4 meget sjældne rapporter om forværret hjertetilstand hos patienter med tidligere eksisterende signifikant hjertesygdom, som midlertidigt blev forbundet med den indledende Betaferon- behandling.
During the postmarketing period very rare reports have been received of worsening of cardiac status in patients with pre-existing significant cardiac disease temporarily associated with the initiation of Betaferon therapy.