Electrical Cardiography Research Articles

Sufficient Conditions for Observability in Electrocardiography Problem

The aim of this paper, is to study electrical cardiography problem. Thus, we construct the state space system of this model as mathematical model. Moreover, we present some definitions and results which is described some concepts of linear control system analysis related to this problem. More precisely, the sufficient conditions which characterize the observability notion of linear dynamical controlled system are presented and discussed. Finally, we prove that, the electrical cardiography model is completely observable system over finite time .

Cardiac output monitoring in paediatric cardiac surgery: a review.

The aim of this review is to present the current options for cardiac output (CO) monitoring in children undergoing cardiac surgery. Current technologies for monitoring identified were a range of invasive, minimally invasive, and non-invasive technologies. These include pulmonary artery catheter, transoesophageal echocardiography, pulse contour analysis, electrical cardiography, and thoracic bioreactance. A literature search was conducted using evidence databases which identified two current guidelines; the NHS Greater Glasgow and Clyde guideline and Royal College of Anaesthetics Guideline. These were appraised using the AGREE II tool and the evidence identified was used to create an overview summary of each technological option for CO monitoring. There is limited evidence regarding the accuracy of modalities available for CO monitoring in paediatric patients during cardiac surgery. Each technology has advantages and disadvantages; however, none could be championed as the most beneficial. Furthermore, a gold standard for CO monitoring has not yet been identified for paediatric populations, nor is it apparent whether one modality is preferable based on the available evidence. Additional evidence using a standardised method for comparing CO measurements should be conducted in order to determine the best option for CO monitoring in paediatrics. Furthermore, cost-effectiveness assessment of each modality should be conducted. Only then will it be possible for clear, evidence-based guidance to be written.

PP143. Relationship between mid-pregnancy placenta growth factor and hemodynamics in the mother, fetus, and uterus

Placental Growth Factor (PlGF) is an angiogenic and vasoregulatory peptide member of the vascular endothelial growth factor family. Reduction of free, circulating PlGF is associated with preeclampsia and fetal growth restriction, and precedes the clinical manifestations of disease by several weeks. It is not known whether aberrant PlGF is related for alterations in endothelial vascular function that cause or exacerbate the placental syndromes of pregnancy. We sought to determine if mid-pregnancy PlGF was related to, and possibly mediating, measures of maternal, fetal, or uterine hemodynamic function in women at risk for placenta-mediated complications of pregnancy. We measured free plasma PlGF (Triage PlGF Assay, Alere, Inc.) between 22 and 25 weeks in high risk subjects referred for assessment of fetal growth and uterine artery Dopplers due to abnormalities of serum screening analytes or other risk factors for preeclampsia. Maternal hemodynamic parameters including mean arterial pressure (MAP), cardiac index (CI), systemic vascular resistance (SVR) and index of contractility (ICON) were measured in recumbent position with noninvasive electrical cardiography (Aesculon EC System, Cardiotronics, Inc.). Doppler measurements of blood flow in the uterine arteries (pulsatility index, PI) and umbilical artery (systolic:diastolic ratio, S/D) were obtained by ultrasound (Voluson E8, GE Healthcare, Inc.), along with the estimated fetal weight (EFW). PlGF was expressed as the log concentration, plotted against the hemodynamic measurements, and analyzed with Spearman's correlation coefficient, R. Statistical significance was set to p=0.05. Data from seventeen fully studied patients were analyzed. The median gestational age was 24.3 weeks. PlGF concentration ranged from 25 to 1180 with a median of 235pg/ml. PlGF was positively related to maternal cardiac index (R=0.56, p=0.02) and ICON (R=0.51, p=0.04) and negatively related to SVR (R=-0.48, p=0.05). There was a non-significant negative correlation with MAP (R=-0.41, p=0.10). PlGF showed a positive correlation to EFW (R=0.52, p=0.03) and a negative relationship to umbilical artery S/D ratio (R=-0.42,p=0.06). There was no correlation between maternal PlGF and uterine artery Doppler PI (R=-0.19, p=0.46). The concentration of circulating free PlGF at mid-pregnancy is related to both maternal systemic hemodynamic function and fetal umbilical artery resistance (and growth) in high risk pregnancies prior to the onset of preeclampsia. It is not, however, related to vascular resistance in the uterine artery. PlGF may play a role in modulating the general vascular function of the fetus and mother after establishment of the uteroplacental circulation.