0000000000331483

AUTHOR

L. Widesott

showing 3 related works from this author

Need of causal analysis for assessing phase relationships in closed loop interacting cardiovascular variability series

2003

The phase spectra obtained by the classical closed loop autoregressive model (2AR) and by an open loop autoregressive model (ARXAR) were compared to shed light on the need of introducing causality in the assessment of the delay between RR and arterial pressure oscillations. The reliability of the two approaches was tested in simulation and real data setting. In simulation, the coupling strength of a bivariate closed loop process was adjusted to obtain a range of working conditions from open to closed loop. In open loop condition, 2AR and ARXAR phases were comparable and in agreement with the imposed delay. In closed loop condition, ARXAR model returned the imposed delays, while 2AR showed a…

Causality (physics)Range (mathematics)Series (mathematics)Autoregressive modelControl theorySettore ING-INF/06 - Bioingegneria Elettronica E InformaticaPhase (waves)Open-loop controllerComputer Science Applications1707 Computer Vision and Pattern RecognitionBivariate analysisCardiology and Cardiovascular MedicineCross-spectrumMathematics
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Causal cross-spectral analysis of heart rate and blood pressure variability for describing the impairment of the cardiovascular control in neurally m…

2006

A causal approach to the calculation of coherence and transfer function between systolic pressure (SP) and RR interval variability was applied in eight patients and eight control subjects during prolonged tilt test for investigating the impairment of cardiovascular control related to neurally mediated syncope. The causal analysis showed a depressed baroreflex regulation in resting patients, with reduced gain and increased latency from SP to RR, and a drop of the baroreflex coupling immediately before syncope. These findings, which were not elicited by traditional cross-spectral analysis, strongly suggest the use of the causal approach for the study of syncope mechanisms. © 2006 IEEE.

AdultMalemedicine.medical_specialtyStatistics as TopicBiomedical EngineeringBlood PressureNeurally-mediated syncopeCardiovascular controlBaroreflexCardiovascular SystemSensitivity and SpecificitySeverity of Illness IndexFeedbackElectrocardiographyHeart RateInternal medicineSeverity of illnessHeart rateSyncope VasovagalmedicineHumansComputer SimulationDiagnosis Computer-AssistedModels Statisticalmedicine.diagnostic_testbusiness.industryTransfer functionModels CardiovascularReproducibility of ResultsBaroreflexBlood pressureData Interpretation StatisticalAnesthesiaCardiologyRegression AnalysisFemalebusinessElectrocardiographyCoherenceAlgorithmsSyncope (phonology)
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Spectral decomposition of RR-variability obtained by an open loop parametric model for the diagnosis of neuromediate syncope

2002

The role of the cardiovascular regulatory mechanism in patients with neuromediate syncope (NS) is poorly understood. The aim of this study was to accomplish continuous non-invasive analysis of the baroreflex mechanism in patients during a head-tip tilt-table test (HTT) using an open-loop autoregressive model with exogenous input. The model describes the causal dependence of the RR interval on the systolic arterial pressure (SAP) variability. Thus, RR variability results as the linear composition of SAP-dependent (Pdep) and SAP-independent parts of the RR power (P). Further, the model allows the estimation of the baroreflex gain using the modulus of the transfer function (G) from SAP to RR i…

medicine.medical_specialtybusiness.industryOpen-loop controllerComputer Science Applications1707 Computer Vision and Pattern RecognitionBaroreflexMatrix decompositionBlood pressureAutoregressive modelControl theoryInternal medicineParametric modelSettore ING-INF/06 - Bioingegneria Elettronica E InformaticamedicineCardiologyHeart rate variabilitybusinessCardiology and Cardiovascular MedicineSyncope (phonology)
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