Troponin Kinetics and Emerging Biomarkers May Help Untangle Myocarditis, Heart Attacks, and Sepsis-Related Heart Injury

Chest pain arrives in the emergency department with a troubling sameness: the electrocardiogram looks abnormal, cardiac troponin is elevated, and the patient is frightened and unwell. Yet three very different conditions—myocarditis, acute coronary syndrome, and sepsis-induced cardiomyopathy—can sit behind that identical clinical picture, and each demands a fundamentally different treatment path. A narrative review published in Frontiers in Cardiovascular Medicine by Yuanyuan Xiao and Tao Xiang of the Third People’s Hospital of Chengdu brings these diagnostic threads together, synthesizing current evidence on how biomarker signatures could be woven into a practical, bedside strategy for telling the three conditions apart. The review, the authors state, is the first integrated biomarker-based framework for this differential diagnosis across all three entities.

The stakes of getting this right are considerable. Roughly 15 million patients in Europe and the United States present to emergency departments each year with chest pain or symptoms suggestive of acute myocardial infarction, and in ST-elevation myocardial infarction, delayed reperfusion costs lives. Current European Society of Cardiology guidelines mandate an immediate reperfusion strategy, preferably primary coronary angiography, with a maximum system delay of 120 minutes from STEMI diagnosis. Only after obstructive coronary artery disease has been excluded may clinicians pursue alternative diagnoses and adjunctive imaging such as echocardiography and cardiac magnetic resonance. The 2025 ESC guidelines for myocarditis and pericarditis reaffirm coronary angiography, alongside endomyocardial biopsy, in patients with clinically suspected myocarditis.

That reliance on angiography creates a genuine clinical burden. Because myocarditis cannot be reliably distinguished from acute myocardial infarction by symptoms, electrocardiogram, or routine laboratory markers alone, the ESC assigns a class IC recommendation to coronary angiography to rule out acute coronary syndrome in suspected myocarditis. Catheterization facilities with an on-call physician are often unavailable, forcing inter-hospital transfers under emergency care support, and the procedure itself carries a 1% to 2% risk of serious complications, including contrast reactions and contrast-induced nephropathy. The problem is compounded by shifting demographics: myocardial infarction increasingly affects younger patients, in whom myocarditis and acute coronary syndrome may be particularly difficult to separate at the bedside. The true population rate of myocarditis remains uncertain, since the gold-standard test, endomyocardial biopsy, is rarely performed, though estimates suggest roughly 22 people per 100,000 worldwide develop the condition each year.

At the center of the review sits high-sensitivity cardiac troponin, the workhorse biomarker of acute myocardial injury. Modern assays detect circulating troponin at concentrations 10 to 100 times lower than conventional tests, a sensitivity that comes at the cost of specificity, since numerous non-ischemic conditions also produce detectable elevations. Serial measurements using 0/1-hour or 0/2-hour algorithms are therefore essential, because absolute delta changes distinguish acute from chronic injury. But the kinetics of troponin release differ tellingly across the three conditions. In acute coronary syndrome, the pattern is a steep rise and fall, with an early peak at 12 to 24 hours in STEMI followed by decline; STEMI values typically exceed five times the sex-specific 99th percentile upper reference limit, while NSTEMI produces more modest elevations. In myocarditis, the pattern is a slower rise with a sustained, prolonged, moderate elevation, reflecting inflammatory cell-mediated disruption of myocyte membranes rather than ischemic necrosis. In sepsis-induced cardiomyopathy, troponin rises gradually in parallel with disease severity and falls with clinical recovery.

These patterns are informative but not definitive. Substantial delta changes can also occur in myocarditis and sepsis-induced cardiomyopathy, and little or no change may be seen when sampling near the troponin peak in acute coronary syndrome. In septic patients, troponin elevations are observed in approximately 40% to 90% depending on the population studied, arising largely through non-ischemic mechanisms such as increased membrane permeability, microcirculatory dysfunction, and catecholamine toxicity. The magnitude of elevation carries graded prognostic significance, and persistent or recurrent elevation during follow-up warrants reassessment for complications. The review stresses that troponin remains the central biomarker, but its interpretation must be embedded in a wider panel.

Among the established complementary markers, C-reactive protein, an interleukin-6-driven acute-phase reactant, rises in parallel with myocardial inflammation and reflects disease activity in myocarditis, yet it lacks specificity, since elevations also occur in acute coronary syndrome secondary to plaque inflammation, pulmonary embolism, and various systemic conditions. Procalcitonin, by contrast, shows superior specificity for bacterial infection: levels typically exceed 0.5 ng/mL in sepsis and correlate closely with disease severity, making it the key inflammatory marker for distinguishing sepsis-induced cardiomyopathy from viral myocarditis or uncomplicated acute coronary syndrome. Interleukin-6 itself is markedly elevated in severe sepsis and cytokine storm syndromes including fulminant myocarditis, but its measurement remains confined to research settings.

Natriuretic peptides add a second dimension to the panel. They are frequently elevated in sepsis, partly because pro-inflammatory interleukins stimulate their synthesis within the cardiac chambers in response to myocardial dysfunction. This yields differential-diagnostic value: a disproportionate rise in NT-proBNP relative to cardiac troponin suggests that ventricular dysfunction, rather than extensive myocyte necrosis, is the dominant process, supporting a diagnosis of sepsis-induced cardiomyopathy. Higher natriuretic peptide levels have also been associated with disease severity and adverse outcomes in sepsis, although they remain supportive rather than definitive markers. In myocarditis, markedly elevated NT-proBNP in the absence of obstructive coronary disease should raise suspicion of fulminant disease requiring urgent intervention.

Beyond these established markers, the review surveys emerging candidates that remain investigational. Matrix metalloproteinases regulate extracellular matrix degradation, and MMP-1 is highly upregulated in the early stages of myocardial injury, promoting cell migration and balancing inflammatory stimuli. Procollagen type I carboxy-terminal propeptide, or PICP, circulates as the residual fragment released when procollagen type I is processed into mature collagen; its serum levels correspond to the myocardial collagen volume fraction on histology and have been linked to worse prognosis across a spectrum of cardiac diseases. One study found that MMP-1 and PICP measurements may differentiate infarct-like myocarditis from NSTEMI in patients with chest pain, elevated troponins, and non-ST-elevation electrocardiogram findings—though the authors emphasize that prospective validation in external emergency department cohorts is essential before such tests can avert invasive procedures.

Circulating microRNAs represent the most speculative frontier. These stable, short, non-coding RNAs play roles in myocardial infarction, arrhythmias, heart failure, and coronary heart disease, and small studies suggest they could help distinguish myocarditis from acute myocardial infarction. Nie and colleagues found that miR-4763-3p levels were much higher only in patients with fulminant myocarditis, while miR-4281 was increased in both myocarditis and myocardial infarction groups compared with healthy people; intriguingly, higher miR-4763-3p levels were linked to less severe disease, suggesting a possible regulatory role. Patients with fulminant myocarditis also showed elevated miR-29b and miR-125b, positively correlated with myocardial edema and negatively correlated with left ventricular function, with miR-29b outperforming miR-125b diagnostically. MiR-155 was higher across viral and fulminant myocarditis groups and associated with greater inflammatory cell infiltration in the heart, but appears less useful for diagnosing acute myocardial infarction, hinting at specificity for inflammation over ischemia. The review cautions that most of this research has been conducted in the laboratory rather than with patients, and that translation awaits standardized assays, validated cut-off values, and prospective multicenter validation.

To convert these biomarker insights into bedside action, the review highlights the Salzburg Myocarditis score, a validated tool that distinguishes acute myocarditis from acute coronary syndrome using six readily available parameters: age, C-reactive protein, leukocyte count, infection within the past four weeks, arterial hypertension, and hyperlipidemia. At a cutoff of 4 points, the score achieved 90.3% sensitivity and 93.1% specificity in its derivation cohort; at 7 points or more, specificity exceeded 99.9%, identifying patients in whom myocarditis is highly probable and in whom inter-hospital transfer for angiography might potentially be avoided in hemodynamically stable patients. The authors are careful to note its limits: the derivation was retrospective and single-center, with a modest validation cohort of 90 patients, so prospective multicenter confirmation is required. They also propose a seven-step integrated algorithm—electrocardiogram and first troponin in parallel, clinical probability scoring, a biomarker panel, echocardiography, cardiac magnetic resonance with the updated Lake Louise criteria, coronary angiography when acute coronary syndrome cannot be excluded, and endomyocardial biopsy in selected cases—while stressing that it supplements rather than replaces guideline-directed pathways. The realistic near-term role of molecular markers, they conclude, is as research-stage adjuncts in specialized centers; multi-biomarker panels may ultimately power point-of-care diagnostics only after turnaround time, pre-analytical variability, assay standardization, and regulatory hurdles are overcome, and none of these tools should postpone guideline-recommended angiography and reperfusion when acute coronary syndrome cannot be excluded.

Subject of Research: Biomarker-based differential diagnosis of myocarditis, acute coronary syndrome, and sepsis-induced cardiomyopathy

Article Title: Biomarkers for differential diagnosis of myocarditis, acute coronary syndrome, and sepsis-induced cardiomyopathy

Article References: Xiao, Y., & Xiang, T. (2026). Biomarkers for differential diagnosis of myocarditis, acute coronary syndrome, and sepsis-induced cardiomyopathy. Frontiers in Cardiovascular Medicine, 13, Article 1956085. https://doi.org/10.3389/fcvm.2026.1956085

Image Credits: AI Generated

DOI: 10.3389/fcvm.2026.1956085

Keywords: myocarditis, acute coronary syndrome, sepsis-induced cardiomyopathy, high-sensitivity troponin, procalcitonin, natriuretic peptides, microRNAs, MMP-1, PICP, SAMY score, emergency medicine, biomarkers