Augmentation of Left Ventricular Torsion with Exercise is Attenuated with Age

Abstract

Left ventricular torsion, resulting from the rotation of the base and apex of the ventricle in opposite directions, may be an important component of normal cardiac function both at rest and with exercise. The effect of exercise on torsion in the general population and the influence of aging on changes in torsion with exercise are not known. Analysis of torsion, positive and negative torsion velocities, and negative torsion acceleration was performed using speckle tracking imaging on 33 stress echocardiograms using supine bicycle stress. Resting and postexercise torsion could be assessed in 14 patients (42%). A total of 19 patients who were significantly older and larger (mean age 57 years, mean body mass index 28.2, both P < .03) were excluded as a result of inadequate frame rate and image quality after exercise. After exercise, significant increases in peak torsion (10.3 +/- 0.8 vs 13.3 +/- 1.3 degrees, P < .04), peak positive torsion (54.2 +/- 5.6 vs 113.6 +/- 12.3 degrees/s, P < .0001), and peak negative torsion (-56.3 +/- 7.9 vs -100.8 +/- 14.8 degrees/s, P < .03) velocities were observed. Ejection fraction correlated with torsion both at rest and after exercise (r = 0.63, P < .0004). At rest, torsion was greater in older individuals (8.9 +/- 0.6 vs 11.6 +/- 1.2 degrees, P < .04). With increasing age, exercise resulted in less augmentation of torsion (r = 0.59, P < .02) and positive torsion velocity (r = -0.79, P < .003), and decreased negative torsional acceleration (r = 0.60, P < .035). Exercise results in increased cardiac plecotropy (the augmentation of torsion parameters in response to load or stimulus) but this effect is attenuated with aging. Further investigation is required to determine whether impairment of plecotropy contributes to the reduced exercise capacity associated with aging.