Insights into the Hypertrophied Hearts: A Cardiac Computed Tomography Study of Myocardial Crypts

Objectives: To determine the prevalence of myocardial crypts in left ventricular (LV) hypertrophy secondary to aortic stenosis (AS), hypertrophic cardiomyopathy (HCM), and systemic hypertension (HTN) using cardiac computed tomography (CT).

Background: Myocardial crypts are discrete invaginations in LV myocardium. Recent magnetic resonance imaging studies suggest a higher prevalence of crypts in patients with HCM and also within small samples of genotype positive but phenotype negative relatives. However, the prevalence of crypts in patients with LV hypertrophy of different etiology is unclear.

Methods: Consecutive 80 patients with severe symptomatic AS, 42 patients with HCM, 40 patients with HTN, and 40 normal subjects underwent ECG-gated, contrast enhanced 256-slice CT. Crypts were defined as >50% invaginations into normal myocardium during diastole and their overall prevalence and location was investigated and compared between different patient groups with LV hypertrophy. LV mass was calculated in the mid-diastolic frame of CT dataset.

Results: The prevalence of crypts was 41% (17/42) in patients with HCM, 33% (26/80) in severe AS, 15% (6/40) in HTN, and 5% (2/40) in the predefined normal control group. The highest incidence of crypts was observed in patients with HCM (P < 0.001); however, their prevalence was not correlated with LV mass (r = 0.12, P = 0.21). They were most commonly located in the septum of the left ventricle (58.5%). Among patients with LV hypertrophy crypts in the infero-basal segment were observed only in patients with HCM.

Conclusions: Myocardial crypts are common in patients with LV hypertrophy, and increasingly common in HCM. Infero-basal myocardial crypts may be characteristic of patients with HCM referred for cardiac CT. The prognostic impact of this finding remains to be determined.