SCMR 22nd Annual Scientific Sessions
Description of Clinical Presentation:
A 13-year-old male presented with orthopnea, vomiting and abdominal pain for 3 days. Past history of influenza infection 6 months ago with initial chest X-ray demonstrating cardiomegaly reported to be resolved in repeat CXR. The D-dimer was 0.69 mcg FEU/ml with an elevated brain natriuretic peptide of 3100 pg/ml on presentation. He had bilateral pleural effusions and ascites. Echocardiogram showed severe bi-atrial enlargement, severe reduced biventricular systolic function and suspected small anterior mediastinal mass. CT scan demonstrated no filling defect in main pulmonary arteries and did not visualize a mass in the mediastinum. ECG had fine atrial fibrillation with rapid ventricular response. CMR was obtained to determine chamber volumes and characterize the mass.
Diagnostic Techniques and Their Most Important Findings:
Contrast enhanced CMR with free breathing moderate sedation was performed while patient being in atrial fibrillation. There was severe right atrial dilation (> 200 ml/m2) and moderate left atrial dilation (44 ml/m2). (Figure 1)There was severe right ventricular chamber dilation (RVEDVi 154 ml/m2) with severely decreased systolic function (EF 21%) with basal akinesia and thinning. There was normal left ventricular chamber size (LVEDVi 92 ml/m2) with severely decreased systolic function (EF 34%). Three right atrial masses (2.5x2.0cm, 1.3x1.1cm, 1.3x1.0cm) appeared devoid of contrast on perfusion imaging (Figure 2). The masses were severely hypointense on early gadolinium enhancement and had outer hypointense rim with central isointense core on late gadolinium enhancement consistent with old thrombi. No myocardial late gadolinium enhancement of the RV or LV was present. Late gadolinium enhancement of the left and right atrial wall including the atrial septum was present. (Figure 3) A diagnosis of mixed type cardiomyopathy with features of arrhythmogenic and restrictive cardiomyopathy and associated right atrial thrombi was made after the CMR.
Cardiac catheterization noted elevated bi-atrial end-diastolic pressure of 17-18 mm Hg and decreased cardiac output (2.13 L/min/m2). Severely reduced biventricular function did not improve with medical therapy so he received a heart transplant one month after diagnosis.
Learning Points from this Case:
CMR completely defined the cardiac mass and further defined the severity of the mixed cardiomyopathy vital to clinical management in this case. Mixed non-ischemic cardiomyopathies in children are very rare and associated with poor prognosis, and this is the first case of suspected arrhythmogenic and restrictive cardiomyopathy reported in a child. Superior tissue characterization, detailed wall motion evaluation, and myocardial viability assessment makes CMR the diagnostic tool of choice in children with suspected cardiomyopathy and intracardiac mass evaluation. The CMR evaluation helped in understanding the extent of RV disease, prognosis, and allowed quick decision making towards heart transplant in this high-risk case.