[Interstitial changes and ventricular hypertrophy in man]

Left ventricular hypertrophy is accompanied by the remodeling of the collagen network. We have studied collagen network in left ventricular hypertrophy secondary to aortic stenosis by cardiac catheterization and endomyocardial biopsies. We have demonstrated that collagen architecture is abnormal in 2/3 of patients with aortic stenosis and is more important than collagen concentration in influencing myocardial stiffness and ejection fraction. Furthermore, we observed that relaxation and asynchrony were influenced by the degree of hypertrophy instead of by the collagen network. The postoperative regression of left ventricular hypertrophy and the changes in interstitial tissue after valve replacement have been studied in a subgroup of patients. The major finding is that the regression of myocardial hypertrophy is a process that occurs over many years after correction of primary hemodynamic abnormality. Six to 7 years after valve replacement we observed, together with the normalization of diastolic stiffness, the complete normalization of interstitial fibrosis that was primarily increased (both pre and early postoperatively).