Open Access

ARTICLE

Anatomic Correlates of Mitral Systolic Anterior Motion in Transposition of the Great Arteries Following Atrial Switch Operation

Norman Aiad^1,2,3,7, Mark V. Sherrid^1,7, Adam J. Small¹, Youssef Elnabawi^1,7, Jodi Feinberg¹, Leon Axel^1,4, Ralph Mosca⁵, T. K. Susheel Kumar⁵, Michael Argilla⁶, Dan G. Halpern^1,7,*

1 Cardiovascular Division, Leon H. Charney Division of Cardiology, NYU Langone Health, School of Medicine, New York University Grossman, New York, USA
2 Department of Cardiovascular Disease, Medical School, The University of Minnesota, Minneapolis, USA
3 The Lillehei Heart Institute, Minneapolis, MN, USA
4 Radiology Department, NYU Langone Health, School of Medicine, New York University Grossman, New York, USA
5 Cardiothoracic Surgery Department, NYU Langone Health, School of Medicine, New York University Grossman, New York, USA
6 Pediatric Cardiology Division, NYU Langone Health, School of Medicine, New York University Grossman, New York, USA
7 Department of Internal Medicine, NYU Langone Health, School of Medicine, New York University Grossman, New York, USA

* Corresponding Author: Dan G. Halpern. Email:

Congenital Heart Disease 2023, 18(3), 267-277. https://doi.org/10.32604/chd.2023.025853

Received 02 August 2022; Accepted 16 November 2022; Issue published 09 June 2023

Abstract

Introduction: We sought to investigate whether the development of sub-pulmonic systolic anterior motion (SAM) may be inherent to the anatomy of the the mitral valve (MV) or affected by external factors, such as a dilated right ventricle or chest abnormalities in d-looped transposition of the great arteries post atrial switch operation (d-TGA/AtS). Methods: Analysis was performed of clinical and cardiac imaging studies acquired on 19 adult patients with d-TGA/AtS (age 42 ± 6 years old, 56% male) between 2015–2019. Echocardiography data included mitral apparatus anatomy, and CT/MRI data included biventricular dimensions, function, and Haller index (HI) for pectus deformity. Results: Patients with leaflet SAM (n = 6) compared to patients without SAM (n = 13) had higher MV protrusion height (2.3 ± 0.5 vs. 1.5 ± 0.4 cm, p ≤ 0.01) and longer anterior MV leaflet length (3.1 ± 0.4 cm vs. 2.6 ± 0.3 cm p ≤ 0.05), when compared to those without. CT/MRI showed higher sub-pulmonic left ventricular ejection fraction (LVEF) in the SAM group (71% ± 8% vs. 54% ± 7%, respectively). RV size and function, significant chest deformity (HI > 3.5), presence of a ventricular lead pacemaker, and septal thickness did not play a role in development of SAM. Conclusions: An elongated mitral apparatus is associated with the development of SAM, and the development of left ventricular outflow tract obstruction (LVOTO), in d-TGA/AtS. LV hyperkinesia is associated with SAM. Systemic RV dimensions, septal thickness, and degree of chest deformity did not differ significantly between subjects with SAM and those without.

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