Objective: To examine the autonomic function using HRV measures in apparently healthy individuals undergoing exercise stress test (EST) and demonstrating slow HRR response. Methods: HRV was measured with 12 lead ECGs ...Objective: To examine the autonomic function using HRV measures in apparently healthy individuals undergoing exercise stress test (EST) and demonstrating slow HRR response. Methods: HRV was measured with 12 lead ECGs during graded EST and analyzed via a post-processing method. Autonomic function was determined by Power Spectral Analysis of the very low frequency (VLF), low frequency (LF), high frequency (HF), and the ratio of LF/HF. We correlated HRV indices with resting, exercise, and recovery data. Results: No differences were found in anthropometric measurements, peak EST HR, and METS between individuals with slow HRR (below 18 b/min) compared with controls (HRR > 18 b/min). Only the VLF component of the HRV indices was statistically different (p = 0.03) at one-minute post-exercise compared with controls. Additionally, a significant correlation between HRR and resting LF and HF indices was found in the individuals with slow HRR but not in the controls. Conclusion: In apparently healthy individuals with slow HRR post-EST, autonomic function did not demonstrate any differences at any phase of the EST, including at one minute of recovery. However, a significant correlation was found between resting LF and HF powers and HRR in individuals with slow vagal reactivation post-exercise. The clinical and prognostic implications of such observation deserve further investigation.展开更多
To study the role of autonomic nervous system in the period of developing syncope induced by head-up tilt test(HUT), we analysed the changes of heart rate power spectral density(HRPSD) in 50 patients with unexplained ...To study the role of autonomic nervous system in the period of developing syncope induced by head-up tilt test(HUT), we analysed the changes of heart rate power spectral density(HRPSD) in 50 patients with unexplained syncope, including 15 positive patients (Group 1) and 35 negative patients(Group 2), and 15 negative healthy persons(Group 3) in 5 minute periods before and after tilting and 5 minutes before the end of test. HRPSD and their changes in total(T), very low-frequence(VLF), low-frequence(LF), high-frequence(HF) and the ratio of low/high frequence(LF/HF) were similar (P>0.05) 5 minutes before and after tilting among three groups. Five minutes before the end of test, Group 1 had obvious increase of T, VLF, LF and LF/HF while Group 2 and 3 had not such significant changes. There was significant difference(P<0.01) compared Group 1 with Group 2, 3. The results showed that the abnormal regulatory function of autonomic nervous system played an important role in the mechanism of symcope induced by HUT, the positive group had abnormal increase of sympathetic tone and imbalance of sympathetic/parasympathetic neural tone before syncope appeared.展开更多
The purpose of this study is to evaluate the relationship between %HRmax and %vVO2max at constant efforts made at different intensities. In randomized order, males healthy subjects (Age: 25 ± 7 years, Weight: 70 ...The purpose of this study is to evaluate the relationship between %HRmax and %vVO2max at constant efforts made at different intensities. In randomized order, males healthy subjects (Age: 25 ± 7 years, Weight: 70 ± 11 kg, VO2max: 55 ± 8 ml·kg–1·min–1) were divided into two groups, a trained one with more than 3 training sessions per week (n = 10) a moderately trained one with 3 drives or less per week (n = 15). The difference between the two groups corresponds to a time to exhaustion above and below 40 min at 80% vVO2max. All subjects performed 5 tests with a gradual increase in speed of 1 km·h–1 every 2 min and 4 constant speed tests at 60%, 70%, 80% and 90% VO2max. All test were performed at the same time of day (i.e., 18:00 h). The results of this study showed that eighteen collective regressions including different independent variables were developed to predict %HRmax. The individual equations developed, have r values between 0.974 and 0.993 and Syx, between 1.2 and 1.9 ml·kg–1·min–1, they are more accurate than the collective equations (one equation for all subjects) with r values between 0.81 to 0.89 and Syx, between 4.1 and 5.3 ml·kg–1·min–1. In conclusion, this study has demonstrated that the model of predictions of %HRmax from %vVO2max in triangular tests were not appropriate for rectangular efforts. From the equations developed, we find that the time to exhaustion at 90% vVO2max is the best predictor of level of endurance then the time limit to 80% vVO2max.展开更多
Objective: To examine the reproducibility of HRR in healthy individuals with slow HRR response undergoing routine annual checkups. Method: HRR data (>18 b/min;Group 1 and 18 b/min;Group 2) were analyzed using ...Objective: To examine the reproducibility of HRR in healthy individuals with slow HRR response undergoing routine annual checkups. Method: HRR data (>18 b/min;Group 1 and 18 b/min;Group 2) were analyzed using a fixed-effects regression model adjusted for age and gender, including random effects group-specific slopes on age. Results: One hundred and thirteen individuals (56.5 ± 9.2 y), underwent 573 cumulative ESTs with an average of 5.1 ± 1.6 tests per individual during a 21-year retrospective follow-up. No differences were found in anthropometric measurements and blood variables. All individuals achieved 94% ± 7.7% of age-predicted HR max at peak EST. Group 2 demonstrated 38% of inconsistent HRR. Regression analysis demonstrated a decrease of 0.5 b/min, on average across individuals, in HRR per each extra year of age. The random effects showed an inter-subject SD level of 9.91 b/min and an SD on the age slope of 0.40 b/min/year. Conclusion: HRR showed low reproducibility in nearly 40% of tests, which was not reflected by the variation of HR nor in the slope of age during a 21-year retrospective follow-up.展开更多
Background: In pseudoexfoliative syndrome (PEX), extraocular accumulation is associated with cardiovascular morbidity and mortality. The aim of this study was to investigate the effect of exercise test on corrected QT...Background: In pseudoexfoliative syndrome (PEX), extraocular accumulation is associated with cardiovascular morbidity and mortality. The aim of this study was to investigate the effect of exercise test on corrected QT dispersion (QTcd) and QTcd recovery in PEX. Patients and Methods: A total of 37 patients diagnosed as PEX were included in the study. The control group consisted of 38 patients. The Electrocardiographies (ECG) were taken. The patients were subjected to an exercise test. Results: In the study group, baseline, peak and third minute recovery QTcd values were 41.35 ± 7.27 ms, 65.19 ± 7.83 ms, and 53.61 ± 6.45 ms, respectively. In the control group, baseline, peak and third minute recovery QTcd values were 29.92 ± 4.23 ms, 38.31 ± 4.22 ms and 28.76 ± 3.09 ms, respectively. There was statistically significant?difference between the baseline and peak QTcd values of the study group and?the control group (t = 8.34224/p 0.00001, t = 18.55079/p 0.00001, respectively). In addition, while there was a statistically significant?difference between the baseline QTcd and the third minute recovery QTcd in the study group, there was no statistically significant difference between the baseline QTcd value and the third minute recovery QTcd value in the control group as heart rate recovery (t = 8.388558/p 0.00001, t = 1.967315/p = 0.056668, respectively).?Conclusion: All of them were found to have a higher risk in terms of malignant ventricular arrhythmia in the study group, both at rest and with effort, in a statistically significant way compared to the control group.展开更多
Objectives To analyze the six-minute walk test （6MWT） and gas exchange of 5 heart transplantation patients and to approach the variation tendency of exercise tolerance, oxygen uptake （ VO2 ） and heart rate chronot...Objectives To analyze the six-minute walk test （6MWT） and gas exchange of 5 heart transplantation patients and to approach the variation tendency of exercise tolerance, oxygen uptake （ VO2 ） and heart rate chronotropic response. Methods 5 cases of heart transplantation patients （ age 25 - 52 years） were undertaken 6MWT 6 - 30 months after operation, synchronizing gas exchanging parameters were measured by wireless portable remote sensing K4B^2 gas analyzer, 51 normal controls were compared. Results The six-minute walk distance （6MWD） of 5 patients were （592.6 ± 26.7 ） m （558 - 625 ） m, the ascending tendency during exercise was slower, the maximum heart rates were 80% ± 6% of age-predicting maximal heart rate, lower than normal control （86%） ; the end point VO2/kg were （21.8 ± 1.4 ） mL/min · kg （ 19. 94 - 23.60） mL/min · kg. Conclusions The 6WMD and VO2 of 5 patients reached normal range, but the heart rate chronotropic response and VO2 ascending tendency were slower than those of normal controls.展开更多
This study was to investigate the changes of autonomic nerve function and hemodynamics in patients with vasovagal syncope(VVS) during head-up tilt-table testing(HUT). HUT was performed in 68 patients with unexplained ...This study was to investigate the changes of autonomic nerve function and hemodynamics in patients with vasovagal syncope(VVS) during head-up tilt-table testing(HUT). HUT was performed in 68 patients with unexplained syncope and 18 healthy subjects served as control group. According to whether bradycardia, hypotension or both took place during the onset of syncope, the patients were divided during the test into three subgroups: vasodepressor syncope(VD), cardioinhibitory syncope(CI) and mixed syncope(MX) subgroups. Heart rate, blood pressure, heart rate variability(HRV), and deceleration capacity(DC) were continuously analyzed during HUT. For all the subjects with positive responses, the normalized low frequency(LFn) and the LF/HF ratio markedly decreased whereas normalized high frequency(HFn) increased when syncope occurred. Syncopal period also caused more significant increase in the power of the DC in positive groups. These changes were more exaggerated compared to controls. All the patients were indicative of a sympathetic surge in the presence of withdrawal vagal activity before syncope and a sympathetic inhibition with a vagal predominance at the syncopal stage by the frequency-domain analysis of HRV. With the measurements of DC, a decreased vagal tone before syncope stage and a vagal activation at the syncopal stage were observed. The vagal tone was higher in subjects showing cardioinhibitory responses at the syncopal stage. DC may provide an alternative method to understand the autonomic profile of VVS patients.展开更多
To evaluate the values of abnormal heart rate recovery （HRR） after treadmill exercise test in patients with coronary artery disease （CAD）. Methods One hundred and seventy-eight consecutive cases of suspected CAD w...To evaluate the values of abnormal heart rate recovery （HRR） after treadmill exercise test in patients with coronary artery disease （CAD）. Methods One hundred and seventy-eight consecutive cases of suspected CAD who underwent symptom-limited treadmill exercise test （TET） and coronary angiography （CAG） were enrolled and divided into normal and abnormal HRR group based on the status of the values of HRR one or two minutes after TET. The clinical characteristics, TET parameters and CAG results of the two groups were compared attempted to assess the value of HRR on patients with CAD. Results （ 1 ） The cases of smoking, diabetes mellitus （DM） and ST segment deviation at rest in abnormal HRR group were more significantly than those in normal HRR group （ all P 〈 0. 05 ）. （2） The subjects of abnormal HRR usually had higher basal heart rate, more cases exhibited ST segment abnormality and or exercise-limited angina during or after TET（P 〈 0. 01 and P 〈 0. 05, respectively）, but lower level of peak heart rate attained （ P 〈 0. 05 ） than those in normal group. The values of metabolism equivalents and duration of TET between the two groups displayed phenomenal difference （ P 〈 0. 05 ）. There were more samples acquired moderate to high level of Duke test score and chronotropic incompetence in the group of abnormal HRR, compared to the normal HRR group （P 〈 0. 01 ）. （3） The cases of negative CAG results in the group of normal and abnormal HRR group were 73 （66. 97 % ） and 24 （34. 78 % ）. Cases of significant coronary lesions （ at least one major coronary vessel ≥ 50 % stenosis） amongst the subgroup of positive CAG were 36 （ 33.03 % ） and 45 （65.22 % ）, severe coronary lesions （ three-vessel, left main or the equivalents of left main） were 10 （9. 17 % ） and 17 （24. 64 % ） for normal and abnormal HRR respectively （P 〈 0. 01 ）. Accordingly, the Gensini scores in the subunit of abnormal HRR increased. （4）Linear correlation analysis indicate there was a negative correlation between the values of HRR in the first and second minutes and indices of severity of CAD （ all P 〈 0. 01 ）. The analysis of auxiliary diagnostic value of abnormal HRR indicated the annexed HRR standard had higher negative predictive value. Conclusions The status of HRR after TET are not only influenced by the clinical factors related to the cardiac autonomic function, but also associated with the extent of CAD. （ S Chin J Cardiol 2009 ; 10（1）：1-8）展开更多
文摘Objective: To examine the autonomic function using HRV measures in apparently healthy individuals undergoing exercise stress test (EST) and demonstrating slow HRR response. Methods: HRV was measured with 12 lead ECGs during graded EST and analyzed via a post-processing method. Autonomic function was determined by Power Spectral Analysis of the very low frequency (VLF), low frequency (LF), high frequency (HF), and the ratio of LF/HF. We correlated HRV indices with resting, exercise, and recovery data. Results: No differences were found in anthropometric measurements, peak EST HR, and METS between individuals with slow HRR (below 18 b/min) compared with controls (HRR > 18 b/min). Only the VLF component of the HRV indices was statistically different (p = 0.03) at one-minute post-exercise compared with controls. Additionally, a significant correlation between HRR and resting LF and HF indices was found in the individuals with slow HRR but not in the controls. Conclusion: In apparently healthy individuals with slow HRR post-EST, autonomic function did not demonstrate any differences at any phase of the EST, including at one minute of recovery. However, a significant correlation was found between resting LF and HF powers and HRR in individuals with slow vagal reactivation post-exercise. The clinical and prognostic implications of such observation deserve further investigation.
文摘To study the role of autonomic nervous system in the period of developing syncope induced by head-up tilt test(HUT), we analysed the changes of heart rate power spectral density(HRPSD) in 50 patients with unexplained syncope, including 15 positive patients (Group 1) and 35 negative patients(Group 2), and 15 negative healthy persons(Group 3) in 5 minute periods before and after tilting and 5 minutes before the end of test. HRPSD and their changes in total(T), very low-frequence(VLF), low-frequence(LF), high-frequence(HF) and the ratio of low/high frequence(LF/HF) were similar (P>0.05) 5 minutes before and after tilting among three groups. Five minutes before the end of test, Group 1 had obvious increase of T, VLF, LF and LF/HF while Group 2 and 3 had not such significant changes. There was significant difference(P<0.01) compared Group 1 with Group 2, 3. The results showed that the abnormal regulatory function of autonomic nervous system played an important role in the mechanism of symcope induced by HUT, the positive group had abnormal increase of sympathetic tone and imbalance of sympathetic/parasympathetic neural tone before syncope appeared.
文摘The purpose of this study is to evaluate the relationship between %HRmax and %vVO2max at constant efforts made at different intensities. In randomized order, males healthy subjects (Age: 25 ± 7 years, Weight: 70 ± 11 kg, VO2max: 55 ± 8 ml·kg–1·min–1) were divided into two groups, a trained one with more than 3 training sessions per week (n = 10) a moderately trained one with 3 drives or less per week (n = 15). The difference between the two groups corresponds to a time to exhaustion above and below 40 min at 80% vVO2max. All subjects performed 5 tests with a gradual increase in speed of 1 km·h–1 every 2 min and 4 constant speed tests at 60%, 70%, 80% and 90% VO2max. All test were performed at the same time of day (i.e., 18:00 h). The results of this study showed that eighteen collective regressions including different independent variables were developed to predict %HRmax. The individual equations developed, have r values between 0.974 and 0.993 and Syx, between 1.2 and 1.9 ml·kg–1·min–1, they are more accurate than the collective equations (one equation for all subjects) with r values between 0.81 to 0.89 and Syx, between 4.1 and 5.3 ml·kg–1·min–1. In conclusion, this study has demonstrated that the model of predictions of %HRmax from %vVO2max in triangular tests were not appropriate for rectangular efforts. From the equations developed, we find that the time to exhaustion at 90% vVO2max is the best predictor of level of endurance then the time limit to 80% vVO2max.
文摘Objective: To examine the reproducibility of HRR in healthy individuals with slow HRR response undergoing routine annual checkups. Method: HRR data (>18 b/min;Group 1 and 18 b/min;Group 2) were analyzed using a fixed-effects regression model adjusted for age and gender, including random effects group-specific slopes on age. Results: One hundred and thirteen individuals (56.5 ± 9.2 y), underwent 573 cumulative ESTs with an average of 5.1 ± 1.6 tests per individual during a 21-year retrospective follow-up. No differences were found in anthropometric measurements and blood variables. All individuals achieved 94% ± 7.7% of age-predicted HR max at peak EST. Group 2 demonstrated 38% of inconsistent HRR. Regression analysis demonstrated a decrease of 0.5 b/min, on average across individuals, in HRR per each extra year of age. The random effects showed an inter-subject SD level of 9.91 b/min and an SD on the age slope of 0.40 b/min/year. Conclusion: HRR showed low reproducibility in nearly 40% of tests, which was not reflected by the variation of HR nor in the slope of age during a 21-year retrospective follow-up.
文摘Background: In pseudoexfoliative syndrome (PEX), extraocular accumulation is associated with cardiovascular morbidity and mortality. The aim of this study was to investigate the effect of exercise test on corrected QT dispersion (QTcd) and QTcd recovery in PEX. Patients and Methods: A total of 37 patients diagnosed as PEX were included in the study. The control group consisted of 38 patients. The Electrocardiographies (ECG) were taken. The patients were subjected to an exercise test. Results: In the study group, baseline, peak and third minute recovery QTcd values were 41.35 ± 7.27 ms, 65.19 ± 7.83 ms, and 53.61 ± 6.45 ms, respectively. In the control group, baseline, peak and third minute recovery QTcd values were 29.92 ± 4.23 ms, 38.31 ± 4.22 ms and 28.76 ± 3.09 ms, respectively. There was statistically significant?difference between the baseline and peak QTcd values of the study group and?the control group (t = 8.34224/p 0.00001, t = 18.55079/p 0.00001, respectively). In addition, while there was a statistically significant?difference between the baseline QTcd and the third minute recovery QTcd in the study group, there was no statistically significant difference between the baseline QTcd value and the third minute recovery QTcd value in the control group as heart rate recovery (t = 8.388558/p 0.00001, t = 1.967315/p = 0.056668, respectively).?Conclusion: All of them were found to have a higher risk in terms of malignant ventricular arrhythmia in the study group, both at rest and with effort, in a statistically significant way compared to the control group.
文摘Objectives To analyze the six-minute walk test （6MWT） and gas exchange of 5 heart transplantation patients and to approach the variation tendency of exercise tolerance, oxygen uptake （ VO2 ） and heart rate chronotropic response. Methods 5 cases of heart transplantation patients （ age 25 - 52 years） were undertaken 6MWT 6 - 30 months after operation, synchronizing gas exchanging parameters were measured by wireless portable remote sensing K4B^2 gas analyzer, 51 normal controls were compared. Results The six-minute walk distance （6MWD） of 5 patients were （592.6 ± 26.7 ） m （558 - 625 ） m, the ascending tendency during exercise was slower, the maximum heart rates were 80% ± 6% of age-predicting maximal heart rate, lower than normal control （86%） ; the end point VO2/kg were （21.8 ± 1.4 ） mL/min · kg （ 19. 94 - 23.60） mL/min · kg. Conclusions The 6WMD and VO2 of 5 patients reached normal range, but the heart rate chronotropic response and VO2 ascending tendency were slower than those of normal controls.
基金supported by a grant from the Wuhan Science and Technology Program of China(No.2014060101010032)
文摘This study was to investigate the changes of autonomic nerve function and hemodynamics in patients with vasovagal syncope(VVS) during head-up tilt-table testing(HUT). HUT was performed in 68 patients with unexplained syncope and 18 healthy subjects served as control group. According to whether bradycardia, hypotension or both took place during the onset of syncope, the patients were divided during the test into three subgroups: vasodepressor syncope(VD), cardioinhibitory syncope(CI) and mixed syncope(MX) subgroups. Heart rate, blood pressure, heart rate variability(HRV), and deceleration capacity(DC) were continuously analyzed during HUT. For all the subjects with positive responses, the normalized low frequency(LFn) and the LF/HF ratio markedly decreased whereas normalized high frequency(HFn) increased when syncope occurred. Syncopal period also caused more significant increase in the power of the DC in positive groups. These changes were more exaggerated compared to controls. All the patients were indicative of a sympathetic surge in the presence of withdrawal vagal activity before syncope and a sympathetic inhibition with a vagal predominance at the syncopal stage by the frequency-domain analysis of HRV. With the measurements of DC, a decreased vagal tone before syncope stage and a vagal activation at the syncopal stage were observed. The vagal tone was higher in subjects showing cardioinhibitory responses at the syncopal stage. DC may provide an alternative method to understand the autonomic profile of VVS patients.
文摘To evaluate the values of abnormal heart rate recovery （HRR） after treadmill exercise test in patients with coronary artery disease （CAD）. Methods One hundred and seventy-eight consecutive cases of suspected CAD who underwent symptom-limited treadmill exercise test （TET） and coronary angiography （CAG） were enrolled and divided into normal and abnormal HRR group based on the status of the values of HRR one or two minutes after TET. The clinical characteristics, TET parameters and CAG results of the two groups were compared attempted to assess the value of HRR on patients with CAD. Results （ 1 ） The cases of smoking, diabetes mellitus （DM） and ST segment deviation at rest in abnormal HRR group were more significantly than those in normal HRR group （ all P 〈 0. 05 ）. （2） The subjects of abnormal HRR usually had higher basal heart rate, more cases exhibited ST segment abnormality and or exercise-limited angina during or after TET（P 〈 0. 01 and P 〈 0. 05, respectively）, but lower level of peak heart rate attained （ P 〈 0. 05 ） than those in normal group. The values of metabolism equivalents and duration of TET between the two groups displayed phenomenal difference （ P 〈 0. 05 ）. There were more samples acquired moderate to high level of Duke test score and chronotropic incompetence in the group of abnormal HRR, compared to the normal HRR group （P 〈 0. 01 ）. （3） The cases of negative CAG results in the group of normal and abnormal HRR group were 73 （66. 97 % ） and 24 （34. 78 % ）. Cases of significant coronary lesions （ at least one major coronary vessel ≥ 50 % stenosis） amongst the subgroup of positive CAG were 36 （ 33.03 % ） and 45 （65.22 % ）, severe coronary lesions （ three-vessel, left main or the equivalents of left main） were 10 （9. 17 % ） and 17 （24. 64 % ） for normal and abnormal HRR respectively （P 〈 0. 01 ）. Accordingly, the Gensini scores in the subunit of abnormal HRR increased. （4）Linear correlation analysis indicate there was a negative correlation between the values of HRR in the first and second minutes and indices of severity of CAD （ all P 〈 0. 01 ）. The analysis of auxiliary diagnostic value of abnormal HRR indicated the annexed HRR standard had higher negative predictive value. Conclusions The status of HRR after TET are not only influenced by the clinical factors related to the cardiac autonomic function, but also associated with the extent of CAD. （ S Chin J Cardiol 2009 ; 10（1）：1-8）
