Correlation between extent of myocardial fibrosis assessed by cardiac magnetic resonance and cardiac troponin T release in patients with nonischemic heart failure.

Persistently high cardiac troponin T (cTnT) levels reflect myocardial damage in heart failure (HF). The presence and extent of myocardial fibrosis assessed by cardiac magnetic resonance (CMR) and high levels of cTnT predict poor prognosis in various cardiomyopathies. However, the association between myocardial fibrosis and transcardiac cTnT release has not been evaluated. This study investigated the correlation between myocardial fibrosis and transcardiac cTnT release from nonischemic failing myocardium. Serum cTnT levels were measured in aortic root (Ao) and coronary sinus (CS) using highly sensitive assay (detection limit >5 ng/L) in 74 nonischemic patients with HF who underwent CMR. Transcardiac cTnT release (ΔcTnT [CS-Ao]) represented the difference between CS and Ao-cTnT levels. Myocardial fibrosis was quantified by late gadolinium enhancement (LGE) volume and %LGE on CMR. cTnT was detectable in 65 patients (88%), and ΔcTnT (CS-Ao) levels were available (ΔcTnT [CS-Ao] >0 ng/L) in 60 patients (81%). LGE was observed in 42 patients (57%), and ΔcTnT (CS-Ao) levels were available in 41 LGE-positive patients (98%). In patients with available cTnT release, ΔcTnT (CS-Ao) levels were significantly higher in LGE-positive patients than those in LGE-negative patients (4.3 [2.2-5.5] vs 1.5 [0.9-2.6] ng/L; p = 0.001). Log (ΔcTnT [CS-Ao]) levels were correlated with LGE volume (r = 0.460, p = 0.003) and %LGE (r = 0.356, p = 0.03). In conclusion, the amount of transcardiac cTnT release was higher in LGE-positive patients than LGE-negative patients and correlated with the extent of LGE in nonischemic patients with HF. These results suggested that ongoing myocardial damage correlates with the presence and extent of myocardial fibrosis.