Dear Editor, Soluble cardiac troponin T (cTnT), an indicator of myocardial injury and stress, is used in decision management for patients with cardiovascular disease (CVD). Compared to subjects with negative clinical hs-cTnT content, subjects with positive clinical hs-cTnT had EVs with significantly lower value of cTnT per EV and smaller size. QSMLM data captures how cTnT-positive EVs differed among patients with different causes and severity of cardiac injury, providing complementary information to clinical hs-cTnT to more comprehensively describe the cardiac secretome. Overall, ~14% of EVs contained cTnT; on average, these EVs had a diameter of 118 nm with two detected molecules of cTnT per EV (Figure S4D,E). [Extracted from the article]