 1 subaortic infundibulum.

Conclusion: The anatomoechocardiographic correlation clearly demonstrates the mechanism of subaortic obstruction. The comparison with corresponding echocardiographic images of different subaortic obstruction types is potentially quite valuable in enhancing the echocardiographer's understanding especially of complex subaortic obstruction.