Assessment of Cardiac Autonomic Function by Using Heart Rate Turbulence in Behcet’s Disease

Behcet’s disease (BD) is a chronic inflammatory disorder that can affect many systems in the body. Cardiac involvement increases the risk of cardiovascular mortality and occurs in 1%-5% of patients with BD. Ventricular arrythmias are believed to be the cause of this increased risk of cardiovascular mortality and it is also thought to be related with cardiac autonomic dysfunction. Heart rate turbulence (HRT) is a new predictor of cardiac autonomic activity. HRT is an independent and powerful predictor of mortality. In this study, we investigated the cardiac autonomic activity which can be determined by HRT in patients with BD. Forty patients with BD (20 men, mean age: 40 ± 9 years, range: 27-55 years) were diagnosed according to the International Study Group Criteria (ISGC) and gender and age matched healthy volunteers (20 men, mean age: 39 ± 8 years, range: 26-56 years) were included in this study. All of the participants (patients and controls) underwent 24 hours Holter electrocardiogram. HRT parameters, turbulence onset (TO) and turbulence slope (TS) were calculated with HRT (View Version 0.60-0.1 of Software Program). There were no significant differences in TO and TS values between patients with BD and control subject (TO-BD: 0.014 ± 0.03, TO-Control: 0.011 ± 0.04;TS-BD: 7.88 ± 4.9, TS-Control: 9.42 ± 6.7 respectively). Although increased cardiovascular mortality rates in BD have been shown in many studies, HRT values—detecting the risk of sudden death—do not seem to be altered in this disease.

Cryptotanshinone attenuates isoprenaline-induced cardiac fibrosis in the mouse associated with upregulation and activation of matrix metalloproteinase-2

Objectives The impairment of matrix metallopro- teinase-2(MMP-2)has been associated with the development of cardiac fibrosis.Although the Chinese herb Salvia miltior-rhiza has been widely used in patients with cardiovascular disorders,the mechanisms involved have not been elucidated. The purpose of the present study was to determine whether the administration of cryptotanshinone,an active ingredient of Salvia miltiorrhiza,could prevent the cardiac fibrosis induced by isoprenaline and to investigate the underlying mechanisms. Methods and Results Male C57BL/6 mice were submitted to receive daily injection of 0.9%saline,3 mg/kg isoprenaline, or isoprenaline plus 20 mg/kg cryptotanshinone by gastric gavage for 2 weeks.Herein,we demonstrate that cryptotanshinone can significantly ameliorate the isoprenaline-induced cardiac fibrosis,which was associated with marked up-regulation and activation of MMP-2 in ventricular myocardium. Additionally,we demonstrate that cryptotanshinone can dose-dependently upregulate and activate MMP-2 in cultured cardiac fibroblast.Moreover,incubation with cryptotanshinone also can prevent isoprenaline-induced downregulation and inactivation of MMP-2 in cultured cardiac fibroblast. Conclusions Taken together,our data suggest that cryptotanshinone may become a novel and potent antifibrotic agent. The present findings might further our understanding of the role of MMP-2 in cardiac fibrosis and antifibrotic mechanisms of cryptotanshinone.

Effect of yelling on maximal aerobic power during an incremental test of cycling performance

Background：People experiencing strong feelings of fatigue during exercise sometimes subconsciously yell to refocus their efforts and,thus,maintain exercise performance.The present study examined the influenc of yelling during high-intensity exercise by analysing cardiorespiratory reactions and integrated electromyography（i EMG） changes in the vastus lateralis during a cycle ergometer test.Methods：A total of 23 moderately trained people were recruited.The cycling test began with a resistance of 25 W/min,which was gradually increased.During the experimental trial,the participants were required to yell at least 3 times when they felt exhausted;during the controlled trial,they were not allowed to produce any yelling sounds.The testing order was randomly assigned and the 2 trials were completed within an interval between 3–10 days.Two-way repeated measures ANOVA was applied to analyse the differences within and between the trials,and interaction of trial and time.Results：The peak power and time to exhaustion（p〈0.01） in the yelling trial were higher than those in the control trial.However,the vastus lateralis iE MG values of both trials at peak power were not significant y different.During the yelling period at 90%–100% of the maximal effort,a significan time-by-trialinteraction（p〈0.05）wasobservedinoxygenconsumption（VO2）,CO2 production,O2 pulse,ventilation,andrespiratoryrate. Alltheabove measures showed a significan between-trial difference（p〈0.02）.However,heart rate,respiratory exchange ratio,end-tidal oxygen pressure,and ventilatory equivalent for oxygen showed only significan between-trial difference（p〈0.05）,but without interaction of trial and time.Conclusion：Yelling enhances the peak O2 pulse and VO2 and maintains CO2-exclusion efficien y during high-intensity exercise.It may enable maintaining muscle activation without stronger EMG signals being required during high-intensity exercise.

AMPK and cardiac remodelling

Cardiac remodelling is generally accepted as a critical process in the progression of heart failure. Myocyte hypertrophy,inflammatory responses and cardiac fibrosis are the main pathological changes associated with cardiac remodelling.AMP-activated protein kinase(AMPK) is known as an energy sensor and a regulator of cardiac metabolism under normal and ischaemic conditions. Additionally, AMPK has been shown to play roles in cardiac remodelling extending well beyond metabolic regulation. In this review, we discuss the currently defined roles of AMPK in cardiac remodelling and summarize the effects of AMPK on cardiac hypertrophy, inflammatory responses and fibrosis and the molecular mechanisms underlying these effects. In addition, we discuss some pharmacological activators of AMPK that are promising treatments for cardiac remodelling.

Effects of Chinese Medicine Shen-Fu Injection(参附注射液)on the Expression of Inflammatory Cytokines and Complements during Post-Resuscitation Immune Dysfunction in A Porcine Model

Objective：To investigate the action of Shen-Fu Injection（参附注射液,SFI） in regulating the expression of the serum complements and inflammatory cytokines synthesized and released in response to the stress of global ischemia accompanying cardiac arrest（CA） and resuscitation.Methods：Thirty pigs were randomly divided into the sham（n=6） and 3 returns of spontaneous circulation（ROSC） groups（n=24）.After 8-min untreated ventricular fibrillation and 2-min basic life support,24 pigs of the ROSC groups were randomized into three groups（n=8 per group）,which received central venous injection of SFI（SFI group）,epinephrine（EP group）,or saline（SA group）.Hemodynamic status and blood samples were obtained at 0,0.5,1,2,4,6,12,and 24 h after ROSC.Results：Serum concentrations of specific activation markers of the complement system C3,C4 and C5b-9 were increased during cardiopulmonary resuscitation th rough1 24 h after ROSC.There were intense changes of various pro-inflammatory cytokines and anti-inflammatory cytokines as early as 0.5 h after CA.Compared with the EP and SA groups,SFI treatment reduced the proinflammatory cytokines levels of interleukin（IL）-6,IL-8and tumor necrosis factor α（TNF-α,P〈0.05）,and increased the anti-inflammatory cytokine levels of IL-4 and IL-10（P〈0.05）.Further,SFI treatment decreased the values of C3,C4 and C5b-9 compared with the EP and SA groups.Conclusions：SFI,derived from the ancient Chinese medicine,has significant effects in attenuating post-resuscitation immune dysfunction by modulating the expression of complements and cytokines levels.The current study provided an experimental basis for the clinical application of a potential pharmacologic target for post resuscitation immune dysfunction.

Sparse current source reconstruction in MCG

Cardiac current source reconstruction is investigated by a fast greedy sparse(FGS) method applied to simulated and real magnetocardiography(MCG) data measured using 61-channel superconducting quantum interference device. The approach reduces the size of the lead field matrix based on a priori knowledge of dipolar magnetic field map. Consequently, the computational demands and the accuracy of sparse source reconstruction are improved simultaneously. The simulation results demonstrate that the FGS method is capable of reconstructing sparse equivalent current sources using the magnetic field data generated by a single current source with varying orientation or multiple current sources generated randomly. In addition, we analyze the cardiac current source reconstructed with real MCG data at typical instants and discuss the electrical excitation conduction during the QRS complex based on moving sparse source imaging.