Aging alters patterns of regional nonuniformity in LV strain relaxation: a 3-D MR tissue tagging study.

Although age-related impairment of diastolic function is well documented, patterns of regional tissue relaxation impairment with age have not been characterized. MRI tissue tagging with a regional three-dimensional (3-D) analysis was performed in 15 younger (age 19-26 yr) and 16 older (age 60-74 yr) normal, healthy volunteers. The peak rate of relaxation of circumferential strain (RC) was decreased in the older group (on average, 105 +/- 28 vs. 163 +/- 18 %/s for older vs. younger, mean +/- SD, P < 0.001) to a greater extent in the lateral wall than in the septum (P = 0.016) and to a greater extent in the apex than in the base (P < 0.001). Peak rate of relaxation of longitudinal strain (RL) was also reduced with age (94 +/- 27 vs. 155 +/- 18 %/s, P < 0.001) to a greater extent in the apex than in the base (P < 0.001). Both RC and RL were greater in the apex than in the base only in the younger subjects (P < 0.001 for each). Peak rate of torsion reversal (RT) was reduced with age (74 +/- 16 vs. 91 +/- 15 degrees/s, P = 0.006) to a greater extent in the base than in the apex (P = 0.035). An increase in regional asynchrony in time to RC and time to RL (P < 0.001 for each), but not time to RT, occurred with age. Thus patterns of regional nonuniformity of myocardial relaxation are altered in a consistent fashion with aging.