ABSTRACTS- Cardiac Function and Heart Failure 181A 11:00 a.m. 854-3 Myocardial Collagen Turnover in Hypertrophic Cardlomyopathy: Comparison to Healthy Subjects R~ffaalla Lombardi, Sandro Betocchi, Maria Angela Losi, Quidno Ciampi, Cado G. Tocchefti, EIpidio Pszzella, Filippo Finizio, Mariano Aversa, Marianna Miranda, Veronica De Crescanzo, Massimo Chiariello, Department of Clinical Medicine, Cardivascular and Immunological Science, University of Naples, Naples, Italy. BACKGROUND LV hypertrophy and fibrosis are characteristics of hypertrophic cardi- omyopathy (HCM). We assessed the impact of collagen turnover on LV anatomy and function in HCM. METHODS We studied 29 HCM patients (36±9 years) and 10 age and sex-matched controls. We assessed cardiac fibrosis by RIA measurement of serum con- centrations of: procollagsn III N-terminal propeptide (PtilNP), index of collagen III synthe- sis; procollagen I C-terminal propeptide (PICP) and collagen I C-terminal telopeptide (ICTP), indexes of collagen I synthesis and degradation. They were In-transformed. LV hypertrophy was quantified by the Wigle's score. Diastolic function was evaluated by the duration difference in antegrada (mitral) and retrograde (pulmonary vein) A wave (Adiff). RESULTS PIIINP and ICTP were higher in HCM than in controls (1.3(.4) vs .9(.3) ng/ml, p=.002; 1.0(.4) vs .8(.2) ng/ml, p=.048) and inversely related to age in HCM (r=-.424, p=.022; r=-.651, p<.001). PICP and ICTP were directly related to one another (r=.395, p=.013). PtlINP was inversely related to LV end-diastolic dimension, while ICTP was directly related to Wigle's score (Figure). PIIINP and ICTP were inversely related to Adiff (r=-.393, p=.035; and r=-.584, p<.001). CONCLUSIONS In HCM patients collagen metabolism is more active than in controls and it decreases with age. Collagen I degra- dation parallels synthesis (steady state). Collagen turnover influences degree of hyper- trophy, cavity size and passive diastolic properties.