Electrophysiologic testing guided risk stratification approach for sudden cardiac death beyond the left ventricular ejection fraction

Sudden cardiac death threats ischaemic and dilated cardiomyopathy patients. Anti- arrhythmic protection may be provided to these patients with implanted cardiac defibrillators(ICD), after an efficient risk stratification approach. The proposed risk stratifier of an impaired left ventricular ejection fraction has limited sensitivity meaning that a significant number of victims will remain undetectable by this risk stratification approach because they have a preserved left ventricular systolic function. Current risk stratification strategies focus on combinations of non invasive methods like T wave alternans, late potentials, heart rate turbulence, deceleration capacity and others, with invasive methods like the electrophysiologic study. In the presence of an electrically impaired substrate with formed post myocardial infarction fibrotic zones, programmed ventricular stimulation provides important prognostic information for the selection of the patients expected to benefit from an ICD implantation, while due to its high negative predictive value, patients at low risk level may also be detected. Clustering evidence from different research groups and electrophysiologic labs support an electrophysiologic testing guided risk stratification approach for sudden cardiac death.

Cardiac Electrophysiological Differences Between Kunming and C57BL6/J Mice

Objective To investigate the alterations of cardiac electrophysiological properties and substantial mechanism and find the stable arrhythmia mouse model in Kunming （KM） and C57BL6/J （C57） mice. Methods Electrocardiogram recordings were used to analyze the QT interval in vivo, and mono- phasic action potential of right and left ventricular epicardium was recorded to elicit changes of action potential duration （APD） in conventional and programmed electrical stimulation （PES）. Transient outward potassium current （Its,） was recorded via whole-cell patch-clamp technique in single right and left epicardial myocytes. Results QT interval was prolonged in KM mice relative to C57 mice （62.51±4.47 ms vs. 52.59±4.85 ms, P〈0.05）. The APD at 50% repolarization of the left ventricular epicardium （18.60±0.91 ms vs. 12.90±0.35 ms）, and APDs at 50% （17.31±6.05 ms vs. 12.00±3.24 ms） and 70% repolarization （36.13±5.32 ms vs. 2 1.95±8.06 ms） of the right ventricular epicardium in KM mice were significantly pro- longed compared with C57 mice, respectively （all P〈0.05）. KM mice were more sensitive to PES-induced ventricular tachycardia （25%, 3 of 12 hearts）, and especially to Burst-induced ventricular tachycardia （50%, 6 of 12 hearts） compared with C57 mice, which were 20% （2 of 10 hearts） and 30% （3 of 10 hearts） respec- tively. It,, densities both in the left and right ventricular epicardial myocytes from KM mice were significantly decreased compared with C57 mice, respectively （all P〈0.01）. Conclusion Our data showed that KM mice with tile prolonged QT interval and APD are ruiner- abilities to ventricular arrhythmia, which are attributed to lower Ito densities in ventricular myocytes ob- tained from KM mice than that from C57 mice.

Surgical cardiac synchronization therapy for the cardiomyopathy heart failure with micro-invasive thoracoscopy techniques

Objective The cardiac synchronization therapy (CRT) was proven to have good treatment for the cardiacconduction disorders patients with serious heart failure. But many disadvantages were gradually be noticed,such as difficulty of sinus electrode implantation,coronary sinus injury and bleeding,still one third

Effects of Calmodulin-dependent Protein Kinase Ⅱ Inhibitor,KN-93,on Electrophysiological Features of Rabbit Hypertrophic Cardiac Myocytes

Cardiac hypertrophy is an independent risk factor for sudden cardiac death in clinical settings and the incidence of sudden cardiac death and ventricular arrhythmias are closely related.The aim of this study was to determine the effects of the calmodulin-dependent protein kinase(CaMK) Ⅱ inhibitor,KN-93,on L-type calcium current(I Ca,L) and early after-depolarizations(EADs) in hypertrophic cardiomyocytes.A rabbit model of myocardial hypertrophy was constructed through abdominal aortic coarctation(LVH group).The control group(sham group) received a sham operation,in which the abdominal aortic was dissected but not coarcted.Eight weeks later,the degree of left ventricular hypertrophy(LVH) was evaluated using echocardiography.Individual cardiomyocyte was isolated through collagenase digestion.Action potentials(APs) and I Ca,L were recorded using the perforated patch clamp technique.APs were recorded under current clamp conditions and I Ca,L was recorded under voltage clamp conditions.The incidence of EADs and I ca,L in the hypertrophic cardiomyocytes were observed under the conditions of low potassium(2 mmol/L),low magnesium(0.25 mmol/L) Tyrode’s solution perfusion,and slow frequency(0.25-0.5 Hz) electrical stimulation.The incidence of EADs and I ca,L in the hypertrophic cardiomyocytes were also evaluated after treatment with different concentrations of KN-92(KN-92 group) and KN-93(KN-93 group).Eight weeks later,the model was successfully established.Under the conditions of low potassium,low magnesium Tyrode’s solution perfusion,and slow frequency electrical stimulation,the incidence of EADs was 0/12,11/12,10/12,and 5/12 in sham group,LVH group,KN-92 group(0.5 μmol/L),and KN-93 group(0.5 μmol/L),respectively.When the drug concentration was increased to 1 μmol/L in KN-92 group and KN-93 group,the incidence of EADs was 10/12 and 2/12,respectively.At 0 mV,the current density was 6.7±1.0 and 6.3±0.7 PA·PF-1 in LVH group and sham group,respectively(P>0.05,n=12).When the drug concentration was 0.5 μmol/L in KN-92 and KN-93 groups,the peak I Ca,L at 0 mV was decreased by(9.4±2.8)% and(10.5±3.0)% in the hypertrophic cardiomyocytes of the two groups,respectively(P>0.05,n=12).When the drug concentration was increased to 1 μmol/L,the peak I Ca,L values were lowered by(13.4±3.7)% and(40±4.9)%,respectively(P<0.01,n=12).KN-93,a specific inhibitor of CaMKII,can effectively inhibit the occurrence of EADs in hypertrophic cardiomyocytes partially by suppressing I Ca,L,which may be the main action mechanism of KN-93 antagonizing the occurrence of ventricular arrhythmias in hypertrophic myocardium.

Pursuing meaningful end-points for stem cell therapy assessment in ischemic cardiac disease

Despite optimal interventional and medical therapy, ischemic heart disease is still an important cause of morbidity and mortality worldwide. Although not included in standard of care rehabilitation, stem cell therapy(SCT) could be a solution for prompting cardiac regeneration. Multiple studies have been published from the beginning of SCT until now, but overall no unanimous conclusion could be drawn in part due to the lack of appropriate endpoints. In order to appreciate the impact of SCT, multiple markers from different categories should be considered: Structural, biological, functional, physiological, but also major adverse cardiac events or quality of life. Imaging end-points are among the most used-especially left ventricle ejection fraction(LVEF) measured through different methods. Other imaging parameters are infarct size, myocardial viability and perfusion. The impact of SCT on all of the aforementioned end-points is controversial and debatable. 2 D-echocardiography is widely exploited, but new approaches such as tissue Doppler, strain/strain rate or 3 D-echocardiography are more accurate, especially since the latter one is comparable with the MRI gold standard estimation of LVEF. Apart from the objective parameters, there are also patient-centered evaluations to reveal the benefits of SCT, such as quality of life and performance status, the most valuable from the patient point of view. Emerging parameters investigating molecular pathways such as non-coding RNAs or inflammation cytokines have a high potential as prognostic factors. Due to the disadvantages of current techniques, new imaging methods with labelled cells tracked along their lifetime seem promising, but until now only pre-clinical trials have been conducted in humans. Overall, SCT is characterized by high heterogeneity not only in preparation, administration and type of cells, but also in quantification of therapy effects.

Diagnostic and prognostic value of cardiac imaging in amyloidosis

Amyloidosis is an infiltrative disease caused by extracellular protein deposition that has accumulated a lot of scientific production in recent years.Different types of amyloidosis can affect the heart.Transthyretin amyloidosis and light chain amyloidosis are the two most common types of cardiac amyloidosis.These entities have a poor prognosis,so accurate diagnostic techniques are imperative for determining an early therapeutic approach.Recent advances in cardiac imaging and diagnostic strategies show that these tools are safe and can avoid the use of invasive diagnostic techniques to histological confirmation,such as endomyocardial biopsy.We performed a review on the diagnostic and prognostic implications of different cardiac imaging techniques in cardiac amyloidosis.We mainly focus on reviewing echocardiography,cardiac magnetic resonance,computed tomography and nuclear imaging techniques and the different safety measurements that can be done with each of them.

Computer Simulation Methods of Cardiac Electrophysiology

The Luo Rudy models of mammalian ventricular cell were chosen in studying cardiac electrophysiology. Rush and Larsen’s algorithm and adaptive time step methods were used to solve the ordinary differential equations (ODE’s). The operator splitting (or time splitting) and adaptive time step methods were used to solve the partial differential equations (PDE’s) in cardiac tissue conduction models. The alternating direction implicit (ADI) method was used to integrate the PDE. Using these methods we accomplished the simulation programs of single cardiomyocyte model, one dimensional cable model(1 D) and two dimensional(2 D) tissue model. The methods of initiating spiral waves were studied with these software. The data getting from 2 D simulation can be used for further study on isopotential contour lines, spiral wave tip trajectories, and pseudo ECG. The software for computer simulation have been successfully used in simulation studying of electrophysiology properties of single cardiomyocyte, conduction in one dimensional cable model(1 D) and two dimensional(2 D) tissue model.

Cardiac evaluation of liver transplant candidates

Physicians previously thought that heart disease was rare in patients with end stage liver disease. However, recent evidence shows that the prevalence of ischemic heart disease and cardiomyopathy is increased in transplant candidates compared to most other surgical candidates. Investigators estimate that up to 26% of all liver transplant candidates have at least one critical coronary artery stenosis and that at least half of these patients will die perioperatively of cardiac complications. Cardiomyopathy also occurs in greater frequency. While all patients with advanced cardiac disease have defects in cardiac performance, a larger than expected number of patients have classical findings of dilated, restrictive and hypertropic cardiomyopathy. This may explain why up to 56% of patients suffer from hypoxemia due to pulmonary edema following transplant surgery. There is considerable controversy on how to screen transplant candidates for the presence of heart disease. Questions focus upon, which patients should be screened and what tests should be used. This review examines screening strategies for transplant candidates and details the prognostic value of common tests used to identify ischemic heart disease. We also review the physiological consequences of cardiomyopathy in transplant candidates and explore the specific syndrome of "cirrhotic cardiomyopathy".

A modified wire-loop snare technique for the retrieval of a large cardiac cement embolus caused by cement leakage after percutaneous vertebroplasty

Percutaneous vertebroplasty(PVP) is an interventional radiological procedure involving the injection of bone cement(polymethylmethacrylate) into a fractured vertebral body to remodel the vertebral body and relieve lumbar pain.

Anaesthetic Challenges in Cardiac Interventional Procedures

The increasing scope of interventions in the cardiac catheterization laboratory (CCL) and electrophysiological laboratory (EPL) has resulted in new challenges for the anaesthesia teams where they deal with different patient categories, complications and safety issues. Collaboration and planning between cardiologist and anaesthesiologist are required for both patient safety and procedural success. This review aims to discuss procedures performed in interventional cardiology and the importance of anaesthesiologists in managing such patients. Percutaneous interventions are being increasingly performed in adult as well as in pediatric patients. Procedures are usually done under mild to moderate sedation. General anaesthesia is required in certain conditions and also in pediatric patients. Knowledge of echocardiography, individual disease condition and fluoroscopy is important. Anaesthesiologists are assuming an increasingly important role in the multidisciplinary management of complex patients and interventions. A comprehensive understanding of procedures is essential to provide a high level of anaesthetic care and maintain patient safety.

Detection of Regional Wall Motion Abnormalities in Compressed Sensing Cardiac Cine Imaging

Background: Recently faster cardiac magnetic resonance (CMR) cine sequences basing on k-t compressed sensing have been developed. Purpose: To compare two compressed sensing CMR sequences-one in breath-hold technique and one during free breathing—with the standard SSFP sequence with respect to regional left ventricular function assessment. Material and Methods: Left ventricular short-axis stacks of two compressed sensing sequences in breath-hold technique (sparse_HB) and during free breathing (sparse_FB;both spatial resolution, 1.8 × 1.8 × 8 mm3) and a standard SSFP cine sequence (spatial resolution, 1.9 × 1.9 × 8 mm3) were acquired in 50 patients on a 1.5 T MR system. Regional wall motion abnormalities (RWMA) were rated qualitatively (normal/hypo-/a-/dyskinesia) by two experienced readers in consensus for all cardiac segments (American Heart Association’s segment model) and sequences. RWMA detection rates were compared between sequences by kappa statistic. Results: In 13 patients, RWMA were detected in at least one cardiac segment. The RWMA detection rates were similar between CMR sequences (hypokinesia, 7.2% to 7.9%;akinesia, 0.8% to 1.3%;dyskinesia 0.3% to 0.4%) and kappa statistics revealed an almost perfect agreement in RWMA detection between both sparse and the standard SSFP sequence (standard versus sparse_HB: kappa, 0.918, p value, p value, Conclusion: Compressed sensing cine CMR acquired during breath-hold or free-breathing allows reliable RWMA detection, thus, might alternatively be used in cine CMR for regional left ventricular function assessment.

Successful upgrade to cardiac resynchronization therapy for cardiac implantation-associated left subclavian vein occlusion:A case report

BACKGROUND Subclavian vein stenosis or occlusion may be caused by a transvenous pacemaker,which makes the reimplantation of a new pacemaker lead difficult.Transvenous pacemaker lead implantation-related subclavian vein occlusion may present difficulty with regard to cardiac resynchronization therapy(CRT)upgrade.CASE SUMMARY We report the case of a 46-year-old man who was admitted with total subclavian vein occlusion caused by a permanent pacemaker that had been implanted 2 years previously.We successfully treated this patient with an upgrade to a CRT pacemaker by utilizing transferable interventional coronary and radiological techniques.The patient recovered uneventfully during the follow-up period.CONCLUSION CRT upgrade is still a viable technique for the treatment of subclavian vein obstruction caused by previous pacemaker implantation.

Femoral Access with Ultrasound-Guided Puncture and Z-Stitch Hemostasis for Adults with Congenital Heart Diseases Undergoing Electrophysiological Procedures

Aims:Although the application of ultrasound-guided vascular puncture and Z-stitch hemostasis to manage femoral access has been widely utilized,there is limited data on this combined application in adult congenital heart disease(ACHD)patients undergoing electrophysiological(EP)procedures.We sought to evaluate the safety and efficacy of ultrasound-guided puncture and postprocedural Z-stitch hemostasis for ACHD patients under-going EP procedures.Methods and Results:The population of ACHD patients undergoing transfemoral EP pro-cedures at the University of Zurich Heart Center between January 2019 and December 2022 was observed and analyzed.During the study period,femoral access(left/right,arterial/venous)was performed under real-time ultrasound guidance.At the end of the procedure,a single Z-stitch was performed at the puncture site.We eval-uated the incidence of in-hospital complications associated with femoral access puncture in this population.Among 101 patients who had a total of 147 previous ipsilateral vascular punctures(mean 1.5 per person),100 patients underwent successful femoral vascular access for EP procedures.The median age of the patients was 47±15 years and 34(34%)were male.Z-stitches were performed after the procedure in 100 patients with 303 femoral vascular accesses(mean 3 punctures per person).No patient developed vascular puncture relevant inguinal hematoma,pseudo aneurysm,arteriovenousfistula,venous or arterial thrombosis.Conclusion:In ACHD patients undergoing EP procedures,optimal femoral access management can be achieved with ultra-sound-guided puncture and postprocedural Z-stitch hemostasis.

Superaligned carbon nanotubes guide oriented cell growth and promote electrophysiological homogeneity for synthetic cardiac tissues

With the support by the National Natural Science Foundation of China,the research team led by Professor Li Yigang(李毅刚)at Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine and Professor Peng Huisheng(彭慧胜)at Fudan University presented a new type of

Epileptic brain network mechanisms and neuroimaging techniques for the brain network

Epilepsy can be defined as a dysfunction of the brain network,and each type of epilepsy involves different brain-network changes that are implicated diffe rently in the control and propagation of interictal or ictal discharges.Gaining more detailed information on brain network alterations can help us to further understand the mechanisms of epilepsy and pave the way for brain network-based precise therapeutic approaches in clinical practice.An increasing number of advanced neuroimaging techniques and electrophysiological techniques such as diffusion tensor imaging-based fiber tra ctography,diffusion kurtosis imaging-based fiber tractography,fiber ball imagingbased tra ctography,electroencephalography,functional magnetic resonance imaging,magnetoencephalography,positron emission tomography,molecular imaging,and functional ultrasound imaging have been extensively used to delineate epileptic networks.In this review,we summarize the relevant neuroimaging and neuroelectrophysiological techniques for assessing structural and functional brain networks in patients with epilepsy,and extensively analyze the imaging mechanisms,advantages,limitations,and clinical application ranges of each technique.A greater focus on emerging advanced technologies,new data analysis software,a combination of multiple techniques,and the construction of personalized virtual epilepsy models can provide a theoretical basis to better understand the brain network mechanisms of epilepsy and make surgical decisions.

Application of an electrophysiological technique combined with auricular acupuncture in gynecological perioperative gastrointestinal dysfunction

Objective:This study aimed to evaluate the effectiveness and safety of combining low-frequency pulsed electrophysiological techniques with auricular acupuncture(a fusion of traditional Chinese and Western medicine)for patients experiencing perioperative gastrointestinal dysfunction(POGD)following gynecological surgery.Methods:Eighty patients undergoing gynecological surgery were randomly assigned to an experimental group and a control group.Both groups received enhanced recovery after surgery(ERAS)care,with the experimental group receiving additional treatment combining electrophysiology and auricular acupuncture.Postoperative recovery indicators,including bowel sound recovery time,time to first exhaust and defecation,duration and incidence of abdominal pain and distension,nausea and vomiting,and specific gastrointestinal markers(HSP70,I-FABP,DAO,D-lactate),were monitored and compared between the two groups.Results:After treatment,the postoperative bowel sound recovery time,first postoperative exhaust time,duration of abdominal pain,and duration of abdominal distension were shorter in the experimental group than in the control group(P<0.05).The 6-hour and 48-hour integral values of the experimental group were significantly lower than those of the control group.In the experimental group,60%of the patients were completely cured of gastrointestinal function after surgery,whereas only 32.5%of the patients in the control group were cured.The main symptom scores(abdominal pain,abdominal distension,nausea and vomiting)on the third postoperative day and the total symptom scores on the third postoperative day were significantly lower in the experimental group than in the control group(P<0.05).The values of HSP70,I-FABP,DAO,and D-lactate in the experimental group on postoperative day one were significantly lower than those in the control group(P<0.05).Conclusion:The combination of the Chinese and Western medicine ERAS programs of low-frequency pulse electrophysiology technology plus auricular acupuncture can accelerate local gastrointestinal blood circulation during the perioperative period of gynecology,promote the recovery of gastrointestinal function,promote anal exhaustion,and prevent the occurrence of postoperative abdominal pain and bloating.The combination of Chinese and Western medicine ERAS can increase gastrointestinal fluid secretion,increase gastrointestinal hormone and blood flow values,increase gastrointestinal electrophysiological detection values,and change the indicators of gastrointestinal dysfunction.

Cardiac differentiation and electrophysiology characteristics of bone marrow mesenchymal stem cells

Objective To review the progress of cardiac differentiation and electrophysiological characteristics of bone marrow mesenchymal stem cells. Data sources The databases of PubMed, Springer Link, Science Direct and CNKI were retrieved for papers published from January 2000 to January 2012 with the key words of ＂bone marrow mesenchymal stem cells, cardiac or heart, electrophysiology or electrophysiological characteristics＂. Study selection The articles concerned cardiac differentiation and electrophysiological characteristics of bone marrow mesenchymal stem cells were collected. After excluding papers that study purposes are not coincident with this review or contents duplicated, 56 papers were internalized at last. Results For the treatment of myocardial infarction and myocardiac disease, the therapeutic effects of transplantation of bone marrow mesenchymal stem cells which have the ability to develop into functional myocardial cells by lots of methods have been proved by many researches. But the arrhythmogenic effect on ventricles after transplantation of bone marrow mesenchymal stem cells derived myocardial cells is still controversial in animal models. Certainly, the low differentiation efficiency and heterogeneous development of electricial function could be the most important risk for proarrhythmia. Conclusion Many studies of cardiac differentiation of bone marrow mesenchymal stem cells have paid attention to improve the cardiac differentiation rate, and the electrophysiology characteristics of the differentiated cells should be concerned for the risk for proarrhythmia as well.

Utility of electrophysiological studies to predict arrhythmic events

AIM:To evaluate the prognostic value of electrophysiological stimulation(EPS) in the risk stratification for tachyarrhythmic events and sudden cardiac death(SCD).METHODS:We conducted a prospective cohort study and analyzed the long-term follow-up of 265 consecutive patients who underwent programmed ventricular stimulation at the Luzerner Kantonsspital(Lucerne,Switzerland) between October 2003 and April 2012. Patients underwent EPS for SCD risk evaluation because of structural or functional heart disease and/or electrical conduction abnormality and/or after syncope/cardiac arrest. EPS was considered abnormal,if a sustained ventricular tachycardia(VT) was inducible. The primary endpoint of the study was SCD or,in implanted patients,adequate ICD-activation.RESULTS:During EPS,sustained VT was induced in 125 patients(47.2%) and non-sustained VT in 60 patients(22.6%); in 80 patients(30.2%) no arrhythmia could be induced. In our cohort,153 patients(57.7%) underwent ICD implantation after the EPS. During follow-up(mean duration 4.8 ± 2.3 years),a primary endpoint event occurred in 49 patients(18.5%). The area under the receiver operating characteristic curve(AUROC) was 0.593(95%CI:0.515-0.670) for a left ventricular ejection fraction(LVEF) < 35% and 0.636(95%CI:0.563-0.709) for inducible sustained VT during EPS. The AUROC of EPS was higher in the subgroup of patients with LVEF ≥ 35%(0.681,95%CI:0.578-0.785). Cox regression analysis showed that both,sustained VT during EPS(HR:2.26,95%CI:1.22-4.19,P = 0.009) and LVEF < 35%(HR:2.00,95%CI:1.13-3.54,P = 0.018) were independent predictors of primary endpoint events.CONCLUSION:EPS provides a benefit in risk stratificationfor future tachyarrhythmic events and SCD and should especially be considered in patients with LVEF ≥ 35%.

超声引导技术在小切口微创心脏手术建立外周体外循环中的应用价值

目的探讨超声引导技术在小切口微创心脏手术经右颈内静脉穿刺置管及股动静脉解剖置管建立外周体外循环中的应用价值。方法分析2021年8月至2022年12月西安交通大学第一附属医院收治的436例进行小切口微创心脏手术患者的临床资料,根据置管过程中是否使用超声引导技术将研究对象分为对照组(给予传统方式置管,102例)和观察组(给予超声引导技术辅助下置管,334例)。比较分析两组患者经右颈内静脉穿刺置管的情况以及相关并发症发生率。比较分析两组患者股动静脉解剖置管的情况以及相关并发症发生率。结果观察组患者经右颈内静脉穿刺置管的穿刺置管成功率高于对照组,置管时间、穿刺困难发生率、误入颈内动脉发生率均短于或低于对照组,差异均有统计学意义(P<0.05)。观察组患者股动静脉解剖置管的置管时间、解剖困难发生率、导管位置异常发生率均短于或低于对照组,差异均有统计学意义(P<0.05)。结论超声引导技术应用于小切口微创心脏手术经右颈内静脉穿刺置管及股动静脉解剖置管建立外周体外循环中,能提高穿刺置管成功率,缩短置管时间,减少导管位置异常、误入颈内动脉等并发症的发生。

临床医生应重视老年人心脏淀粉样变的诊断与处理

心脏淀粉样变(CA)是淀粉样蛋白错误折叠沉积于心肌细胞外基质所致的心脏疾病。CA好发于老年人,由于症状缺乏特异性且既往被认为是一种罕见病,老年CA患者极易被误诊和漏诊。近年来随着对该病诊断意识的提高及无创性影像学诊断方法的进步,诊断为CA的患者有所增加;治疗CA的药物研究也有重大突破,研发了多种特异性治疗药物。早期治疗可以防止淀粉样蛋白进一步沉积导致的器官损伤,从而改善老年CA患者预后。因此,临床医生应该充分了解老年CA患者的临床特征,重视老年CA的诊断及治疗。