The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Hatem Alkadhi - One of the best experts on this subject based on the ideXlab platform.
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dual source ct coronary angiography image quality mean Heart Rate and Heart Rate variability
American Journal of Roentgenology, 2007Co-Authors: David Matt, Hans Scheffel, Sebastian Leschka, Thomas Flohr, Borut Marincek, Philipp A Kaufmann, Hatem AlkadhiAbstract:OBJECTIVE. The purpose of this study was to evaluate the effect of mean Heart Rate and Heart Rate variability on the image quality of dual-source CT coronary angiography.SUBJECTS AND METHODS. Eighty patients underwent dual-source CT coronary angiography. Thirteen data sets were reconstructed in 5% steps from 20-80% of the R-R interval. Heart Rate variability was calculated as SD of mean Heart Rate. Two independent blinded reviewers assessed the image quality of each segment.RESULTS. Mean Heart Rate was 65.3 ± 13.9 (SD) beats per minute (bpm) (range, 35-99 bpm) with a variability of 3.4 ± 4.1 bpm (range, 0.4-17.5 bpm). Image quality was sufficient for diagnosis for 97.8% (1,043/1,066) of arterial segments. No significant correlation was found between mean Heart Rate and image quality in any segment or any coronary artery. No significant correlation was found between Heart Rate variability and image quality in any segment, the right coronary artery, or the left anterior descending artery, but there was a si...
Iwona Cygankiewicz - One of the best experts on this subject based on the ideXlab platform.
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Heart Rate turbulence
Progress in Cardiovascular Diseases, 2013Co-Authors: Iwona CygankiewiczAbstract:Abstract Heart Rate turbulence (HRT) is a baroreflex-mediated biphasic reaction of Heart Rate in response to premature ventricular beats. Heart Rate turbulence is quantified by: turbulence onset (TO) reflecting the initial acceleration of Heart Rate following premature beat and turbulence slope (TS) describing subsequent deceleration of Heart Rate. Abnormal HRT identifies patients with autonomic dysfunction or impaired baroreflex sensitivity due to variety of disorders, but also may reflect changes in autonomic nervous system induced by different therapeutic modalities such as drugs, revascularization, or cardiac resynchronization therapy. More importantly, impaired HRT has been shown to identify patients at high risk of all-cause mortality and sudden death, particularly in postinfarction and congestive Heart failure patients. It should be emphasized that abnormal HRT has a well-established role in stratification of postinfarction and Heart failure patients with relatively preserved left ventricular ejection fraction. The ongoing clinical trials will document whether HRT can be used to guide implantation of cardioverter-defibrillators in this subset of patients, not covered yet by ICD guidelines. This review focuses on the current state-of-the-art knowledge regarding clinical significance of HRT in detection of autonomic dysfunction and regarding the prognostic significance of this parameter in predicting all-cause mortality and sudden death.
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relationship between Heart Rate turbulence and Heart Rate Heart Rate variability and number of ventricular premature beats in coronary patients
Journal of Cardiovascular Electrophysiology, 2004Co-Authors: Iwona Cygankiewicz, Jerzy Krzysztof Wranicz, Halina Bolinska, Janusz Zaslonka, Wojciech ZarebaAbstract:Introduction: Heart Rate variability (HRV) illustRates regulation of the Heart by the autonomic nervous system whereas Heart Rate turbulence (HRT) is believed to reflect baroreflex sensitivity. The aim of this study was to determine the association between HRT and HRV parameters and the relationship between HRT parameters and Heart Rate and number of ventricular premature beats (VPBs) used to calculate HRT parameters. Methods and Results: In 146 patients (117 males and 29 females; mean age 62 years) with coronary artery disease, a 24-hour ECG Holter monitoring was performed to calculate mean Heart Rate (RR interval), number of VPBs, time- and frequency-domain HRV parameters and two HRT parameters: turbulence onset (TO) and turbulence slope (TS). Univariate and multivariate regression analyses were performed to evaluate the association between tested parameters. Significant correlation between TS and mean RR interval was observed (r = 0.42; p < 0.001), while no association for TO vs. RR interval was found. TS values were significantly higher in patients with less than 10 VPBs/24 hours than in patients with more frequent VPBs. Significant associations between HRT and HRV parameters were found with TS showing stronger correlation with HRV parameters than TO (r value ranging from 0.35 to 0.62 for TS vs. −0.16 to −0.38 for TO). Conclusion: HRT parameters correlate strongly with HRV parameters indicating that HRT should be considered as a reflection of both baroreceptors response and overall autonomic tone. Heart Rate dependence of turbulence slope indicates the need to adjust this parameter for Heart Rate. (J Cardiovasc Electrophysiol, Vol. 15, pp. 731-737, July 2004)
David Matt - One of the best experts on this subject based on the ideXlab platform.
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dual source ct coronary angiography image quality mean Heart Rate and Heart Rate variability
American Journal of Roentgenology, 2007Co-Authors: David Matt, Hans Scheffel, Sebastian Leschka, Thomas Flohr, Borut Marincek, Philipp A Kaufmann, Hatem AlkadhiAbstract:OBJECTIVE. The purpose of this study was to evaluate the effect of mean Heart Rate and Heart Rate variability on the image quality of dual-source CT coronary angiography.SUBJECTS AND METHODS. Eighty patients underwent dual-source CT coronary angiography. Thirteen data sets were reconstructed in 5% steps from 20-80% of the R-R interval. Heart Rate variability was calculated as SD of mean Heart Rate. Two independent blinded reviewers assessed the image quality of each segment.RESULTS. Mean Heart Rate was 65.3 ± 13.9 (SD) beats per minute (bpm) (range, 35-99 bpm) with a variability of 3.4 ± 4.1 bpm (range, 0.4-17.5 bpm). Image quality was sufficient for diagnosis for 97.8% (1,043/1,066) of arterial segments. No significant correlation was found between mean Heart Rate and image quality in any segment or any coronary artery. No significant correlation was found between Heart Rate variability and image quality in any segment, the right coronary artery, or the left anterior descending artery, but there was a si...
Albert V.g. Bruschke - One of the best experts on this subject based on the ideXlab platform.
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Heart Rate and Heart Rate variability as indexes of sympathovagal balance.
The American journal of physiology, 1994Co-Authors: Marianne Bootsma, Cees A. Swenne, H. H. Van Bolhuis, P. C. Chang, V.m. Cats, Albert V.g. BruschkeAbstract:According to the Rosenblueth-Simeone model, the Heart Rate (HR) is proportional to the sympathovagal balance. The individual proportionality constant is the intrinsic Heart Rate, which can only be determined invasively. The normalized low-frequency Heart Rate variability power (LF) has been raised as a calibRated noninvasive alternative. To concrete this assumption, we studied the individual LF-HR relation during incremental head-up tilt (0, 10, 20, 30, 40, 45, 50, 55, 60, 65, 70, 75, and 80 degrees) in 21 young, healthy males. HR (means +/- SD) increased from 61.0 +/- 9.1 beats/min at 0 degree to 85.9 +/- 18.3 beats/min at 80 degrees. LF increased from 45.8 +/- 16.7 nu at 0 degrees to 79.8 +/- 13.8 nu at 80 degrees (nu meaning normalized units). Individual regressions of LF on HR yielded correlation coefficients of 0.80 +/- 0.13 (means +/- SD). The demonstRated linear relation between LF and HR confirms the potential significance of Heart Rate variability as a noninvasive means of assessing the sympathovagal balance.
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Heart Rate and Heart Rate variability as indexes of sympathovagal balance
American Journal of Physiology-heart and Circulatory Physiology, 1994Co-Authors: Marianne Bootsma, Cees A. Swenne, H. H. Van Bolhuis, P. C. Chang, V.m. Cats, Albert V.g. BruschkeAbstract:According to the Rosenblueth-Simeone model, the Heart Rate (HR) is proportional to the sympathovagal balance. The individual proportionality constant is the intrinsic Heart Rate, which can only be ...
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Average Heart Rate, Heart Rate variability and the sympathovagal balance
[1990] Proceedings Computers in Cardiology, 1990Co-Authors: M.j.a. Janssen, Cees A. Swenne, V.m. Cats, Albert V.g. BruschkeAbstract:Investigated are the responses of the average Heart Rate and of the balance between the 0.07-0.14 and 0.14-0.40-Hz components of the Heart power spectrum to gravitational stress. This was done by taking finger blood pressure measurements in 18 young normals during two 1-hour sessions. In each session there were two supine-standing and two standing-supine transitions. For each transition the changes in average Heart Rate and spectral balance were computed. These changes were individually linearly related. This suggests that, for these postural transitions the spectral balance assesses the tonic autonomic balance, as well as the absolute value of the average Heart Rate. >
Marek Malik - One of the best experts on this subject based on the ideXlab platform.
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Relation of mean Heart Rate and Heart Rate variability in patients with left ventricular dysfunction.
American Journal of Cardiology, 1999Co-Authors: Antti E. Hedman, A. John Camm, Jan Poloniecki, Marek MalikAbstract:: The new finding was that mean Heart Rate and Heart Rate variability were more closely coupled in patients with more advanced LV dysfunction. Mean Heart Rate explained a larger portion of variance in Heart Rate variability in patients in the lowest LVEF quartile than in those in the highest one. These results support our hypothesis that sympathetic activation in patients with more severe LV dysfunction results in closer correlation between Heart Rate and Heart Rate variability. Generally, the correlation between mean Heart Rate and Heart Rate variability is weak because Heart Rate and Heart Rate variability represent different modalities of cardiovascular regulation. Mean Heart Rate is normally determined by the interactions of both the sympathetic and parasympathetic nervous systems, whereas modulation of these activities, with different gains, determines the magnitude of Heart Rate variability. This results in great complexity in control of the Heart by the autonomic nervous system. However, Heart Rate is likely to be more dominantly regulated by the sympathetic nervous system because of vagal withdrawal in patients with more severe LV dysfunction. The effect of sympathetic cardiac modulation has been shown to be more sluggish than that of the parasympathetic nervous system in beat-to-beat regulation of Heart Rate. This may result in more blunted Heart Rate variability concomitantly with elevated mean Heart Rate. Thus, variation in Heart Rate variability in any given mean Heart Rate is likely to be lower than in patients with more preserved LV function, and hence with more complex cardiac autonomic regulation with involvement of the parasympathetic nervous system. Indeed, even the slopes of regression lines between mean Heart Rate and Heart Rate variability were similar in the first and fourth LVEF quartile; the intercept of the regression line was significantly higher in the fourth quartile than in the first one. This further supports our hypothesis.
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Heart Rate variability
Current Opinion in Cardiology, 1998Co-Authors: Marek MalikAbstract:Heart Rate variability is a recognized tool for the estimation of cardiac autonomic modulations. Recently, several studies have advanced the field of Heart Rate variability in three areas: 1) in technical modes of electrocardiogram processing and Heart Rate variability assessment, 2) in physiologic
