Labour analgesia effects on foetal heart rate. A mini-review

Foetal well-being during labour is of utmost importance. One of the ways to attempt to assess foetal well-being is by recording foetal heart rate (FHR). Loss of variability and deceleration patterns are known to be associated with foetal distress. Decelerations and foetal bradycardia have been described after any type of effective labour analgesia. This review addresses the questions if certain analgesic techniques and/or analgesics lead to clinically relevant FHR changes, what is their aetiology, and how we should manage these FHR changes.

Video-Based Deception Detection with Non-Contact Heart Rate Monitoring and Multi-Modal Feature Selection

Deception detection plays a crucial role in criminal investigation.Videos contain a wealth of information regarding apparent and physiological changes in individuals,and thus can serve as an effective means of deception detection.In this paper,we investigate video-based deception detection considering both apparent visual features such as eye gaze,head pose and facial action unit(AU),and non-contact heart rate detected by remote photoplethysmography(rPPG)technique.Multiple wrapper-based feature selection methods combined with the K-nearest neighbor(KNN)and support vector machine(SVM)classifiers are employed to screen the most effective features for deception detection.We evaluate the performance of the proposed method on both a self-collected physiological-assisted visual deception detection(PV3D)dataset and a public bag-oflies(BOL)dataset.Experimental results demonstrate that the SVM classifier with symbiotic organisms search(SOS)feature selection yields the best overall performance,with an area under the curve(AUC)of 83.27%and accuracy(ACC)of 83.33%for PV3D,and an AUC of 71.18%and ACC of 70.33%for BOL.This demonstrates the stability and effectiveness of the proposed method in video-based deception detection tasks.

Quran memorisation and heart rate variability:How do they correlate?

BACKGROUND Heart rate variability(HRV)was shown to be affected by performing religious activities.AIM To examine the relationship between the level of Quran(the holy book of Muslims)memorisation and HRV among teenagers.METHODS This experimental study included 16 Tahfiz students and 16 non-Tahfiz students(n=32).The HRV was measured in three tasks:Recalling familiar verses,memorising new verses,and recalling the newly memorised verses of the Quran.HRV analysis was done using these parameters:Standard deviation of N-N(heartbeat peak)interval;low frequency(LF);high frequency(HF)and LF/HF ratio.RESULTS There were significant differences between tasks for all parameters(P<0.05).However,between the groups,only the LF/HF ratio had significant differences,with F=5.04,P<0.05.Pearson correlation showed a moderate positive correlation between the number of pages memorised and the LF/HF ratio(r=0.61,P<0.05).CONCLUSION Quran memorisation increased the HRV and our results suggested that this activity could be developed as an effective sympathovagal modulation training activity.

A comprehensive review of heart rate variability as an indicator in the regulation of the autonomic nervous system by acupuncture:a bibliometric analysis

This study sought to conduct a bibliometric analysis of acupuncture studies focusing on heart rate variability(HRV)and to investigate the correlation between various acupoints and their effects on HRV by utilizing association rule mining and network analysis.A total of 536 publications on the topic of acupuncture studies based on HRV.The disease keyword analysis revealed that HRV-related acupuncture studies were mainly related to pain,inflammation,emotional disorders,gastrointestinal function,and hypertension.A separate analysis was conducted on acupuncture prescriptions,and Neiguan(PC6)and Zusanli(ST36)were the most frequently used acupoints.The core acupoints for HRV regulation were identified as PC6,ST36,Shenmen(HT7),Hegu(LI4),Sanyinjiao(SP6),Jianshi(PC5),Taichong(LR3),Quchi(LI11),Guanyuan(CV4),Baihui(GV20),and Taixi(KI3).Additionally,the research encompassed 46 reports on acupuncture animal experiments conducted on HRV,with ST36 being the most frequently utilized acupoint.The research presented in this study offers valuable insights into the global research trend and hotspots in acupuncture-based HRV studies,as well as identifying frequently used combinations of acupoints.The findings may be helpful for further research in this field and provide valuable information about the potential use of acupuncture for improving HRV in both humans and animals.

TCM-HIN2Vec:A strategy for uncovering biological basis of heart qi deficiency pattern based on network embedding and transcriptomic experiment

Objective:To elucidate the biological basis of the heart qi deficiency(HQD)pattern,an in-depth understanding of which is essential for improving clinical herbal therapy.Methods: We predicted and characterized HQD pattern genes using the new strategy,TCM-HIN2Vec,which involves heterogeneous network embedding and transcriptomic experiments.First,a heterogeneous network of traditional Chinese medicine(TCM)patterns was constructed using public databases.Next,we predicted HQD pattern genes using a heterogeneous network-embedding algorithm.We then analyzed the functional characteristics of HQD pattern genes using gene enrichment analysis and examined gene expression levels using RNA-seq.Finally,we identified TCM herbs that demonstrated enriched interactions with HQD pattern genes via herbal enrichment analysis.Results: Our TCM-HIN2Vec strategy revealed that candidate genes associated with HQD pattern were significantly enriched in energy metabolism,signal transduction pathways,and immune processes.Moreover,we found that these candidate genes were significantly differentially expressed in the transcriptional profile of mice model with heart failure with a qi deficiency pattern.Furthermore,herbal enrichment analysis identified TCM herbs that demonstrated enriched interactions with the top 10 candidate genes and could potentially serve as drug candidates for treating HQD.Conclusion: Our results suggested that TCM-HIN2Vec is capable of not only accurately identifying HQD pattern genes,but also deciphering the basis of HQD pattern.Furthermore our finding indicated that TCM-HIN2Vec may be further expanded to develop other patterns,leading to a new approach aimed at elucidating general TCM patterns and developing precision medicine.

Postpartum quality of life and mental health in women with heart disease:Integrated clinical communication and treatment

BACKGROUND Postpartum quality of life(QoL)in women with heart disease has been neglected.AIM To improve clinical communication and treatment,we integrated medical data and subjective characteristics to study postpartum QoL concerns.METHODS The study assessed QoL 6 wk after birth using the 12-Item Short-Form Health Survey.The Edinburgh Postnatal Depression Scale,Cardiac Anxiety Questionnaire,European Heart Failure Self-Care Behavior Scale,and a self-designed questionnaire based on earlier research were also used to assess patient characteristics.Patient data were collected.Prediction models were created using multiple linear regression.RESULTS This retrospective study examined postpartum QoL in 105 cardiac patients.Postpartum QoL scores were lower(90.69±13.82)than those of women without heart disease,with physical component scores(41.09±9.91)lower than mental component scores(49.60±14.87).Postpartum depression(33.3%),moderate anxiety(37.14%),pregnancy concerns(57.14%),offspring heart problems(57.14%),and life expectancy worries(48.6%)were all prevalent.No previous cardiac surgery,multiparity,higher sadness and cardiac anxiety,and fear of unfavorable pregnancy outcomes were strongly related to lower QoL(R^(2)=0.525).CONCLUSION Postpartum QoL is linked to physical and mental health in women with heart disease.Our study emphasizes the need for healthcare workers to recognize the unique characteristics of these women while developing and implementing comprehensive management approaches during their maternity care.

Chlorogenic acid ameliorates heart failure by attenuating cardiomyocyte ferroptosis

Objective:To elucidate the effects of chlorogenic acid(CGA),a bioactive polyphenol compound prevalent in traditional Chinese medicine and various foods,including Lonicera japonica Thunb.(Jin Yin Hua),Eucommia ulmoides Oliv.(Du Zhong Ye),tea,and coffee,on cardiomyocyte ferroptosis and heart failure.Methods: We assessed the effect of CGA on cardiac function using a mouse model of heart failure induced by transverse aortic constriction(TAC).These indicators included the left ventricular ejection fraction(LVEF),fractional shortening(LVFS),end-systolic volume(LVESV),end-diastolic volume(LVEDV),end-systolic diameter(LVESD),and end-diastolic diameter(LVEDD).An isoprenaline hydrochloride(ISO)-induced H9c2 cardiomyocyte cell model was also established,and the cells were treated with various concentrations of CGA.To assess the effect of CGA on ferroptosis in cardiomyocytes,we measured cell viability and evaluated the levels of intracellular reactive oxygen species(ROS),ferrous ions(Fe^(2+)),and lipid peroxidation using fluorescent staining.To clarify the ferroptosis signaling pathway regulated by CGA,western blotting was used to examine the expression of ferroptosis biomarkers,specifically solute carrier family 7 member 11(SLC7A11)and glutathione peroxidase 4(GPX4),in H9c2 cardiomyocytes and mouse myocardial tissues.Results: CGA significantly enhanced cardiac performance indices such as LVEF,LVFS,LVESV,LVEDV,LVESD,and LVEDD.H9c2 cardiomyocytes exposed to ISO showed decreased cell viability and increased ROS levels,Fe^(2+)content,and lipid peroxidation levels.However,CGA treatment significantly ameliorated these changes.Additionally,in both H9c2 cardiomyocytes and myocardial tissue obtained from mice with TAC,CGA increased the expression of ferroptosis-related proteins,including SLC7A11 and GPX4.Conclusion: CGA has the potential to enhance cardiac function and diminish lipid peroxidation and ROS levels in cardiomyocytes via the SLC7A11/GPX4 signaling pathway.This process alleviates ferroptosis in cardiomyocytes.These results provide new insights into the clinical use of CGA and the management of heart failure.

Application Value of NLR,PLR,LMR,HEART score,and POCT in Early Warning and Accurate Graded Diagnosis of High-Risk Chest Pain in Emergency Medicine

Objective: To evaluate the application value of neutrophils/lymphocytes (NLR), platelets/lymphocytes (PLR), lymphocytes/monocytes (LMR), HEART (history, electrocardiogram, age, risk factors, and troponin) score, and point-of- care testing (POCT) in the early warning and precise diagnosis of high-risk chest pain in emergency medicine. Methods: A total of 157 patients with acute chest pain who were admitted to the emergency department and chest pain treatment unit of our hospital between August 2022 and September 2023 were selected. Rapid testing of bedside myocardial markers (ultrasensitive troponin (hs-cTnI), myoglobin (MYO), creatine kinase isoenzyme (CK-MB), D-dimer (D-Dimer), and N-terminal B-type natriuretic peptide precursor (NT-proBNP)) was performed on the patients using a POCT device (ThermoKing BioMQ60proB). A HEART score was used to classify the patients into low (n = 53), intermediate (n = 59), and high-risk (n = 45) groups, and the NLR, PLR, and LMR were calculated. The NLR, PLR, and LMR values were compared among the three groups of patients, and the optimal cutoff values as well as sensitivity and specificity were determined based on receiver operating characteristic (ROC) analysis. Results: The HEART scores of patients in the low-risk, intermediate-risk, and high-risk groups were (2.72 ± 0.24), (4.75 ± 0.56), and (5.32 ± 0.73) respectively, and the differences were statistically significant (P < 0.05). Compared with the low-risk group, the intermediate-risk group and high-risk group had a significantly higher NLR and PLR, and a significantly lower LMR;the high-risk group had higher NLR and PLR and lower values of LMR as compared to the other two groups, and the difference was statistically significant (P < 0.05). The ROC curves suggested that the area under the curve, sensitivity, and specificity of the combined diagnosis of NLR, PLR, LMR, HEART score, and POCT were greater than those of LR, PLR, and LMR with HEART score and POCT alone. Conclusion: The combined application of NLR, PLR, LMR, HEART score, and POCT has significant application value in the early warning and precise diagnosis of emergency high-risk chest pain. It provides a more simple, easy-to-access, and efficient assessment index for the clinical prediction and treatment of emergency high- risk chest pain.

Modeling Dynamical Noises Corrupted Chaotic System for Heart Rate Variability Analysis

It is difficult to establish the process of chaos in time series from cardiac dynamics. The output from such a system is probably the result of both its internal dynamics, and the input to the system from its surroundings. We present an optimization algorithm to find a time series that is as close as possible to the heart rate series subject to the constraint that it is deterministic with respect to some dynamics. The algorithm is tested by some famous forced dynamical systems, and applied to heart rate data. We find that the deterministic components of heart rate variability are chaotic.

Does heart rate variability correlate with long-term prognosis in myocardial infarction patients treated by early revascularization?

AIMTo assess the prevalence of depressed heart rate variability (HRV) after an acute myocardial infarction (MI), and to evaluate its prognostic significance in the present era of immediate reperfusion.METHODSTime-domain HRV (obtained from 24-h Holter recordings) was assessed in 326 patients (63.5 ± 12.1 years old; 80% males), two weeks after a complicated MI treated by early reperfusion: 208 ST-elevation myocardial infarction (STEMI) patients (in which reperfusion was successfully obtained within 6 h of symptoms in 94% of cases) and 118 non-ST-elevation myocardial infarction (NSTEMI) patients (percutaneous coronary intervention was performed within 24 h and successful in 73% of cases). Follow-up of the patients was performed via telephone interviews a median of 25 mo after the index event (95%CI of the mean 23.3-28.0). Primary end-point was occurrence of all-cause or cardiac death; secondary end-point was occurrence of major clinical events (MCE, defined as mortality or readmission for new MI, new revascularization, episodes of heart failure or stroke). Possible correlations between HRV parameters (mainly the standard deviation of all normal RR intervals, SDNN), clinical features (age, sex, type of MI, history of diabetes, left ventricle ejection fraction), angiographic characteristics (number of coronary arteries with critical stenoses, success and completeness of revascularization) and long-term outcomes were analysed.RESULTSMarkedly depressed HRV parameters were present in a relatively small percentage of patients: SDNN < 70 ms was found in 16% and SDNN < 50 ms in 4% of cases. No significant differences were present between STEMI and NSTEMI cases as regards to their distribution among quartiles of SDNN (χ2 =1.536, P = 0.674). Female sex and history of diabetes maintained a significant correlation with lower values of SDNN at multivariate Cox regression analysis (respectively: P = 0.008 and P = 0.008), while no correlation was found between depressed SDNN and history of previous MI (P = 0.999) or number of diseased coronary arteries (P = 0.428) or unsuccessful percutaneous coronary intervention (PCI) (P = 0.691). Patients with left ventricle ejection fraction (LVEF) < 40% presented more often SDNN values in the lowest quartile (P < 0.001). After > 2 years from infarction, a total of 10 patients (3.1%) were lost to follow-up. Overall incidence of MCE at follow-up was similar between STEMI and NSTEMI (P = 0.141), although all-cause and cardiac mortality were higher among NSTEMI cases (respectively: 14% vs 2%, P = 0.001; and 10% vs 1.5%, P = 0.001). The Kaplan-Meier survival curves for all-cause mortality and for cardiac deaths did not reveal significant differences between patients with SDNN in the lowest quartile and other quartiles of SDNN (respectively: P = 0.137 and P = 0.527). Also the MCE-free survival curves were similar between the group of patients with SDNN in the lowest quartile vs the patients of the other SDNN quartiles (P = 0.540), with no difference for STEMI (P = 0.180) or NSTEMI patients (P = 0.541). By the contrary, events-free survival was worse if patients presented with LVEF < 40% (P = 0.001).CONCLUSIONIn our group of patients with a recent complicated MI, abnormal autonomic parameters have been found with a prevalence that was similar for STEMI and NSTEMI cases, and substantially unchanged in comparison to what reported in the pre-primary-PCI era. Long-term outcomes did not correlate with level of depression of HRV parameters recorded in the subacute phase of the disease, both in STEMI and in NSTEMI patients. These results support lack of prognostic significance of traditional HRV parameters when immediate coronary reperfusion is utilised.

Relationship between Ambient Fine Particles and Ventricular Repolarization Changes and Heart Rate Variability of Elderly People with Heart Disease in Beijing, China

Objective To explore the effects of particulate matters less than 2.5 μm in aerodynamic diameter （PM2.5） on heart repolarization/depolarization and heart rate variability （HRV）. Methods We conducted a panel study for elderly subjects with heart disease in Beijing from 2007 to 2008. PM2.5 was measured at a fixed station for 20 h continuously each day while electrocardiogram （ECG） indexes of 42 subjects were also recorded repeatedly. Meteorological data was obtained from the China Meteorological Data Sharing Service System. A mixed linear regression model was used to estimate the associations between PMz.s and the ECG indexes. The model was adjusted for age, body mass index, sex, day of the week and meteorology. Results Significant adverse effects of PM2.5 on ECG indexes reflecting HRV were observed statistically and the strongest effect of PM2.s on HRV was on lag i day in our study. However, there were no associations between PM2.5 and ECG indexes reflecting heart repolarization/depolarization. Additionally, the effects of PM2.5 on subjects with hypertension were larger than on the subjects without hypertension. Conclusion This study showed ambient PM2.5could affect cardiac autonomic function of the elderly people with heart disease, and subjects with hypertension appeared to be more susceptive to the autonomic dysfunction induced by PM2.5.

Association of resting heart rate and hypertension stages on all-cause and car- diovascular mortality among elderly Koreans： the Kangwha Cohort Study

Background Elevated resting heart rate and hypertension independently increase the risk of mortality. However, their combined ef- fect on mortality in stages of hypertension according to updated clinical guidelines among dderly population is unclear. Methods We fol- lowed a cohort of 6100 residents （2600 males and 3500 females） of Kangwha County, Korea, ranging from 55 to 99 year-olds as of March 1985, for all-cause and cardiovascular mortality for 20.8 years until December 31, 2005. Mortality data were collected through telephone calls and visits （to 1991）, and were confirmed by death record matching with the National Statistical Office （1992-2005）. Hazard ratios were calculated for all-cause and cardiovascular mortality by resting heart rate and hypertension defined by Eighth Joint National Committee crite- ria using the Cox proportional hazard model after controlling for confounding factors. Results The hazard ratios associated with resting heart rate 〉 80 beats/min were higher in hypertensive men compared with normotensives with heart rate of 61-79 beats/rain, with hazard ratios values of 1.43 （95% CI： 1.00-1.92） on all-cause mortality for prehypertension, 3.01 （95% CI： 1.07-8.28） on cardiovascular mortality for prehypertension, and 8.34 （95% CI： 2.52-28.19） for stage 2 hypertension. Increased risk （HR： 3.54, 95% CI： 1.16-9.21） was observed among those with both a resting heart rate 〉 80 beats/rain and prehypertension on cardiovascular mortality in women. Conclusions Indi- viduals with coexisting elevated resting heart rate and hypertension, even in prehypertension, have a greater risk for all-cause and cardiovas- cular mortality compared to those with elevated resting heart rate or hypertension alone. These findings suggest that elevated resting heart rate should not be regarded as a less serious risk factor in elderly hypertensive patients.

Increased heart rate and atherosclerosis: Potential implications of ivabradine therapy

Despite all the therapeutic advances in the field of cardiology, cardiovascular diseases, and in particular coronary artery disease, remain the leading cause of death and disability worldwide, thereby underlining the importance of acquiring new therapeutic options in this field. A reduction in elevated resting heart rate (HR) has long been postulated as a therapeutic approach in the management of cardiovascular disease. An increased HR has been shown to be associated with increased progression of coronary atherosclerosis in animal models and patients. A high HR has also been associated with a greatly increased risk of plaque rupture in patients with coronary atherosclerosis. Endothelial function may be an important link between HR and atherosclerosis. An increased HR has been shown experimentally to cause endothelial dysfunction. Inflammation plays a significant role in the pathogenesis and progression of atherosclerosis. In the literature, there is data that shows an association between HR and circulating markers of vascular inflammation. In addition, HR reduction by pharmacological intervention with ivabradine (a selective HR-lowering agent that acts by inhibiting the pacemaker ionic current If in sinoatrial node cells) reduces the formation of atherosclerotic plaques in animal models of lipid-induced atherosclerosis. The aim of this editorial is to review the possible role of ivabradine on atherosclerosis.

High Physical Activity is Associated with an Improved Lipid Profile and Resting Heart Rate among Healthy Middle-aged Chinese People

Objective To investigate the effects of physical activity （PA） on dyslipidemia and elevated resting heart rate （RHR） in a large-scale cross-sectional study in China. Methods We recruited community-based individuals who were 40-60 years old using a cluster sampling method. The PA levels of the participants were classified as low, moderate, or high, using the International Physical Activity Questionnaire. Dyslipidemia was defined as the detection of abnormalities in lipid indicators, and 4 lipid parameters were evaluated using fasting blood samples. Multivariate logistic regression analyses were used to evaluate the associations of PA with dyslipidemia and RHR. Results A total of 10,321 participants （38.88% men） were included in this study. The percentages of individuals with high, moderate, and low PA levels were 46.5%, 43.9%, and 9.6%, respectively. In both men and women, high PA provided odds ratios of 0.88 [95% confidence interval （CI）： 0.83, 0.94] for dyslipidemia and 0.82 （95% CI： 0.73, 0.92） for elevated RHR, compared to participants with low PA. Conclusion Our data suggested that substantial health benefits （related to dyslipidemia and elevated RHR） occurred at higher intensity PA, with greater energy consumption, in middle-aged Chinese people, and particularly in men.

Heart rate variability： a new tool to predict complications in adult cardiac surgery

Heart rate variability （HRV） refers to the variations between consecutive heartbeats, which depend on the continuous modulation of the sympathetic and parasympathetic branches of the autonomic nervous system. HRV has been shown to be effective as a predictor of risk after myocardial infarction and an early warning sign of diabetic neuropathy, and in the cardiology setting is now recognized to be a useful tool for risk-stratification after hospital admission and after discharge. Recent evidences suggest that HRV analysis might predict complications even in patients undergoing cardiac surgery, and the present review summarizes the importance of HRV analysis in adult cardiac surgery and the perspectives for HRV use in current clinical practice. Although future larger studies are warranted before HRV can be included into daily clinical practice in adult cardiac surgery, HRV is a novel tool which might detect autonomic instability in the early postoperative phase and during hospital stay, thus predicting or prompt-diagnosing many of the post-operative complications.

Elevated Resting Heart Rate is Associated with Dyslipidemia in Middle-aged and Elderly Chinese

Objective To study the relationship between resting heart rate and blood lipid level. Methods A total of 9 415 subjects aged≥40 years were included in the present study. Their resting heart rate was monitored and their serum levels of triglyceride （TG）, total cholesterol （TC）, low density lipoprotein cholesterol （LDL-C） and high density lipoprotein cholesterol （HDL-C） were measured to define dyslipidemia according to the 2007 Chinese Guidelines on Prevention and Treatment of Dyslipidemia in Adults. Results The subjects were divided into group A with their resting heart rate〈70 beats/min, group B with their resting heart rate=70-79 beats/min, group C with their resting heart rate=80-89 beats/min, and group D with their resting heart rate≥90 beats/min. High TG, TC, and LDL-C were presented across the resting heart rate （Ptrend〈0.01）. Multiple logistic regression analysis revealed that the risk of high TG and TC was higher in subjects with their resting heart rate≥90 beats/min than in those with their resting heart rate〈70 beats/min （OR=1.42;95%CI：1.16-1.74 and OR=1.33;95%CI：1.09-1.64, respectively）. Conclusion Elevated resting heart rate is associated with high TG and TC in middle-aged and elderly Chinese subjects.

Feasibility and Diagnostic Accuracy for Assessment of Coronary Artery Stenosis of Prospectively Electrocardiogram-gated High-pitch Spiral Acquisition Mode Dual-source CT Coronary Angiography in Patients with Relatively Higher Heart Rates: in Comparison wit

Objective To prospectively investigate the diagnostic accuracy for coronary artery stenosis of prospectively electrocardiogram-triggered spiral acquisition mode (high pitch mode) dual-source computed tomography coronary angiography (CTCA) in patients with relatively higher heart rates (HR) compared with catheter coronary angiography (CCA). Methods Forty-seven consecutive patients with relatively higher HR (>65 and <100 bpm) (20 male, 27 female; age 55±10 years) who both underwent dual-source CTCA and CCA were prospectively included in this study. All patients were performed CTCA using high pitch mode setting at 20%-30% of the R-R interval for the image acquisition. All coronary segments were evaluated by two blinded and independent observers with regard to image quality on a three-point scale (1: excellent to 3: non-diagnostic) and for the presence of significant coronary stenoses (defined as diameter narrowing exceeding 50%). Considered CCA as the standard of reference, the sensitivity, specificity, positive predictive value and negative predictive value were calculated. Radiation dose values were calculated using the dose-length product. Results Image quality was rated as being score 1 in 92.4% of segments, score 2 in 6.1% of segmentsand score 3 in 1.5% of segments. The average image quality score per segment was 1.064±0.306. The HR variability of patients with image score 1, 2 and 3 were 2.29±1.06 bpm, 5.17±1.37 bpm, 8.88±1.53 bpm, respectively. The average HR variability of patients with different image scores were significantly different (F=170.402, P=0.001). The sensitivity, specificity, positive and negative predictive values were 92.6%, 97.0%, 87.6%, 98.3%, respectively, per segment and 90.0%, 95.2%, 85.3%, 96.9%, respectively, per vessel and 100%, 63.6%, 90.0%, 100%, respectively, per patient. The effective radiation dose was on average 0.86±0.16 mSv. Conclusion In patients with HR more than 65 bpm and below 100 bpm without cardiac arrhythmia, the prospectively electrocardiogram-gated high-pitch spiral acquisition mode with image acquired timing set at 20%-30% of the R-R interval provides a high diagnostic accuracy for the assessment of coronary stenoses combined with a 1.5% of non-diagnostic coronary segments and a radiation dose below 1 mSv.

An Implanted Closed-loop Chip System for Heart Rate Control:System Design and Effects in Conscious Rats

Objective： To evaluate the efficiency of an implanted chip system for the control of heart rate （HR）. Methods： The HR was recorded in six conscious Sprague-Dawley （SD） rats. An implanted chip system was designed to regulate the HR by stimulating the right cervical vagus nerve according to the feedback of real time HR. Each rat was subjected to 30-min regulation and 30-min recovery. The change of HR during the regulation period was compared with the control. The ECG was recorded during the experiment for 24 h. Results： The ECG signals were successfully recorded during the experiment. The HR was significantly decreased during the period of regulation compared with control （-79.3 ± 34.5, P 〈 0.01, n = 6） and then recovered to normal after regulation. Conclusion： The described implanted chip system can regulate the HR to a designated set point.

Effects of Impaired Glucose Metabolism on Heart Rate Variability and Blood Pessure Variability in Essential Hpertensive Patients

To investigate the effects of impaired glucose metabolism （IGM） on cardiovascular autonomic nervous systems in essential hypertensive （EH） patients by comparing heart rate variability （HRV） and blood pressure variability （BPV） in EH patients with or without type 2 diabetes mellitus （T2DM）. Simultaneous 24-h recordings of ambulatory ECG and blood pressure monitoring were performed in 36 male old patients with simple EH and 33 male old patients with EH combined with T2DM. HRV analysis included time domain parameters such as SDNN, SDANN, SDNNi, rMSSD and pNN50, and total spectral power （TP） of HRV, which mainly consists of VLF, LF and HF component along with LF/HF ratio, was also obtained. The value of ambulatory blood pressure was represented as the mean blood pressure （mean systolic/mSBP, diastolic/mDBP and pulse pressure/mPP） during different periods （24 h/24 h, day time/d and night time/n）. Standard deviation （SD） as well as coefficient of variance （CV） of blood pressure during each above-mentioned period were obtained to reflect the long-term BPV. Our result showed that SDNN, SDNNi, SDANN, rMSSD, PNN50, TP and HF of HRV in cases of EH with T2DM were all significantly lower than those in simple EH subjects （P〈0.05）. No significant differences in VLF or LF was found between the two groups （P〉0.05）, while LF/HF ratio was significantly higher in EH with T2DM patients than in simple EH subjects （P〈0.01）. Moreover, dmSBP, 24 h-mPP and dmPP were all significantly higher in EH with T2DM patients than in simple EH subjects （P〈0.05）, while nmSBP, 24 h-mSBP, 24 h-mDBP, dmDBP, nmDBP or nmPP showed no significant difference between this two groups of patients （P〉0.05）. And dSBPSD, dSBPCV and 24 h-SBPSD were all significantly higher in EH with T2DM patients than in simple EH subjects （P〈0.05）, while the other BPV indexes showed no significant difference between this two groups （P〉0.05）. It is concluded that the cardiovascular autonomic nervous systems in EH patients was further impaired by T2DM, displaying lowering of HRV and enlargement of BPV, which in turn induced abnormal structural and functional changes of cardiovascular systems. Therefore, improving cardiovascular autonomic nervous systems might reduce the occurrence of cardiovascular complications in the EH patients with IGM.

Nomenclature,categorization and usage of formulae to adjust QT interval for heart rate

Assessment of the QT interval on a standard 12 lead electrocardiogram is of value in the recognition of a number of conditions. A critical part of its use is the adjustment for the effect of heart rate on QT interval. A systematic search was conducted to identify studiesthat proposed formulae to standardize the QT interval by heart rate. A nomenclature was developed for current and subsequent equations based on whether they are corrective(QTc) or predictive(QTp). QTc formulae attempt to separate the dependence of the length of the QT interval from the length of the RR interval. QTp formulae utilize heart rate and the output QTp is compared to the uncorrected QT interval. The nomenclature consists of the first letter of the first author's name followed by the next two consonance(whenever possible) in capital letters; with subscripts in lower case alphabetical letter if the first author develops more than one equation. The single exception was the Framingham equation,because this cohort has developed its own "name" amongst cardiovascular studies. Equations were further categorized according to whether they were linear,rational,exponential,logarithmic,or power based. Data show that a person's QT interval adjusted for heart rate can vary dramatically with the different QTc and QTp formulae depending on the person's heart rate and QT interval. The differences in the QT interval adjustment equations encompasses values that are considered normal or significant prolonged. To further compare the equations,we considered that the slope of QTc versus heart rate should be zero if there was no correlation between QT and heart rate. Reviewing a sample of 107 patient ECGs from a hospital setting,the rank order of the slope- from best(closest to zero) to worst was QTc DMT,QTc RTHa,QTc HDG,QTc GOT,QTcF RM,QTcF RD,QTcB ZT and QTcM YD. For two recent formulae based on large data sets specifically QTcD MT and QTcR THa,there was no significant deviation of the slope from zero. In summary a nomenclature permits easy reference to QT formulae that adjust for heart rate. Twenty different formulae can produce discordant calculations of an adjusted QT interval. While the formulae developed by Bazett and Fridericia(QTc BZT and QTc FRD respectively) may continue to be used clinically,recent formulae from large population studies specifically QTcD MT and QTcR THa appear to be betterto adjust QT for heart rate in clinical practice.