Prevalence of inferobasal myocardial crypts among patients referred for cardiovascular magnetic resonance.

Background: Crypts or clefts in the left ventricular inferobasal myocardium have been detected by cardiovascular magnetic resonance (CMR), but the extent to which they represent prephenotypic markers of hypertrophic cardiomyopathy (HCM) or incidental structural variants remains controversial.
Methods and Results: We examined retrospectively the routine vertical long-axis cines in 686 consecutive patients (48±20 years, 55% men) referred for CMR. Crypts were identified in 46 (6.7%), 17 being among patients (8.7% of 196) with otherwise normal CMR findings and without a known family history of HCM. Higher percentages were found in patients with HCM (16%), myocarditis (15%), and hypertension (14%) but without reaching statistical significance (P=0.12). Only 1 (5%) of 20 phenotype-negative HCM family members had a visible crypt. Relative to those without, patients with crypts had lower indexed left ventricular end-systolic volumes (P=0.042) and higher indexed left and right ventricular stroke volumes (P=0.007 and P=0.015) and ejection fractions (P=0.003 and P=0.021). Crypts tended to narrow in systole, varying slightly in size, shape- and number, without obvious group-related features.
Conclusions: Single or paired inferobasal myocardial crypts were an occasional and by no means rare finding among patients referred for CMR without a pretest suspicion of HCM. This, together with similar previous findings in a cohort of healthy volunteers, supports their being regarded, in such individuals, as incidental variants of local myocardial structure, unlikely to require further investigation. However, a larger registry-type study may be justified to investigate the clinical implications of multiple crypts, especially if associated with HCM family history.