AIMS: To investigate the sensitivity of the rate of pressure rise obtained by Doppler to changes in the inotropic state by comparing it to simultaneous invasive measurements of dP/dt under different conditions of contractility. METHODS AND RESULTS: Mitral regurgitation was provoked in five pigs, and simultaneous measurements of dP/dt and the Doppler-estimated rate of pressure rise were made with a micro-manometer and with continuous-wave Doppler. Changes in the inotropic state were induced by drug infusion and by ischaemia. One hundred and twenty-seven simultaneous measurements were made with a correlation coefficient between the Doppler-estimated rate of pressure rise and dP/dt of 0.85 (P<0.001). Sensitivity to inotropic changes was estimated as the percentage change of each parameter in each condition of contractility, and showed that the Doppler-estimated rate of pressure rise had better sensitivity than dP/dt. CONCLUSION: The sensitivity of Doppler-estimated rate of pressure rise to changes in the inotropic state is greater than that of dP/dt. The correlation between the rate of pressure rise obtained by Doppler and dP/dt is maintained even in extreme conditions of contractility. Therefore, the rate of pressure rise can be considered a good parameter to assess linear changes of contractility.
AIMS: To investigate the sensitivity of the rate of pressure rise obtained by Doppler to changes in the inotropic state by comparing it to simultaneous invasive measurements of dP/dt under different conditions of contractility. METHODS AND RESULTS:Mitral regurgitation was provoked in five pigs, and simultaneous measurements of dP/dt and the Doppler-estimated rate of pressure rise were made with a micro-manometer and with continuous-wave Doppler. Changes in the inotropic state were induced by drug infusion and by ischaemia. One hundred and twenty-seven simultaneous measurements were made with a correlation coefficient between the Doppler-estimated rate of pressure rise and dP/dt of 0.85 (P<0.001). Sensitivity to inotropic changes was estimated as the percentage change of each parameter in each condition of contractility, and showed that the Doppler-estimated rate of pressure rise had better sensitivity than dP/dt. CONCLUSION: The sensitivity of Doppler-estimated rate of pressure rise to changes in the inotropic state is greater than that of dP/dt. The correlation between the rate of pressure rise obtained by Doppler and dP/dt is maintained even in extreme conditions of contractility. Therefore, the rate of pressure rise can be considered a good parameter to assess linear changes of contractility.