Systolic contraction of obliquely oriented cardiac myofibers results in a twisting motion (torsion) of the LV. The total torsion, Θ T , is defined as the difference in twisting between the base and apex. We hypothesized that measurements of torsion could be used to differentiate normal from abnormal patterns of regional contractile function. Accordingly, we compared Θ T in 6 patients with hypertrophic cardiomyopathy (HCM) (13-27 yrs, 6 M/0 F) to that in 10 healthy volunteers (23-41 yrs, 5 M/5 F) using tagged cine MRI. Tagged two-dimensional short axis images were obtained at the base and apex. Θ T for 4 regions of the LV wall are presented. In the normal group, the anterior and lateral walls demonstrated greater total torsion than did the inferior and septal walls (p < 0.01). This regional difference was not present in the HCM group (p = NS). The HCM septum and inferior wall showed significantly greater total torsion as compared to the normals (p < 0.01) and more uniform total torsion throughout all 4 walls. These pronounced regional differences in myocardial torsion indicate an enhanced contribution of the inferior and septal regions to overall myocardial torsion in HCM, which may reflect altered patterns of intramural fiber strain due to regional fiber disarray in HCM.