Glucocorticoids and immunosuppressive drugs represent the first-line treatment of eosinophilic granulomatosis with polyangiitis (EGPA, former Churg-Strauss syndrome), even though the combined therapy is not successful in achieving the disease remission in some patients with neurological or cardiac involvement. We describe a case of an EGPA male patient with impaired left ventricular function not responsive to glucocorticoid and immunosuppressive therapy. We observed that high-dose (2 g/kg/4 weeks) intravenous immunoglobulin (IVIG) therapy significantly improved cardiac function, which was deteriorated after reducing IVIG dose at 0.5 g/kg/4 weeks, and was restored increasing again IVIG dose to 2 g/kg/4 weeks. The finding highlights the relevance of IVIG as treatment of choice in EGPA patients with cardiac involvement not responsive to the standard glucocorticoid and immunosuppressive therapy. Moreover, at a follow-up of 24 months, the continuance of high dose IVIG therapy was required to maintain a sustained remission of the heart failure.