Abstract 12802: Basal Septal Hypertrophy is an Early Imaging Biomarker of Hypertrophy in Physiologic and Pathologic Stress
Ventricular hypertrophy is an adaptive response to physiologic and pathologic stress. It remains unclear whether hypertrophy is more regional in early stages. The aim was to evaluate the evolution of left ventricular hypertrophy (LVH) and myocardial function during prolonged physiologic (exercise) and pathologic (transverse aorta constriction) stress.
Methods/Results: Weight matched CF-1 male mice were separated into 3 groups: group 1: controls (n=10), group 2: exercise on treadmill for 1 hour daily x 5 days a week (n=7) and group 3: transverse aortic construction via thoractomy (TAC, n=7). All mice underwent B-mode and tissue Doppler echocardiography at baseline and weekly thereafter for 8 weeks. No mice died during the study. Significant hypertrophy was noted first in the LV septal base compared to other segments in group 2 (0.84 vs. 0.79 mm, p=0.03) and group 3 (0.86 vs. 0.77 mm, p=0.02) at 4 and 3 weeks, respectively. Relative wall thickness (RWT) was 0.31, 0.39 and 0.50 in the 3 groups, respectively, at 8 weeks. LV area increased in group 2 (13.5 vs. 19.7 mm2, p=0.0001); there were no significant changes in LV area in group 1 (13.8 vs. 13.9 mm2, p>0.05) or group 3 (14.4 vs. 13.9 mm2, p>0.05). At 8 weeks, eccentric LVH was noted in group 2 and concentric LVH in group 3 (Figure). Septal E/E’ ratio increased in group 3 (32.6 vs. 49, p=0.02)compared with the groups 1 and 2 (32.3 vs. 32.8 and 31.2 vs. 28.2, respectively, p>0.05 for both). Septal s’ decreased in group 3 (21 vs. 17 cm/s, p=0.04); it increased in group 2 (19.6 vs. 29.2 cm/s, p=0.02) and was unchanged in group 1 (20.1 vs. 20.9 cm/s, p>0.05).
Conclusion: In both physiologic and pathologic stress, ventricular hypertrophy is noted earliest in the LV septal base. The remodeling becomes global with eccentric hypertrophy and preserved LV function noted with physiologic stress and concentric hypertrophy and reduced LV function noted with pathologic stress.
- © 2011 by American Heart Association, Inc.