Purpose: To demonstrate the spectrum of imaging findings in CT and cardiac MR showing a rare association of congenital heart disease with hypertrophic cardiomyopathy phenotype.
Methods: The case series consists of 6 patients with known cyanotic congenital heart disease associated with hypertrophic cardiomyopathy phenotype. Out of 6, 3 are TOF, one transposition of great arteries and 2 atrial septal defects. All the patients were evaluated with cardiac magnetic resonance (MR) imaging except one, who underwent a cardiac CT. Native T1 mapping was done using a modified look locker inversion recovery (MOLLI) sequence.
Results: These patients, in addition to the septal defects causing right to left shunts, had classical imaging features of HCM with outflow tract / cavity obstruction and myocardial fibrosis. Five patients demonstrated narrowing of both the right and left ventricular outflow tracts. Post contrast late gadolinium enhanced (LGE) images revealed areas of myocardial scarring in 3 of these patients. All five patients who underwent CMR revealed elevated native T1 values suggesting myocardial fibrosis.
Conclusion: Hypertrophic cardiomyopathy is typically an isolated cardiac pathology, although there have been rare reports of its association with other entities. In this case series, we have showed its association with cyanotic congenital heart disease. The presence of HCM with outflow obstruction complicates the presentation of these congenital heart diseases and identification of this association is important in the treatment planning and prognostication.