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Sarcoid AV Block Reversibility — EECC MCQ

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ModerateCardiomyopathySarcoid AV Block ReversibilityEECC

A 42-year-old man with sarcoidosis develops complete heart block requiring permanent pacemaker. His LVEF is 50% and he has no ventricular arrhythmias. FDG-PET shows active myocardial inflammation. He is started on corticosteroids. What is the prognosis of AV block in cardiac sarcoidosis with immunosuppression?

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Correct answer: E — AV block may be partially or fully reversible with immunosuppressive therapy if caused by active granulomatous inflammation rather than established fibrosis; however, a permanent pacemaker should still be implanted as relapse is unpredictable

AV block is the most common conduction abnormality in cardiac sarcoidosis (occurring in up to 30-60% of those with cardiac involvement). It can be caused by: (1) active granulomatous inflammation of the conduction system (potentially reversible with immunosuppression); (2) established fibrotic scar in the conduction system (irreversible). FDG-PET positivity (active inflammation) predicts a higher likelihood of AV block reversibility with corticosteroids. However, the ESC 2021 Pacing Guidelines and 2023 Cardiomyopathy Guidelines recommend permanent pacemaker implantation regardless of potential reversibility because: (1) relapse of inflammation is unpredictable; (2) sudden recurrence of complete heart block without a backup pacemaker is dangerous. A CRT-D rather than simple pacemaker should be considered given the arrhythmic risk of cardiac sarcoidosis.

Reference: ESC (2023): Cardiomyopathies Guidelines; ESC (2021): Pacing Guidelines