Effect of induced ventricular tachycardia on atrial natriuretic peptide in humans

The effects of induced sustained ventricular tachycardia on the release of plasma-immunoreactive atrial natriuretic peptide were evaluated in 11 adult patients undergoing diagnostic electrophysiologic study. Plasma concentrations of atrial natriuretic peptide withdrawn from the right atrium before and during sustained ventricular tachycardia (mean tachycardia cycle length 320 ± 68 ms, duration >30 s) were determined by radioimmunoassay. Hemodynamic measurements included phasic femoral artery blood pressure and mean right atrial blood pressure before and during ventricular tachycardia.During ventricular tachycardia, atrial natriuretic peptide increased from 93 ± 49 pg/ml to 234 ± 195 pg/ml (p < 0.05), systolic arterial blood pressure decreased from 120 ± 16 to 70 ± 23 mm Hg (p < 0.001), diastolic arterial blood pressure decreased from 63 ± 8 to 51 ± 16 mm Hg (p = NS) and mean right atrial blood pressure increased from 3 ± 1 to 8 ± 5 mm Hg (p < 0.02). In six patients, all hemodynamic variables and the atrial natriuretic peptide were measured during repeated stimulation protocols to investigate the effect of ventricular stimulation for ventricular tachycardia induction on atrial natriuretic factor release. Compared with the values obtained during sinus rhythm, there was no significant increase in atrial natriuretic factor during ventricular stimulation at a cycle length of 600 ms (45 ± 20 versus 52 ± 21 pg/ml) or at a cycle length of 400 ms (45 ± 20 versus 57 ± 18 pg/ml). No significant linear relation could be found among the changes in mean right atrial pressure, systolic arterial blood pressure and the increase in atrial natriuretic peptide.It is concluded that 1) ventricular tachycardia immediately increases the plasma concentrations of atrial natriuretic peptide; 2) the release of atrial natriuretic peptide in acute ventricular tachycardia is not related to changes in mean right atrial pressure; 3) it is possible that the high plasma concentrations of atrial natriuretic peptide during ventricular tachycardia contribute to the hypotension associated with ventricular tachycardia