Relationship between serum biochemical markers of myocardial fibrosis and diastolic function at rest and with exercise in hypertrophic cardiomyopathy.
OBJECTIVE
Recent studies have demonstrated the usefulness of biochemical markers of collagen turnover as markers of myocardial fibrosis in various diseases. In this study, we hypothesized that increased collagen markers in patients with hypertrophic cardiomyopathy (HCM) were correlated with diastolic function at rest and diastolic functional reserve during exercise.


METHODS
Thirty-six patients with HCM and 21 controls with normal left ventricular thickness were studied. Mitral septal annular velocities and mitral inflow velocities were measured at rest and during graded supine bicycle exercise (25 W, 3-minute increments) for the assessment of diastolic function at rest and during exercise. By radioimmunoassay, a byproduct of collagen III synthesis (PIIINP) and peptides resulting from collagen I synthesis (PINP) and degradation (ICTP) were measured. The patients with HCM were divided into two groups according to the median value of the PINP/ICTP ratio in the group.


RESULTS
At rest, the mitral annular early diastolic velocity (E') was lower and the E/E' was higher in the patients with HCM with high a PINP/ICTP ratio compared with patients with HCM with a low PINP/ICTP ratio and controls (p<0.001, p=0.012). With exercise, the Doppler parameters were increased in all groups, but there was no significant difference in the change in E' and E/E' during exercise according to collagen turnover markers.


CONCLUSIONS
A higher PINP/ICTP ratio was associated with resting diastolic dysfunction in patients with HCM; however, there was no relationship with augmented diastolic dysfunction during exercise. We suggest that the type I collagen synthesis-to-degradation ratio is a useful marker of resting diastolic function in patients with HCM.
Shim
Chi Young
CY
Division of Cardiology, Cardiovascular Center, Yonsei University College of Medicine, Seoul, Korea.
Ha
Jong-Won
JW
Choi
Eui-Young
EY
Lee
Hyun-Jin
HJ
Moon
Sun-Ha
SH
Kim
Jin-Mi
JM
Rim
Se-Joong
SJ
Chung
Namsik
N