Cardiac troponin I release in non-ischemic reversible myocardial injury from parvovirus B19 myocarditis

Blood cardiac biomarkers responses are associated with 24 h ultramarathon performance

Purpose

Clinical significance of cardiac biomarkers response in ultra-endurance runners are not completely elucidated because events vary in distance/duration and competitors modulate running intensity according to individual running capacity. The aim of this study was to examine the relationship between self-selected exercise intensity with cardiac biomarkers comparing experienced (EXP, N = 11) and novice (NOV, N = 14) runners able to finish a 24h ultramarathon (24UM) with significant differences in performance.

Methods

Cardiac biomarkers (i.e. CKMB/totalCK, cTnT and NT-proBNP), inflammatory markers (i.e. leukocytes and CRP) and cortisol were analyzed before and after a 24UM.

Results

EXP finished the race with significant (p < 0.05) longer distance than NOV (158.8 ± 15.8 vs 116.8 ± 10.3 Km). Two-way mixed ANOVA showed significant time × performance level interaction with greater increase of cTnT (F(1,23) = 6.18, p = 0.021), NT-proBNP (F(1,23) = 9.27, p = 0.006) and cortisol (F(1, 23) = 5.13, p = 0.03) in the EXP group. CKMB/totalCK (F(1, 23) = 71.90, p < 0.0001) decreased while leukocytes (F(1, 23) = 100.06, p < 0.0001) and CRP (F(1, 23) = 93.37, p < 0.0001) increased in both groups (main effect of time). Correlations were found between 24UM distance and cortisol (r = 0.58; p = 0.002), CKMB (r = 0.47; p = 0.017), cTnT (r = 0.44; p = 0.027) or NT-proBNP (r = 0.56; p = 0.003). Cortisol and NT-proBNP were also significantly correlated (r = 0.51; p = 0.01).

Conclusions

Although there is no clear evidence of cardiac risk when comparing cardiac biomarkers levels with clinical cut-off values, cardiac biomarkers are associated with running performance and pituitary-adrenocortical system response. In EXP runners, higher levels of cardiac biomarkers and cortisol suggest a more hemodynamically challenged heart during prolonged endurance exercise.

Prognostic implications of troponin I elevation in emergency department patients with tachyarrhythmia

Background

Tachyarrhythmias are very common in emergency medicine, and little is known about the long‐term prognostic implications of troponin I levels in these patients.

Hypothesis

This study aimed to investigate the correlation of cardiac troponin I (cTnI) levels and long‐term prognosis in patients admitted to the emergency department (ED) with a primary diagnosis of tachyarrhythmia.

Methods

A retrospective cohort study was conducted between January 2012 and December 2013, enrolling patients admitted to the ED with a primary diagnosis of tachyarrhythmia and having documented cTnI measurements. Clinical characteristics and 5‐year all‐cause mortality were analyzed.

Results

Of a total of 222 subjects with a primary diagnosis of tachyarrhythmia, 73 patients had elevated levels of cTnI (32.9%). Patients with elevated cTnI levels were older and presented significantly more cardiovascular risk factors. At the 5‐year follow‐up, mortality was higher among patients with elevated cTnI levels (log‐rank test P < 0.001). In the multivariable Cox regression analysis, elevated cTnI was an independent predictor of all‐cause death (hazard ratio, 1.95, 95% confidence interval: 1.08‐3.50, P = 0.026), in addition to age and prior heart failure.

Conclusion

Patients admitted to the ED with a primary diagnosis of tachyarrhythmia and high cTnI levels have higher long‐term mortality rates than patients with low cTnI levels. cTnI is thus a biomarker with predictive capacity for mortality in late follow‐up, conferring utility in the risk stratification of this population.

Elevated CK-MB with a normal troponin does not predict 30-day adverse cardiac events in emergency department chest pain observation unit patients

BACKGROUND

Prior studies indicate that an elevated creatinine kinase (CK)-MB imparts poor prognosis in patients with acute coronary syndrome despite a normal troponin. Its prognosis in the undifferentiated chest pain observation unit (CPU) population remains undefined.

OBJECTIVE

To compare rates and predictors of 30-day adverse cardiac events in 2 cohorts (CK ±/MB+ vs. normal [CK ±/MB-]) in low-moderate-risk CPU patients.

METHODS

Consecutive CPU patients were followed in a retrospective cohort study for primary outcome (acute coronary syndrome, percutaneous transluminal coronary angioplasty, coronary artery bypass graft, abnormal stress test, cardiac hospitalization, or death within 30 days) by using standardized chart reviews and national death registry. Exclusions were: those aged 30 years or younger, positive troponin, ischemic electrocardiogram, hemodynamic instability, heart failure, or dialysis.

RESULTS

Between January 2006 and April 2009, 2979 patients were eligible, of which 350 excluded and 2629 analyzed. MB+ compared with normal patients were more likely to be: older (mean, 53.4 ± 14 vs. 51.5 ± 12 years; P = 0.04); male (71% vs. 40%; P = 0.01); renal insufficient (5% vs. 2%; P = 0.01); hypertensive (50% vs. 44%; P = 0.04); dyslipidemic (44% vs. 33%; P = 0.01) obese (55% vs. 43%; P = 0.01); and with known coronary artery disease (14% vs. 5%; P < 0.01). Composite adverse events were 213 (8%) and did not significantly differ for either initial MB+ vs. normal (9.1%, 8.0%; odds ratio, 1.1, 0.7-1.9) or serial MB+ vs. normal (7.5%, 7.4%; odds ratio, 1.0, 0.5-1.8). In a multiple logistic regression model, male sex, diabetes, and prior CAD predicted adverse events, whereas CK-MB along with race, hypertension, smoking, dyslipidemia, family history, and obesity did not.

CONCLUSIONS

Elevated CK-MB does not add value to serial troponin testing in low-moderate-risk CPU patients.

Parvovirus B19 is a bystander in adult myocarditis

BACKGROUND

The genomic DNA of parvovirus B19, a small single-stranded DNA virus of the genus Erythrovirus, has been shown to persist in solid tissues of constitutionally healthy, immunocompetent individuals. Despite these data, many case reports and series have linked the presence of parvovirus B19 genomic DNA, detected through nucleic acid amplification testing, with myocarditis and cardiomyopathy. Herein, we use multiple tools to better assess the relationship between parvovirus B19 and myocarditis and cardiomyopathy.

METHODS

Nucleic acid amplification testing, immunohistochemistry, in situ hybridization, and electron microscopy were used to assess the location and activity of parvovirus B19 in cases of myocarditis and in cases with no significant cardiac disease.

RESULTS

Nucleic acid amplification testing for parvovirus B19 genomic DNA was positive in 73% of patients with myocarditis/cardiomyopathy and in 26% of patients with no significant disease. In situ hybridization and immunohistochemistry showed that, in cases with amplifiable parvovirus B19 DNA, parvovirus B19 genomic DNA and viral protein production were present in rare mononuclear cells.

CONCLUSIONS

In a majority of cases of myocarditis and a significant number of otherwise normal hearts, nucleic acid amplification testing detected persistent parvovirus B19 genomic DNA that did not play a significant pathogenic role. The source of parvovirus B19 DNA appeared to be interstitial mononuclear inflammatory cells and not myocardial or endothelial cells. Therefore, nucleic acid amplification testing alone is not diagnostically helpful for determining the etiology of adult myocarditis.

Exercise-induced cardiac troponin elevation: evidence, mechanisms, and implications

Regular physical exercise is recommended for the primary prevention of cardiovascular disease. Although the high prevalence of physical inactivity remains a formidable public health issue, participation in exercise programs and recreational sporting events, such as marathons and triathlons, is on the rise. Although regular exercise training reduces cardiovascular disease risk, recent studies have documented elevations in cardiac troponin (cTn) consistent with cardiac damage after bouts of exercise in apparently healthy individuals. At present, the prevalence, mechanism(s), and clinical significance of exercise-induced cTn release remains incompletely understood. This paper will review the biochemistry, prevalence, potential mechanisms, and management of patients with exercise-induced cTn elevations.

Atrial fibrillation associated with exogenous subclinical hyperthyroidism, changing axis deviation, troponin-I positive and without acute coronary syndrome

Changing axis deviation has been rarely reported also during atrial fibrillation or atrial flutter. Changing axis deviation has been also rarely reported during acute myocardial infarction associated with atrial fibrillation or at the end of atrial fibrillation during acute myocardial infarction. Subclinical hyperthyroidism is an increasingly recognized entity that is defined as a normal serum free thyroxine and free triiodothyronine levels with a thyroid-stimulating hormone level suppressed below the normal range and usually undetectable. It has been reported that subclinical hyperthyroidism is not associated with coronary heart disease or mortality from cardiovascular causes but it is sufficient to induce arrhythmias including atrial fibrillation and atrial flutter. It has also been reported that increased factor X activity in patients with subclinical hyperthyroidism represents a potential hypercoagulable state. Serum troponin-I is a sensitive indicator of myocardial damage but abnormal troponin-I levels have been also reported without acute coronary syndrome and without cardiac damage. Abnormal troponin-I levels after supraventricular tachycardia have been also reported. We present a case of changing axis deviation in a 49-year-old Italian man with atrial fibrillation, exogenous subclinical hyperthyroidism and troponin-I positive without acute coronary syndrome. Also this case focuses attention on changing axis deviation, on subclinical hyperthyroidism and on the importance of a correct evaluation of abnormal troponin-I levels.