Intracoronary IgG4-related disease as an unusual cause of sudden cardiac arrest: a case series.

IgG4-related disease presenting as sudden cardiac death without any preceding symptoms is very rare (six prior cases identified on literature review). Reported targeted successful interventions for intracoronary IgG4-RD diagnosed in life have included steroid therapy and B cell depleting therapy (i.e. rituximab). If cardiac symptoms are present in a patient with known IgG4-RD, cardiac investigations should be promptly arranged.