To date there are no data suggesting substantial effects of hormonal interaction after percutaneous closure of the left atrial appendage (LAA). Our hypothesis is that by excluding the LAA from blood flow physiologic stimuli for ANP and BNP produce may be impaired and consecutive release of the hormones may be reduced. Here, we present our experience of ANP and BNP secretion in the early postprocedural period after transcatheter closure of the LAA.