Figure 1. Maternal heart rate response during spinal anesthesia. Vasopressor infusions were started immediately after induction of spinal anesthesia (time-zero). Maternal heart rate was significantly lower (P < 0.001) across time in the angiotensin group than in the ephedrine group. Heart rate data were excluded at all measurements in a given patient after intravenous administration of either atropine (n = 1), phenylephrine (n = 2), or mephentermine (n = 1).