Abstract 14984: Left Ventricular Longitudinal Contraction Abnormality Reflects the Subendocardial Fibrosis in Heart Failure with Preserved Ejection Fraction Model Rat
Background: Left ventricular (LV) longitudinal contraction has been reported to be the feature of early cardiac dysfunction in heart failure with preserved ejection fraction (HFpEF). However, the underlying pathological abnormality has not been well clarified. We perfomed this experimental study with Dahl salt-sensitive (DSS) rats to investigate the association between the myocardial contraction abnormality and the underlying pathological findings in HFpEF.
Methods: DSS rats were fed with a high-salt (HT-group, n=7) or a low-salt diet (Normal-group, n=7) from 6 weeks of age. LV radial (RS), circumferential (CS), and longitudinal strain (LS) were repeatedly measured every 2 weeks using speckle tracking echocardiography system (Vevo2100, VisualSonics). At 12 weeks, pathological studies were perfomed to assess percent fibrosis area (%fibrosis) in subendo-, mid-, and subepicardial myocardium tissue specimens.
Results: In HT-group, blood pressure (BP) dramatically elevated with aging (mean BP, baseline; 76±16, 12 weeks; 188±24mmHg) accompanied with significant LV hypertrophy (LV wall thickness, baselie;1.79±0.51, 12 weeks;2.44±0.26mm, p<0.001). LS in HT-group decreased with aging, and LS at 12 weeks was lower in HT-group than in Normal-group (Figure A).In contrast, EF, RS, and CS showed no difference between two groups over time.In HT-group, subendocardial fibrosis was more prominet than subepicardial fibrosis, whereas transmural fibrosis was not apparent in Normal-group (Figure B). LS significantly related with subendocardial %fibrosis (Figure C).
Conclusions: Reduced LV longitudinal strain was identified in DSS rats with severe LV hypertrophy and preserved EF. Our findings suggest the longitudinal systolic dysfunction reflects subendocardial fibrosis in HFpEF.
- © 2011 by American Heart Association, Inc.