Age-related changes in the biomechanics of left ventricular twist measured by speckle tracking echocardiography

Abstract

The increasing number and proportion of aged individuals in the population warrants knowledge of normal physiological changes of left ventricular (LV) biomechanics with advancing age. LV twist describes the instantaneous circumferential motion of the apex with respect to the base of the heart and has an important role in LV ejection and filling. This study sought to investigate the biomechanics behind age-related changes in LV twist by determining a broad spectrum of LV rotation parameters in different age groups, using speckle tracking echocardiography (STE). The final study population consisted of 61 healthy volunteers (16–35 yr, n = 25; 36–55 yr, n = 23; 56–75 yr, n = 13; 31 men). LV peak systolic rotation during the isovolumic contraction phase (Rot_early), LV peak systolic rotation during ejection (Rot_max), instantaneous LV peak systolic twist (Twist_max), the time to Rot_early, Rot_max, and Twist_max, and rotational deformation delay (defined as the difference of time to basal Rot_max and apical Rot_max) were determined by STE using QLAB Advanced Quantification Software (version 6.0; Philips, Best, The Netherlands). With increasing age, apical Rot_max ( P < 0.05), time to apical Rot_max ( P < 0.01), and Twist_max ( P < 0.01) increased, whereas basal Rot_early ( P < 0.001), time to basal Rot_early ( P < 0.01), and rotational deformation delay ( P < 0.05) decreased. Rotational deformation delay was significantly correlated to Twist_max ( R² = 0.20, P < 0.05). In conclusion, Twist_max increased with aging, resulting from both increased apical Rot_max and decreased rotational deformation delay between the apex and the base of the LV. This may explain the preservation of LV ejection fraction in the elderly.