Detection of myocardial involvement in systemic lupus erythematosus: mismatch between normal perfusion scans with 201Thallium and pathological 18FDG uptake.

BACKGROUND

Systemic lupus erythematosus (SLE) patients can frequently present cardiac symptoms, however its etiology is not well known.

EXPERIMENTAL

DESIGN

prospective study.

SETTINGS: specialized out-patient unit for SLE patients at an university hospital.

PATIENTS: 15 SLE patients (13 females, 2 males; age range 18-64 years).

INTERVENTIONS: metabolic studies of the heart were done using 18F-deoxy-glucose (18FDG, 296-333 MBq on a 2-head hybrid system) as well as heart perfusion studies (111MBq 201Tl). Additional studies: resting ECG, echocardiography, stress ECG, immunological activity parameters, antibody analyses (ANA, ENA, anti-cardiolipin antibodies), CPK, troponin-T, and lipid profiles.

MEASURES: degree of correlation between conventional diagnostics and the imaging techniques.

RESULTS

Abnormal ECG in 10 cases, pericardial involvement in 11 cases, elevated CPK in 1 case. ANTIBODY PROFILES: anti-cardiolipin in 10/15, ENA in 9/15, ANA in 14/15. None of these changes were associated with parameters of immune activation. In the majority of cases (10/15) the 18FDG scan showed a speckled, inhomogeneous pattern of distribution, which contrasted sharply with a normal 201Tl scan. A similar pattern was observed in the patients with ocular mitochondrial myopathy, the anti-phospholipid syndrome as well as in dermatomyositis.

CONCLUSIONS

Our preliminary results suggest that SLE patients with cardiac symptoms may have an abnormal glucose metabolism of the myocardium as shown by a pathological 18FDG scan, whereas perfusion appears to be normal (reversed mismatch). The lack of correlation with acute elevation of cardiac enzymes or with ECG changes suggest a chronic process.