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Prediction of life-threatening events in infants using heart rate variability measurementsXu, Xueyan. January 2002 (has links)
Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains viii, 250 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 240-250).
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An investigation of the relationship between lightwaves and cardiac rateCortes, Tara A., January 1976 (has links)
Thesis (Ph. D.)--New York University, School of Education. / Also on film. eContent provider-neutral record in process. Description based on print version record.
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Transfer of heart rate feedback training to reduce heart rate response to laboratory tasksGoodie, Jeffrey L. January 2001 (has links)
Thesis (Ph. D.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains vii, 123 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 59-66).
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Influence of skin type and wavelength on light wave reflectanceFallow, Bennett Ames 24 July 2012 (has links)
Heart rate monitoring (HRM) is an essential tool for monitoring physical activity and as a diagnostic tool in the clinical setting. The ability to monitor heart rate gives users and clinicians vital information about the current condition of the cardiovascular system before, during, and after exercise. However, HRM requires a telemetric chest strap, and comfort, transmission and fit can become problems with the chest strap. New technology using photoplethysmography (PPG) has emerged recently to provide the possibility of HRM without a telemetric chest strap during exercise. The aim of this study was to determine if a new device could detect heart rate over a broad range of skin types (I-V), and whether what wavelength would be most suitable for detecting the signals. A light emitting diode (LED) based PPG system was used to determine heart rate by change in pulsatile blood flow on 22 apparently healthy individuals (11 male and 11 female, 20-59 years old) of varying skin type. Skin type was classified according to a questionnaire in combination with digital photographs with a skin type chart. Each subject was exposed to four different wavelengths (470 nm, 520 nm, 630 nm, and 880 nm) and multiple trials were conducted on each wavelength. Heart rate detection was represented by modulation of the incident light wave and normalized by saturation into a pulsatile waveform represented as modulation average. The 520nm wavelength classified as visible green light provided a significantly greater (p<0.001) ability to detect heart rate. Increasing levels of melanin, or darker skin type (Type V) showed decreased modulation however this trend was not significant (p<0.067). There was no significant interaction between the wavelength of light and the skin type. In conclusion, a PPG based device can detect heart rate across skin types and use of a green light wavelength provides an even greater resolution. / text
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Changes in Autonomic Tone Resulting from Circumferential Pulmonary Vein IsolationSeaborn, Geoffrey 13 December 2010 (has links)
In patients with normal hearts, increased vagal tone is associated with the onset of paroxysmal atrial fibrillation (AF). Vagal denervation of the atria renders AF less inducible. Circumferential pulmonary vein ablation (CPVA), with or without isolation (CPVI), is effective for treating paroxysmal AF, and has been shown to impact HRV indices, in turn reflecting vagal denervation.
We examined the impact of CPVI on HRV indices over time, and evaluated the relationship between vagal modification and rate of recurrence of AF. High resolution ECG recordings were collected from 64 patients (49 male, 15 female, mean age 57.1±9.7) undergoing CPVI for paroxysmal (n=46) or persistent (n=18) AF. Recordings were made pre-procedure, and at intervals up to 12 months. Success was defined as no recurrence.
After CPVI, 27 patients presented recurrence. Pre-procedure HRV variables did not differ from controls in patients with a subsequent successful procedure. However, patients with recurrence demonstrated significantly-reduced pre-procedure HRV compared both with controls, and with patients having successful procedures (39.6±23.4 & 33.7±19.2 vs 21.8±11.8, P =0.01 & P=0.04). Following the procedure, HRV was reduced vs pre-procedure in patients with successful procedures (33.7±19.2 vs 18.6±15.8, P=0.01), and did not differ from unsuccessful procedures over a 12 month FU. Both groups were reduced compared with a control value. There was no significant difference in HRV between patients who experienced recurring AF (n=9), and those who experienced AT or flutter (n=18).
Our data suggests that patients experiencing recurrence after one procedure have reduced HRV that is not changed by CPVI; whereas patients with a successful single procedure experience a change in HRV variables that is sustained over a long period, but is no different post-procedure from patients experiencing recurrence. These data suggest that denervation associated with CPVI may benefit patients with normal vagal tone prior to the procedure, but that sustained denervation is not a critical factor in successful outcome after CPVI. / Thesis (Master, Computing) -- Queen's University, 2010-12-07 08:32:15.066
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Non-invasive procedure for fetal electrocardiographyFox, Alice J Sophia, Women's & Children's Health, Faculty of Medicine, UNSW January 2007 (has links)
Antenatal fetal surveillance is a field of increasing importance in modern obstetrics. Measurements extracted (such as fetal heart rate) from antenatal fetal monitoring techniques have the potential to reduce the social, personal and financial burdens of fetal death on families, health care systems and the community. Techniques to monitor the fetus through pregnancy have been developed with the aim of providing information to enable the clinician to diagnose fetal wellbeing, characterise development and detect abnormality. An early diagnosis before delivery may increase the effectiveness of the appropriate treatment. Over the years, various research efforts have been carried out in the field of fetal electrocardiography by attaching surface electrodes to the maternal body. Unfortunately the desired fetal heartbeat signals at the electrode output are buried in an additive mixture of undesired interference disturbances. In this thesis, a non-invasive fetal electrocardiogram machine has been designed, constructed and implemented. This machine is composed of three modified electrocardiogram circuits and an external soundcard. Data was acquired from four surface electrodes placed on the maternal body. Eleven pregnant subjects, with a gestation age between the 30th and 40th weeks of pregnancy, were used to investigate the validity of this machine. Fetal R-waves were detected in 72.7 percent of subjects. The development of a non-invasive machine, capable of detecting and recording valuable anatomic and electrophysiological information of a fetus, represents an important tool in clinical and investigative obstetrics.
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Detection of myocardial ischemia : clinical and experimental studies with focus on vectorcardiography, heart rate and perioperative conditions /Häggmark, Sören, January 2005 (has links)
Diss. (sammanfattning) Umeå : Univ., 2005. / Härtill 4 uppsatser.
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Alterations in intrinsic heart rate in endotoxemiaWearden, Peter D. January 1999 (has links)
Thesis (Ph. D.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains x, 166 p. : ill. (some col.) Vita. Includes abstract. Includes bibliographical references (p. 139-162).
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Heart rate response during hatha yoga and the effects on health-related physical fitness /Wells, Melissa Delaney January 2007 (has links)
Master's thesis - - State University of New York College at Cortland, 2007 - - Department of Kinesiology. / Includes bibliographical references (p.46-7).
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Comparison of algorithms for fetal ECG extractionPeddaneni, Hemanth. January 2004 (has links)
Thesis (M.S.)--University of Florida, 2004. / Title from title page of source document. Document formatted into pages; contains 58 pages. Includes vita. Includes bibliographical references.
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