Circulating Levels of Heart-Type Fatty Acid-Binding Protein and Its Relation to Thallium-201 Perfusion Defects in Patients With Hypertrophic Cardiomyopathy

Myocyte loss and replacement fibrosis have been observed in patients with hypertrophic cardiomyopathy (HC) with heart failure. This study was designed to elucidate whether heart-type fatty acid-binding protein (H-FABP), a sensitive biochemical marker for myocardial damage, indicates ongoing myocardial damage in patients with HC. We studied 48 patients with HC and 17 control subjects. Patients with HC were divided into 2 groups according to the New York Heart Association (NYHA) functional class: NYHA I + II (n = 40) and NYHA III + IV (n = 8). Serum H-FABP and myoglobin levels were measured, and extent score was used to assess the extent of thallium-201 perfusion defect. Serum H-FABP levels were significantly higher in patients with HC than in control subjects (3.8 ± 1.6 vs 2.6 ± 0.7 ng/ml, p = 0.0032). Furthermore, serum H-FABP levels were significantly higher in NYHA III + IV than in NYHA I + II (5.2 ± 1.3 vs 3.5 ± 1.5 ng/ml, p = 0.0043). Serum myoglobin levels showed no significant difference among the 3 groups (control, 46.6 ± 15.0 ng/ml; NYHA I + II, 55.5 ± 26.4 ng/ml; NYHA III + IV, 65.1 ± 33.6 ng/ml, p = 0.2115). Extent score correlated positively with serum H-FABP levels (r = 0.420, p = 0.0026) and negatively with fractional shortening (r = −0.542, p <0.0001). Increased H-FABP levels indicate ongoing myocardial damage, which could result in clinical deterioration in patients with HC.