[Plasma levels of atrial natriuretic peptide (ANP) in patients with paroxysmal supraventricular tachycardia and concomitant polyuria (urina spastica)].

A concomitant diuresis and natriuresis has been reported to occur in 30-50% of patients with paroxysmal supraventricular tachycardia. While the increase of the diuresis may be secondary to an inhibition of vasopressin, the etiology of the natriuresis is presently not well understood. To determine the role of atrial natriuretic peptide (ANP) in the pathogenesis of tachycardia-induced polyuria, we measured ANP levels in two female patients (aged 59 and 68 years) with recurrent episodes of paroxysmal supraventricular tachycardia during such attacks, as well as after conversion to a normal sinus rhythm. In both patients, episodes of supraventricular tachycardia were associated with both a large increase in ANP plasma levels (560 resp. 1.208 pg/ml; normal range: 50 +/- 10 pg/ml) and polyuria. Despite elevated ANP plasma levels, no diuretic and natriuretic response to tachycardia could be observed during episodes of shorter duration, some of which occurred in the older patient studied. After restoration of a normal sinus rhythm, ANP plasma levels decreased to baseline levels (107 resp. 32 pg/ml). The results of this study show that the secretion of ANP is increased during episodes of paroxysmal supraventricular tachycardia, suggesting that ANP might contribute to the pathogenesis of natriuresis and diuresis frequently associated with supraventricular tachycardia.