TTN mutation-positive hypertrophic cardiomyopathy in congenitally corrected transposition of the great arteries: A rare coexistence

Figures

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  Figure 1. Electrocardiogram (ECG), echocardiogram, and cardiac magnetic resonance imaging findings in congenitally corrected transposition of the great arteries (CCTGA) with hypertrophic cardiomyopathy. Multimodality imaging showing systemic right ventricular hypertrophy (RVH) in CCTGA with TTN mutation-associated cardiomyopathy. (a) ECG showing sinus rhythm, normal axis deviation, and deep T-wave inversions over precordial leads, consistent with systemic RVH. (b) Transesophageal echocardiogram demonstrating the systemic RV with prominent trabeculations and interventricular septal thickening; the morphologic left ventricle is subpulmonary. (c) Four-chamber cardiac magnetic resonance (CMR) image confirming concentric hypertrophy of the systemic RV with thickened apex and free wall. (d) Sagittal CMR image depicting the morphologic RV ejecting into the aorta, characteristic of CCTGA. Ao: Aorta, IVS: Interventricular septum, LA: Left atrium, LV: Left ventricle, RV: Right ventricle

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  Figure 2. Pathophysiologic basis of TTN truncating mutation in systemic right ventricular hypertrophy (RVH). Schematic illustrating the mechanism of TTN truncating mutation, leading to sarcomeric dysfunction and hypertrophic cardiomyopathic phenotype of the systemic RV in CCTGA. Schematic representation of the TTN truncating mutation showing defective titin, leading to impaired sarcomeric elasticity, altered mechanotransduction, and abnormal stress-response signaling. These changes cause myocyte hypertrophy, fibrosis, and disarray (a), which manifest as a systemic RVH cardiomyopathic phenotype in CCTGA (b)