[Permanent idiopathic sinus tachycardia in pregnancy. Description of a case].

A 35 year old primigravida presented a rare arrhythmia defined as persistent idiopathic sinus tachycardia, which appeared strongly symptomatic during the first weeks of pregnancy. Based on electrophysiological evaluation and pharmacological tests, we retained that the pathogenetic mechanism was due to enhanced automaticity in the sinus node, or in a near "atrial ectopic focus", as a result of a localized autonomic dysfunction. The maternal-foetal prognosis resulted extremely favorable thanks to antiarrhythmic drug association during the last six months of pregnancy.