Abstract 3292: Torsional Deformation Compensates for Depressed Systolic Myocardial Strains in Hypertensive Concentric Left Ventricular Hypertrophy
Background: Hypertensive patients may have a normal LV ejection fraction (EF) despite depressed myocardial strain.
Hypothesis: We hypothesized that increased torsional deformation preserves LVEF.
Methods: 80 patients with resistant hypertension (HTN) and 40 healthy control subjects were studied with cine-magnetic resonance imaging and tissue tagging with three-dimensional (3-D) analysis. Plasma marker for type I collagen synthesis was also evaluated.
Results: HTN group demonstrated increased LV EF, LV mass and reduced R/T (indicative of concentric remodeling) compared to controls. Midventricular longitudinal and circumferential systolic strains and strain rates were significantly decreased in HTN compared to controls. Longitudinal and circumferential shortening showed significant negative correlation with mass (r=−0.56, p<0.001 and r=−0.27, p=0.019 respectively) and concentricity (r=−0.58, p<0.001 and r=−0.3, p<0.01 respectively). Peak torsion angle, twist, and mid wall circumferential-longitudinal (C/L) shear were significantly increased in the HTN group. There were positive correlations between degree of concentric remodeling and peak torsion angle (r=0.23, p=0.047) and C/L shear (r=0.39, p<0.001). Plasma carboxy-terminal propeptide of type I collagen, a marker of collagen synthesis correlated with peak torsion angle (r=0.30, p=0.04) and C/L shear (r=0.32, p=0.03).
Conclusions: Torsional deformation allows for increased LVEF despite decreased systolic strains. Its relation to concentric LV remodeling and collagen synthesis suggests that myocardial hypertrophy and increased matrix cell connections may play an important role to increase systolic torsion.