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Heart rate variability (HRV) patterns reflect the changing sympathetic and parasympathetic modulation of the autonomic nervous system. While overall and circadian heart rate (HR) and HRV are well characterized by traditional measures, ultradian cycles of HR and HRV are not. We have developed a method for capturing these rhythms during sleep and have now applied it to 24-hour recordings. HR/HRV for...
Heart rate variability (HRV) patterns reflect the changing sympathetic and parasympathetic modulation of the autonomic nervous system. While overall and circadian heart rate (HR) and HRV are well characterized by traditional measures, ultradian cycles of HR and HRV are not. We have developed a method for capturing these rhythms during sleep and have now applied it to 24-hour recordings. HR/HRV for...
Vagally-induced action potential duration (APD) heterogeneity can lead to the breakdown of atrial flutter into fibrillation. The exact distribution of vagal mediated effects in the atria is unknown, however. This study analyzed canine electrograms in order to determine changes in APD. Electrograms were recorded under control, and left and right vagal nerve stimulation. Simulations in a computer model...
Vagally-induced action potential duration (APD) heterogeneity can lead to the breakdown of atrial flutter into fibrillation. The exact distribution of vagal mediated effects in the atria is unknown, however. This study analyzed canine electrograms in order to determine changes in APD. Electrograms were recorded under control, and left and right vagal nerve stimulation. Simulations in a computer model...
The purpose of this study, was to asses whether LF/(LF+HF) obtained from ventricular repolarization variability (VRV) reflects the state of sympathovagal balance. The VRV time series and heart rate variability (HRV) time series from seventy two electrocardiogram (ECG) records in four different autonomic nervous system (ANS) profiles (athletes, cardiac transplant patient, heart failure patients and...
The purpose of this study, was to asses whether LF/(LF+HF) obtained from ventricular repolarization variability (VRV) reflects the state of sympathovagal balance. The VRV time series and heart rate variability (HRV) time series from seventy two electrocardiogram (ECG) records in four different autonomic nervous system (ANS) profiles (athletes, cardiac transplant patient, heart failure patients and...
Beat-to-beat changes in cardiac signals or heart rate variability (HRV) are controlled by the two branches of autonomic nervous system (ANS) in a very complex manner. Although traditional HRV (tHRV) analysis has shown to provide information on cardiac ANS control, it often fails to isolate the effect of two branches in HRV signals. This problem becomes more obvious especially at low respiratory rates...
Beat-to-beat changes in cardiac signals or heart rate variability (HRV) are controlled by the two branches of autonomic nervous system (ANS) in a very complex manner. Although traditional HRV (tHRV) analysis has shown to provide information on cardiac ANS control, it often fails to isolate the effect of two branches in HRV signals. This problem becomes more obvious especially at low respiratory rates...
Analysis of heart rate variability is a valuable method to investigate the sympathetic and parasympathetic function of the autonomic nervous system. Although such analyses can provide quantitative estimates of autonomic neural activity, simultaneous recording of neural activities and ECG will allow more direct investigation of neural modulation of heart rate. We developed a method that allows direct...
Analysis of heart rate variability is a valuable method to investigate the sympathetic and parasympathetic function of the autonomic nervous system. Although such analyses can provide quantitative estimates of autonomic neural activity, simultaneous recording of neural activities and ECG will allow more direct investigation of neural modulation of heart rate. We developed a method that allows direct...
High cost of diagnostic studies to detect sleep disordered breathing and lack of availability of certified sleep laboratories in all inhabited areas make investigation of alternative methods of detecting sleep disordered breathing attractive. This study aimed to explore the possibility of discerning obstructive sleep apnea (OSA) from Cheyne-Stokes respiration (CSR) using overnight electrocardiography...
High cost of diagnostic studies to detect sleep disordered breathing and lack of availability of certified sleep laboratories in all inhabited areas make investigation of alternative methods of detecting sleep disordered breathing attractive. This study aimed to explore the possibility of discerning obstructive sleep apnea (OSA) from Cheyne-Stokes respiration (CSR) using overnight electrocardiography...
Spectral decomposition of the heart rate variability during whole night recordings was obtained, in order to assess the characteristic fluctuations in the heart rate and their spectral parameters during REM and NREM sleep stages. A time-varying autoregressive model was used in the analysis since it allows both real time and transitory episodes evaluation of spectral parameters of the heart rate variability...
Spectral decomposition of the heart rate variability during whole night recordings was obtained, in order to assess the characteristic fluctuations in the heart rate and their spectral parameters during REM and NREM sleep stages. A time-varying autoregressive model was used in the analysis since it allows both real time and transitory episodes evaluation of spectral parameters of the heart rate variability...
This paper reports a preliminary investigation to evaluate the significance of various nonlinear dynamics approaches to analyze the heart rate variability (HRV) signal in children with sleep disordered breathing (SDB). Data collected from children in the age group of 1-17 years diagnosed with sleep apnea were used in this study. Both short term (5 minutes) and long term data from a full night polysomnography...
This paper reports a preliminary investigation to evaluate the significance of various nonlinear dynamics approaches to analyze the heart rate variability (HRV) signal in children with sleep disordered breathing (SDB). Data collected from children in the age group of 1-17 years diagnosed with sleep apnea were used in this study. Both short term (5 minutes) and long term data from a full night polysomnography...
Direct recording of Purkinje fiber activity may lead to a better understanding of the role of the specialized conduction system in pathological cardiac conditions. Two studies were conducted in pigs to determine guidelines for effective plunge needle recording techniques. In the first experiment, Purkinje fiber activations were recorded at 16 KHz with 3 bipolar electrodes (2 mm spacing) on epoxy plunge...
Direct recording of Purkinje fiber activity may lead to a better understanding of the role of the specialized conduction system in pathological cardiac conditions. Two studies were conducted in pigs to determine guidelines for effective plunge needle recording techniques. In the first experiment, Purkinje fiber activations were recorded at 16 KHz with 3 bipolar electrodes (2 mm spacing) on epoxy plunge...
This paper presents an analysis of the Arruda accessory pathway localization method (for patients suffering from Wolff-Parkinson-White syndrome) with suggestions to increase the overall performance. The Arruda method was tested on a total of 121 patients, and a 90% localization performance was reached. This was considered almost as performing result as the highest published (90%) by L. Boersma in...
This paper presents an analysis of the Arruda accessory pathway localization method (for patients suffering from Wolff-Parkinson-White syndrome) with suggestions to increase the overall performance. The Arruda method was tested on a total of 121 patients, and a 90% localization performance was reached. This was considered almost as performing result as the highest published (90%) by L. Boersma in...
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