Introduction and objectives: In hypertrophic cardiomyopathy (HCM), it has been suggested that regional fiber disarray produces segments that exhibit no or severely reduced deformation, and that these segments are distributed nonuniformly within the left ventricle (LV). This contrasts with observations in other types of hypertrophy, such as in athlete's heart or hypertensive left ventricular hypertrophy (HLVH), in which abnormal cardiac deformation may exist but the reduction is not so severe that some segments exhibit no deformation. Our aim was to use the strain distribution to study deformation in HCM.
Methods: We used tagged magnetic resonance imaging to reconstruct LV systolic deformation in 12 controls, 10 athletes, 12 patients with HCM, and 10 patients with HLVH. Deformation was quantified using a fast nonrigid registration algorithm and peak radial and circumferential systolic strain values were determined in 16 LV segments.
Results: Patients with HCM had significantly lower average strain values than individuals in other groups. However, while the deformation observed in healthy subjects and HLVH patients clustered around the mean, in HCM patients, segments with normal contraction coexisted with segments exhibiting no or significantly reduced deformation, which resulted in a greater heterogeneity of strain values. Moreover, some nondeforming segments were observed even when fibrosis and hypertrophy were absent.
Conclusions: The strain distribution characterized specific patterns of myocardial deformation in patients with LVH due to different etiologies. Patients with HCM had significantly lower mean strain values and a greater heterogeneity in strain values than controls, athletes and HLVH patients. In addition, they had nondeforming regions.