3 In addition, ICG provides various indices of LV function/contractility, derived from the rate of change of electrical impedance in the thorax. Impedance cardiography (ICG) is a simple, operatorвЂђindependent, noninvasive method that can approximate stroke volume, allowing for the assessment of cardiac output, systemic SVR, and the stroke volume/pulse pressure ratio (SV/PP an index of total arterial compliance). A similar phenomenon can occur with pulse pressure (a key determinant of systolic hypertension), which may be associated with multiple combinations of stroke volume and conduit artery compliance. Furthermore, an increase in SVR may not be apparent by BP measurements alone in individuals with relatively low cardiac output. An increased mean arterial pressure can result from an increase in cardiac output, SVR, or both. 1 It follows that patients with identical BP may have substantially different hemodynamic patterns.

Mean arterial pressure is the product of cardiac output and systemic vascular resistance (SVR), whereas pulse pressure results from the interaction between the stroke volume generated by the left ventricle (LV) and the biophysical properties of conduit arteries. Blood pressure (BP) is determined by interactions between the heart and arterial properties. Subjects without stage 2 hypertension who demonstrate abnormal impedance cardiography indices of cardiac contractility represent a large subpopulation could benefit from moreвЂђaggressive or earlier interventions, which should be addressed in future studies.ДЄrterial hemodynamic phenomena are increasingly recognized as important determinants of hypertensive target organ damage. Parameters measured by impedance cardiography (total arterial compliance index and indices of cardiac contractility) predict mortality in the general population, even after adjustment for multiple confounders and blood pressure. Among subjects without stage 2 hypertension (n=1563), indices of cardiac contractility were independently predictive of death and identified a subpopulation (25% of nonвЂђstageвЂђ2 hypertensives) that demonstrated a high 10вЂђyear mortality risk, equivalent to that of stage 2 hypertensives. These remained independently predictive of death after adjustment for multiple confounders, as well as systolic and diastolic blood pressure. The strongest predictors were total arterial compliance index (standardized hazard ratio=0.38 95% confidence interval=0.31вЂ“0.46 P<0.0001) and indices of cardiac contractility: velocity index (standardized hazard ratio=0.45 95% confidence interval=0.37вЂ“0.55 P<0.0001) and acceleration index (standardized hazard ratio=0.44 95% confidence interval=0.35вЂ“0.55 P<0.0001). We assessed the relationship between hemodynamic parameters measured at baseline and allвЂђcause mortality over a mean followвЂђup of 10.9В years. We used ICG to measure hemodynamic parameters and metrics of cardiac function. We studied 1639 adults aged 18 to 80В years from the general population. Stroke: Vascular and Interventional Neurology.Journal of the American Heart Association (JAHA).Circ: Cardiovascular Quality & Outcomes.Arteriosclerosis, Thrombosis, and Vascular Biology (ATVB).This new impedance cardiograph device deserves further study using other populations and situations. We conclude that the Physio Flow provides a clinically acceptable and non-invasive evaluation of cardiac output under these conditions. Thoracic hyperinflation did not alter QcPF. The difference between the two methods exceeded 20% in only 2.5% of the cases at rest, and 9.3% of the cases during exercise. The limits of agreement, defined as mean difference +/- 2SD, were -1.34, +1.41 l x min(-1)] at rest and -2.34, +2.92 l x min(-1) during exercise. The mean difference between the two methods (QcFick - QcPF) was 0.04 l x min(-1) at rest and 0.29 l x min(-1) during exercise.

The subjects' oxygen consumption values ranged from 0.14 to 1.19 l x min(-1). Forty patients referred for right cardiac catheterisation, 14 with sleep apnoea syndrome and 26 with chronic obstructive pulmonary disease, took part in this study. We compared cardiac output determined simultaneously by two methods, the Physio Flow (QcPF) and the direct Fick (QcFick) methods. The objectives of this study were to evaluate the reliability and accuracy of a new impedance cardiograph device, the Physio Flow, at rest and during a steady-state dynamic leg exercise (work intensity ranging from 10 to 50 W) performed in the supine position.

Define cardiograph