Spontaneous type 1 pattern, ventricular arrhythmias and sudden cardiac death in Brugada Syndrome： an updated systematic review and meta-analysis

Brugada syndrome （BrS） is primary electrical disorder characterized by ST segment elevation with right bundle branch block morphology in patients with apparent structurally normal hearts, It predisposes affected individuals to ventricular tachycardia/fibrillation （VT/VF） and sudden cardiac death （SCD）.A number of studies have identified risk factors that are associated with a more malignant course of disease. These include male gender, syncope, a spontaneous type 1 ECG pattern, family history of SCD, family history of Brugada syndrome,

Control of cardiac excitability and arrhythmias by microRNAs

Recent studies revealing the important roles of microRNAs（miRNAs） in regulating expression of ion channel genes have opened up a research field for extending and deepening our investi- gation into the cardiac excitability and the associated arrhythmogenesis.Cardiac excitability,the fundamental property of the cardiac myocytes,defines the cardiac conduction,repolarization,automaticity,intracellular calcium handling,and their regional heterogeneity. Our previous and ongoing studies and the work from other laboratories have demonstrated the significant involvement of miRNAs in regulating every aspects of cardiac excitability.We have found earlier that the muscle-specific miRNA miR-1 boosts up the arrhythmogenic potential through targeting gap junction channel connexin 43 in myocardial infarction.A subsequent study revealed that miR-1 can also cause arrhythmias by impairing Ca2+ handling by targeting phosphatase.We then identified another muscle-specific miRNA miR-133 promotes abnormal QT prolongation by repressing HERG K+ channel expression in diabetic cardiomyopathy. Subsequently,we discovered that both miR- 1 and miR-133 are involved in the reexpression of pacemaker channels HCN2/HCN4 to enhance abnormal automaticity in cardiac hypertrophy.Recently, we further identified miR-328 as an important determinant for atrial fibrillation（AF） and the associated adverse atrial electrical remodeling via targeting L-type Ca2+ channels.While all the above-mentioned miRNAs are proarrhythmic,we have newly identified for the first time a natural antiarrhythmic miRNA miR-26.We found that all three members of the miR-26 family is downregulated in their expression in AF tissues and this downregulation increases AF vulnerability as a result of removal of an endogenous antiarrhythmic factor.miR-26 downregulation shortens atrial action potential favoring AF by increasing inward rectifier K+ current（IK1） density. This is caused by an upregulation of Kir2.1 K+ channel subunit due to derepression of its encoding gene KCNJ2 as we have validated KCNJ2 as a target gene for miR-26.Administration of a LNA-modified antimiR-26 antisense through tail vein injection increases AF vulnerability as indicated by increased number of mice with AF induction by intracardiac pacing.And this effect is blunted by co-injection of either an adenovirus vector carrying miR-26 precursor sequence or a LNA-modified miR-26 mimic to specifically target KCNJ2.We further discovered that the activity of NFAT transcription factor is enhanced in AF which represses the transcription of miR-26. We characterized the promoter region of the host genes of all three members of the miR-26 miRNA family and identified a common cis-acting element for NFAT binding.Thus,our study unraveled a novel miRNA signaling pathway AF NFAT miR-26 KC-NJ2 /Kir2.1/IK1 AF as a positive feedback loop favoring AF and the remodeling process.

Cardiac arrhythmias and cardiac arrest related to mushroom poisoning: A case report

BACKGROUND Mushroom exposure is a global health issue.The manifestations of mushroom poisoning (MP) may vary.Some species have been reported as rhabdomyolytic,hallucinogenic,or gastrointestinal poisons.Critical or even fatal MPs are mostly attributable to Amanita phalloides,with the development of severe liver or renal failure.Myocardial injury and even cases mimicking ST-segment elevation myocardial infarction (STEMI) have been previously reported,while cardiac arrhythmia or cardiac arrest is not commonly seen.CASE SUMMARY We report a 68-year-old woman with MP who suffered from delirium,seizure,long QT syndrome on electrocardiogram (ECG),severe cardiac arrhythmias of multiple origins,and cardiac arrest.She was intubated and put on blood perfusion.Her kidney and liver functions were intact;creatine kinase-MB was mildly elevated,and then fell within normal range during her hospital stay.We sent the mushrooms she left for translation elongation factor subunit 1α,ribosomal RNA gene sequence,and internal transcribed spacer sequence analyses.There were four kinds of mushrooms identified,two of which were found to be toxic.CONCLUSION This is the first time that we found cardiac toxicity caused by Panaeolus subbalteatus and Conocybe lactea,which were believed to be toxic to the liver,kidney,and brain.We suggest that intensive monitoring and ECG follow-up are essential to diagnose prolonged QT interval and different forms of tachycardia in MP patients,even without the development of severe liver or renal failure.The mechanisms need to be further investigated and clarified based on animal experiments and molecular signal pathways.

Associations between cardiac arrhythmia,incident disability in activities of daily living and physical performance:the ILSA study

Background Cardiac arrhythmias are common conditions in older people.Unfortunately,there is limited literature on associations between cardiac arrhythmias and physical performance or disability.We therefore aimed to prospectively investigate associations between cardiac arrhythmias and changes in disability and physical performance during 8 years of follow-up,using data from the Italian Longitudinal Study on Aging(ILSA).Methods Cardiac arrhythmias diagnosis was posed through a screening phase,confirmed by a physician.The onset of disability in activities of daily living(ADL)and the changes in several physical performance tests during follow-up were considered as outcomes.Fully-adjusted and propensity-score Cox Proportional Hazard models and mixed models were used for exploring associations between cardiac arrhythmia and the outcomes of interest.Results The prevalence of cardiac arrhythmia at baseline was 23.3%.People reporting cardiac arrhythmia at the baseline were significantly older,more frequently male,smokers and reported a higher presence of all medical conditions investigated(hypertension,heart failure,angina,myocardial infarction,diabetes,stroke),but no difference in dementia,Parkinsonism,cognitive or mood disorder.Cardiac arrhythmia at baseline was significantly associated with the incidence of disability in ADL(HR=1.23;95%:CI:1.01–1.50;P=0.0478 in propensity score analyses;HR=1.28;95%CI:1.01–1.61;P=0.0401 in fully adjusted models).Cardiac arrhythmia at baseline was also associated with a significant worsening in balance test(P=0.0436).Conclusions The presence of cardiac arrhythmia at baseline was associated with a significant higher risk of disability and of worsening in some physical performance tests,particularly those relating to balance.Screening and frequently assessing physical performance in older people affected by cardiac arrhythmia can be important to prevent a loss of physical performance,with further,potential,complications of medical management.

Heart rate-adjusted PR as a prognostic marker of long-term ventricular arrhythmias and cardiac death in ICD/CRT-D recipients

Objective To evaluate the PR to RR interval ratio (PR/RR,heart rate-adjusted PR) as a prognostic marker for long-term ventricular arrhythmias and cardiac death in patients with implantable cardioverter defibrillator (ICDs) and cardiac resynchronization therapy with defibrillators (CRT-D).Methods We retrospectively analyzed data from 428 patients who had an ICD/CRT-D equipped with home monitoring.Baseline PR and RR interval data prior to ICD/CRT-D implantation were collected from standard 12-lead electrocardiograph,and the PR/RR was calculated.The primary endpoint was appropriate ICD/CRT-D treatment of ventricular arrhythmias (VAs),and the secondary endpoint was cardiac death.Results During a mean follow-up period of 38.8 ± 10.6 months,197 patients (46%) experienced VAs,and 47 patients (11%) experienced cardiac death.The overall PR interval was 160 ± 40 ms,and the RR interval was 866 ± 124 ms.Based on the receiver operating characteristic curve,a cut-off value of 18.5% for the PR/RR was identified to predict VAs.A PR/RR ≥ 18.5% was associated with an increased risk of VAs [hazard ratio (HR)= 2.243,95% confidence interval (CI)= 1.665–3.022,P < 0.001) and cardiac death (HR = 2.358,95%CI = 1.240–4.483,P = 0.009) in an unadjusted analysis.After adjustment in a multivariate Cox model,the relationship remained significant among PR/RR ≥ 18.5%,VAs (HR = 2.230,95%CI = 1.555–2.825,P < 0.001) and cardiac death (HR = 2.105,95%CI = 1.101–4.025,P = 0.024.Conclusions A PR/RR ≥ 18.5% at baseline can serve as a predictor of future VAs and cardiac death in ICD/CRT-D recipients.

Cardioprotective activity of alcoholic extract of Tinospora cordifolia (Willd.) Miers in calcium chloride-induced cardiac arrhythmia in rats

The present study investigated the antiarrhythmic activity of alcoholic extract of Tinospora cordifolia （T. cordifolia） in CaCl2 induced arrhythmia. CaCl2 （25 mg/kg） was administered by intravenous infusion （iv） to produce arrhythmia in rats. The animals were then treated with T. cordifolia extract （150, 250, and 450 mg/kg） and verapamil （5 mg/kg,iv）. Lead II electrocardiogram was monitored. Plasma calcium, sodium and potassium levels were measured. In CaCl2 induced arrhythmia, heart rate was decreased by 41.10%, T. cordifolia at 150, 300, and 450 mg/kg decreased the heart rate by 26.30%, 29.16%, and 38.29%, respectively, and verapamil reduced the heart rate by 9.70% compared to the normal group. The PQRST waves were normalized and atrial and ventricular fibrillation was controlled in rats treated with verapamil and T. cordifolia. CaCl2 increased calcium and sodium levels and decreased potassium levels in blood. T. cordifolia dose-dependently decreased calcium and sodium levels and increased potassium levels. Hence, T. cordifolia can be used in antiarrhythmic clinical settings and beneficial in atrial and ventricular fibrillation and flutter and may be indicated in ventricular tachyarrhythmia.

Amiodarone Therapy for Cardiac Arrhythmias: Is It Associated with the Development of Cancers?

Amiodarone is used worldwide to treat cardiac arrhythmias, as well as highly symptomatic cases of atrial fibrillation. With this expanded use, especially following its 1985 United States Food and Drug Administration approval, and its use as a long-term therapy in common practice, reports of cancers temporarily related to amiodarone have begun to increase. Animal studies, several clinical trials, numerous case reports, and a population-based cohort study have suggested that cancers may be associated with amiodarone use. This review focuses on the ever increasing evidence in the literature that suggests amiodarone therapy, especially with long-term use, may increase the potential risk of cancer development. It also expresses the need for more definitive studies to be conducted to provide clinicians with a clear answer to this important question.

Cell and gene therapy for arrhythmias： Repair of cardiac conduction damage

Action potentials generated in the sinoatrial node （SAN） dominate the rhythm and rate of a healthy human heart. Subsequently, these action potentials propagate to the whole heart via its conduction system. Abnormalities of impulse generation and/or propagation in a heart can cause arrhythmias. For example, SAN dysfunction or conduction block of the atrioventricular node can lead to serious bradycardia which is currently treated with an implanted electronic pacemaker. On the other hand, conduction damage may cause reentrant tachyarrhythmias which are primarily treated pharmacologically or by medical device-based therapies, including defibrillation and tissue ablation. However, drug therapies sometimes may not be effective or are associated with serious side effects. Device-based therapies for cardiac arrhythmias, even with well developed technology, still face inadequacies, limitations, hardware complications, and other challenges. Therefore, scientists are actively seeking other alternatives for antiarrhythmic therapy. In particular, cells and genes used for repairing cardiac conduction damage/defect have been investigated in various studies both in vitro and in vivo. Despite the complexities of the excitation and conduction systems of the heart, cell and gene-based strategies provide novel alternatives for treatment or cure of cardiac arrhythmias. This review summarizes some highlights of recent research progress in this field.

Short-term exposure to ambient ozone associated with cardiac arrhythmias in healthy adults

Objective The exact biological mechanism whereby exposure to ambient ozone(O3)may contribute to clinical onset of cardiovascular events remains unclear.In this study,we aim to examine the impacts of O3 exposure on cardiac arrhythmias and potential pathways involved through autonomic dysfunction and myocardial injury.Methods Seventy-three non-smoking healthy adults were followed with 4 repeated measurements of 24-hour ambulatory arrhythmias,heart rate variability,ST-segment deviation,and blood pressure(BP)in Beijing,China,2014‒2016.Generalized additive mixed models coupled with distributed lag nonlinear models were constructed to evaluate the associations and potential interlinks between O3 exposure and outcome measurements.Results During the study period,24-hour average concentrations of ambient O3 were 47.4µg/m3(ranging from 1.0 to 165.9µg/m3).Increased risks of premature ventricular contraction and ventricular tachycardia were associated with interquartile range increases in O3 exposure during the last 5 days before each participant's clinic visit,with relative risks of 2.14(95%confidence interval[CI]:1.95 to 2.32)and 5.47(95%CI:3.51 to 7.43),respectively.Mediation analyses further showed that sympathetic activation,parasympathetic inhibition,and elevated BP levels,as well as heightened risks of ST-segment depression could mediate up to 47.74%of the risks of arrhythmias attributable to O3 exposure.Conclusion Our results suggest that short-term exposure to ambient O3 could prompt the genesis of arrhythmias partially through worsening autonomic function and myocardial burden.

ARRHYTHMIA INDUCED BY NICOTINE ACTIVATING CARDIAC INTRINSIC NEURONS IN CANINE ATRIAL AND VENTRICULAR GANGLIAL PLEXUS

Objective To study the arrhythmia induced by stimulation of nicotine-sensitive neurons in cardiac ganglial plexuses. Methods When nicotine (100 μg ) was injected into canine right atrial ganglial plexus (RAGP) and ganglial plexus between aorta and pulmonary artery (A-PGP) in 33 anesthetized open-chest dog, electrocardiogram, atrial force and ventricular intramyocardial pressures (IMP) were recorded. The responses were also recorded following administration of atropine or propranolol and after heart acute decentralization. Results Ventricular arrhythmia (VA) was induced by injections of nicotine into A-PGP, but not by injections of nicotine into RAGP in 13 dogs. Atrioventricilar (A-V) block was induced by nicotine activating RAGP in 10 dogs, but not by nicotine activating A-PGP. Propranolol could reduce the frequency of VA elicited by stimulating A-PGP, atropine could reduce the frequency of A-V block elicited by stimulating RAGP. After acute decentralization, VA was still induced by activation of A-PGP in 9 dogs, but A-V block elicited by stimulating RAGP was decreased. Conclusion VA is induced by stimulating N receptor in cardiac nicotine-sensitive efferent sympathetic neurons of ventricular ganglial plexus (A-PGP), and then modifying β receptor of ventricles. A-V block is elicited by stimulating N receptor in atrial ganglial plexus (RAGP), then modifying M receptor of A-V node not only via efferent parasympathetic neurons, but also via afferent pathway.

Ambient Particulate Matter Pollution and Hospital Visits for Cardiac Arrhythmia in Beijing,China

Cardiac arrhythmia is a serious public health problem in many countries.Previous studies estimated that 33.5 million people are affected by cardiac arrhythmia worldwide,and this number will continue to grow as society ages.Despite improvements in diagnostic and therapeutic interventions in electrophysiology,the disease burden,incidence and prevalence of cardiac arrhythmia continue to increase and have aroused public health concern.Increasing evidence has indicated that air pollution may be associated with cardiac autonomic nervous system.Among air pollutants,particulate matter with an aerodynamic diameter of≤2.5μm(PM_(2.5))is considered exert more toxicity than other air pollutants,as it provides a larger surface area and absorbs or condenses more toxic substances per unit mass.

Wenxin granule for cardiac arrhythmia: an overview of systematic reviews

Objectives: Evaluating the quality of systematic reviews/meta-analysis of Wenxin granule in treating cardiac arrhythmia to provide evidence for clinical practice, and analyzing the problems in the research to identify potential research priorities for researchers. Method: The systematic reviews of Wenxin granule in treating cardiac arrhythmia were searched from 8 databases. The methodological quality and evidence quality were assessed by AMSTAR and GRADE respectively. Results: Nineteen eligible systematic reviews with 52,905 participants were included. The overall scores of AMSTAR ranged from 3 to 10 with a mean score of 6.5, the median score was 6. There were 9 (9/19, 47.37%) systematic reviews had the score of 7 or more. 6 of them with appropriate information were assessed the quality of evidence by GRADE. The results showed that the overall quality of evidence was limited (range from “very low” to “low”), no “moderate” or “high” quality of evidence existed. For the outcome reporting, no systematic reviews reported endpoints and limited evidence showed that there is causality between Wenxin granule and adverse effects/events. The outcome matrix showed that there are obvious heterogeneity and incompleteness for the outcome reporting in included systematic reviews, so that some included studies cannot be conducted meta-analysis. Meanwhile, there were studies excluded because of inappropriate outcome measures, such as outcome measures did not meet inclusion criteria, treatment time did not meet inclusion criteria, treatment time was unclear, incomplete data or the data cannot be extracted. Conclusions: Wenxin granule have limited efficacy and safety for treating arrhythmia. In the future, high quality of RCTs and systematic reviews should be conducted. Core outcome set for cardiac arrhythmia is needed to improve outcome reporting and decrease waste.

Evaluation of the Effect of Irbesartan Combined with PMA on Arrhythmia and Cardiac Function in Patients with Rheumatic Heart Disease

Objective:To investigate the clinical effect of irbesartan combined with potassium magnesium aspartate(PMA)in the treatment of rheumatic heart disease.Methods:A total of 316 patients with rheumatic heart disease who were treated in our hospital during the period of March 2018 to January 2021 were selected as the research objects.According to the different treatment methods,they were divided into group A(treatment with irbesartan only)and group B(Using Irbesartan combined with PMA treatment),analyze and compare the cardiac function,diastolic blood pressure,systolic blood pressure,heart rate and clinical treatment effect of the two groups of patients after treatment.Results:After treatment,the left ventricular end-systolic diameter(LVESD),left atrial diameter(LAD),and left ventricular end-diastolic diameter(LVEDD)of the two groups were significantly lower than before treatment,and left ventricular ejection fraction(LVEF)was significantly higher than after treatment,(P<0.05),and the improvement of the above indicators in group B was significantly better than that of group A,(P<0.05).After treatment,the diastolic blood pressure,systolic blood pressure and heart rate of group B were significantly lower than those of group A,(P<0.05);the total effective rate of treatment in group B(87.4%)was higher than that of group A(76.3%),(P<0.05).Conclusion:Irbesartan combined with PMA in the treatment of rheumatic heart disease has a better clinical effect than irbesartan alone.It can promote the reconstruction of ventricular function,improve the clinical symptoms of patients,prevent heart failure,and can effectively promote the recovery of cardiac function in patients.

Phoneutria Spider Toxins Target Channels Involved in Cardiac Arrhythmias, Ischemia and Pain

Toxins isolated from the venom of the spider Phoneutria nigriventer either inhibit or activate a vast number of targets, such as ion channels, with high selectivity and affinity. PhTx3-1 toxin is a selective blocker of IA currents of K^＋ channels, and PhTx3-3 and PhTx3-4 are calcium channel blockers of the P/Q-type calcium channels. The spider neurotoxin PhTx3-6 reversibly and non-specifically inhibits high-voltage-activated Ca^2＋ channels with varying potency （N 〉 R 〉 P/Q 〉 L） in heterologous and native systems. There has been a huge increase in the range of medical disorders involving ionic channels, and blockers of these channels have potential as therapeutic agents. The mechanism of action of each toxin family is different; thus, each needs to be evaluated for its therapeutic potential. This review will focus on peptide toxins purified from the venom of the spider Phoneutria nigriventer that are currently being evaluated in preclinical tests as possible drugs for the treatment of pain, cardiac arrhythmias and ischemia.

Ventricular Arrhythmia-Free Survival Following Therapeutic Hypothermia in Patients with Sudden Cardiac Death Due to Ventricular Tachycardia or Fibrillation

Background: The potential benefits of implantable cardioverter-defibrillator (ICD) therapy in patients with sudden cardiac death (SCD) treated with therapeutic hypothermia (TH) have not been well studied. Methods: Incidence of recurrent non-sustained ventricular arrhythmia, ICD therapy, and death were ascertained in 64 consecutive survivors of SCD due to ventricular fibrillation or tachycardia, who were treated with TH. Follow-up was 31.5 +/- 3.3 months in 41 ICD recipients and 36.3 +/- 3.9 months in 23 patients who did not receive an ICD due to the presence of a reversible cause of cardiac arrest, an acute myocardial infarction in 87%. Results: Combined incidence of ventricular arrhythmia, ICD therapy, or death in patients who underwent ICD placement (21.9%) were similar to overall mortality in the patients who did not receive an ICD (21.7%, p = 0.752). ICD placement was associated with a significant mortality benefit;95.1% survival in ICD recipients vs. 78.3% in the no-ICD group (p = 0.038). Electrocardiographic findings of ST segment elevation on admission were associated with increased event rate in ICD recipients (p = 0.039) and increased mortality in SCD patients who did not receive an ICD (p Conclusions: SCD survivors treated with TH are at increased risk for recurrent arrhythmic events and derive significant mortality benefit from ICD implantation. Increased mortality in revascularized SCD patients with acute coronary syndrome, thought to have a reversible cause of cardiac arrest, calls for prospective trials investigating utility of ICD in this vulnerable patient population.

The gender difference of utilization of cardiac implantable electronic device in China： data from Arrhythmia Interventional Therapy Data Registry

Background Cardiac implantable electronic devices （CIEDs） greatly improve survival and life quality of patients. However, there are gender differences regarding both the utilization and benefit of these devices. In this prospective CIED registry, we aim to appraise the gender differences in CIED utilization in China. Methods Twenty centers from 14 provinces in China were included in our registry study. All patients who underwent a CIED implantation in these twenty centers between Jan 2015 and Dec 2016 were included. Results A total of 8570 patients were enrolled in the baseline cohort, including 7203 pacemaker, 664 implantable cardiac defibrillators （ICD） implants and 703 cardiac resynchronization therapy device （CRT/D）. Totally, 4117 （48.0%） CIED patients were female, and more than 59% pacemaker patients were female, but women account only one third of ICD or CRT/D implantation in this registry. There were significant differences between genders at pacemaker and ICD indications. Female was more likely received a pacemaker due to sick sinus syndrome （SSS） （63.9% vs. 51.0%, P 〈 0.001）. Female patients receiving an ICD were more likely due to cardiac ion channel disease （29.2% vs. 4.2%, P 〈 0.001）. The percentage of utilization of dual-chamber pacemaker in female patients was significantly higher than male （85.3% vs. 81.1%, P 〈 0.001）. But male patients were more likely received a cardiac resynchronization therapy devices with defibrillator than female （56.5% vs. 41.9%, P = 0.001）. In pacemaker patient, male was more likely to have structure heart disease （31.3% vs. 28.0%, P = 0.002）. In ICD patient, male patients were more likely to have ischemic heart disease （48.2% vs. 29.2%, P 〈 0.001）. The mean age of women at the time of CRT/D implantation was older than men （P = 0.014）. Nonischemic cardiomyopathy （70.9%） was the most common etiology in the patients who underwent the treat？ment of CRT/D, no matter male or female. Conclusions In real-world setting, female do have different epidemiology, pathophysiology and clinical presentation of many cardiac rhythm disorders when compared with male, and all these factors may affect the utilization of CIED implantation. But it also possibility that cultural and socioeconomic features may play a role in this apparent discrimination.

Hypoxia-preconditioned bone marrow-derived mesenchymal stem cells protect neurons from cardiac arrest-induced pyroptosis

Cardiac arrest can lead to severe neurological impairment as a result of inflammation,mitochondrial dysfunction,and post-cardiopulmonary resuscitation neurological damage.Hypoxic preconditioning has been shown to improve migration and survival of bone marrow–derived mesenchymal stem cells and reduce pyroptosis after cardiac arrest,but the specific mechanisms by which hypoxia-preconditioned bone marrow–derived mesenchymal stem cells protect against brain injury after cardiac arrest are unknown.To this end,we established an in vitro co-culture model of bone marrow–derived mesenchymal stem cells and oxygen–glucose deprived primary neurons and found that hypoxic preconditioning enhanced the protective effect of bone marrow stromal stem cells against neuronal pyroptosis,possibly through inhibition of the MAPK and nuclear factor κB pathways.Subsequently,we transplanted hypoxia-preconditioned bone marrow–derived mesenchymal stem cells into the lateral ventricle after the return of spontaneous circulation in an 8-minute cardiac arrest rat model induced by asphyxia.The results showed that hypoxia-preconditioned bone marrow–derived mesenchymal stem cells significantly reduced cardiac arrest–induced neuronal pyroptosis,oxidative stress,and mitochondrial damage,whereas knockdown of the liver isoform of phosphofructokinase in bone marrow–derived mesenchymal stem cells inhibited these effects.To conclude,hypoxia-preconditioned bone marrow–derived mesenchymal stem cells offer a promising therapeutic approach for neuronal injury following cardiac arrest,and their beneficial effects are potentially associated with increased expression of the liver isoform of phosphofructokinase following hypoxic preconditioning.

Cardiac arrhythmias detection in an ECG beat signal using fast fourier transform and artificial neural network

Cardiac Arrhythmias shows a condition of abnor-mal electrical activity in the heart which is a threat to humans. This paper presents a method to analyze electrocardiogram (ECG) signal, extract the fea-tures, for the classification of heart beats according to different arrhythmias. Data were obtained from 40 records of the MIT-BIH arrhythmia database (only one lead). Cardiac arrhythmias which are found are Tachycardia, Bradycardia, Supraventricular Tachycardia, Incomplete Bundle Branch Block, Bundle Branch Block, Ventricular Tachycardia. A learning dataset for the neural network was obtained from a twenty records set which were manually classified using MIT-BIH Arrhythmia Database Directory and docu- mentation, taking advantage of the professional experience of a cardiologist. Fast Fourier transforms are used to identify the peaks in the ECG signal and then Neural Networks are applied to identify the diseases. Levenberg Marquardt Back-Propagation algorithm is used to train the network. The results obtained have better efficiency then the previously proposed methods.

CARDIAC ARRHYTHMIA AFTER LUNG CANCER SURGERY －－ANALYSIS OF 140 PNEUMONECTTOMY CASES

Among 808 surgically resected lung cancer cases at Shanghai Chest Hospital during 1991 to 1992, 140 of them (17.3%) underwent Pneumonectomy. Of the 140 cases:124 male, 16 female; aged 27-74 yrs, 35.7% elder (60 and over), preoperative abnormal EKG was found in 38 cases, operative mortality was 4.3%. The histopathological diagnosis were: squamous 43.6%, adeno. 36.4%, small cell 8.6%, mixed type 11.4%. The pTNM stages: stage I 2.9%, II 17.1%, IIIa 55.0%, IIIb 21.4%, IV 3.6%.Postoperatively, arrhythmia occuried in 76 cases, with an incidence of 54.3%. Of the 76 arrhythmias, atrial fibrillation was seen in 7 patients, atrial premature beats in 2, supraventricular tachycardia in 1, and sinus tachycardia in 66. The incidences of cadiac arrhythmia during the postoperative day (DO), first day (D1), D2, D3,and D4 were 48.7%, 35.5%, 7.9%, 4.0%and 2.6%respectively. Conclusion: the cardiac arrhythmia is the most common complication after pneumonectomy for lung cancer surgery. The major causes were incisional pain, hypovolemia due to blood loss and respirative insufficiency due to anomia. The perioperative prevention and treatment for arrhythmia were also discussed.

Cardiac autonomic nerve distribution and arrhythmia

OBJECTIVE： To analyze the distribution characteristics of cardiac autonomic nerves and to explore the correlation between cardiac autonomic nerve distribution and arrhythmia. DATA RETRIEVAL： A computer-based retrieval was performed for papers examining the distribution of cardiac autonomic nerves, using “heart, autonomic nerve, sympathetic nerve, vagus nerve, nerve distribution, rhythm and atrial fibrillation” as the key words. SELECTION CRITERIA： A total of 165 studies examining the distribution of cardiac autonomic nerve were screened, and 46 of them were eventually included. MAIN OUTCOME MEASURES： The distribution and characteristics of cardiac autonomic nerves were observed, and immunohistochemical staining was applied to determine the levels of tyrosine hydroxylase and acetylcholine transferase （main markers of cardiac autonomic nerve distribution）. In addition, the correlation between cardiac autonomic nerve distribution and cardiac arrhythmia was investigated. RESULTS： Cardiac autonomic nerves were reported to exhibit a disordered distribution in different sites, mainly at the surface of the cardiac atrium and pulmonary vein, forming a ganglia plexus. The distribution of the pulmonary vein autonomic nerve was prominent at the proximal end rather than the distal end, at the upper left rather than the lower right, at the epicardial membrane rather than the endocardial membrane, at the left atrium rather than the right atrium, and at the posterior wall rather than the anterior wall. The main markers used for cardiac autonomic nerves were tyrosine hydroxylase and acetylcholine transferase. Protein gene product 9.5 was used to label the immunoreactive nerve distribution, and the distribution density of autonomic nerves was determined using a computer-aided morphometric analysis system. CONCLUSION： The uneven distribution of the cardiac autonomic nerves is the leading cause of the occurrence of arrhythmia, and the cardiac autonomic nerves play an important role in the occurrence, maintenance, and symptoms of arrhythmia.