Two cases of inflammatory muscle disease presenting with raised serum concentrations of troponin T

A Pilot Clinical Study of Liquid Ubiquinol Supplementation on Cardiac Function in Pediatric Dilated Cardiomyopathy

Background: Pediatric dilated cardiomyopathy (PDCM) is a life-threatening type of cardiac muscle dysfunction in children. Ubiquinone is a lipid-soluble nutrient that participates in energy synthesis. Recently, a novel hydrophilic ubiquinol supplement was developed. The purpose of this study was to assess the effect of liquid ubiquinol supplementation (10 mg/kg body weight/day) on cardiac function in children with PDCM. Methods: Ten children diagnosed with PDCM were recruited to this study and administered with liquid ubiquinol for 24 weeks. The cardiac function was measured by echocardiography. The New York Heart Association (NYHA) functional classification was used to assess symptoms of heart failure. Plasma coenzyme Q10 levels were measured during the study. Results: Ejection fraction (EF) and fractional shortening (FS) were significantly higher than the baseline values until week 16 of supplementation. Subjects who had higher plasma coenzyme Q10 concentration had significantly better EF and FS values. In addition, 30% of the subjects showed improvement in the NYHA classification after 24 weeks of supplementation. Conclusion: Liquid ubiquinol supplementation is associated with an increase the level of coenzyme Q10 to complementary improve cardiac function (particularly EF and FS) and ameliorate the symptoms of heart failure in children with PDCM.

Cardiac troponin testing in idiopathic inflammatory myopathies and systemic sclerosis-spectrum disorders: biomarkers to distinguish between primary cardiac involvement and low-grade skeletal muscle disease activity

Primary cardiac involvement, an under-recognised manifestation of the idiopathic inflammatory myopathies (IIM) and systemic sclerosis (SSc)-spectrum disorders, is associated with significant mortality. Within these two conditions, traditional skeletal muscle enzyme testing may not effectively distinguish between skeletal and cardiac muscle involvement, especially in patients with subclinical cardiac disease. Accurate biomarkers are thus required to screen for cardiac disease, to better inform both therapeutic decision-making and treatment response. The widespread uptake of cardiac troponin testing has revolutionised the management of acute coronary syndromes. While cardiac troponin I (cTnI) appears specific to the myocardium, cardiac troponin T (cTnT) is also expressed by skeletal muscle, including regenerating skeletal muscle tissue. There is increasing interest about the role of cardiac troponins as a putative biomarker of primary cardiac involvement in IIM and SSc-spectrum disorders. Herewith we discuss subclinical cardiac disease in IIM and SSc-spectrum disorders, the respective roles of cTnI and cTnT testing, and the re-expression of cTnT within regenerating skeletal muscle tissue. There remains wide variation in access to cardiac troponin testing nationally and internationally. We propose two pragmatic clinical pathways using cardiac troponins, preferably measuring concomitant cTnT followed by confirmatory (cardiac) cTnI to screen patients for subclinical cardiac disease and/or low-grade skeletal muscle disease activity, and also an agenda for future research.

Misleading Elevation of Troponin T caused by Polymyositis

BACKGROUND

Elevations of cardiac enzymes are commonly used to indicate myocardial ischemia, but they can be elevated due to other conditions. Different forms of Troponin (cTnT, sTnT, cTnI), can cause cross-reactivity in the Troponin T assay, leading to false positives. This report describes a patient with polymyositis who had elevated Troponin T, but no cardiac abnormalities. The purpose is to show that Troponin T, which is believed to be solely from cardiac muscle breakdown, can be seen in inflammatory muscle disease, so Troponin I should be used instead.

DESCRIPTION

This is a case report of a 70-year-old woman with a history of diabetes, hypertension, gout and polymyositis, who presented with one-day history of lightheadedness and abdominal pain. To rule out myocardial ischemia, cardiac enzyme testing was ordered which showed elevated CK, CK-MB, and Troponin T. A full cardiac workup was performed which showed no signs of ischemia. Troponin I was <0.05 ng/mL, (normal).

DISCUSSION

In inflammatory myositis, there are elevations in many cardiac markers due to non-cardiac causes, which could be related to muscle regeneration and gene expression. This is not seen certain isoforms of Troponin I, specifically cardiac Troponin I.

CONCLUSION

In patients with history of diabetes and other comorbidities, silent myocardial ischemias should be ruled out. Non-cardiac elevations in Troponin T can be seen in patients with inflammatory, so Troponin I should be ordered to get an accurate interpretation. Patients with inflammatory myopathies can have elevations in CK, CK-MB, and Troponin T, but not Troponin I.

Positive troponin-T in noncompaction is associated with neuromuscular disorders and poor outcome

OBJECTIVES

Though cardiac troponin-T may be positive in hypertrophic and dilated cardiomyopathy, it is not known how often troponin-T is positive in left ventricular hypertrabeculation/ noncompaction (LVHT), an unclassified cardiomyopathy. This retrospective study aimed to assess how often troponin-T is positive in LVHT, is associated with elevated CK, is attributable to cardiac or extra-cardiac causes, in particular neuromuscular disorders (NMDs), or if it is a predictor of poor survival.

RESULTS

Among 100 patients, detected over a period of 11 years, troponin-T was determined at least once in 71 (71%) of them. Troponin-T was determined once in 36 patients, twice in 8 cases, three times in 11 patients, and more than three times in 16 cases. Troponin- T was positive at least once in 12 patients (17%). Forty-five of the 71 patients suffered from a NMD (63%). Troponin-T positivity was associated with elevated CK in 6 cases. Troponin-T-positivity was attributable to acute myocardial ischemia in a single case, to chronic renal failure in 5 cases, to dilated cardiomyopathy in 4 cases, to atrial fibrillation in 3 cases, to heart failure in 4 cases, and to NMD in 10 cases. Troponin-T positivity in LVHT patients with NMD was assumed to be due to cardiac involvement in the disease. Among the 22 patients who died during the observational period troponin was determined in 16 and was positive in 4 (25%).

CONCLUSIONS

Troponin-T is positive in 17% of the patients with LVHT. Most of these patients suffer from a NMD. Troponin-T positivity in LVHT predicts the presence of NMD and poor survival.

Raised troponin T in inclusion body myositis is common and serum levels are persistent over time

Cardiac Troponin T (cTnT), creatine kinase (CK) and creatine kinase isoenzyme MB (CKMB) were measured in 42 consecutive patients with sporadic inclusion body myositis (s-IBM). 26 patients (62%) had a cTnT level >0.05 microg/L, the cut off used in the diagnosis of myocardial infarction. The cTnT levels correlated somewhat more closely to CKMB (rho=0.83, p<0.0001) than to CK (rho=0.60, p<0.0001). Patients on immunosuppressive treatment had lower cTnT levels than untreated, while there were no significant differences according to age, disease duration or gender. Repeated samples in 26 patients showed that the cTnT levels were essentially unchanged over time up to 17 months. None of the patients had signs of myocardial damage or renal failure at time of sampling. It may be of value to analyse cTnT at some occasion(s) in s-IBM patients.