The Experts below are selected from a list of 135 Experts worldwide ranked by ideXlab platform
Richard B Devereux - One of the best experts on this subject based on the ideXlab platform.
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relation of various degrees of body mass index in patients with systemic hypertension to left ventricular mass cardiac output and Peripheral Resistance the hypertension genetic epidemiology network study
American Journal of Cardiology, 2001Co-Authors: Vittorio Palmieri, Giovanni De Simone, Donna K Arnett, Jonathan N Bella, Dalane W Kitzman, Albert Oberman, Paul N Hopkins, Michael A Province, Richard B DevereuxAbstract:Abstract The impact of different methods of indexation of left ventricular (LV) mass and systemic hemodynamic variables on prevalences and correlates of cardiovascular abnormalities in relation to level of obesity in populations remains unclear. We evaluated 1,672 participants in the Hypertension Genetic Epidemiology Network Study to investigate the relations of overweight and level of obesity to LV mass and prevalences of LV hypertrophy, abnormal cardiac output, and Peripheral Resistance detected using different indexations for body size. In our study population, 1,577 subjects were clinically healthy nondiabetic hypertensive and 95 were normotensive normal-weight nondiabetic reference subjects. Fat-free mass (FFM) did not differ between the reference group and the normal-weight hypertensive subjects, and increased with overweight. In hypertensive subjects, LV mass and cardiac output increased and total Peripheral Resistance decreased with overweight. Indexation of LV mass for FFM or body surface area (BSA) resulted in no difference or even lower prevalence of LV hypertrophy in severely obese compared with normal-weight hypertensive subjects. In contrast, indexation of LV mass for height2.7 identified an increased prevalence of LV hypertrophy with overweight and obesity. Absolute cardiac output increased and total Peripheral Resistance decreased with overweight. Prevalence of elevated cardiac output indexed for height1.83 increased and for elevated total Peripheral Resistance-height1.83 index decreased with greater overweight, whereas opposite trends were seen when cardiac output and total Peripheral Resistance were indexed for BSA or FFM. Thus, in hypertensive subjects, FFM increases with overweight and is directly related to LV mass, stroke volume, and cardiac output, and inversely related to total Peripheral Resistance. Indexations of LV mass and systemic hemodynamics for FFM or BSA obscured associations of LV hypertrophy and abnormal cardiac and total Peripheral Resistance indexes with overweight, whereas LV mass/height2,7, cardiac output/height1.83, and total Peripheral Resistance-height1.83 detected significant preclinical cardiovascular abnormalities with obesity.
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relation of various degrees of body mass index in patients with systemic hypertension to left ventricular mass cardiac output and Peripheral Resistance the hypertension genetic epidemiology network study
American Journal of Cardiology, 2001Co-Authors: Vittorio Palmieri, Giovanni De Simone, Donna K Arnett, Jonathan N Bella, Dalane W Kitzman, Albert Oberman, Paul N Hopkins, Michael A Province, Richard B DevereuxAbstract:The impact of different methods of indexation of left ventricular (LV) mass and systemic hemodynamic variables on prevalences and correlates of cardiovascular abnormalities in relation to level of obesity in populations remains unclear. We evaluated 1,672 participants in the Hypertension Genetic Epidemiology Network Study to investigate the relations of overweight and level of obesity to LV mass and prevalences of LV hypertrophy, abnormal cardiac output, and Peripheral Resistance detected using different indexations for body size. In our study population, 1,577 subjects were clinically healthy nondiabetic hypertensive and 95 were normotensive normal-weight nondiabetic reference subjects. Fat-free mass (FFM) did not differ between the reference group and the normal-weight hypertensive subjects, and increased with overweight. In hypertensive subjects, LV mass and cardiac output increased and total Peripheral Resistance decreased with overweight. Indexation of LV mass for FFM or body surface area (BSA) resulted in no difference or even lower prevalence of LV hypertrophy in severely obese compared with normal-weight hypertensive subjects. In contrast, indexation of LV mass for height(2.7) identified an increased prevalence of LV hypertrophy with overweight and obesity. Absolute cardiac output increased and total Peripheral Resistance decreased with overweight. Prevalence of elevated cardiac output indexed for height(1.83) increased and for elevated total Peripheral Resistance-height(1.83) index decreased with greater overweight, whereas opposite trends were seen when cardiac output and total Peripheral Resistance were indexed for BSA or FFM. Thus, in hypertensive subjects, FFM increases with overweight and is directly related to LV mass, stroke volume, and cardiac output, and inversely related to total Peripheral Resistance. Indexations of LV mass and systemic hemodynamics for FFM or BSA obscured associations of LV hypertrophy and abnormal cardiac and total Peripheral Resistance indexes with overweight, whereas LV mass/height(2,7), cardiac output/height(1.83), and total Peripheral Resistance-height(1.83) detected significant preclinical cardiovascular abnormalities with obesity.
Ramakrishna Mukkamala - One of the best experts on this subject based on the ideXlab platform.
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Estimation of the total Peripheral Resistance baroreflex impulse response from spontaneous hemodynamic variability.
American journal of physiology. Heart and circulatory physiology, 2007Co-Authors: Xiaoxiao Chen, Jong-kyung Kim, Javier A. Sala-mercado, Robert L. Hammond, Rafat I. Elahi, Tadeusz J. Scislo, Gokul Swamy, Donal S. O'leary, Ramakrishna MukkamalaAbstract:We previously developed a mathematical analysis technique for estimating the static gain values of the arterial total Peripheral Resistance (TPR) baroreflex (GA) and the cardiopulmonary TPR baroref...
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Estimation of arterial and cardiopulmonary total Peripheral Resistance baroreflex gain values: validation by chronic arterial baroreceptor denervation.
American journal of physiology. Heart and circulatory physiology, 2005Co-Authors: Ramakrishna Mukkamala, Jong-kyung Kim, Javier A. Sala-mercado, Robert L. Hammond, Tadeusz J. Scislo, Donal S. O'learyAbstract:Feedback control of total Peripheral Resistance (TPR) by the arterial and cardiopulmonary baroreflex systems is an important mechanism for short-term blood pressure regulation. Existing methods for...
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Noninvasive identification of the total Peripheral Resistance baroreflex
American journal of physiology. Heart and circulatory physiology, 2002Co-Authors: Ramakrishna Mukkamala, Karin Toska, Richard J. CohenAbstract:We propose two identification algorithms for quantitating the total Peripheral Resistance (TPR) baroreflex, an important contributor to short-term arterial blood pressure (ABP) regulation. Each algorithm analyzes beat-to-beat fluctuations in ABP and cardiac output, which may both be obtained noninvasively in humans. For a theoretical evaluation, we applied both algorithms to a realistic cardiovascular model. The results contrasted with only one of the algorithms proving to be reliable. This algorithm was able to track changes in the static gains of both the arterial and cardiopulmonary TPR baroreflex. We then applied both algorithms to a preliminary set of human data and obtained contrasting results much like those obtained from the cardiovascular model, thereby making the theoretical evaluation results more meaningful. This study suggests that, with experimental testing, the reliable identification algorithm may provide a powerful, noninvasive means for quantitating the TPR baroreflex. This study also provides an example of the role that models can play in the development and initial evaluation of algorithms aimed at quantitating important physiological mechanisms.
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A noninvasive method for total Peripheral Resistance baroreflex identification
Computers in cardiology, 2000Co-Authors: Ramakrishna Mukkamala, Richard J. CohenAbstract:We developed a noninvasive method for estimating the static gains of the arterial and cardiopulmonary total Peripheral Resistance (TPR) baroreflexes. The method involves a system identification analysis of beat-to-beat fluctuations in arterial blood pressure (ABP), cardiac output (CO), and stroke volume (SV) in order to identify two transfer functions relating CO fluctuations to ABP fluctuations and SV fluctuations to ABP fluctuations. The static gains of each of the TPR baroreflexes may then be computed from the static gains of the two identified transfer functions. In order to evaluate the method, we constructed a computer model of the human cardiovascular system. We applied the method to data generated from the computer model and found close agreement between the estimated and actual static gains of the model TPR baroreflexes. We also applied the method to experimental human data and obtained encouraging results. These results motivate the experimental validation of the method.
Vittorio Palmieri - One of the best experts on this subject based on the ideXlab platform.
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relation of various degrees of body mass index in patients with systemic hypertension to left ventricular mass cardiac output and Peripheral Resistance the hypertension genetic epidemiology network study
American Journal of Cardiology, 2001Co-Authors: Vittorio Palmieri, Giovanni De Simone, Donna K Arnett, Jonathan N Bella, Dalane W Kitzman, Albert Oberman, Paul N Hopkins, Michael A Province, Richard B DevereuxAbstract:Abstract The impact of different methods of indexation of left ventricular (LV) mass and systemic hemodynamic variables on prevalences and correlates of cardiovascular abnormalities in relation to level of obesity in populations remains unclear. We evaluated 1,672 participants in the Hypertension Genetic Epidemiology Network Study to investigate the relations of overweight and level of obesity to LV mass and prevalences of LV hypertrophy, abnormal cardiac output, and Peripheral Resistance detected using different indexations for body size. In our study population, 1,577 subjects were clinically healthy nondiabetic hypertensive and 95 were normotensive normal-weight nondiabetic reference subjects. Fat-free mass (FFM) did not differ between the reference group and the normal-weight hypertensive subjects, and increased with overweight. In hypertensive subjects, LV mass and cardiac output increased and total Peripheral Resistance decreased with overweight. Indexation of LV mass for FFM or body surface area (BSA) resulted in no difference or even lower prevalence of LV hypertrophy in severely obese compared with normal-weight hypertensive subjects. In contrast, indexation of LV mass for height2.7 identified an increased prevalence of LV hypertrophy with overweight and obesity. Absolute cardiac output increased and total Peripheral Resistance decreased with overweight. Prevalence of elevated cardiac output indexed for height1.83 increased and for elevated total Peripheral Resistance-height1.83 index decreased with greater overweight, whereas opposite trends were seen when cardiac output and total Peripheral Resistance were indexed for BSA or FFM. Thus, in hypertensive subjects, FFM increases with overweight and is directly related to LV mass, stroke volume, and cardiac output, and inversely related to total Peripheral Resistance. Indexations of LV mass and systemic hemodynamics for FFM or BSA obscured associations of LV hypertrophy and abnormal cardiac and total Peripheral Resistance indexes with overweight, whereas LV mass/height2,7, cardiac output/height1.83, and total Peripheral Resistance-height1.83 detected significant preclinical cardiovascular abnormalities with obesity.
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relation of various degrees of body mass index in patients with systemic hypertension to left ventricular mass cardiac output and Peripheral Resistance the hypertension genetic epidemiology network study
American Journal of Cardiology, 2001Co-Authors: Vittorio Palmieri, Giovanni De Simone, Donna K Arnett, Jonathan N Bella, Dalane W Kitzman, Albert Oberman, Paul N Hopkins, Michael A Province, Richard B DevereuxAbstract:The impact of different methods of indexation of left ventricular (LV) mass and systemic hemodynamic variables on prevalences and correlates of cardiovascular abnormalities in relation to level of obesity in populations remains unclear. We evaluated 1,672 participants in the Hypertension Genetic Epidemiology Network Study to investigate the relations of overweight and level of obesity to LV mass and prevalences of LV hypertrophy, abnormal cardiac output, and Peripheral Resistance detected using different indexations for body size. In our study population, 1,577 subjects were clinically healthy nondiabetic hypertensive and 95 were normotensive normal-weight nondiabetic reference subjects. Fat-free mass (FFM) did not differ between the reference group and the normal-weight hypertensive subjects, and increased with overweight. In hypertensive subjects, LV mass and cardiac output increased and total Peripheral Resistance decreased with overweight. Indexation of LV mass for FFM or body surface area (BSA) resulted in no difference or even lower prevalence of LV hypertrophy in severely obese compared with normal-weight hypertensive subjects. In contrast, indexation of LV mass for height(2.7) identified an increased prevalence of LV hypertrophy with overweight and obesity. Absolute cardiac output increased and total Peripheral Resistance decreased with overweight. Prevalence of elevated cardiac output indexed for height(1.83) increased and for elevated total Peripheral Resistance-height(1.83) index decreased with greater overweight, whereas opposite trends were seen when cardiac output and total Peripheral Resistance were indexed for BSA or FFM. Thus, in hypertensive subjects, FFM increases with overweight and is directly related to LV mass, stroke volume, and cardiac output, and inversely related to total Peripheral Resistance. Indexations of LV mass and systemic hemodynamics for FFM or BSA obscured associations of LV hypertrophy and abnormal cardiac and total Peripheral Resistance indexes with overweight, whereas LV mass/height(2,7), cardiac output/height(1.83), and total Peripheral Resistance-height(1.83) detected significant preclinical cardiovascular abnormalities with obesity.
Raja Lekshmi - One of the best experts on this subject based on the ideXlab platform.
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Selective Peripheral Resistance to Thyroid Hormone – A Case Report
Kerala Medical Journal, 2009Co-Authors: Raja LekshmiAbstract:Thyroid hormone Resistance syndrome is a very rare disorder characterized by partial Resistance of the target tissue to thyroid hormone. We present a case of a 52 year old male with hypothyroidism and selective Peripheral Resistance to thyroid hormone. who required very high doses of thyroid hormone to relieve his symptoms. TSH remained very low suggesting normal pituitary response. Keywords: Thyroid function, Resistance to thyroid hormone, RTH syndrome.
Richard J. Cohen - One of the best experts on this subject based on the ideXlab platform.
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Noninvasive identification of the total Peripheral Resistance baroreflex
American journal of physiology. Heart and circulatory physiology, 2002Co-Authors: Ramakrishna Mukkamala, Karin Toska, Richard J. CohenAbstract:We propose two identification algorithms for quantitating the total Peripheral Resistance (TPR) baroreflex, an important contributor to short-term arterial blood pressure (ABP) regulation. Each algorithm analyzes beat-to-beat fluctuations in ABP and cardiac output, which may both be obtained noninvasively in humans. For a theoretical evaluation, we applied both algorithms to a realistic cardiovascular model. The results contrasted with only one of the algorithms proving to be reliable. This algorithm was able to track changes in the static gains of both the arterial and cardiopulmonary TPR baroreflex. We then applied both algorithms to a preliminary set of human data and obtained contrasting results much like those obtained from the cardiovascular model, thereby making the theoretical evaluation results more meaningful. This study suggests that, with experimental testing, the reliable identification algorithm may provide a powerful, noninvasive means for quantitating the TPR baroreflex. This study also provides an example of the role that models can play in the development and initial evaluation of algorithms aimed at quantitating important physiological mechanisms.
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A noninvasive method for total Peripheral Resistance baroreflex identification
Computers in cardiology, 2000Co-Authors: Ramakrishna Mukkamala, Richard J. CohenAbstract:We developed a noninvasive method for estimating the static gains of the arterial and cardiopulmonary total Peripheral Resistance (TPR) baroreflexes. The method involves a system identification analysis of beat-to-beat fluctuations in arterial blood pressure (ABP), cardiac output (CO), and stroke volume (SV) in order to identify two transfer functions relating CO fluctuations to ABP fluctuations and SV fluctuations to ABP fluctuations. The static gains of each of the TPR baroreflexes may then be computed from the static gains of the two identified transfer functions. In order to evaluate the method, we constructed a computer model of the human cardiovascular system. We applied the method to data generated from the computer model and found close agreement between the estimated and actual static gains of the model TPR baroreflexes. We also applied the method to experimental human data and obtained encouraging results. These results motivate the experimental validation of the method.
