Elevations of Cardiac Troponin I Associated With Myocarditis

Present and Future Biochemical Markers for Detection of Acute Coronary Syndrome

The use of biochemical markers in the diagnosis and management of patients with acute coronary syndrome has increased continually in recent decades. The development of highly sensitive and cardiac-specific troponin assays has changed the view on diagnosis of myocardial infarction and also extended the role of biochemical markers of necrosis into risk stratification and guidance for treatment. The consensus definition of myocardial infarction places increased emphasis on cardiac marker testing, with cardiac troponin replacing creatine kinase MB as the "gold standard" for diagnosis of myocardial infarction. Along with advances in the use of more cardiac-specific markers of myocardial necrosis, biochemical markers that are involved in the progression of atherosclerotic plaques to the vulnerable state or that signal the presence of vulnerable plaques have recently been identified. These markers have variable abilities to predict the risk of an individual for acute coronary syndrome. The aim of this review is to provide an overview of the well-established markers of myocardial necrosis, with a special focus on cardiac troponin I, together with a summary of some of the potential future markers of inflammation, plaque instability, and ischemia.

Fulminant myocarditis

Fulminant myocarditis is an inflammatory process that occurs in the myocardium and causes acute-onset heart failure. If patients with fulminant myocarditis are aggressively supported in a timely manner, nearly all can have an excellent recovery. In this Review, we discuss the clinical and histological distinguishing features of fulminant myocarditis and contrast this disease entity with nonfulminant myocarditis. The epidemiology, pathophysiology, clinical presentation, methods of diagnosis, management options and prognosis of fulminant myocarditis are reviewed in detail.

Prognostic significance of troponin T elevation in patients without chest pain

Increased cardiac troponin with chest pain is important for the diagnosis, triage, and treatment of patients in the emergency department. However, the use of troponin for the diagnosis and triage of patients without chest pain is poorly established. The aim of this study was to determine 30-day and 1-year mortality and morbidity of troponin T increases in patients without chest pain. This retrospective study compared 92 hospitalized patients without (study group) and 91 patients with chest pain (control group), followed up for 1 year. Study group patients had troponin T >0.04 microg/L, normal creatine kinase or creatine kinase-MB fraction <5%, and no electrocardiographic ischemia. Excluded were high-risk patients with end-stage kidney disease, those with left ventricular ejection fraction <40%, and the critically ill. Outcome variables included 30-day and 1-year death, myocardial infarction, unstable angina, and coronary revascularization rates. Thirty-day (13.0% vs 4.4%; p = 0.032) and 1-year (33% vs 4.6%; p <0.001) mortality rates were significantly higher in the study group, whereas myocardial infarction, unstable angina, and revascularization were infrequent. In conclusion, patients with increased troponin T and no chest pain had a high mortality rate and required careful follow-up.

Acute myopericarditis with focal ECG findings mimicking acute myocardial infarction

BACKGROUND

Although history, physical examination, laboratory data points, and electrocardiogram (ECG) are helpful, distinguishing among pericarditis, myopericarditis, and myocardial infarction can be difficult.

OBJECTIVES

This case, which presents as pericarditis with concomitant myocarditis (myopericarditis), illustrates the four evolving ECG stages of pericarditis and highlights some of the potential difficulties in differentiating between myopericarditis and acute myocardial infarction.

CASE REPORT

We present the case of a previously healthy 15-year-old boy who presented to the Emergency Department (ED) from his family physician's office for chest pain and presumed pericarditis. The patient's initial ECG showed infero-lateral ST-segment elevation, and his troponin T was elevated at 1.54 ng/mL (ref. < 0.03). Several hours after presentation to the ED, the patient experienced "10/10" chest pain, and a repeat ECG showed ST elevation increased from the prior ECG. After an emergent echocardiogram revealed no regional wall abnormalities, he was transferred to a pediatric cardiac intensive care unit, where a heart catheterization revealed no coronary irregularities. He was discharged 4 days later with the diagnosis of myopericarditis.

CONCLUSION

This case report illustrates some of the difficulties in differentiating among myopericarditis and myocardial infarction in a 15-year-old patient presenting with chest pain.

Determination of Cardiac Troponin I in the Blood and Heart of Calves with Foot-and-Mouth Disease

The current study was designed to determine the changes of the cardiac troponin I (cTnI) expression in blood and tissue during the myocardial degeneration in calves with foot-and-mouth disease (FMD). Seventeen crossbred calves presenting pathological signs for FMD confirmed by viral analysis were studied. A biochemistry panel and immunohistochemistry were performed on 17 diseased calves and 7 calves used as controls. Creatine kinase (CK), CK-myocardial band (CK-MB), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) activities were analyzed for both groups. Cardiac troponin I levels were measured by a commercially available enzyme-linked immunosorbent assay kit. Mean cTnI (14.8 ± 1.9 ng/ml) concentration and CK (573 ± 407 U/l), CK-MB (238 ± 37 U/l), AST (84 ± 7), and LDH (298 ± 29 U/l) activities were higher in FMD cases compared with controls. Immunohistochemistry revealed loss or depletion of cTnI expression in myocardium of all cases. None of the 7 controls showed loss of cTnI expression. Increased serum cTnI concentration correlated with myocardial injury and loss of cTnI immunolabeling in cardiomyocytes of calves with FMD.

Autoimmune myocarditis

Myosin-induced autoimmune myocarditis (EAM) is a model of inflammatory heart disease initiated by CD4(+) T cells. It is a paradigm of the immune-mediated cardiac damage believed to play a role in the pathogenesis of a subset of postinfectious human cardiomyopathies. Myocarditis is induced in susceptible mice by immunization with purified cardiac myosin or specific peptides derived from cardiac myosin, or by adoptive transfer of myosin-reactive T cells. Myocarditis is induced in Lewis rats by immunization with purified cardiac myosin or by adoptive transfer of T cells stimulated by specific peptides derived from cardiac myosin. Myocarditis begins 12 to 14 days after the first immunization, and is maximal after 21 days. In addition to the protocols used to induce EAM in mice and rats, support protocols are included for preparing purified cardiac myosin using mouse or rat heart tissue, preparing purified cardiac myosin for injection, and collecting and assessing hearts by histopathological means.

Troponin I in the intensive care unit setting: from the heart to the heart

When measured in the plasma, cardiac troponins T (cTnT) and I (cTnI) are considered to be highly specific markers of myocardial cell damage; however, research has demonstrated that troponin elevation may associated with causes other than coronary artery disease. In the intensive care unit (ICU) setting, increased cTnI levels are quite common findings and when documented, even on admission, intensivists should bear in mind that this laboratory finding holds a prognostic role independent of the reason for ICU admission. The mechanism(s) (such as demand ischemia, myocardial strain, etc.) and not simply the cause (i.e., renal failure) of the increment in serum cTnI should be investigated to better tailor the therapeutical regimen in the single patient. In this review, we therefore consider the nonthrombotic causes of troponin elevation in the critical setting.

Myopericarditis: Etiology, management, and prognosis

Acute pericarditis is often accompanied by some degree of myocarditis. In clinical practice both pericarditis and myocarditis coexist because they share common etiologic agents, mainly cardiotropic viruses. The term "myopericarditis" indicates a primarily "pericarditic syndrome" and it is responsible for the majority of cases. The clinical presentation is varied, reflecting the variability of myocardial involvement, that may be focal or diffuse, affecting any or all cardiac chambers. Probably many cases may be subclinical and subtle cardiac symptoms and signs may be overshadowed by the systemic manifestations of the viral infection. Echocardiography is essential for the diagnosis of left ventricular dysfunction in even subclinical cases and for follow-up of patients with apparently normal left ventricular function. Magnetic resonance imaging holds promise for an effective non-invasive diagnostic tool. Either for acute pericarditis or myopericarditis there is a lack for adequate controlled clinical trials. In myopericarditis the use of NSAID should be cautious, because in animal models of myocarditis, NSAID are not effective and may actually enhance the myocarditic process and increase mortality. In clinical practice lower anti-inflammatory doses are mainly considered to control symptoms. The natural history of myopericarditis in large populations is not known with accuracy. On follow-up, the majority of these cases had objective normalization of echocardiography, electrocardiography, laboratory testing, and functional status, although up to 14% may report atypical, non-limiting chest discomfort. Unfortunately, few data have been published on myopericarditis, the paper reviews current available evidence on the presentation, management, and prognosis of myopericarditis.

Pathogenesis of myocarditis and dilated cardiomyopathy

Myocarditis is a disease with a variable clinical presentation, ranging from asymptomatic to a fatal outcome. Among the recognized causes of myocarditis are mutations in multiple genes; infection by bacterial, rickettsial, mycotic, protozoan, and viral agents; and exposure to drugs, toxins, and alcohol. Some subtypes of myocarditis, such as giant cell myocarditis or eosinophilic necrotizing myocarditis, are suspected to be caused by an autoimmune inflammation. Several lines of evidence support the involvement of autoimmunity in myocarditis. These include the production of antibodies against relevant self-antigens, the fact that myocarditis symptoms can be relieved by immunosuppressive therapy in some patients, and a co-occurrence of myocarditis with other autoimmune diseases. Most of the evidence that myocarditis is an autoimmune disease comes from animal models. In this chapter, we discuss coxsackievirus B3-induced myocarditis and myosin-induced myocarditis as models of both viral and autoimmune inflammation in the heart. The latest advances in the study of autoimmunity have been concentrated on T helper cells, particularly the newly discovered subset, Th17 cells. Experimental autoimmune myocarditis (EAM), a mouse model of myocarditis induced by cardiac myosin, is partly an IL-17-driven disease. However, we have shown recently in IL-13 knockout mice that the disease can be driven through other pathways, and that the Th1 helper cells also lead to severe heart inflammation. Most importantly, IL-17A knockout mice are not fully protected against EAM and still develop mild myocarditis. The most abundant cells in heart infiltrate in human giant cell myocarditis or EAM are monocyte/macrophages, and there is now evidence that macrophages play a decisive role in the course of EAM.

New potential uses for cardiac troponins

This review briefly synthesizes the molecular biology of troponin, which is currently the best biochemical marker for the detection of cardiac injury and, thus, acute myocardial infarction as well. Potential new uses for the marker based on these insights, with a specific interest in cardiac troponin fragments that potentially could be linked to distinct clinical conditions, are described. Some of the clinical problems clinicians are faced with including how to use the markers in renal failure and the difficulties associated with the heterogeneity of current troponin assays are also discussed. Finally, we present the possibility of specific cardiac troponin fragments resulting from modification or degradation, associated with distinct pathological processes, as new potential uses for this biomarker.

Cardiac emergencies in the first year of life

Cardiac emergencies in the first year of life can be anxiety provoking for the health care provider. An understanding of the pathophysiology involved in the most common emergency department presentations is crucial to the development of appropriate treatment plans. This article discusses the most common causes of cyanotic and acyanotic heart disease in infants.

Early recognition of clozapine-induced myocarditis

Recently, there has been an increased recognition of the association of clozapine with myocarditis and myocardiopathy. Commonly used diagnostic tests have very limited sensitivity in diagnosing this potentially life-threatening complication. We present 3 case reports of clozapine-induced myocarditis/cardiomyopathy that illustrate the development of a combined approach involving a clinical questionnaire and diagnostic testing at our hospital. This combination approach helped in the early recognition and successful treatment of clozapine myocarditis in one of our patients. Given the increasing recognition of this adverse reaction, we felt it timely to report our experience in diagnosing and treating this clinical syndrome.

[Troponin dosage in a patient with asymptomatic myocarditis due to trichinellosis]

Human trichinellosis is a potentially severe parasitic disease occurring after ingestion of undercooked meat infected with Trichinella sp. larvae. We report the case of a patient who ate an undercooked bear meat hunted in Canada; he presented with the usual symptoms of trichinellosis (i.e, facial oedema, myalgias and fever) complicated with an asymptomatic myocarditis. Myocarditis is a rare, but potentially lethal complication of trichinellosis. Myocarditis should be screened systematically even when specific symptoms are missing; dosage of troponin serum is a simple and reliable mean for such screening.

Use and Misuse of Cardiac Troponins in Clinical Practice

Cardiac troponins are very sensitive and specific markers of myocardial injury. Elevated troponin levels in the setting of acute coronary syndrome are diagnostic of acute myocardial infarction and provide guidance to clinicians with regard to appropriate use of intensive medical and revascularization therapies. However, elevated troponin levels are commonly seen in several noncoronary ischemia presentations and create considerable confusion among clinicians in these settings. In this review article, we discuss the utility of troponins in various clinical settings and present a "common sense" approach to interpreting troponin elevation outside the setting of acute coronary syndrome.

Cardiac troponin I in patients with acute lower limb ischemia

The presence, cause, and clinical significance of elevated cardiac troponin I in patients with acute lower limb ischemia is yet unknown. Forty-six patients (20 men [43%]; mean age 72 +/- 10 years, range 42 to 92) with acute lower limb ischemia were enrolled in this study. Serial creatine kinase (CK), CK isoenzyme MB (CK-MB), and troponin I measurements were obtained in all consecutive patients. Peak levels were evaluated for each patient. Twenty-four patients (52%) had elevated peak troponin I levels (>0.2 ng/ml) during their hospitalization. Patients were divided into 3 groups according to their peak troponin I levels: 11 patients (24%) had peak troponin I levels >1 ng/ml (the high troponin I group), 13 (28%) had levels of 0.2 to 1 ng/ml (the intermediate troponin I group), and the remaining 22 (48%) had peak troponin I levels <0.2 ng/ml (the low troponin I group). The peak CK levels were 10,263 +/- 16,513, 1,294 +/- 1,512, and 934 +/- 1,045 IU/ml (p = 0.04) in the 3 different troponin I subgroups, respectively, and the peak CK-MB levels were 143 +/- 170, 38 +/- 31, and 38 +/- 43, respectively (p = 0.04). Troponin I was positively correlated with CK (R = 0.35, p = 0.017) and CK-MB (R = 0.38, p = 0.009). The mean length of hospitalization was 8.3 +/- 6.2 days for the whole study group and did not vary among the 3 troponin I groups (10.5 +/- 10.9 vs 8.6 +/- 4.9 vs 7.2 +/- 4.0 days, p = 0.762). There were no differences in mortality during hospitalization among the 3 groups (4 of 11 vs 1 of 13 vs 4 of 22 patients, p = 0.22). In conclusion, patients with acute lower limb ischemia often have elevated cardiac troponin I levels. Elevated troponin I levels were not associated with the duration of hospitalization or with in-hospital mortality in this group of patients.

Acute myopericarditis after multiple vaccinations in an adolescent: case report and review of the literature

We report a case of postvaccination acute myopericarditis in an adolescent. The patient presented with acute chest pain, diffuse ST-segment elevation, and elevated cardiac enzyme levels. Cardiac MRI was consistent with acute myocarditis. He recovered within a few days with nonsteroidal antiinflammatory treatment and remains clinically stable, with improvement of MRI findings at the 10-week follow-up. Postvaccination cases of myopericarditis reported in the pediatric literature are also reviewed.

Evaluation of serum cardiac troponin I concentration in Boxers with arrhythmogenic right ventricular cardiomyopathy

OBJECTIVE

To evaluate serum cardiac troponin I (cTnI) concentrations in Boxers with arrhythmogenic right ventricular cardiomyopathy (ARVC), unaffected (control) Boxers, and control non-Boxers.

ANIMALS

10 Boxers with a clinical diagnosis of ARVC defined by > or = 1,000 ventricular premature complexes (VPCs)/24 h on an ambulatory ECG, 10 control Boxers assessed as normal by the presence of < 5 VPCs/24h, and 10 control non-Boxers.

PROCEDURES

Serum was extracted from a blood sample from each dog. Analysis of serum cTnI concentrations was performed.

RESULTS

Mean +/- SD serum cTnI concentration was 0.142 +/- 0.05 ng/mL for Boxers with ARVC, 0.079 +/- 0.03 ng/mL for control Boxers, and 0.023 +/- 0.01 ng/mL for control non-Boxers. A significant difference in serum cTnI concentrations was observed among the 3 groups. In the combined Boxer population (ie, Boxers with ARVC and control Boxers), a significant correlation was found between serum cTnI concentration and number of VPCs/24 h (r = 0.78) and between serum cTnI concentration and grade of ventricular arrhythmia (r = 0.77).

CONCLUSIONS AND CLINICAL RELEVANCE

Compared with clinically normal dogs, Boxers with ARVC had a significant increase in serum cTnI concentration. For Boxers, correlations were found between serum cTnI concentration and number of VPCs/24 h and between concentration and the grade of arrhythmia. Because of the overlap in serum cTnI concentrations in control Boxers and Boxers with ARVC, future studies should evaluate the correlation of serum cTnI concentration with severity of disease in terms of degree of myocardial fibrofatty changes.

Clostridium sordellii lethal toxin kills mice by inducing a major increase in lung vascular permeability

When intraperitoneally injected into Swiss mice, Clostridium sordellii lethal toxin reproduces the fatal toxic shock syndrome observed in humans and animals after natural infection. This animal model was used to study the mechanism of lethal toxin-induced death. Histopathological and biochemical analyses identified lung and heart as preferential organs targeted by lethal toxin. Massive extravasation of blood fluid in the thoracic cage, resulting from an increase in lung vascular permeability, generated profound modifications such as animal dehydration, increase in hematocrit, hypoxia, and finally, cardiorespiratory failure. Vascular permeability increase induced by lethal toxin resulted from modifications of lung endothelial cells as evidenced by electron microscopy. Immunohistochemical analysis demonstrated that VE-cadherin, a protein participating in intercellular adherens junctions, was redistributed from membrane to cytosol in lung endothelial cells. No major sign of lethal toxin-induced inflammation was observed that could participate in the toxic shock syndrome. The main effect of the lethal toxin is the glucosylation-dependent inactivation of small GTPases, in particular Rac, which is involved in actin polymerization occurring in vivo in lungs leading to E-cadherin junction destabilization. We conclude that the cells most susceptible to lethal toxin are lung vascular endothelial cells, the adherens junctions of which were altered after intoxication.

Fatal myocarditis related to Campylobacter jejuni infection: a case report

Infectious myocarditis can be caused by a variety of agents, with enteroviruses being the most common. Myocarditis due to enteric bacteria is rare. We present pathological documentation of a rare case of a Campylobacter jejuni bowel infection leading to rapidly fatal myocarditis.

A personal history of markers of myocyte injury [myocardial infarction]

BACKGROUND

The measurement of proteins in blood to reflect damage to the heart is one of the most successful examples of easily measured biomarkers identifying a serious major health problem. The concept of using a blood test to reflect organ or cell injury requires a substance that is very abundant in the target cell, has a means of reaching blood, a reasonable half-life in blood, and ideally a specific form reflective only of the target cell in tissue. The myocyte's major role is contraction so proteins involved in contraction or the energy to support it should be good candidate markers.

CONCLUSIONS

All the various biomarkers that have been used to detect cardiac damage are involved in contraction or energy metabolism, but the markers evolved empirically starting with transaminases in the 1950s leading to troponins in the 1990s. This history is reviewed with reflections on my experiences with developing assays for CK-MB and Troponin I.

Acute effects of periodontal therapy on bio-markers of vascular health

AIM

We aimed to study the impact of periodontal therapy on several bio-markers related to vascular health.

MATERIAL AND METHODS

Fifty-five consecutive subjects (age range 30-64 years) having severe periodontitis received an intensive session of periodontal therapy under local anaesthesia and provided blood samples before and 1 and 7 and 30 days following therapy. High-sensitivity assays were utilized to quantify serum concentrations of inflammatory markers [interleukin (IL)-1beta, tumour necrosis factor-alpha], plasma haemostatic (D-dimer) and endothelial soluble markers [soluble E-selectin (s-Es) and von Willebrand factor antigen (r-WF:Ag)].

RESULTS

Periodontal therapy elicited a significant activation of the haemostatic system (38% and 68% mean increases of plasma D-dimer 1 and 7 days after therapy, respectively, p<0.001), together with moderate endothelial dysfunction (10% and 30% mean increases at 24 h in plasma soluble E-selectin, p<0.05 and von-Willebrand factor, p<0.01, respectively). D-Dimer and s-Es acute changes were significantly correlated with periodontal treatment time (p<0.05). Cigarette smoking status and body mass index strongly influenced the acute release of IL-1beta (p<0.05), D-dimer (p<0.01) and s-Es (p<0.01).

CONCLUSIONS

Periodontal therapy represents a novel and reliable non-drug-induced model to investigate in vivo the interplay between inflammation, coagulation and endothelial cell activation.

Myocarditis

Viruses are the most common cause of myocarditis in economically advanced countries.

Enteroviruses and adenoviruses are the most common etiologic agents.

Viral myocarditis is a triphasic process. Phase 1 is the period of active viral replication in the myocardium during which the symptoms of myocardial damage range from none to cardiogenic shock. If the disease process continues, it enters phase 2, which is characterized by autoimmunity triggered by viral and myocardial proteins. Heart failure often appears for the first time in phase 2. Phase 3, dilated cardiomyopathy, is the end result in some patients. Diagnostic procedures and treatment should be tailored to the phase of disease.

Viral myocarditis is a significant cause of dilated cardiomyopathy, as proved by the frequent presence of viral genomic material in the myocardium, and by improvement in ventricular function by immunomodulatory therapy.

Myocarditis of any etiology usually presents with heart failure, but the second most common presentation is ventricular arrhythmia. As a result, myocarditis is one of the most common causes of sudden death in young people and others without preexisting structural heart disease.

Myocarditis can be definitively diagnosed by endomyocardial biopsy. However, it is clear that existing criteria for the histologic diagnosis need to be refined, and that a variety of molecular markers in the myocardium and the circulation can be used to establish the diagnosis.

Treatment of myocarditis has been generally disappointing. Accurate staging of the disease will undoubtedly improve treatment in the future. It is clear that immunosuppression and immunomodulation are effective in some patients, especially during phase 2, but may not be as useful in phases 1 and 3. Since myocarditis is often selflimited, bridging and recovery therapy with circulatory assistance may be effective. Prevention by immunization or receptor blocking strategies is under development.

Giant cell myocarditis is an unusually fulminant form of the disease that progresses rapidly to heart failure or sudden death. Rapid onset of disease in young people, especially those with other autoimmune manifestations, accompanied by heart failure or ventricular arrhythmias, suggests giant cell myocarditis.

Peripartum cardiomyopathy in economically developed countries is usually the result of myocarditis.

Acute effects of short duration, maximal exercise on cardiac troponin I in healthy horses

This study evaluated the effects of exercise on cardiac troponin I (cTnI) concentrations in healthy, adult horses.

Fifteen fit, healthy horses determined to have a normal cardiovascular system completed a standardized exercise test on a high-speed treadmill. Heparinized blood was collected for plasma cTnI concentrations before maximal exercise, and 1, 3, 6, 9, 12 and 24 h post-exercise. The cTnI concentrations were measured with a commercial system (Stratus CS, Dade Behring, Inc.). Results were analysed by a multivariate ANOVA, where indicatedpost hocanalysis was done by Tukey–Kramer HSD and significance was placed atp < 0.05.

All horses had elevations in cTnI concentrations after maximal exercise. Values for cTnI trended higher at 3 h (0.066 ± 0.011 ng ml− 1) and 6 h (0.062 ± 0.011 ng ml− 1) post-exercise compared with pre-exercise (0.039 ± 0.007 ng ml− 1), although this did not reach statistical significance. Mean cTnI concentrations were within our normal reference range at all time points, although four individuals were above our normal range after exercise.

These data show that short-term, high-intensity exercise induces a small rise in plasma cTnI in normal horses. This should be kept in mind when evaluating cTnI concentrations in horses that have recently completed intense exercise. In addition, these data suggest that 3–6 h after intense exercise may be the optimal time for measurement of cTnI concentrations in horses with suspected exercise-induced myocardial damage.

Valeurs de la troponine I au cours des rhabdomyolyses chez les personnes âgées admises aux urgences

OBJECTIVE

The objective of this study was to assess the utility of determining serum cardiac troponin I (TcI) levels in the elderly.

METHODS

During the nine-month study period, all patients older than 70 years admitted to the emergency department presenting rhabdomyolysis (defined by creatine kinase>500 IU/L) were included in this prospective descriptive study, except for those with acute coronary syndrome or pulmonary embolism. Patients were classified into two groups according to their serum TcI level:>0.15 or<or=0. 15 ng/mL. The groups were compared for clinical, laboratory and treatment variables at inclusion and for mortality at six months.

RESULTS

The study included 67 patients: 30 in the group with TcI>0.15 ng/mL group and 37 in the other group. Clinical and laboratory indicators were similar in the two groups. In contrast, significantly more patients in the TcI>0.15 ng/mL group had been treated with a curative dose of heparin (14 versus 2, p=0.01). This difference between the two groups was noted in both the emergency department and other hospital units. Serum TcI levels were not correlated with creatine kinase levels. Concordance between emergency department diagnosis and discharge diagnosis was 95%. No patient was discharged with a diagnosis of acute coronary syndrome; one patient, with a serum TcI level<or=0.15 ng/mL, was diagnosed with a pulmonary embolism. Fewer than half the patients underwent cardiac ultrasonography. Segmental hypokinesia was observed in only a few cases (6% in the TcI>0. 15 ng/mL group versus 8% in the other group). Mortality at six months was higher among patients with an elevated serum TcI level, but the difference was not significant (23% versus 8%, p=0.07).

CONCLUSION

This study indicated a trend toward higher mortality among patients with elevated serum TcI levels, although the factors underlying these increased concentrations remain unclear.

Noninvasive imaging in myocarditis

Increased recognition of the role of inflammation in acute and chronic dilated cardiomyopathy has revived an interest in noninvasive imaging for detection of myocarditis. Diagnostic strategies that are based on molecular imaging promise to further advance our understanding and improve diagnostic precision. This article reviews the strengths and limitations of common clinical tests used for the diagnosis of myocarditis, with a focus on the emerging role of cardiovascular magnetic resonance imaging. Novel imaging modalities that are currently in preclinical development are discussed with recommendations for future clinical research.

Dosage des isoformes cardiaques des troponines T ou I : intérêt en cardiologie et en anesthésie–réanimation

Measurement of cardiac troponin I or T in serum (highly specific for the myocardium) have replaced classical markers, such as creatine kinase MB. Cardiac troponins are preferred markers because of their high specificity and sensitivity. This had led to modifications of the original World Health Organization criteria for acute myocardial infarction. Furthermore, the place of the troponins as superior markers of subsequent cardiac risk in acute coronary syndrome has now become firmly established, for both diagnostic and risk stratification purposes. The use of C-reactive protein and/or other inflammatory biomarkers may add independent information in this context. After non cardiac surgery, the total cardiospecificity of cardiac troponins explains why other biomarkers of necrosis should no longer be used. Recent studies suggest that any elevation of troponin in the postoperative period is indicative of increased risk of long-term cardiac complications. This prognostic value has been previously demonstrated in other clinical settings such as invasive coronary intervention (surgical myocardial revascularization and percutaneous coronary intervention) and after heart valve surgery. Increases of troponin indicate cardiac damage, whatever the mechanism (ischemic or not). Other causes of cardiac injury include: pulmonary embolism, myocarditis, pericarditis, congestive heart failure, septic shock, myocardial contusion. In most cases, elevation of troponins has been shown to be associated with a bad outcome.

Myocarditis and heart failure associated with hepatitis C virus infection

BACKGROUND

The aim of study is to determine the prevalence of hepatitis C virus (HCV) infection and myocardial injury among patients enrolled in the Myocarditis Treatment Trial. HCV infection has recently been noted in patients with cardiomyopathies and myocarditis. However, prevalence of HCV infection in myocarditis and heart failure remains to be clarified.

METHODS AND RESULTS

Patients with heart failure up to 2 years in duration without a distinct cause were enrolled in the trial between 1986 and 1990. Frozen blood samples were available from 1355 among 2233 patients enrolled and examined for presence of anti-HCV antibodies, circulating cardiac troponins I and T, and N-terminal pro-brain natriuretic peptide (NT-proBNP). Anti-HCV antibodies were identified in 59 of 1355 patients (4.4%). This higher prevalence of HCV infection than that observed in the general US population (1.8%), varied widely (0-15%) among the different medical centers and regions. The concentrations of circulating cardiac troponin (cTn) I were elevated in 17 of 56 patients (30%), and cTnT was detectable in 28 of 59 patients (48%) with HCV antibodies, suggesting the persistence of ongoing myocardial injury. The concentrations of NT-proBNP were elevated in 42 of 42 patients (100%) with HCV antibodies, (10,000 +/- 5860 pg/mL), a mean value significantly greater than in 1276 patients without HCV antibody (2508 +/- 160 pg/mL, P < .0001).

CONCLUSION

Anti-HCV antibodies were identifiable in sera stored for 13 to 17 years and were more prevalent in patients with myocarditis and HF than in the general population. In regions where its prevalence is high, HCV infection may be an important cause of myocarditis and HF. NT-proBNP is a more sensitive marker of myocardial injury than cardiac troponins in patients with heart failure from HCV myocarditis.

Elevated troponin level is not synonymous with myocardial infarction

BACKGROUND

Elevated troponin I in the absence of angiographically visible coronary lesions is seen in up to 10-15% of those undergoing angiography for suspected coronary artery disease. This study aims to elucidate the etiology of elevated cardiac troponin I in patients with normal coronary arteries on angiography.

METHODS

We identified 1551 (8.6%) patients with normal coronary arteries from our catheterization database of 17,950 patients from Jan 2000 to Jun 2004. Elevated troponin I levels were found in 217 (14%) of 1551 patients with normal coronary arteries. Of these 217 patients, 73 surgical patients were excluded, and the remaining 144 patients formed the study population. The study population was compared with age and gender matched patients with myocardial infarction and coronary artery disease (Group II).

RESULTS

The patients with elevated cardiac troponin I (cTnI) with normal coronary arteries had significantly lower prevalence of atherosclerotic risk factors and significantly higher left ventricular ejection fractions. The cTnI in patients with normal coronary arteries was elevated due to a number of causes including tachycardia, myocarditis, pericarditis, severe aortic stenosis, gastrointestinal bleeding, sepsis, left ventricular hypertrophy, severe congestive heart failure, cerebrovascular accident, electrical trauma, myocardial contusion, hypertensive emergency, myocardial bridging, pulmonary embolism, diabetic ketoacidosis, chronic obstructive pulmonary disease exacerbation and coronary spasm.

CONCLUSIONS

Cardiac troponin I could be elevated in a number of conditions, apart from acute myocardial infarction, and could reflect myonecrosis. Acute myocardial infarction is a clinical diagnosis as the laboratory is an aide to, not a replacement for, informed decision making.

Unusually high frequency of autoantibodies to PL-7 associated with milder muscle disease in Japanese patients with polymyositis/dermatomyositis

OBJECTIVE

Autoantibodies to aminoacyl transfer RNA synthetases, such as histidyl (Jo-1), threonyl (PL-7), alanyl (PL-12), glycyl (EJ), and isoleucyl (OJ), are closely associated with a subset of patients with polymyositis/dermatomyositis (PM/DM) complicated by interstitial lung disease (ILD). Anti-Jo-1 is by far the most common, found in 15-25% of patients with PM/DM, whereas the other types are found in only approximately 3% of these patients. In this study, the clinical associations of these autoantibodies in Japanese patients with PM/DM were investigated.

METHODS

The diagnoses of PM/DM and amyopathic DM (ADM) were based on the Bohan and Peter criteria and Sontheimer's definition, respectively. Sera from 36 Japanese patients with PM/DM (13 with PM, 20 with DM, 3 with ADM) were screened by immunoprecipitation and by enzyme-linked immunosorbent assay (for Jo-1). Clinical and laboratory data were collected.

RESULTS

The frequencies of autoantibodies to Jo-1 (22%) and to EJ, OJ, and PL-12 (3-6%) were similar to those found in previous studies, including studies of Japanese subjects. However, anti-PL-7 was found in 17% of patients, in contrast to a frequency of 1-4% in previous studies (P < 0.02-0.0002). The 6 anti-PL-7-positive patients were not related, and no skewing in year or month of disease development, place of residence or work, or occupation was found. All patients had ILD, consistent with the clinical features of antisynthetase-positive patients. The patients with anti-PL-7 had lower serum muscle enzyme levels and milder muscle weakness (P < 0.05) compared with anti-Jo-1-positive patients.

CONCLUSION

Anti-PL-7 was found at an unusually high frequency in this group of Japanese patients with myositis. Although anti-PL-7, similar to anti-Jo-1, is associated with PM/DM with ILD, muscle involvement in the patients with anti-PL-7 appeared to be milder than that in the anti-Jo-1 subset.

Frequency of clinically unsuspected myocardial injury at a children's hospital

BACKGROUND

Ill children are at risk but rarely screened for myocardial injury. The frequency of such injury in ill children is unknown. Elevated levels of plasma cardiac troponin I (cTnI) can detect subclinical myocardial injury.

METHODS

We measured cTnI levels from 283 Children's Hospital, Boston patients (median age 2.10 years, range 0.13-22.4 years) seen in an outpatient or emergency clinic without clinically apparent cardiac disease. We took > or = 0.5 ng/mL as an indication of myocardial injury. We also measured plasma creatine kinase-MB, total creatine kinase, and myoglobin, and performed a chart review.

RESULTS

Fifteen (7.8%) of the 193 acutely ill children and 4 (4.4%) of the 90 well children had an elevated cTnI level (P = .44). Within the acutely ill group, the children with elevated cTnI were younger and had lower mean hemoglobin and hematocrit levels. Cardiac troponin I levels correlated with creatine kinase-MB (r = 0.22; P < .001) but not with creatine kinase or myoglobin. The 4 children with cTnI > 0.89 ng/mL, who also had plasma cardiac troponin T measured, showed cardiac troponin T elevations that were consistent with unstable angina levels in adults. Four children had high-level cTnI elevations (> 2 ng/mL) consistent with acute myocardial infarction levels in adults.

CONCLUSIONS

Elevated cTnI levels occur in children without clinically apparent cardiac disease and can be at adult unstable angina or acute myocardial infarction levels. Prospective studies to determine the clinical significance of these findings and their relationship to the development of cardiomyopathy are warranted.

La troponine et les autres marqueurs de souffrance myocardique, quelle signification en médecine interne ?

PURPOSE

Troponin is now the gold standard for the diagnosis of myocardial infarction. Aiming at improving the management of a patient suspect of an acute coronary syndrome, this article will point the interpretation of troponin dosages according to the clinical presentation and concomitant diseases.

ACTUALITIES

First, the interest of troponin dosage as compared with other markers of myocardial ischemia will be underlined. Then, the literature available about troponin in cardiovascular diseases but also in extracardiac diseases will be analysed. Finally, the difficulties of assay will be discussed.

PERSPECTIVES

The availability of a sensitive and specific marker such as troponin is definitively a progress in the management of patients with an acute coronary syndromes. But it remains a biological contribution to the global management of the patient. It is important to know the causes susceptible to increase the levels of troponin to avoid a wrong interpretation of the dosage, leading to diagnostic but also therapeutic mistakes.

Enteritis-associated myocarditis

We describe two cases in which myocarditis was associated with a prodromal diarrhoeal illness as a result of bacterial enteritis. Both cases were associated with elevated troponin T and chest pain mimicking myocardial infarction.

Regression of cardiac enzyme and ventriculocoronary communication in an infant with pulmonary atresia and intact ventricular septum after radiofrequency valvulotomy and valvuloplasty

I report on a 3-month-old infant with pulmonary atresia-intact ventricular septum and ventriculocoronary communication (VCC) who underwent percutaneous radiofrequency valvulotomy and valvuloplasty (RFVV). The patient's cardiac troponin-I, creatine kinase (CK), and myocardial fraction of (CK-MB) were elevated before RFVV and were gradually regressed to normal levels 12 days after RFVV. The VCC disappeared after RFVV. The transvalvular pressure gradients across the pulmonary valve were less than 30 mmHg in the follow-up echocardiography at 4-12 months of age. Oxygen saturation was approximately 90% in room air. Dipyridamole-thallium myocardial scintigraphy showed positive reperfusion over the apex and interventricular septum.

Cardiac involvement in a patient with clinical and serological evidence of African tick-bite fever

Background

Myocarditis and pericarditis are rare complications of rickettsiosis, usually associated with Rickettsia rickettsii and R. conorii. African tick-bite fever (ATBF) is generally considered as a benign disease and no cases of myocardial involvement due to Rickettsia africae, the agent of ATBF, have yet been described.

Case presentation

The patient, that travelled in an endemic area, presented typical inoculation eschars, and a seroconversion against R. africae, was admitted for chest pains and increased cardiac enzymes in the context of an acute myocarditis.

Conclusion

Our findings suggest that ATBF, that usually presents a benign course, may be complicated by an acute myocarditis.

Normal angiogram in acute coronary syndrome-preangiographic risk stratification, angiographic findings and follow-up

BACKGROUND

Coronary angiographies performed during acute coronary syndrome show different coronary morphologies-vessel occlusions, thrombi and various types of stenoses. In a few cases of acute coronary syndrome, angiography reveals normal coronary arteries. It is the purpose of this study to analyze this specific subset of patients who presented with an acute coronary syndrome but had a normal coronary angiogram with respect to the preangiographic diagnostics, risk stratification and clinical follow-up.

METHODS AND RESULTS

A total of 897 coronary angiographies were performed as an emergency procedure in our institution. The majority of patients (n = 821) presented with coronary artery disease and the majority was treated by mechanical revascularization (86.3%). In 76 patients (8.5%), no coronary artery stenosis was documented. However, according to the preangiographic risk stratification, coronary artery disease was expected in these patients. Observations documented angiographically included coronary spasms (6.6%) and muscle bridges (5.3%). During a mean follow-up of 11.2 +/- 6.4 months, one patient developed an acute myocardial infarction requiring coronary intervention. All other patients were free of any cardiac event.

CONCLUSIONS

In summary, we have to consider that coronary angiography may not always detect the cause of myocardial ischemia in every patient. There is a small group of patients with normal coronary angiograms during acute coronary syndrome. Additional diagnostic procedures like intravascular ultrasound (IVUS) or the assessment of intracoronary physiological parameters may increase the diagnostic value of angiography.

Advances in cardiac biomarkers

The diagnostic and prognostic roles of new and established cardiac biomarkers are continually changing. This update article discusses clinical diagnosis as a framework for directing biomarker testing. Markers are reviewed in the settings of acute coronary syndromes, decompensated heart failure, and noncardiac clinical scenarios.

Diagnostic performance of cardiovascular magnetic resonance in patients with suspected acute myocarditis: comparison of different approaches

OBJECTIVES

The aim of this research was to identify the diagnostic performance of gadolinium-enhanced and T2-weighted cardiovascular magnetic resonance (CMR) in suspected acute myocarditis.

BACKGROUND

Acute myocarditis is difficult to diagnose; CMR provides various means to visualize myocardial inflammatory changes. A CMR approach with clear-cut diagnostic criteria would be desirable.

METHODS

We investigated 25 patients with suspected acute myocarditis (18 males, 44 +/- 17 years) and 23 healthy controls (13 males, 29 +/- 10 years). Cardiovascular magnetic resonance studies included the following sequences: 1) T2-weighted triple inversion recovery; 2) T1-weighted spin echo before and over 4 min after gadolinium injection; and 3) inversion recovery-gradient echo 10 min after gadolinium injection. Qualitative and quantitative image analysis was performed for: 1) focal and global T2 signal intensity (SI); 2) myocardial global relative enhancement (gRE); and 3) areas of late gadolinium enhancement (LGE).

RESULTS

Both global T2 SI and gRE were higher in patients than in controls (T2: 2.3 +/- 0.4 vs. 1.7 +/- 0.4; p < 0.0001, gRE: 6.8 +/- 4.0 vs. 3.7 +/- 2.3; p < 0.001). The sensitivity, specificity, and diagnostic accuracy for T2 (cutoff value of 1.9) were 84%, 74%, and 79%, respectively; gRE: (cutoff value of 4.0) 80%, 68%, and 74.5% respectively; LGE: 44%, 100%, and 71%, respectively. The best diagnostic performance was obtained when "any-two" of the three sequences were positive in the same patient yielding a 76% sensitivity, 95.5% specificity, and 85% diagnostic accuracy.

CONCLUSIONS

A combined CMR approach using T2-weighted imaging, early and late gadolinium enhancement, provides a high diagnostic accuracy and is a useful tool in the diagnosis and assessment of patients with suspected acute myocarditis.

Cardiac troponin I: evaluation of a biomarker for the diagnosis of heart disease in the dog

OBJECTIVES

To assess the value of measuring blood levels of the myocardial protein cardiac troponin I (cTnl) in the diagnosis of congenital and acquired heart disease in the dog and in the evaluation of the severity of heart failure.

METHODS

Serum samples obtained from healthy dogs (n = 26) and from dogs diagnosed with a variety of congenital and acquired heart conditions (n = 35) were assayed for cTnl concentration using an automated immunoassay method. Results were also analysed according to the degree of heart failure as assessed using the International Small Animal Cardiac Health Council's scheme.

RESULTS

Healthy dogs had very low or undetectable blood cTnl levels, as did dogs with congenital heart disease. However, cTnl levels were significantly elevated in dogs with acquired mitral valve disease, dilated cardiomyopathy and pericardial effusion. Blood cTnl levels also varied with severity of heart failure.

CLINICAL SIGNIFICANCE

Measurement of blood cTnl levels may be a useful aid in the diagnosis of dogs with suspected heart disease and in indicating the severity of heart failure.