PMC5412661_01
A: An electrocardiogram recorded at presentation. B: An electrocardiogram recorded 2 months after initial presentation shows progressive conduction system disease with PR prolongation and new left anterior hemiblock.
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A 44-year-old male endurance athlete with no significant medical history was referred by his primary physician for cardiac electrophysiological evaluation because of asymptomatic resting bradycardia (Figure 1A). An ECG revealed sinus bradycardia at 34 beats per minute, a conducted PR interval of 422 milliseconds, and a new left anterior hemiblock in addition to his right bundle branch block (Figure 1B).
A repeat cardiac magnetic resonance image, which was taken 2 months after cardiac magnetic resonance imaging with normal results, shows a small inferior delayed hyperenhancement.
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Repeat CMR results showed a new LV basal anteroseptal and mid-posterolateral late gadolinium enhancement (Figure 2).
A: Normal technetium-99m sestamibi rest-and-stress perfusion image. B: Result of a cardiac fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography scan. Fluorine-18-fluorodeoxyglucose uptake is present in the right atrium, septum, and lateral left ventricle. C: Repeat image that was taken after 3 months of steroid therapy. VLA = vertical long axis; HLA = horizontal long axis; APX: = apex; INF = inferior; LAT = lateral; BAS = basal; SEP = septal.
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Results of myocardial perfusion imaging with intravenous technetium-99m sestamibi were normal (Figure 3A); however, focal uptake of 18F-FDG was noted in the right atrium, basal LV anteroseptum, and basal LV posterolateral wall (Figure 3B). A repeat 18F-FDG PET-CT scan was performed 3 months following the initiation of steroid therapy, and the results showed significant improvement of 18F-FDG uptake in the mediastinal lymph nodes, right atrium, and lateral left ventricle (Figure 3C).