The diagnostic role of cardiac magnetic resonance imaging in detecting myocardial inflammation in systemic lupus erythematosus. Differentiation from viral myocarditis.

OBJECTIVE: The objective of this paper is to evaluate the diagnostic role of cardiac magnetic resonance imaging (CMR) in detecting myocardial inflammation in systemic lupus erythematosus (SLE) and its differentiation from viral myocarditis. PATIENTS AND METHODS: Fifty patients with suspected infective myocarditis (IM), with chest pain, dyspnoea or altered ECG, increase in troponin I and/or NT-pro BNP, with or without a history of flu-like syndrome or gastroenteritis and elevated C-reactive protein (CRP) within three to five (median four) weeks before admission, 25 active SLE patients, aged 38 ± 3 years, and 20 age-matched controls were prospectively evaluated by clinical assessment, ECG, echocardiogram and CMR. All patients underwent coronary angiography, and those with significant coronary artery disease (CAD) were excluded. CMR was performed using STIR T2-W (T2W), early T1-W (EGE) and late T1-W (LGE). Endomyocardial biopsies were performed when clinically indicated by current guidelines. Specimens were examined by immunohistological and polymerase chain reaction (PCR) analysis. RESULTS: Positive coronary angiography for CAD excluded 10/50 suspected IM and 5/25 active SLE. Positive clinical criteria for acute myocarditis were fulfilled by 28/40 suspected IM and only 5/20 active SLE. CMR was positive for myocarditis in 35/40 suspected IM and in 16/20 active SLE. Endomyocardial biopsy (EMB), performed in 25/35 suspected IM and 7/16 active SLE with positive CMR, showed positive immunohistology in 18/25 suspected IM and 3/7 active SLE. Infectious genomes were identified in 24/25 suspected IM and 1/7 active SLE. CONCLUSIONS: CMR-positive IM patients were more symptomatic than active SLE. More than half of CMR-positive patients also had positive EMB. PCR was positive in almost all IM, but unusual in SLE. Due to the subclinical presentation of SLE myocarditis and the limitations of EMB, CMR presents the best alternative for the diagnosis of SLE myocarditis.

Isolated right ventricular infarction during percutaneous coronary intervention.

Isolated right ventricular infarction (RVI) is an increasingly recognized cause of precordial ST-segment elevation (STE). A patient is described who developed STE in leads V1-V5 secondary to occlusion of the right ventricular branch during stent angioplasty to the right coronary artery. The pattern of precordial STE was thought to be suggestive of anteroseptal myocardial infarction because of progressive STE toward lead V3. Repeat angiography disclosed a patent left anterior descending artery. Subsequent scrutiny of the electrocardiogram (ECG) revealed that leads V2 and V3 were switched and ECG interpretation considering this technical error revealed STE in V2>V3, which favored RVI. Furthermore, the mean spatial ST vector was approximately +120° in the frontal plane producing ST-segment depression in lead I which argued against anteroseptal myocardial infarction and indicated right ventricular epicardial injury. This report highlights that analysis of the ECG using vector concepts is a useful adjunct to pattern recognition for the diagnosis of RVI.