Reversal of third-degree AV block with ruxolitinib in VEXAS-associated myocarditis: a case report.

Background: VEXAS syndrome is a newly described autoinflammatory condition; cardiac involvement is exceedingly rare. This case illustrates a reversible complete heart block due to myocarditis in VEXAS, successfully treated with targeted therapy. Case summary: A 69-year-old man with known VEXAS syndrome presented with dizziness and syncope. Workup revealed third-degree atrioventricular (AV) block and imaging consistent with myocarditis. Standard therapy (atropine, isoprenaline infusion) stabilized the patient, and ruxolitinib (a JAK inhibitor) was initiated alongside corticosteroids to treat the underlying inflammatory syndrome. Within days, the patient's AV conduction was restored without the need for pacemaker insertion. He was discharged with improved cardiac function and ongoing immunomodulatory therapy. Discussion: Targeted immunomodulation can reverse cardiac conduction block caused by inflammation in VEXAS syndrome. This case underscores the importance of recognizing autoinflammatory syndromes as a cause of heart block and suggests a potential role for JAK inhibitors in treating inflammatory myocarditis.