ABSTRACT
BACKGROUND: Previous studies showed that exercise may increase cardiac troponin serum levels; whether the occurrence of myocardial ischemia influences the changes of exercise-induced troponin raise, however, remains debatable. METHODS: We prospectively enrolled consecutive patients undergoing for the first time an elective stress myocardial perfusion scintigraphy (MPS) because of clinical suspicion of obstructive coronary artery disease (CAD). Patients were divided into 3 groups based on the evidence and degree of stress-induced myocardial ischemia at MPS: 1) group 1, no myocardial ischemia (≤4 %); 2) group 2, mild myocardial ischemia (5-10 %); 3) group 3, moderate-to-severe myocardial ischemia (≥10 %). High-sensitivity cardiac troponin I (cTnI) was measured immediately before (T0) and 1 hour (T1) and 4 h (T2) after the stress test. RESULTS: One hundred-seven patients (71 males; age 65.6 ± 9.4 years) were enrolled in the study. Serum hs-cTnI concentrations (logarithmic values) significantly increased after MPS, compared to baseline, in the whole population, from 1.47±1.26 ng/L at T0, to 1.68±1.12 ng/L at T1 (p<0.001) and 2.15±1.02 ng/L at T2 (p<0.001 vs. both T0 and T1). The increase in hs-cTnI did not significantly differ between the 3 groups (p = 0.44). The heart rate achieved during the test was the strongest determinant of cTnI increase (p < 0.001) after the stress test. CONCLUSIONS: In patients with suspected CAD, stress MPS induces an increase of cTnI that is independent of the induction and extension/severity of myocardial ischemia and is mainly related to myocardial work, as indicated by the heart rate achieved during the test.
ABSTRACT
BACKGROUND: A 49-year-old man presented at a hospital with an arthritic flare-up and stress dyspnea with a cough. He had a 5-year history of symmetrical polyarthritis, for which he was prescribed 5-15 mg prednisolone daily. He was subsequently diagnosed with rheumatoid arthritis and prescribed 20 mg methotrexate weekly, 3 mg/kg ciclosporin daily and 5 mg prednisolone daily. Infliximab therapy was initiated after 3 months because of persistent joint pain and inflammation. Six months later, however, the patient was readmitted to hospital with a new arthritic flare-up, acute retrosternal chest pain and stress dyspnea. INVESTIGATIONS: Laboratory analyses, electrocardiography, chest radiography, high-resolution CT, echocardiography, technetium-99m-labeled (99mTc)-methoxyisobutyl-isonitrile stress myocardial scintigraphy and coronary angiography. DIAGNOSIS: Lupus anticoagulant and ischemic myocardial microangiopathy. MANAGEMENT: Drug therapy with prednisolone, methotrexate, anakinra, aspirin and clopidogrel.
