Elevations of Cardiac Troponin I Associated With 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.

New cut-off values of cardiac markers for risk stratification of angina pectoris

BACKGROUND

The aim of this present prospective study was to investigate the accuracy of cardiac markers for the prediction of subsequent cardiac events (cardiac death, acute myocardial infarction and recurrent ischemia requiring coronary revascularization).

METHODS

Fibrinogen, cardiac troponin T, troponin I, creatine phosphokinase myocardial fraction, C-reactive protein and myoglobin at baseline and after 6 h were measured on 154 patients (109 male, 63+/-11 years) with chest pain. Receiver operator characteristic analyses were performed to determine cut-off points of cardiac markers in prediction of adverse events.

RESULTS

The following cut-off values for prediction of cardiac events were calculated: troponin I at baseline 0.3 ng/ml (predictive accuracy=0.870), troponin I at 6 h 0.50 ng/ml (p.a.=0.909); troponin T at baseline 0.05 ng/ml (p.a.=0.643), troponin T at 6 h 0.05 ng/ml (p.a.=0.612), creatine phosphokinase myocardial fraction at baseline 2.0 ng/ml (p.a.=0.721), creatine phosphokinase myocardial fraction at 6 h 2.5 ng/ml (p.a.=0.734), myoglobin at baseline 23 ng/ml (p.a.=0.623), myoglobin at 6 h 26 ng/ml (p.a.=0.617), C-reactive protein at baseline 0.31 mg/dl (p.a.=0.662), C-reactive protein at 6 h 0.55 mg/dl (p.a.=0.682), and fibrinogen at baseline 360 mg/dl (p.a.=0.701). The combination of baseline troponin I with different parameters resulted in a higher sensitivity of up to 98%, with a similar predictive accuracy, but a lower specificity. Additive measurements of cardiac troponin I at 6 h to baseline cardiac troponin T and I proved to be the best combination for prediction of subsequent cardiac events.

CONCLUSIONS

Changes in cut-off levels of cardiac markers and inflammatory parameters results in a high accuracy of risk stratification in patients with chest pains. Combination of these measurements might further help in the identification of patients who would benefit from early coronary revascularization.

Troponin I as a specific marker of myocardial injury: from theory to clinical practice in the diagnosis of acute coronary syndrome

OBJECTIVE

To assess the diagnostic accuracy of troponin I (TnI) elevation in patients with acute coronary syndrome (ACS) in the emergency department (ED).

METHODS

We retrospectively studied 166 patients with elevated TnI and electrocardiographic (ECG) change consistent with non-ST-segment elevation myocardial infarction. They were transferred from the ED to our coronary care unit (CCU) to undergo coronary angiography.

RESULTS

Significant coronary stenosis were identified in 101 (61%) of patients. The other 65 patients were found to have different cardiac diseases (n=52) and in 13 patients diagnoses were not even related to the cardiovascular system. Wall motion abnormalities were assessed by echocardiographic wall motion score index (WMSI). Positive predictive value (PPV) of TnI varied from 53 to 65% for higher progressive values of the biomarker. The following PPVs were then calculated: PPV(TnI+CK-MB)=64%; PPV(TnI+WMSI)=72%, PPV(TnI+CK-MB+WMSI)=74%.

CONCLUSIONS

Abnormal values of TnI were detected in a variety of diseases not related to ACS. Even if troponin release indicates myocardial injury, it is not always synonymous with infarction or ischemia. A misinterpretation of TnI elevation may give rise to a diagnostic dilemma and cause unnecessary morbidity. An integration of biomarkers (TnI and CK-MB), ECG and WMSI will help identify false-positive ACS patients and avoid inappropriate admissions to CCU.

Myocarditis: emergency department recognition and management

Myocarditis is an acute inflammatory syndrome involving the heart and related structures. In many instances, the presentation is obvious, and appropriate treatment and disposition follow accordingly. In other situations, patients present with viral illness of the respiratory or gastrointestinal tracts (or both) or nonspecific symptoms such as fatigue and weakness,leading the clinician astray. Management is largely supportive, including aggressive cardiorespiratory support.

Prognostic value of low-level cardiac troponin-I elevations in patients without definite acute coronary syndromes

BACKGROUND

Low-level cardiac troponin-I (cTn-I) elevations predict adverse cardiovascular outcomes in patients with definite acute coronary syndromes (ACS), as defined by the presence of chest pain accompanied by ischemic electrocardiographic changes. However, their prognostic value in other clinical situations remains unclear.

METHODS

We studied 366 patients with suspected myocardial infarction (MI) but without definite ACS, including 57 patients with low-level cTn-I elevations (1.0 to 3.0 ng/mL) and 309 patients with cTn-I <1.0 ng/mL. All cTn-I measurements were made with the Dade Stratus II analyzer. We determined the adjusted 1-year risk of nonfatal MI or death from coronary heart disease (CHD death) in each group by using Cox proportional hazards models.

RESULTS

Among patients with cTn-I elevations between 1.0 and 3.0 ng/mL, 6 (11%) had a nonfatal MI or CHD death at 1 year compared with 12 (4%) patients in the cTn-I <1.0 ng/mL group [hazard ratio (HR), 3.5; 95% CI, 1.4 to 8.8]. After adjusting for baseline clinical characteristics, cTn-I levels between 1.0 and 3.0 ng/mL remained strongly associated with nonfatal MI or CHD death (adjusted HR, 3.4; 95% CI, 1.3 to 9.4). This association persisted even in the 215 patients who presented without chest pain (adjusted HR, 4.3; 95% CI, 1.4 to 13).

CONCLUSIONS

Low-level cTn-I elevations identify a subset of patients at increased risk for future cardiovascular events, even when obtained outside the context of definite ACS or presentation with chest pain.

Common causes of troponin elevations in the absence of acute myocardial infarction: incidence and clinical significance

Cardiac troponin is a preferred biomarker of acute myocardial infarction (MI). Unfortunately, elevation of troponin can be detected in a variety of conditions other than acute MI. This review focuses on the incidence and clinical significance of increased troponin in conditions commonly associated with troponin elevations, particularly in those that may resemble acute MI.

Smallpox vaccination and myopericarditis: a clinical review

Smallpox is a devastating viral illness that was eradicated after an aggressive, widespread vaccination campaign. Routine U.S. childhood vaccinations ended in 1972, and routine military vaccinations ended in 1990. Recently, the threat of bioterrorist use of smallpox has revived the need for vaccination. Over 450,000 U.S. military personnel received the vaccination between December 2002 and June 2003, with rates of non-cardiac complications at or below historical levels. The rate of cardiac complications, however, has been higher than expected, with two confirmed cases and over 50 probable cases of myopericarditis after vaccination reported to the Department of Defense Smallpox Vaccination Program. The practicing physician should use the history and physical, electrocardiogram, and cardiac biomarkers in the initial evaluation of a post-vaccination patient with chest pain. Echocardiogram, cardiac catheterization, magnetic resonance imaging, nuclear imaging, and cardiac biopsy may be of use in further workup. Treatment is with non-steroidal anti-inflammatory agents, four to six weeks of limited exertion, and conventional heart failure treatment as necessary. Immune suppressant therapy with steroids may be uniquely beneficial in myopericarditis related to smallpox vaccination, compared with other types of myopericarditis. If a widespread vaccination program is undertaken in the future, many more cases of post-vaccinial myopericarditis could be seen. Practicing physicians should be aware that smallpox vaccine-associated myopericarditis is a real entity, and symptoms after vaccination should be appropriately evaluated, treated if necessary, and reported to the Vaccine Adverse Events Reporting System.

[Cardiac troponin I and T: specific biomarkers of cardiomyocyte]

PURPOSE

Cardiac troponin I and troponin T have replaced creatine kinase MB (CK-MB) for the diagnosis of cardiomyocyte necrosis. Cardiac specificity of these new markers leads to a change in our practice.

CURRENT KNOWLEDGE AND KEY POINTS

Following necrosis, intracellular proteins are released into blood. This easy concept overlaps a biological complexity since troponins are released as complexes leading to various cut-off values depending on the assay used, as least for cardiac troponin I. The increase in both specificity and analytical sensitivity of these markers reached to propose a new definition of myocardial infarction. The diagnosis of acute coronary syndrome is a clinical based diagnosis, the use of troponin contributing to their classification. Finally, pathological processes leading to cardiac injury may induce an increase in the cardiac troponin level.

FUTURE PROSPECTS AND PROJECTS

Troponin standardization is a challenge for the near future leading to better follow-up of patients and comparison between cohorts.

Elevated troponin T concentrations in critically ill patients

OBJECTIVE

To determine the incidence of troponin T elevations among a selected group of critically ill patients, to correlate these findings to electrocardiographs, and to compare troponin T-positive and T-negative patients in relation to clinical parameters.

DESIGN

Prospective study.

SETTING

Mixed surgical and medical intensive care unit.

PATIENTS

Thirty-four consecutive critically ill patients who were mechanically ventilated or underwent thoracic or vascular surgery.

INTERVENTIONS

Blood samples were collected at admission, the next morning, and 24 h after the second blood sampling. These samples were used for troponin T measurement and electrocardiographs were made when troponin T levels were elevated.

MAIN RESULTS

Eleven of 34 patients (32%) had elevated troponin T levels, which were already present upon admission in eight out of 11 patients (73%). Most patients underwent surgery prior to ICU admission (21 of 34 patients). Significantly ( P=0.0055) more troponin T-positive patients underwent acute surgery, and significantly more ( P=0.045) troponin T-positive patients suffered from hypotension. Only four of the troponin T-positive patients were diagnosed as suffering from an acute myocardial infarction based on electrocardiographs. All troponin T-positive patients had coronary artery disease: nine had a history of CAD and two had actual CAD. No difference in mortality rates was observed between troponin T-positive and T-negative patients.

CONCLUSIONS

An unexpectedly high percentage of included patients had troponin T elevations, which could be corroborated by electrocardiographs in only four cases suggesting that a high percentage of critically ill patients with a history of CAD suffer from clinically unrecognised (minor) myocardial damage.

[Circulating troponin I assay: uses and misuses in medical practice]

Cardiac troponin I (cTnI) contributes to the modulation of the myocardial contractile function in the troponins complex. The assay of circulating cTnI is highly specific of the cardiac isoform and allows a quantification of the myocardial injury provided that both free and combined cTnI were recognized by the antibodies. The assay is a major contribution to the diagnosis of postoperative cardiac complications through its specificity because peripheral muscle trauma is a confounding factor during this period. Circulating cTnI mirrors the magnitude of an acute circulatory failure whatever the origin (cardiac, hemorrhagic or septic). A positive cTnI assay in an "asymptomatic" patient has to be confirmed and needs some investigations to discard an occult cardiac disease; cTnI has a limited role by itself in predicting mortality and hospital admissions. Circulating cTnI confirms the severity of an acute coronary syndrome and has a level-dependent prognostic value.

Myocarditis related to Campylobacter jejuni infection: a case report

BACKGROUND

Myocarditis can develop as a complication of various infections and is most commonly linked to enterovirus infections. Myocarditis is rarely associated with bacterial infections; salmonellosis and shigellosis have been the most frequently reported bacterial cause. We report a case of myocarditis related to Campylobacter jejuni enteritis.

CASE PRESENTATION

A 30-year-old previously healthy man presented with a history of prolonged chest pain radiating to the jaw and the left arm. Five days prior to the onset of chest pain, he developed bloody diarrhea, fever and chills. Creatine kinase (CK) and CK-MB were elevated to 289 U/L and 28.7 microg/L. Troponin I was 30.2 microg/L. The electrocardiogram (ECG) showed T wave inversion in the lateral and inferior leads. The chest pain resolved within 24 hours of admission. The patient had a completely normal ECG stress test. The patient was initiated on ciprofloxacin 500 mg po bid when Campylobacter jejuni was isolated from the stool. Diarrhea resolved within 48 hours of initiation of ciprofloxacin. The diagnosis of Campylobacter enteritis and related myocarditis was made based on the clinical and laboratory results and the patient was discharged from the hospital in stable condition.

CONCLUSION

Myocarditis can be a rare but severe complication of infectious disease and should be considered as a diagnosis in patients presenting with chest pain and elevated cardiac enzymes in the absence of underlying coronary disease. It can lead to cardiomyopathy and congestive heart failure. There are only a few reported cases of myocarditis associated with Campylobacter infection.

A formidable challenge: the diagnosis and treatment of viral myocarditis in children

It is generally well accepted that one third of patients with viral myocarditis experience a complete recovery of normal cardiac function, one third improve clinically but show residual cardiac dysfunction, and one third experience chronic heart failure and die or require heart transplantation. It is hoped that a better understanding of the underlying cause and pathogenesis of this disease will increase the number of patients who experience a complete recovery. New advances in both the diagnosis and treatment of viral myocarditis continue to enter clinical practice at a rapid pace, and it is likely that a genomic approach to the diagnostic evaluation and treatment of this disease will become possible in the near future. Viral myocarditis, however, will remain a significant diagnosticand therapeutic challenge to both physicians and scientists alike.

Long-term outcome of acute myocarditis is independent of cardiac enzyme release

BACKGROUND

There are few data concerning prognostic markers of acute myocarditis. The purpose of this study was to assess the prognostic value of initial measurements of creatine kinase (CK), cardiac troponin I (cTnI) and myoglobin as regards late recovery of the left ventricular ejection fraction on follow-up.

METHODS

A total of 22 patients (53+/-15 years old, 11 female) with acute myocarditis were followed up in a prospective observational study. Of these, 11 (50%) showed a history of acute infection prior to hospitalisation and seven (32%) had pericardial effusion. The median ejection fraction during the acute phase was 47+/-17%; after a mean follow-up of 119+/-163 days it improved to 60+/-9% (P<0.001). Considering maximal CK-rise values of 641+/-961 U/l (P=0.38), cTnI-rise values of 3.7+/-8.6 microg/l (P=0.16) and myoglobin values of 7.4+/-12 nmol/l (P=0.69), there was no correlation between initial cardiac enzyme levels and the initial and late left ventricular ejection fraction.

CONCLUSION

After acute myocarditis, there is late recovery of left ventricular ejection fraction, which is independent of the initial myocardial damage measured by cardiac enzyme release.

Minor increases in plasma troponin I predict decreased left ventricular ejection fraction after high-dose chemotherapy

BACKGROUND

Increased cardiac troponin I (cTnI) in patients treated with high-dose chemotherapy (HDCT) for aggressive malignancy has been proposed as an early marker of late HDCT-induced cardiac dysfunction. We investigated whether cTnI measured by the Stratus CS (Dade Behring) would allow detection of minimal cTnI increases in patients treated with HDCT.

METHODS

Plasma cTnI concentrations were determined in 179 consecutive patients before HDCT, at the end of the treatment, and after 12, 24, 36, and 72 h. Cardiac function was explored by echocardiography, and left ventricular ejection fraction (LVEF) was recorded during follow-up. The greatest variation in LVEF from the baseline value was used as a measure of cardiac damage.

RESULTS

In 99 healthy volunteers, the 99th percentile was at 0.07 microg/L. On the basis of ROC curve analysis (area under the curve, 0.89), a cutoff of 0.08 microg/L was chosen (sensitivity, 82%; specificity, 77%). cTnI > or =0.08 microg/L occurred in 57 patients (32%) with echocardiographic monitoring revealing a mean decrease in LVEF of 18%. In comparison, the group of cTnI-negative patients had a mean decrease in LVEF of 2.5% (P <0.001).

CONCLUSIONS

Plasma cTnI, as measured with the Stratus CS, can detect minor myocardial injury in patients treated with HDCT.

Serum cardiac troponin I and cardiac troponin T concentrations in dogs with gastric dilatation-volvulus

OBJECTIVE

To determine whether serum concentrations of cardiac troponin I (cTnI) and cardiac troponin T (cTnT) are increased in dogs with gastric dilatationvolvulus (GDV) and whether concentrations correlate with severity of ECG abnormalities or outcome.

DESIGN

Prospective case series.

ANIMALS

85 dogs with GDV.

PROCEDURE

Serum cTnl and cTnT concentrations were measured 12 to 24, 48, 72, and 96 hours after surgery. Dogs were grouped on the basis of severity of ECG abnormalities and outcome.

RESULTS

cTnl and cTnT were detected in serum from 74 (87%) and 43 (51%) dogs, respectively. Concentrations were significantly different among groups when dogs were grouped on the basis of severity of ECG abnormalities (none or mild vs moderate vs severe). Dogs that died (n = 16) had significantly higher serum cTnI (24.9 ng/ml) and cTnT (0.18 ng/ml) concentrations than did dogs that survived (2.05 and < 0.01 ng/ml, respectively). Myocardial cell injury was confirmed at necropsy in 4 dogs with high serum cardiac troponin concentrations.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicate that concentrations of cTnI and cTnT suggestive of myocardial cell injury can commonly be found in serum from dogs with GDV and that serum cardiac troponin concentrations are associated with severity of ECG abnormalities and outcome.

Coronary vasospasm as a possible cause of elevated cardiac troponin I in patients with acute coronary syndrome and insignificant coronary artery disease

BACKGROUND

Abnormal levels of serum cardiac troponin I (cTnI) are occasionally found in patients presenting with acute coronary syndromes but having insignificant coronary artery disease. Before one concludes that an abnormal cTnI level is a false-positive result, the possibility of coronary vasospasm should be considered. This study investigated whether coronary vasospasm could be a reason for elevated cTnI in this patient population.

METHODS AND RESULTS

This investigation enrolled 93 patients who presented to the emergency department with suspected coronary ischemia and had insignificant coronary artery disease. cTnI was elevated in 23 patients (25%) and was normal in 70 patients (75%). Coronary vasospasm, documented by an ergonovine provocation test, was found in 38 patients (41%). Patients with elevated cTnI levels, compared with those with normal cTnI, were older (63 +/- 13 y vs 56 +/- 14 y, P =.032), had a higher incidence of males (78% vs 52%, P =.049) and positive ergonovine provocation tests (74% vs 30%, P <.0001), and tended to have a lower incidence of hypercholesterolemia (26% vs 48%, P =.088) and normal electrocardiograms (48% vs 70%, P =.078). Multivariate analysis showed that the variables independently associated with an elevated cTnI level included coronary vasospasm (odds ratio 2.41, 95% CI 1.48-3.18, P <.0001) and hypercholesterolemia (odds ratio 0.64, 95% CI 0.47-0.99, P =.049). Coronary vasospasm (positive ergonovine provocation test) could explain 74% of elevated cTnI levels in patients with insignificant coronary stenosis.

CONCLUSIONS

In patients with acute coronary syndrome with elevated cTnI and insignificant coronary artery disease, the possibility of coronary vasospasm as a cause of elevated cTnI should be considered.

Cardiac troponin I: a potential marker of exercise intolerance in patients with moderate heart failure

BACKGROUND

In severe heart failure, increased values of cardiac troponins have been detected during decompensation. In this study, we investigated whether an increase of cardiac troponin I can be observed after symptom-limited exercise and after an exercise training session in patients with moderate heart failure.

METHODS

Twenty-seven patients with moderate heart failure (New York Heart Association II-III, ejection fraction 31% +/- 8%) were compared with 9 patients with mild heart failure and 10 subjects without heart failure. They underwent a symptom-limited exercise test and a bicycle exercise training session at >80% of maximal heart rate over 20 to 30 minutes. Plasma cTnI levels were measured at baseline, after symptom-limited exercise (hourly for 5 hours), and after training (4 and 10 hours).

RESULTS

Patients with moderate heart failure showed an increase of cTnI from 37 +/- 49 pg/mL to 73 +/- 59 pg/mL (P <.001) after symptom-limited exercise. Four patients with moderate and 1 with mild heart failure and normal cTnI values at rest showed an increase of cTnI above 100 pg/mL after acute exercise but not after training. Subjects without heart failure had lower cTnI levels at rest and significantly lower values after symptom-limited exercise and training (P <.05 for each).

CONCLUSION

Patients with symptomatic heart failure reveal an increase of cTnI after symptom-limited exercise at levels that indicate minor myocardial damage. The prognostic impact of this finding should, therefore, be further investigated.

Dilated cardiomyopathy in juvenile Portuguese Water Dogs

Dilated cardiomyopathy recently has been recognized in juvenile Portuguese Water Dogs. The purpose of this study was to evaluate unaffected and affected puppies by physical examination, electrocardiogram (ECG), echocardiogram, specific biochemical assays, and ultrastructure to document disease progression and to develop a method of early detection. Results of segregation analysis were consistent with autosomal recessive inheritance. Of 124 puppies evaluated clinically and echocardiographically, 10 were affected. No significant differences were found between unaffected and affected puppies for blood and myocardial carnitine or taurine concentrations, serum chemical variables, results of ophthalmological examinations, ECGs, or measurement of urine metabolites. Ultrastructural examination of myocardium from affected dogs revealed myofibrillar atrophy and small regions of myo‐fibrillar degeneration, most prominently at the region of the intercalated discs. Only echocardiography allowed detection of affected puppies before clinical signs became evident. Echocardiography revealed a significant difference in the shortening fraction, E point to septal separation, and the end systolic and diastolic left ventricular internal diameters. Affected puppies were detected 1–4 weeks before the development of acute congestive heart failure.

Soluble adhesion molecule profile in normal pregnancy and pre-eclampsia

OBJECTIVE

An exaggerated inflammatory response has been implicated as the cause of endothelial cell dysfunction and the maternal syndrome of pre-eclampsia. Adhesion molecules play a central role in the adherence of leukocytes to endothelial cells and the subsequent migration of white blood cells into perivascular tissue. Cellular forms of adhesion molecules mediate specific steps of leukocyte-endothelial cell interaction, and have been implicated in the pathophysiology of preeclampsia. Soluble forms of these molecules can be detected in plasma, and their concentrations are thought to reflect the degree of activation of a particular cell type. Elevations in soluble P-selectin (sP-selectin) reflect platelet activation; changes in soluble L-selectin (sL-selectin) suggest leukocyte activation; and an increase in soluble forms of E-selectin (sE-selectin), vascular cell adhesion molecule 1 (sVCAM-1), intercellular adhesion molecule 1 (sICAM-1) and platelet endothelial cell adhesion molecule (sPECAM-1) indicate endothelial cell activation/dysfunction. The objective of this study was to determine whether normal pregnancy and pre-eclampsia were associated with changes in the concentrations of soluble selectins and members of the immunoglobulin superfamily of adhesion molecules.

STUDY DESIGN

A cross-sectional study was conducted to determine the plasma concentrations of sL-selectin, sE-selectin, sP-selectin, sVCAM-1, sICAM-1 and sPECAM-1 in peripheral blood obtained from non-pregnant women (n = 20), normal pregnant women (n = 100) and patients with pre-eclampsia (n = 55). Concentrations of soluble adhesion molecules were determined with enzyme-linked immunoassays. Parametric statistics were used for data analysis.

RESULTS

Normal pregnancy was associated with a significant increase in the maternal plasma concentration of sP-selectin, a decrease in sL-selectin, and no change in sE-selectin, sVCAM-1, sICAM-1 and sPECAM-1. In contrast, pre-eclampsia was associated with a significant increase in sP-selectin, sE-selectin and sVCAM-1, a decrease in sL-selectin, but no change in sICAM-1 and sPECAM-1 concentrations.

CONCLUSIONS

The increased concentration of sP-selectin and decreased sL-selectin, as well as the lack of change in endothelial cell-associated soluble adhesion molecules suggest that pregnancy is associated with platelet and leukocyte activation, but not endothelial cell activation. In contrast, pre-eclampsia appears to be characterized by activation of platelets, leukocytes and endothelial cells.

Myocarditis in a patient with salmonella and campylobacter enteritis

Myocarditis associated with bacterial enteritis has only rarely been described and the pathogenesis is unclear. Herein we report a case where a young adult developed myocarditis during the acute stage of an infection with Salmonella heidelberg and Campylobacter jejunii/coli. The patient's troponin I value was elevated. We suggest that use of cardiac-sensitive troponins may be a useful tool for diagnosis of acute myocarditis in the context of bacterial enteritis. We also suggest the need for further investigation of the pathogenesis of myocarditis associated with enteric pathogens.

Peripartum Cardiomyopathy

It is critical that the diagnosis of peripartum cardiomyopathy is limited to women with congestive heart failure and decreased systolic function of the left ventricle in last month of pregnancy or within 5 months after delivery. Patients must have no pre-existing cardiac disease and no other cause for current cardiac dysfunction. The inclusion of patients before the last month of pregnancy or after 5 months postpartum introduces a large number of patients with cardiac disorders due to causes other than peripartum cardiomyopathy. Ventricular performance at rest and with exertion determines the type of management, its intensity, and duration. Patients whose ventricular function is normal at rest and with exercise or dobutamine can have their heart failure therapy tapered and ultimately discontinued after 6 to 12 months of standard treatment. Those with normal resting but abnormal stress cardiac function should continue some form of medical therapy (afterload reduction or beta-blocker) for longer periods of time, if not for life. Those with persistently abnormal ventricular function must receive optimal heart failure therapy forever and face the same relatively poor prognosis as patients with dilated cardiomyopathy from any cause. Options for management include standard heart failure therapy (digoxin, diuretics, afterload reduction, and anticoagulation), Swan-Ganz catheter monitoring and use of inotropic agents, intra-aortic balloon counterpulsation, and left ventricular assist device. Patients with peripartum cardiomyopathy are candidates for heart transplantation, assuming they meet all other criteria.

HIV-associated cardiovascular complications: a new challenge for emergency physicians

Cardiac complications associated with the AIDS may present to emergency physicians and are often secondary to opportunistic infections or malignancy, but may also be associated with other aspects of the human immunodeficiency virus (HIV) or its treatment. In this review article, we will discuss HIV-associated cardiac disease which may be encountered in the ED, emphasizing the prevalence, pathogenesis, and treatment of related disorders.

Acute coronary syndromes. The diagnostic role of troponins

Acute coronary syndromes (ACSs) represent the acute life-threatening phases of coronary heart disease. Clinical symptoms, EKG, and CK-MB measurements are frequently insufficient to evaluate patients without persisting ST elevations. Serial determinations of troponin T or troponin I after arrival in hospital disclose minor myocardial injury in patients presenting as unstable angina. This finding allows the currently best risk stratification and may contribute to cost-effectiveness. Without elevated troponins the risk for death or myocardial infarction during 30 days follow-up is not more than 1%. The lack of elevated troponins does not implicate that these patients do not have coronary artery disease. Patients with positive evidence of troponins represent a high-risk group who should be hospitalized and further evaluated, because the risk for myocardial infarction and death in 30 days is approximately 20%. Current studies indicate that early revascularization under glycoprotein IIb/IIIa antagonists represent the optimal treatment.

In patients with chronic atrial fibrillation and left ventricular systolic dysfunction, restoration of sinus rhythm confers substantial benefit

STUDY OBJECTIVES

To evaluate the benefit of sinus rhythm (SR) restoration in patients with chronic controlled atrial fibrillation (AF) and left ventricular systolic dysfunction (LVSD).

DESIGN

Prospective case-control study on the short-term outcome (6 to 9 months) of clinical and echocardiographic variables following attempted cardioversion.

SETTING

Outpatient clinic of a university hospital.

PATIENTS

Fifteen men and 5 women, ranging in age from 40 to 76 years, who had chronic controlled (mean [+/- SD] ventricular rate, 82 +/- 10 beats/min) AF and left ventricular fractional shortening (LVFS) of < 28% at baseline. Control was provided by retrospective paired echocardiographic examinations of six AF patients, plus the study cases with potentially unsuccessful cardioversion or early recurrence of AF.

INTERVENTIONS

Attempt to restore SR with amiodarone or electrical countershock.

MEASUREMENTS AND RESULTS

Conversion was attained in 17 patients, but AF recurred early in 4 patients, 3 of whom had proven ischemic LVSD. In the 13 patients with sustained SR, LVFS increased from 20 +/- 4% to 31 +/- 6% (p < 0.0001). In contrast, no changes were detected in the control group (n = 13). This improvement was paralleled by decreases in left ventricular (LV) end-diastolic dimension (from 55 +/- 7 to 51 +/- 6 mm; p = 0.014), LV mass (from 181 +/- 28 to 159 +/- 37 g; p = 0.015), and left atrial diameter (from 45 +/- 9 mm to 42 +/- 7; p = 0.003). A marked decrease in heart rate (from 82 +/- 9 to 64 +/- 5 beats/min; p < 0.0001) and a reduction in New York Heart Association functional class (from 2.3 +/- 0.9 to 1.2 +/- 0.4; p = 0.0007) also were observed in patients with sustained SR but not among subjects in the control group.

CONCLUSIONS

Even when adequate control of the ventricular rate has been achieved, the LV function of patients with chronic AF greatly improves after restoration and maintenance of SR.

Non-invasive assessment of rejection in pediatric transplant patients: serologic and echocardiographic prediction of biopsy-proven myocardial rejection

BACKGROUND

Cardiac allograft rejection is a multifocal immune process that is currently assessed using biopsy-guided histologic classification systems (International Society for Heart and Lung Transplantation). Cardiac troponin T and I are established serologic markers of global myocyte damage. The use of load-independent measures of contractility have also been shown to accurately assess the presence of ventricular dysfunction. Little is known about their utility in accurately predicting rejection in the pediatric age group. We undertook the present study to compare rejection grade with echocardiographic and serologic estimates of transplant rejection-related myocardial damage.

METHODS

We compared histologic rejection grades (0 to 4) with patient characteristics, echocardiographic measurements, catheterization measurements, and biochemical markers for 86 evaluations in 37 transplant recipients at Children's Hospital.

RESULTS

In univariate analyses, biopsy scores correlated (p < 0.05) inversely with left ventricular systolic function (shortening fraction) and contractility (stress velocity index, SVI), and directly with mitral E-wave amplitude. In multivariate analyses, lower contractility and higher mitral E-wave amplitude remained significantly (p < or = 0.01) associated with rejection (SVI, p = 0.002, odds ratio = 0.393; E wave, p = 0.0002, odds ratio = 228). Most rejection episodes were associated with elevation of biochemical markers of myocardial injury. Although troponin I was weakly associated with differences between rejection grades (p = 0.034), troponin T, creatine kinase-MB fraction, and C-reactive protein did not differ with biopsy-rejection scores. Serum markers had a poor predictive capacity for biopsy-detected rejection. Troponin T and I did correlate with increased left ventricular wall thickness and mass.

CONCLUSION

Progressively depressed left ventricular contractility and diastolic function are found with worsening pediatric heart transplant rejection-biopsy score; however, sensitive and specific serum markers do not correspond to the degree of active myocardial injury. The use of echocardiographic measures of contractility is associated with a specificity of 91.8% but low sensitivity of 66.7%. Overall we found poor concordance between serum markers and grade of rejection. It is unclear whether myocardial injury as assessed by serum markers, echocardiography, or histologic scoring is more important for assessment of acute rejection or long-term outcome, but it does not appear that serum and tissue markers of rejection can be used interchangeably.

Cardiac Troponins I and T Are Biological Markers of Left Ventricular Dysfunction in Septic Shock

Background: Cardiac depression in severe sepsis and septic shock is characterized by left ventricular (LV) failure. To date, it is unclear whether clinically unrecognized myocardial cell injury accompanies, causes, or results from this decreased cardiac performance. We therefore studied the relationship between cardiac troponin I (cTnI) and T (cTnT) and LV dysfunction in early septic shock.

Methods: Forty-six patients were consecutively enrolled, fluid-resuscitated, and treated with catecholamines. Cardiac markers were measured at study entry and after 24 and 48 h. LV function was assessed by two-dimensional transesophageal echocardiography.

Results: Increased plasma concentrations of cTnI (≥0.4 μg/L) and cTnT (≥0.1 μg/L) were found in 50% and 36%, respectively, of the patients at one or more time points. cTnI and cTnT were significantly correlated (r = 0.847; P &lt;0.0001). Compared with cTnI-negative patients, cTnI-positive subjects were older, presented higher Acute Physiology and Chronic Health Evaluation II scores at diagnosis, and tended to have a worse survival rate and a more frequent history of arterial hypertension or previous myocardial infarction. In contrast, the two groups did not differ in type of infection or pathogen, or in dose and type of catecholamine administered. Continuous electrocardiographic monitoring in all patients and autopsy in 12 nonsurvivors did not disclose the occurrence of acute ischemia during the first 48 h of observation. LV dysfunction was strongly associated with cTnI positivity (78% vs 9% in cTnI-negative patients; P &lt;0.001). In multiple regression analysis, both cTnI and cTnT were exclusively associated with LV dysfunction (P &lt;0.0001).

Conclusions: These findings suggest that in septic shock, clinically unrecognized myocardial cell injury is a marker of LV dysfunction. The latter condition tends to occur more often in severely ill older patients with underlying cardiovascular disease. Further studies are needed to determine the extent to which myocardial damage is a cause or a consequence of LV dysfunction.

Performance of the enhanced Abbott AxSYM cardiac troponin I reagent in patients with heterophilic antibodies

The presence of heterophilic antibodies in the serum of a small subpopulation of individuals continues to cause false results for modern-day immunoassays. In order to determine the frequency of heterophilic antibody (HA)-related false positives within our population of positive cardiac troponin I (cTnI) patients, we assayed 200 samples using the original in-house cTnI assay (Abbott AxSYM) and the Bayer ACS:180 cTnI, which we had previously observed to be more effective at blocking HA interference. Four samples were identified as false positives based on discordant results between the two assays, as well as the correction of the false positives by treatment of the samples with heterophilic antibody blocking reagent (HBR). An 'enhanced' version of the AxSYM cTnI reagent was designed to greatly reduce or eliminate HA interference, and has now replaced the original reagents. The present study shows that the enhanced reagent significantly reduced or eliminated much of the HA interference. Comparative studies between the enhanced cTnI reagent and the original Abbott AxSYM cTnI reagent showed excellent correlation and equivalent diagnostic concordance, when HA samples were excluded from the analysis.

2001--a biomarker odyssey

It is a time of transition in the area of biomarkers. Confusion is rampant, progress immense and the challenges invigorating. Better diagnosis is possible if we progress in a rational way and avoid the chaos so often characteristic of transitions by relying on the science of the discipline to keep us on track.

Elevation of serum cardiac troponin I in noncardiac and cardiac diseases other than acute coronary syndromes

This study evaluated the role of serum cardiac troponin I as a biochemical marker for the diagnosis of acute coronary syndromes in the presence of noncardiac diseases. Diagnostic characteristics were examined in 102 consecutive patients who were found to have serum cardiac troponin I levels higher than the upper reference limit of 0.6 ng/mL. Of 102 patients with cardiac troponin I levels of >0.6 ng/mL, 35 did not have the final diagnoses of acute coronary syndromes (myocardial infarction or unstable angina) but had various other final diagnoses, including nonischemic dilated cardiomyopathy, muscular disorders, central nervous system disorders, HIV disease, chronic renal failure, sepsis, lung diseases, and endocrine disorders. The mean value of serum cardiac troponin I in the patients with diseases other than acute coronary syndromes was significantly lesser than in those with acute coronary syndromes (2.0+/-1.9 [SD] v. 24.7+/-28.2 ng/mL; P<.0001). There were significantly fewer histories of chest pain and prior myocardial infarction in patients with diseases other than acute coronary syndromes than in those with acute coronary syndromes (history of chest pain, 3 v. 48 patients [P<.001]; history of prior myocardial infarction, 0 v. 30 patients [P<.001]). In conclusion, elevated serum levels of cardiac troponin I, especially in the lower ranges, should be interpreted with caution, particularly in patients suffering from acute illnesses who lack other diagnostic features suggestive of acute coronary ischemic events.

A proposed strategy for utilization of creatine kinase-MB and troponin I in the evaluation of acute chest pain

In recent years, cardiac troponins have attracted great interest as a marker for myocardial injury. However, there are limited data on strategies for use of creatine kinase (CK)-MB and troponin I (cTnI) in clinical practice. We sought to develop a testing strategy using prospectively collected clinical data including serial CK-MB and cTnI levels from 1,051 patients aged > or = 30 years admitted to a teaching hospital for acute chest pain. Diagnostic performance was evaluated for peak values of CK-MB and cTnI obtained during the first 24 hours for the combined end point of acute myocardial infarction and/or major cardiac events within 72 hours. The overall diagnostic accuracy was similar for both cardiac markers alone, and for the combination of cTnI and CK-MB (receiver-operating characteristic curve 0.84, 0.86, and 0.87, respectively). In the multivariate analysis, models including cardiac markers showed that both CK-MB and cTnI added information to clinical data to predict the combined end point, but cTnI added significantly less. Using recursive partitioning analysis, we developed a strategy that would restrict routine cTnI use to patients with normal CK-MB results and findings on the electrocardiogram consistent with ischemia. This strategy would divide patients with suspected myocardial ischemia into 4 groups with risks for the combined end point of 4%, 13%, 26%, and 85%. Thus, cTnI adds information to CK-MB mass and clinical data for predicting major cardiac events, but this contribution is mainly in patients with evidence of myocardial ischemia on their electrocardiograms.

Elevated circulating cardiac troponin I in patients with cirrhosis

It has been shown that certain patients with cirrhosis have asymptomatic cardiac abnormalities that have not yet been explained. Thus, cardiac troponin I, a specific marker of myocardial injury, has been measured in patients with cirrhosis without previous cardiac disease. Thirty-two consecutive patients (age 49 +/- 11) with cirrhosis and normal ECG were selected, 22 of which were alcoholic. Hemodynamic investigations were performed. Left ventricular function and mass were evaluated by echocardiography. Serum creatine kinase MB mass, myoglobin, and cardiac troponin I concentrations were measured. Cardiac troponin I concentrations were elevated in 10 patients (32%) (range 0.06-0.25 microg/L) whereas creatine kinase MB mass and myoglobin were normal in all patients. Abnormal troponin I values were not related to the severity of cirrhosis, to the degree of portal hypertension, or to other hemodynamic values. In contrast, elevated serum cardiac troponin I concentrations were related to a decreased stroke-volume index (P <. 05) and a decreased left ventricular mass (P <.05). These results show a high prevalence of slightly elevated serum cardiac troponin I in patients with cirrhosis, especially in those with alcoholic cirrhosis. Elevated troponin I is associated with subclinical left ventricular myocardial damage. These findings may be linked to a lack of left ventricular adaptation in certain patients with cirrhosis and alcoholic cardiomyopathy.

Cardiac troponin I and troponin T: recent players in the field of myocardial markers

The troponin (Tn) complex consists of three subunits referred to as TnT, TnI and TnC. Myocardium contains TnT and TnI isoforms which are not present in skeletal muscles and which can be separated from the muscular isoforms by immunological techniques. Using commercially available immunoassays, clinical laboratories are able to determine cardiac TnT and TnI (cTnT and cTnI) quickly and reliably as classical cardiac markers. After acute myocardial infarction, cTnT and cTnI concentrations start to increase in serum in a rather similar way than CK-MB, but return to normal after longer periods of time (approximately one week). Because of their excellent cardiac specificity, Tn subunits appear ideally suited for the differential diagnosis of myocardial and muscular damage, for example in noncardiac surgery patients, in patients with muscular trauma or with chronic muscular diseases, or after intense physical exercise. cTnT and cTnI may also be used for detecting evidence of minor myocardial damage: therefore they have found new clinical applications, in particular risk stratification in patients with unstable angina. In spite of the possible reexpression of cTnT in human skeletal muscles, and of the lack of standardization of cTnI assays, Tn subunits are not far to meet the criteria of ideal markers for acute myocardial injury. Only an insufficient sensitivity in the first hours following the acute coronary syndroms requiries to maintain an early myocardial marker in the cardiac panel for routine laboratory testing.

Early laboratory indicators of acute myocardial infarction

Biochemical markers of myocardial injury have evolved so that the diagnosis or exclusion of acute myocardial infarction can be determined within a short time with a high degree of sensitivity and specificity. The use of these markers in patients complaining of chest pain allows for medically appropriate and cost-effective triage decision making in the emergency department.

Changes in cardiac troponin I in Kawasaki disease before and after treatment with intravenous gammaglobulin

Changes in cardiac troponin I (cTnI) in Kawasaki disease before and after treatment with intravenous gamma-globulins (i.v.GG) were investigated in 42 cases in order to confirm the usefulness of cTnI as a serological test for the early onset of acute myocarditis and the effectiveness of i.v.GG as treatment for it. The level of cTnI before i.v.GG treatment was increased in 42.9% (18/42), but 89% (16/18) were in the normal range after treatment as shown by improved clinical symptoms and signs; 9.5% (4/42) were treated twice with i.v.GG because of recurrent high fever, with a positive level of cTnI in the second test. Despite the improved clinical symptoms and signs after retreatment with i.v.GG, 4.7% (2/42) continued to have an increased level of cTnI in follow-up studies. In conclusion, the measurement of cTnI is a useful serologic test for the early diagnosis of myocarditis or myocardial cell injury and for confirming the effectiveness of i.v.GG therapy for the cure and prevention of cardiovascular abnormalities in KD patients.