Immune checkpoint inhibitor myocarditis with complete heart block: a case series

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Immune checkpoint inhibitor (ICI) myocarditis is a life-threatening condition characterized by lymphocytic myocardial infiltration[1]. Complete heart block (CHB) occurs in 15% cases and often fatal[2-4]. The nature optimal management this often-malignant poorly understood[5]. Purpose This case series assesses prognostic factors associated with survival at 90 days among people ICI CHB. Methods electronic patient record system was used to identify patients admitted myocarditis. A two-physician review assess the presence ICI-associated Wilcoxon rank sum Spearman’s correlation were for categorical quantitative variables respectively. Data analysed using STATA/IC 16.1. primary outcome person-day after presenting symptom onset. Results Six included final analysis. Mean 47 person days. All had metastatic disease presented 15 32 first infusion. muscle weakness. Other common self-symptoms shortness breath (4), blurred vision double (3), collapse leg swelling (1). Proximal myopathy (2), fatigable (1), ptosis peripheral oedema (1) present on examination. Raised troponin T white blood cell count (WBC) 90-day (see Table 1). Nt-pro BNP, AST, CK levels raised all patients. Two tested anti-striated antibody titres, both strongly positive. Increase QRS duration compared baseline ECG lower Only one CHB admission. Steroid dose, IVIG, plasmapheresis weren’t survival. One declined device therapy. permanent pacemaker (PPM) insertion transvenous (TVP). Both died within 2 weeks. Three underwent (TVP) followed PPM (table 2). three eventually 100 received isoproterenol immunosuppression as bridge survived. managed initially TVP but subsequently insertion. removal resulted recurrence, they shortly discharge. therapy while receiving comfort care. Lead malfunction frequent. experienced bradycardia arrest failure lead capture, another dislodgement. Conclusion secondary fatal. It should be considered symptoms myositis, increased duration. Despite small sample size, study identifies several which can guide physicians decision-making. Larger studies are needed better understand role population.