A Wolf in Sheep’s Clothing - Unmasking Cardiac Sarcoidosis Through Pacemaker Dysfunction: a case report

Figures

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  Figure 1. Cardiac magnetic resonance imaging performed before pacemaker implantation in 2018 showing extensive, rather patchy fibrosis of the septum (arrows).

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  Figure 2. Echocardiography showing a modified apical five-chamber view. At the interventricular septum, two small, localized, left-sided aneurysms can be appreciated (arrows).

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  Figure 3. (A) The X-ray with the old dual-chamber transvenous pacemaker and the new leadless pacemaker implanted at the level of the right ventricular apex (blue circle). (B) The 12-lead electrocardiogram with atrial pacing through the transvenous pacemaker (red circle) and the ventricular pacing through the leadless pacemaker in VDD mode (blue circle), resulting in correct sequential atrioventricular pacing. The transvenous pacemaker was programmed to AAIR-DDDR at 60–120 b.p.m., whereas the leadless pacemaker to VDD at 50–130 b.p.m. The programmed vector was 2 + 3 with A3 and A4 thresholds at 3.8 and 2.1 m/s2, respectively and A3 window at 790 ms. Once the transvenous pacemaker threshold normalized, the programming was changed to DDDR at 60–120 b.p.m., whereas the leadless pacemaker was programmed to VVI at 30 b.p.m. as back-up.

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  Figure 4. Positron emission tomography-computer tomography performed after a carbohydrate-free diet of 48 h and overnight fasting using an fluoro deoxyglucose (FDG) dose of 2.5 MBq/kg with image acquisition performed 60 min after 18F-FDG injection. Left upper pannel: pulmonary nodule with elevated metabolic activity (SUVmax of 6.3 g/mL). Left lower pannel: elevated metabolic activity of pulmonary lymph nodes (SUVmax 10.2 g/mL). Right-sided pannels: elevated metabolic activity at the cardiac level (arrows) with a SUVmax of 4.8 g/mL. These findings are suggestive of systemic sarcoidosis with pulmonary and cardiac involvement.

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  Figure 5. Evolution of the right ventricular threshold over 6 months of immunosuppressive therapy showing a gradual reduction from 4 V × 0.5 ms in January to 1.25 V × 0.5 ms in July. On the y-axis, the threshold amplitudes are depicted, which were all performed at an impulse duration of 0.5 ms. On the x-axis, the months of each performed threshold testing is depicted. * 30 mg of prednisone QD. ** 15 mg of prednisone QD and 500 mg of mycophenolate b.i.d. + 10 mg of prednisone QD and 500 mg of mycophenolate b.i.d. ++ 7.5 mg of prednisone QD and 500 mg of mycophenolate b.i.d.