Background: We hypothesized that the alterations of myocardial collagen turnover in patients with hypertension may be involved in the early changes of regional contractile function assessed by a new speckle tracking method.
Methods: In 56 patients with untreated hypertension (48 +/- 11 years, ejection fraction > 55%) and 20 age-matched control subjects, the serum levels of aminoterminal propeptide of procollagen I/III and tissue inhibitor of matrix metalloproteinase (TIMP)-1 were measured by radioimmunoassay and enzyme immunoassay. To assess the regional contractile function, the average of negative longitudinal strain of 6 segments at apical 4-chamber view (longitudinal epsilon), the average of radial strain (radial epsilon) and the average of circumferential strain (circumferential epsilon) of 6 mid-left ventricular (LV) segments, and basal-to-apical torsion were obtained by 2-dimensional speckle tracking imaging.
Results: Compared with control group, longitudinal epsilon was significantly decreased (-20.4 +/- 3.0% vs -22.1 +/- 2.2%, P = .030) and basal-to-apical torsion was increased (20.5 +/- 5.7 degrees vs 17.4 +/- 3.7 degrees, P = .013) in patient group. The serum level of log TIMP-1 was higher in the patients (3.6 +/- 0.6 vs 3.0 +/- 0.5, P < .001). The serum log TIMP-1 significantly correlated with longitudinal epsilon (r = 0.405, P = .015), basal-to-apical torsion (r = 0.331, P = .017), and the LV mass (r = 0.266, P = .047). In multivariate analysis, longitudinal epsilon (beta = 0.326, P = .015) and basal-to-apical torsion (beta = 0.402, P = .003) independently correlated with the serum TIMP-1 level.
Conclusion: In patients who are hypertensive with normal ejection fraction, impaired longitudinal epsilon and increased LV torsion correlated with serum TIMP-1, which suggests that the change in collagen turnover and the myocardial fibrotic process may affect the early contractile dysfunction of LV.