Evaluation of baroreflex sensitivity (BRS) is considered an important tool for diagnosis and prognosis in pot-MI patients. A dynamic linear parametric model was designed to separate the fraction of RR variability driven by systolic arterial pressure (SAP) changes from that independent of the SAP variations and to quantify the gain of the RR-SAP relationship in an open loop condition. After patient stabilization in resting condition, one lead ECG and non-invasive arterial pressure were continuously recorded for ten minutes on 30 patients (61±10 years) with recent (10±3 days) myocardial infarction. The reliability of the proposed non-invasive estimation of baroreflex gain (), was assessed by comparison with values of phenylephrine test. In this case BRS was measured as slope of regression analysis between SAP and RR changes induced by infusion of the vasoactive drug (2 g/Kg) determining an open-loop physiological condition. Two other methods (spectral: ; cross-spectral: ) for non-invasive evaluation of BRS based on closed-loop model of SAP and RR spontaneous variations were also considered. Variance analysis showed that mean values of  (12.2 ±5.9) and  (8.9±5.5) estimation of baroreflex gain were significantly different from the reference values (6.4±4.6), while the  (5.2±3.3) values were comparable. Although all noninvasive methods showed a significant correlation, regression analysis selected  first in correlation with phenylephrine gain measurement (r=0.76, y=0.86+0.86x; p<0.01). Baroreflex gain estimated with this novel dynamic linear parametric model showed higher correlation with the phenylephrine method than the closed-loop spectral models. Development of reliable and non-invasive estimation of BRS can significantly improve the application of this methodology in clinical setting
Open loop model for non-invasive baroreflex sensitivity assessment in patients with recent myocardial infarction
Nollo, Giandomenico;Faes, Luca;Ravelli, Flavia
1999-01-01
Abstract
Evaluation of baroreflex sensitivity (BRS) is considered an important tool for diagnosis and prognosis in pot-MI patients. A dynamic linear parametric model was designed to separate the fraction of RR variability driven by systolic arterial pressure (SAP) changes from that independent of the SAP variations and to quantify the gain of the RR-SAP relationship in an open loop condition. After patient stabilization in resting condition, one lead ECG and non-invasive arterial pressure were continuously recorded for ten minutes on 30 patients (61±10 years) with recent (10±3 days) myocardial infarction. The reliability of the proposed non-invasive estimation of baroreflex gain (), was assessed by comparison with values of phenylephrine test. In this case BRS was measured as slope of regression analysis between SAP and RR changes induced by infusion of the vasoactive drug (2 g/Kg) determining an open-loop physiological condition. Two other methods (spectral: ; cross-spectral: ) for non-invasive evaluation of BRS based on closed-loop model of SAP and RR spontaneous variations were also considered. Variance analysis showed that mean values of (12.2 ±5.9) and (8.9±5.5) estimation of baroreflex gain were significantly different from the reference values (6.4±4.6), while the (5.2±3.3) values were comparable. Although all noninvasive methods showed a significant correlation, regression analysis selected first in correlation with phenylephrine gain measurement (r=0.76, y=0.86+0.86x; p<0.01). Baroreflex gain estimated with this novel dynamic linear parametric model showed higher correlation with the phenylephrine method than the closed-loop spectral models. Development of reliable and non-invasive estimation of BRS can significantly improve the application of this methodology in clinical settingI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
