心臟血管反射對動脈阻抗頻譜之作用

Effects of Cardiovascular Reflex on the Arterial Impedance Spectra

10.6440/TZUCMJ.199206.0073

陳幸一(Hsing I Chen)；奚道鈞(Daw-Jiun Hsi)；胡正濤(Cheng-Tao Hu)；張國柱(Kou-Chou Chang)

動脈阻抗 ； 心室後負荷 ； Bezold-Jarisch反射 ； 感壓反射 ； aortic impedance ； ventricular afterload ； Bezold-Jarisch reflex ； baroreflex

慈濟醫學雜誌

4卷2期（1992 / 06 / 01）

73 - 84

繁體中文

In the present study, Bezold-Jarisch reflex was induced by intravenous infusion of veratridine, and baroreceptor reflex by common carotid occlusion (CCO). We used the technique of aortic impedance analysis to evaluate the hemodynamic responses to Bezold-Jarisch and baroreceptor reflexes. A Millar catheter with high fidelity sensors was placed in the aortic root to record the pressure and flow waves. The pulsatile parameters were analyzed by discrete Fourier transform to obtain the impedance data such as characteristic impedance (Zc), peripheral resistance (Rp), first zero crossing frequency (fo), reflection ratio (Rf), backward arrival time (BWAT) and arterial compliance (C) etc. In 6 dogs anesthetized with pentobarbital sodium (30 mg/kg, intraperitoneal), an iv infusion of veratridine (5 μg/kg/min) was accomplished to activate the ventricular receptors and thereby induce Bezold-Jarisch reflex. The latter has been shown to occur in patients with myocardial infarction and considered to be beneficial to the damanged myocardium. During the steady state after veratridine infusion, the heart rate, arterial pressure, Rp, Zc, Rf and fo were significantly decreased (p＜0.05), while cardiac output, stroke volume and arterial compliance were increased (p＜0.05). In 4 anesthetized dogs before cervical vagotomy, CCO produced an increase in arterial pressure by 18 mmHg accompanying a tendency of increasing Rp, Zc, Rf and fo and decreaing compliance. After vagotomy, CCO increased arterial pressure by 38 mmHg. Rp, Zc, Rf and fo were significantly increased (p＜0.05), while arterial compliance was decreased (p＜0.05). The results indicate that Bezold-Jarisch reflex due to activation of the ventricular receptors produces hemodynamic changes that significantly improve the ventricular afterload. Baroreceptor reflex due to CCO provokes the opposite changes. These changes become manifest after cervical vagotomy because the counterbalancing effects of aortic baroreceptors are eliminated.

In the present study, Bezold-Jarisch reflex was induced by intravenous infusion of veratridine, and baroreceptor reflex by common carotid occlusion (CCO). We used the technique of aortic impedance analysis to evaluate the hemodynamic responses to Bezold-Jarisch and baroreceptor reflexes. A Millar catheter with high fidelity sensors was placed in the aortic root to record the pressure and flow waves. The pulsatile parameters were analyzed by discrete Fourier transform to obtain the impedance data such as characteristic impedance (Zc), peripheral resistance (Rp), first zero crossing frequency (fo), reflection ratio (Rf), backward arrival time (BWAT) and arterial compliance (C) etc. In 6 dogs anesthetized with pentobarbital sodium (30 mg/kg, intraperitoneal), an iv infusion of veratridine (5 μg/kg/min) was accomplished to activate the ventricular receptors and thereby induce Bezold-Jarisch reflex. The latter has been shown to occur in patients with myocardial infarction and considered to be beneficial to the damanged myocardium. During the steady state after veratridine infusion, the heart rate, arterial pressure, Rp, Zc, Rf and fo were significantly decreased (p＜0.05), while cardiac output, stroke volume and arterial compliance were increased (p＜0.05). In 4 anesthetized dogs before cervical vagotomy, CCO produced an increase in arterial pressure by 18 mmHg accompanying a tendency of increasing Rp, Zc, Rf and fo and decreaing compliance. After vagotomy, CCO increased arterial pressure by 38 mmHg. Rp, Zc, Rf and fo were significantly increased (p＜0.05), while arterial compliance was decreased (p＜0.05). The results indicate that Bezold-Jarisch reflex due to activation of the ventricular receptors produces hemodynamic changes that significantly improve the ventricular afterload. Baroreceptor reflex due to CCO provokes the opposite changes. These changes become manifest after cervical vagotomy because the counterbalancing effects of aortic baroreceptors are eliminated.