Effect of variations of heart rate within the normal range on renal artery Doppler indices in nonpregnant and pregnant women.

The effect of heart rate on Doppler indices in the renal artery was studied in 21 nonpregnant, 17 normal and 27 preeclamptic pregnant patients. The central hemodynamics was evaluated by Doppler ultrasound in all pregnant women. The study demonstrated no influence of heart rate on renal artery Doppler indices. Central hemodynamic parameters, such as cardiac output, stroke volume, mean arterial pressure and total systemic resistance did not change with increasing heart rate. We do not recommend any correction of the renal artery Doppler indices for heart rate in the range considered clinically normal (60 to 95 beats/min). Above or below this range further investigations are required to determine if corrections would be necessary.