Elevations of Cardiac Troponin I Associated With Myocarditis

Abstract

Background Endomyocardial biopsy is currently the standard method used to diagnose myocarditis. However, it is invasive and has a low diagnostic yield. Because the histological diagnosis of myocarditis requires the presence of myocyte injury, we sought to determine whether measurement of cardiac troponin I (cTnI), which is a serum marker with high sensitivity and specificity for cardiac myocyte injury, could aid in the diagnosis of myocarditis. Methods and Results To validate this approach, cTnI values were first measured in mice with autoimmune myocarditis. cTnI values were elevated in 24 of 26 mice with myocarditis but were not elevated in any of the control animals ( P <.001). Next, cTnI values were measured in the sera from 88 patients referred to the Myocarditis Treatment Trial and were compared with creatine kinase–MB (CK-MB) values measured in the same patients. cTnI values were elevated in 18 (34%) of 53 patients with myocarditis and in only 4 (11%) of 35 patients without myocarditis ( P =.01). In contrast, CK-MB values were elevated in only 3 (5.7%) of 53 patients with myocarditis and 0 of 35 patients without myocarditis ( P =.27). Thus, elevations of cTnI occurred more frequently than did elevations of CK-MB in patients with biopsy-proven myocarditis ( P =.001). Importantly, elevations of cTnI in patients with myocarditis were significantly correlated with ≤1 month duration of heart failure symptoms ( P =.02), suggesting that the majority of myocyte necrosis occurs early, and thus the window for diagnosis and treatment may be relatively brief. Conclusions cTnI was superior to CK-MB for detection of myocyte injury in myocarditis, and cTnI elevations were substantially more common in the first month after the onset of heart failure symptoms.

Neutrophils Ameliorate Lung Injury and the Development of Severe Disease during Influenza Infection

“…1: 1A8 ϭ 110.2 Ϯ 11.6 mg compared with IgG ϭ 140.0 Ϯ 11.0 mg, p Ͻ 0.01 and Expt. 2: 1A8 ϭ 113.6 Ϯ 2.8 mg compared with IgG ϭ 149.6 Ϯ 15.8 mg, p Ͻ 0.01; n ϭ 5 mice per group); however, no differences were noted in levels of cardiac troponin I, a marker of myocardial injury (29,30), in serum from neutropenic or control mice at day 7 postinfection (data not shown).…”

Venoarterial Extracorporeal Membrane Oxygenation for Acute Fulminant Myocarditis in Adult Patients: A 5-Year Multi-Institutional Experience

“…In the Myocarditis Treatment Trial, 34% of 53 patients with histologic diagnoses of myocarditis had increased troponin-I values, whereas only 5.7% of the patients had increased creatine phosphokinase myocardial isoenzyme concentrations [17]. Elevated troponin-I concentrations were associated with a rapid course of heart failure (less than 1-month duration), suggesting that myocardial necrosis is an early event that requires a prompt diagnosis and aggressive treatment in most patients to limit such an overwhelming process [18]. Our study population was characterized by AFM and was expected to have a lethal outcome if not aggressively and rapidly treated.…”

“…Severity of myocardial illness at ECMO implantation, as indicated by elevated creatine kinase cardiac isoform or troponin-I concentrations (>12 mg/L), predicted unsuccessful weaning and death [12,18]. Furthermore, rapid cardiac contractile recovery and decline of troponin-N blood concentrations were also shown to reflect a better in-hospital outcome [4,9].…”

Narrative Review: Alternative Causes for Elevated Cardiac Troponin Levels when Acute Coronary Syndromes Are Excluded

“…Inflammatory disorders leading to troponin elevation include acute pericarditis (31), myocarditis (32), and an immune response after heart transplantation. In fact, chronically elevated troponin levels after cardiac transplantation may be associated with a poorer prognosis.…”