GLOMERULAR HEMODYNAMICS DURING SUPRAVENTRICULAR TACHYCARDIA

Supraventricular tachycardia (SVT) was induced in 7 patients by progra mmed cardiac stimulation via an esophageal lead. Blood pressure, renal function, and hormonal factors were measured before, during, and afte r SVT. The glomerular filtration rate increased during SVT, while rena l blood flow did not change. The parameters of glomerular hemodynamics were calculated according to the method of Gomez. Glomerular pressure was 64 +/- 3 (mean +/- SE) mmHg before SVT, and rose significantly (p < 0.01) to 76 +/- 5 during SVT. This rise in glomerular pressure was associated with a decrease in afferent vascular resistance (from 3355 +/- 610 to 1770 +/- 517 dynes x sec/cm(5), p < 0.05) and an increase i n efferent vascular resistance (from 3726 +/- 758 to 4814 +/- 780 dyne s x sec/cm(5), p < 0.05). Since atrial natriuretic peptide (ANP) incre ased during SVT (from 40 +/- 15 to 208 +/- 72 pg/ml, p < 0.01), these changes in glomerular hemodynamics may be attributed to the physiologi c action of ANP. Despite the changes in glomerular hemodynamics during SVT, natriuresis appeared after SVT and not during SVT. This suggests that natriuresis accompanying SVT could not be attributed to the chan ges in glomerular hemodynamics.