“…Also, cerebral perfusion is lowered during paroxysms of atrial fibrillation ( Totaro et al ., 1993 ) and during tachycardia in patients with coronary artery disease ( Hagendorff et al ., 1994 ), and both cerebral blood flow and cognitive function increase following pacemaker implantation in patients with bradycardia ( Koide et al ., 1994 ). Arterial hypertension, diabetes ( Kastrup et al ., 1990 ) and familial hypercholesterolaemia ( Rodriguez et al ., 1994 ) influence regulation of cerebral blood flow, and cerebral auto‐regulation is impaired in patients resuscitated after cardiac arrest ( Nishizawa & Kudoh, 1996). In the heart failure patient with cerebral symptoms, cerebral hypoxia can be expected even in the face of near normal blood pressure and blood gas variables, and in this study, some patients presented with a critically lowered ScO 2 despite near‐normal MAP, SaO 2 and PaCO 2 .…”