Background-Left ventricular (LV) torsional deformation, based in part on the helical myocardial fiber architecture, is an important component of LV systolic and diastolic performance. However, there is no comprehensive study describing its normal development during childhood and adult life. Methods and Results-Forty-five normal subjects (25 children and 20 adults; aged 9 days to 49 years; divided into 5 groups: infants, children, adolescents, and young and middle-age adults) underwent assessment of LV torsion and untwisting rate by Doppler tissue imaging. LV torsion increased with age, primarily owing to augmentation in basal clockwise rotation during childhood and apical counterclockwise rotation during adulthood. Although LV torsion and untwisting overall showed age-related increases, when normalized by LV length, they showed higher values in infancy and middle age. The proportion of untwisting during isovolumic relaxation was lowest in infancy, increased during childhood, and leveled off thereafter, whereas peak untwisting performance (peak untwisting velocity normalized by peak LV torsion) showed a decrease during adulthood. Conclusions-We have shown the maturational process of LV torsion in normal subjects. Net LV torsion increases gradually from infancy to adulthood, but the determinants of this were different in the 2 age groups. The smaller LV isovolumic untwisting recoil during infancy and its decline in adulthood may suggest mechanisms for alterations in diastolic function.

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Background-The cascade of events by which early diastolic left ventricular (LV) filling increases with exercise is not fully elucidated. Doppler tissue imaging (DTI) can detect myocardial motion, including torsion, whereas color M-mode Doppler (CMM) can quantify LV intraventricular pressure gradients (IVPGs). Methods and Results-Twenty healthy volunteers underwent echocardiographic examination with DTI at rest and during submaximal supine bicycle exercise. We assessed LV long-/short-axis function, torsion, volume, inflow dynamics, and early diastolic IVPG derived from CMM data. LV torsion and untwisting velocity increased with exercise (torsion, 11Ϯ4°to 24Ϯ8°; untwisting velocity, Ϫ2.0Ϯ0.7 to Ϫ5.6Ϯ2.3 rad/s) that was associated with an increase in IVPG (1.4Ϯ0.5 to 3.7Ϯ1.2 mm Hg). Untwisting in normal subjects occurred during isovolumic relaxation and early filling, significantly before long-axis lengthening or radial expansion. The clinical feasibility of this method was tested in 7 patients with hypertrophic cardiomyopathy (HCM); torsion was higher at rest but did not increase with exercise (16Ϯ4°to 14Ϯ6°), whereas untwisting was delayed and unenhanced (Ϫ1.6Ϯ0.8 to Ϫ2.3Ϯ1.2 rad/s). In concert, IVPG was similar at rest (1.2Ϯ0.3 mm Hg), but the exercise response was blunted (1.6Ϯ0.8 mm Hg). In normal subjects and HCM patients, there was a similar linear relation between IVPG and untwisting rate, with an overall correlation coefficient of rϭ0.75 (PϽ0.0001). Conclusions-LV untwisting appears to be linked temporally with early diastolic base-to-apex pressure gradients, enhanced by exercise, which may assist efficient LV filling, an effect that appears blunted in HCM. Thus, LV torsion and subsequent rapid untwisting appear to be manifestations of elastic recoil, critically linking systolic contraction to diastolic filling. (Circulation. 2006;113:2524-2533.)