https://orcid.org/0000-0002-9726-3995
A 27-year-old male presented with exertional dyspnoea for 1 year (New York Heart Association Class II). Physical examination revealed pulsus bisferiens, a heaving apex, and a grade III medium-pitched ejection systolic murmur at the left upper sternal border. Transthoracic echocardiography revealed severe left ventricular hypertrophy (Panel B). Grade 2 systolic anterior motion (SAM) of anterior mitral leaflet (Panel C; white arrows represent SAM) and dynamic left ventricular outflow tract obstruction with a late-peaking (dagger-shaped) gradient reaching 180 mmHg at rest (Panel D) were also noted. A large myocardial crypt was identified in the mid-to-basal septum in a modified apical 4 chamber view (Panel A; white arrow). The crypt demonstrated diastolic prominence with complete systolic obliteration, a hallmark feature (see Supplementary data online, Video S1). Cardiac MRI confirmed a deep myocardial crypt in the basal septum (Panel E), while T2-mapping highlighted asymmetrical septal hypertrophy (asterisk) and a deep myocardial crypt (white arrow) in the basal-inferoseptal myocardium (Panel F).
Myocardial crypts are narrow invaginations of compact myocardium, best detected via cardiac MRI. They are defined by diastolic penetration >50% into the myocardium with systolic obliteration and frequently occur in genotype-positive individuals without overt hypertrophy thus serving as an early phenotypic marker. They are also found in 4% of cases with overt HCM. In HCM, crypts predominantly localize to the basal septum or posterior left ventricular wall.
Recognition of myocardial crypts in patients with a strong family history of HCM warrants genetic counselling, long-term surveillance, and risk-based management strategies.
Supplementary data are available at European Heart Journal - Cardiovascular Imaging online.
Funding
No funding received.
Data availability
All the data related to this case is available with the corresponding author and can be provided at reasonable request.
Author notes
Conflict of interest: None declared.
