Background: The relationship between the extent of myocardial interstitial
fibrosis, the percentage of each type of collagen, and cardiac function in
patients with hypertrophic cardiomyopathy (HC) has not been established.
Hypothesis: The study aimed to establish that increases in some types of co
llagen may correlate with cardiac dysfunction.
Methods: Mallory-Azan staining and immunohistochemical staining by the avid
in-biofin-complex (ABC) method using anticollagen antibodies were performed
on the myocardial biopsy specimens in 35 patients with HC, and the percent
age and type of collagen present was determined. Left ventricular (LV) func
tion was evaluated by cardiac catheterization and ventriculography.
Results: The percentage of myocardial interstitial fibrosis correlated high
ly with indices of LV diastolic and systolic function. The amount of type I
II collagen correlated significantly with the peak negative dp/dt, the rapi
d filling volume/stroke volume, and the ejection fraction (EF). Significant
correlations also were noted between the amount of type VI collagen and pe
ak negative dp/dt, peak positive dp/dt, and EE Type I collagen did not corr
elate with any of the LV function indices, and type IV collagen correlated
only with peak ejection rate. Type V collagen did not accumulate substantia
lly in the myocardial interstitium.
Conclusions: The progression of myocardial interstitial fibrosis in the HC
heart adversely impacts both the diastolic and systolic function of the LV.
Increases in the percentage of type III and VI collagen correlate with car