Sympathetic stimulation, hemodynamic factors, and indices of cardiac inotropic state

Publisher Website
Google Scholar
Abstract
The influence of hemodynamic factors on indices of the inotropic state of the heart were studied before and during cardiac sympathetic nerve stimulation in 23 open-chested dogs anesthetized with sodium pentobarbital. Neural reflexes and the cardiovascular system remained intact during electrical stimulation of the left ventral ansa subclavian nerve. The influence of diastolic blood pressure (DBP), heart rate (HR) and left atrial pressure (LAP) on the maximal rate of left ventricular (LV dP/dt) and aortic pressure development (Ao dP/dt) were examined with multiple regression techniques. Diastolic blood pressure and LAP were positively related to LV dP/dt during both control and nerve stimulation, with HR being negatively related to LV dP/dt during control periods, but positively related to LV dP/dt during nerve stimulation. Left atrial pressure and HR were positively related to Ao dP/dt during control and nerve stimulation, and DBP was negatively related to Ao dP/dt during control and nerve stimulation. A positive inotropic effect on the heart was evidenced during nerve stimulation in LV dP/dt and Ao dP/dt, regardless of the relationship with other variables. Both LV dP/dt and Ao dP/dt reflect changes in the inotropic state of the heart, but are not totally independent of intrinsic influences on cardiovascular performance of the heart.