REGIONAL REMODELING AND NONUNIFORM CHANGES IN DIASTOLIC FUNCTION IN PATIENTS WITH LEFT-VENTRICULAR DYSFUNCTION - MODIFICATION BY LONG-TERM ENALAPRIL TREATMENT

Objectives. The purpose of the present study was to assess the process of late regional remodeling and the changes in regional diastolic function at the base and apex of the left ventricle in patients with chronic systolic dysfunction. Background. Remodeling has been suggested to play an important role in the progression of left ventricular dysfunction and heart failure. However, the regional difference in the process of late remodeling and its relation to diastolic function remain unclear. Methods. In 32 patients with previous myocardial infarction and left ventricular ejection fraction less than or equal to 35%, left ventricular hemodynamic and angiographic data were studied before and 1 year after randomization to conventional therapy with placebo (n = 12) or enalapril, 10 mg twice daily (n = 20). Left ventricular regional wall dynamics were analyzed in the basal and apical regions by the area method. Results. In the placebo group, left ventricular end-diastolic and end-systolic regional areas increased significantly over time at the base but were unchanged at the apex. At the base, the diastolic left ventricular pressure-regional area relation shifted rightward and the regional stiffness constant decreased (6.9 +/- 4.3 to 5.0 +/- 3.1 x 10(-3) mm(-2), p < 0.05), indicating an increase in regional distensibility. At the apex, however, the diastolic pressure-regional area relation shifted upward slightly, and the regional stiffness constant increased from 11.5 +/- 4.4 to 14.4 +/- 5.6 x 10(-3) mm(-2) (p = 0.08). The regional peak filling rate was maintained at the base but decreased at the apex (1,014 +/- 436 to 762 +/- 306 mm(2)/s, p < 0.05); further, the changes in regional peak filling rate during follow-up were inversely related to the changes in the regional stiffness constant (r = -0.78, p < 0.001) at the apex. In contrast, in the enalapril group, end-diastolic and end-systolic regional areas significantly decreased over time both at the base and at the apex. Diastolic pressure-regional area relations shifted leftward, but the regional stiffness constant and regional peak filling rate did hot change significantly either at the base or at the apex. Conclusions. These findings suggest that in patients with severe systolic left ventricular dysfunction, there was a regional difference in the process of late remodeling between the base and apex of the left ventricle, which was associated with nonuniform changes in regional diastolic function in the placebo group. The data also suggest that the nonuniform progression of regional remodeling and diastolic dysfunction was prevented by long-term enalapril treatment.