Can cMyc challenge cTn?

Introduction: The early diagnosis of acute coronary syndrome remains challenging, with high-sensitivity cardiac troponin (hs-cTn) exhibiting limitations in the first 3 hours after symptom onset. Cardiac myosin-binding protein C (cMyc) shows promise as an earlier, more specific biomarker.

Methods: Comparative analyses of cMyc vs hs-cTn in multicenter studies (eg, the Kaier trial, n = 1954) and the integration of this testing into 0/1-hour algorithms were assessed. Applications in myocardial infarction subtyping, cardiac surgery, heart failure, and prehospital settings were also examined.

Results: Cardiac myosin-binding protein appears in circulation within 30 minutes of ischemia and peaks earlier (6 times faster than hs-cTnT). In non-ST-segment elevation myocardial infarction, cMyc combined with hs-cTn increased rule-out rates from 10.9% to 41.9% (P < .001). Its cardiac-specific N-terminal fragment (C0C1f) minimizes false positives, and point-of-care testing feasibility (70-minute turnaround) was demonstrated. Cardiac myosin-binding protein also showed prognostic value in heart failure and cardiac surgery.

Discussion: Cardiac myosin-binding protein demonstrates superior early diagnostic capability for acute coronary syndrome compared with hs-cTn, with potential to transform current diagnostic paradigms.