To solve the low power transfer efficiency and magnetic field leakage problems of cardiac pacemaker wireless powering, we proposed a wireless power supply system suitable for implanted cardiac pacemaker based on mu-ne...To solve the low power transfer efficiency and magnetic field leakage problems of cardiac pacemaker wireless powering, we proposed a wireless power supply system suitable for implanted cardiac pacemaker based on mu-negative(MNG) and mu-nearzero(MNZ) metamaterials. First, a hybrid metamaterial consisted of central MNG unit for magnetic field concentration and surrounding MNZ units for magnetic leakage shielding was established by theoretical calculation. Afterwards, the magnetic field distribution of wireless power supply system with MNG-MNZ metamaterial slab was acquired via finite element simulation and verified to be better than the distribution with conventional MNG slab deployed. Finally, an experimental platform of wireless power supply system was established with which power transfer experiment and system temperature rise experiment were conducted.Simulation and experimental results showed that the power transfer efficiency was improved from 44.44%,19.42%, 8.63% and 6.19% to 55.77%, 62.39%, 20.81%and 14.52% at 9.6 mm, 20 mm, 30 mm and 50 mm,respectively. The maximum SAR acquired by SAR simulation under human body environment was-7.14 dbm and maximum reduction of the magnetic field strength around the receiving coil was 2.82 A/m. The maximum temperature rise during 30min charging test was 3.85℃,and the safety requirements of human bodies were met.展开更多
BACKGROUND Mesenchymal stem cells(MSC)modified by gene transfer to express cardiac pacemaker channels such as HCN2 or HCN4 were shown to elicit pacemaker function after intracardiac transplantation in experimental ani...BACKGROUND Mesenchymal stem cells(MSC)modified by gene transfer to express cardiac pacemaker channels such as HCN2 or HCN4 were shown to elicit pacemaker function after intracardiac transplantation in experimental animal models.Human MSC derived from adipose tissue(haMSC)differentiate into cells with pacemaker properties in vitro,but little is known about their behavior after intracardiac transplantation.AIM To investigate whether haMSC elicit biological pacemaker function in vivo after transplantation into pig hearts.METHODS haMSC under native conditions(nhaMSC)or after pre-conditioning by medium differentiation(dhaMSC)(n=6 pigs each,5×106 cells/animal)were injected into the porcine left ventricular free wall.Animals receiving PBS injection served as controls(n=6).Four weeks later,total atrioventricular(AV)-block was induced by radiofrequency catheter ablation,and electronic pacemaker devices were implanted for backup stimulation and heart rate monitoring.Ventricular rate and rhythm of pigs were evaluated during a follow-up of 15 d post ablation by 12-lead-ECG with heart rate assessment,24-h continuous rate monitoring recorded by electronic pacemaker,assessment of escape recovery time,and pharmacological challenge to address catecholaminergic rate response.Finally,hearts were analyzed by histological and immunohistochemical investigations.RESULTS In vivo transplantation of dhaMSC into the left ventricular free wall of pigs elicited spontaneous and regular rhythms that were pace-mapped to ventricular injection sites(mean heart rate 72.2±3.6 bpm;n=6)after experimental total AV block.Ventricular rhythms were stably detected over a 15-d period and were sensitive to catecholaminergic stimulation(mean maximum heart rate 131.0±6.2 bpm;n=6;P<0.001).Pigs,which received nhaMSC or PBS presented significantly lower ventricular rates(mean heart rates 47.2±2.5 bpm and 37.4±3.2 bpm,respectively;n=6 each;P<0.001)and exhibited little sensitivity towards catecholaminergic stimulation(mean maximum heart rates 76.4±3.1 bpm and 60.5±3.1 bpm,respectively;n=6 each;P<0.05).Histological and immunohistochemical evaluation of hearts treated with dhaMSC revealed local clusters of transplanted cells at the injection sites that lacked macrophage or lymphocyte infiltrations or tumor formation.Intense fluorescence signals at these sites indicated membrane expression of HCN4 and other pacemaker-specific proteins involved in cardiac automaticity and impulse propagation.CONCLUSION dhaMSC transplanted into pig left ventricles sustainably induced rate-responsive ventricular pacemaker activity after in vivo engraftment for four weeks.The data suggest that pre-conditioned MSC may further differentiate along a pacemakerrelated lineage after myocardial integration and may establish superior pacemaker properties in vivo.展开更多
AIM:To determine if there were any interactions between cardiac devices and small bowel capsules secondary to electromagnetic interference (EMI) in patients who have undergone small bowel capsule endoscopy (SBCE).METH...AIM:To determine if there were any interactions between cardiac devices and small bowel capsules secondary to electromagnetic interference (EMI) in patients who have undergone small bowel capsule endoscopy (SBCE).METHODS:Authors conducted a chart review of 20 patients with a cardiac pacemaker (CP) or implantable cardioverter defibrillator (ICD) who underwent continuous electrocardiographic monitoring during their SBCE from 2003-2008.authors searched for unexplained electrocardiogram (ECG) findings,changes in CP andICD set parameters,any abnormality in transmitted capsule data,and adverse clinical events.RESULTS:There were no adverse events or hemodynamically significant arrhythmias reported.CP and ICD set parameters were preserved.The majority of ECG abnormalities were also found in pre-or post-SBCE ECG tracings and the CP behavior during arrhythmias appeared appropriate.Two patients seemed to have episodes of undersensing by the CP.However,similar findings were documented in ECGs taken outside the time frame of the SBCE.One patient was observed to have a low signal encountered from the capsule resulting in lack of localization,but no images were lost.CONCLUSION:Capsule-induced EMI remains a possibility but is unlikely to be clinically important.CPinduced interference of SBCE is also possible,but is infrequent and does not result in loss of images transmitted by the capsule.展开更多
The usability assessment of a pacemaker is a complex task where the dedicated programmer for testing programmed algorithms is necessary.This paper provides the outcomes of development and complex testing of the artifi...The usability assessment of a pacemaker is a complex task where the dedicated programmer for testing programmed algorithms is necessary.This paper provides the outcomes of development and complex testing of the artificial cardiac system to evaluate the pacemaker’s functionality.In this work,we used the modular laboratory platform ELVIS II and created graphical user interface in LabVIEW programming environment.The electrical model of the heart allows signals generation(right atrium,right ventricle)and the monitoring of the stimulation pulses.The LabVIEW user interface allows to set the parameters of the generated signals and the simulation of the cardiac rhythm disorders as well as the monitoring and visualization of the pacemaker behavior in real-time.The results demonstrate the capability of proposed system to evaluate the paced and sensed pulses.The proposed solution allows the scientists to test the behavior of any cardiac pacemaker for its pre-programmed settings and pacing mode.In addition,the proposed system can simulate various disorders and test cardiac pacemakers in different working modes.展开更多
Objectives: The purpose of this study is to identify how to manage oversensing of pacemakers in chest CT. Methods: Four different models of pacemakers were examined to select the pacemaker generating oversensing. To t...Objectives: The purpose of this study is to identify how to manage oversensing of pacemakers in chest CT. Methods: Four different models of pacemakers were examined to select the pacemaker generating oversensing. To the pacemaker with oversensing, intermittent switching X-ray was exposed using ECG-gated CT helical scan system at prospective CTA mode. IVY Model was used to synchronize the ECG. Only during in the alert period that is non-refractory and sensing is available, intermittent switching X-ray (300 msec/sec) was exposed in chest CT. For comparison, the same intermittent switching X-ray (300 msec/sec) was exposed in the refractory period when sensing was not available. Results: Oversensing was detected only in one of the four pacemakers tested. In this pacemaker, oversensing was generated by exposure of the intermittent switching X-ray in the alert (non-refractory) period, but oversensing was not observed in the refractory period. Conclusion: A pacemaker has alert and refractory periods. Oversensing of a pacemaker was found to be inhibited by selective ECG-synchronized exposure in the refractory period. Since all pacemakers have the refractory period, the results of this study can be widely applied to the patients with pacemakers in chest CT, and their chest CT can be operated safely.展开更多
Wireless capsule endoscopy is a new endoscopic tool for the diagnosis and management of small bowel diseases. The main indication at present is the evaluation of GI bleeding of obscure origin, Crohn’s disease, coelia...Wireless capsule endoscopy is a new endoscopic tool for the diagnosis and management of small bowel diseases. The main indication at present is the evaluation of GI bleeding of obscure origin, Crohn’s disease, coeliac disease and small bowel tumors. Studies suggest that capsule endoscopy is associated with few adverse events. Whether cardiac pacemaker may interfere with capsule endoscopy is still a controversial issue. We here report a case showing that there is a possibility of interference between the two procedures, cardiac pacemaker affecting the proper functioning of capsule endoscopy and that this is related to the distance between the pacemaker and the recorder.展开更多
Objective: To inquire into the effect of systematic family nursing guidance on improving the Quality of Life for elderly patients with implanted cardiac pacemaker. Methods: 41 elderly patients in accordance with the c...Objective: To inquire into the effect of systematic family nursing guidance on improving the Quality of Life for elderly patients with implanted cardiac pacemaker. Methods: 41 elderly patients in accordance with the corresponding requirements were studied after offering systematic family nursing guidance and surveyed through the questionnaires about the QOL (quality of life) respectively 1 month, 3 months and 6 months after leaving hospital. Results: Compared with that of 1 month and 3 months after the operation, the questionnaire scores for 6 months after the operation were found to have significant improvement, and the differences were statistically significant. Conclusion: Systematic family nursing guidance can effectively improve the QOL for elderly patients with implanted cardiac pacemaker, which makes them spend their old age in comfort and happiness.展开更多
In view of the omnipresence of electronic article surveillance (EAS) systems in daily life and the increasing number of patients with active implants, there is concern about adverse electromagnetic interference in par...In view of the omnipresence of electronic article surveillance (EAS) systems in daily life and the increasing number of patients with active implants, there is concern about adverse electromagnetic interference in particular cardiac pacemakers (CPM) and cardioverter defibrillators (ICD), which due to sensing electrocardial signals are particularly vulnerable. To provide quantitative information interference of monopolar CPM and ICD by EAS systems operating at 8.2MHz radiofrequency electromagnetic fields (EMF) investigations have been performed by exposing numerical anatomical models of pacemaker patients with implants at the conventional left or right pectoral sites and at the abdomen to magnetic fields of a simulated EAS gate source. Investigation of normal position in the centre and worst case with the back next to the gate showed that adverse interference such as inadequate sensing need not be expected at any position. This applies for conventional sensing thresholds even if the exposure span of existing EAS systems is taken into account. However, if full use is made of the newly expanded exposure budget, adverse interference cannot be excluded.展开更多
Background:High cost of imported pacemakers is a main obstacle for Chinese patients suffering from bradyarrhythmia,and a domestically developed pacemaker will help lower the burden.This study aimed to evaluate the sa...Background:High cost of imported pacemakers is a main obstacle for Chinese patients suffering from bradyarrhythmia,and a domestically developed pacemaker will help lower the burden.This study aimed to evaluate the safety and efficacy ofQinming8631 DR (Qinming Medical,Baoji,China),the first domestically developed dual-chamber pacemaker of China,compared with a commercially available pacemaker Talos DR (Biotronik,Berlin,Germany) in Chinese patients.Methods:A prospective randomized trial was conducted at 14 centers in China.Participants were randomized into trial (Qinming8631 DR) and control (Talos DR) groups.Parameters of the pacing systems were collected immediately after device implantation and during follow-ups.The effective pacing rate at 6-month follow-up was recorded as the primary end point.Electrical properties,magnet response,single-and double-pole polarity conversion,rate response function,and adverse events of the pacing system were analyzed.The Cochran-Mantel-Haenszel Chi-square test,paired t-test,and Wilcoxon signed-rank test were used for measuring primary qualitative outcomes and comparing normally and abnormally distributed measurement data.Results:A total of 225 patients with a diagnosis ofbradyarrhythmia and eligible for this study were randomly enrolled into the trial (n =113) and control (n =112) groups.They underwent successful pacemaker implantation with acceptable postoperative pacing threshold and sensitivity.Effective pacing rates of trial and control groups were comparable both in the full analysis set and the per protocol set (81.4% vs.79.5%,P =0.712 and 95.4% vs.89.5%,P =0.143,respectively).In both data sets,noninferiority of the trial group was above the predefined noninferiority limit(-9.5%).Conclusions:This study established the noninferiority ofQinming8631 DR to Talos DR.The safety and efficacy ofQinming8631 DR pacemaker were comparable to those of Talos DR in treating patients with cardiac bradyarrhythmia.展开更多
BACKGROUND Pacemaker lead-induced heart perforation is a rare but life-threatening complication of pacemaker implantation,and timely diagnosis remains a challenge for clinicians.Here,we report a case of pacemaker lead...BACKGROUND Pacemaker lead-induced heart perforation is a rare but life-threatening complication of pacemaker implantation,and timely diagnosis remains a challenge for clinicians.Here,we report a case of pacemaker lead-induced cardiac perforation rapidly diagnosed by a“bow-and-arrow”sign on point-of-care ultrasound(POCUS).CASE SUMMARY A 74-year-old Chinese woman who had undergone permanent pacemaker implantation 26 d before suddenly developed severe dyspnea,chest pain,and hypotension.The patient had received emergency laparotomy for an incarcerated groin hernia and was transferred to the intensive care unit 6 d before.Computed tomography was not available due to unstable hemodynamic status,so POCUS was performed at the bedside and revealed severe pericardial effusion and cardiac tamponade.Subsequent pericardiocentesis yielded a large volume of bloody pericardial fluid.Further POCUS by an ultrasonographist revealed a unique“bow-and-arrow”sign indicating right ventricular(RV)apex perforation by the pacemaker lead,which facilitated the rapid diagnosis of lead perforation.Given the persistent drainage of pericardial bleeding,urgent off-pump open chest surgery was performed to repair the perforation.However,the patient died of shock and multiple organ dysfunction syndrome within 24 h post-surgery.In addition,we also performed a literature review on the sonographic features of RV apex perforation by lead.CONCLUSION POCUS enables the early diagnosis of pacemaker lead perforation at the bedside.A step-wise ultrasonographic approach and the“bow-and-arrow”sign on POCUS are helpful for rapid diagnosis of lead perforation.展开更多
BACKGROUND Bradyarrhythmias are typically treated with permanent pacemakers(PM). The elimination of bradyarrhythmia by PM implantation improves the patient’s quality of life and prognosis, but it can also result in a...BACKGROUND Bradyarrhythmias are typically treated with permanent pacemakers(PM). The elimination of bradyarrhythmia by PM implantation improves the patient’s quality of life and prognosis, but it can also result in a number of sequalae. It is still unclear how PM implantation affects the hemostasis system’s parameters and how such parameters relate to different consequences after PM placement.AIM To assess the blood coagulation factor activity in PM patients throughout the perioperative period.METHODS Patients treated in the Department of Surgical Therapy of Cardiac Arrhythmias and Pacing at the Ryazan State "Regional Clinical Cardiology Dispensary" from April 2020 to December 2021 were included in the study. Before surgery, 7 and 30 d after PM placement, peripheral venous blood samples were withdrawn to measure the level of blood coagulation factor Ⅰ(FⅠ) and the activity of blood coagulation factors Ⅱ(FⅡ), Ⅴ(FⅤ), Ⅶ(FⅦ), Ⅷ(FⅧ), ⅸ(Fⅸ), ⅹ(Fⅹ), Ⅺ(FⅪ), Ⅻ(FⅫ). We used an automatic coagulometer Sysmex CA 660(Sysmex Europe, Germany) and reagents from Siemens(Siemens Healthcare Diagnostics Products GmbH, Germany).RESULTS The study included 146 patients. The activity of factors FⅤ [147.7(102.1-247.55)% vs 103.85(60-161.6)% vs 81.8(67.15-130.65)%, P = 0.002], FⅧ [80.4(60.15-106.25)% vs 70.3(48.5-89.1)% vs 63.7(41.6-88.25)%, P = 0.039], Fⅸ [86.2(70.75-102.95)% vs 75.4(59.2-88.3)% vs 73.9(56.45-93.05)%, P = 0.014], Fⅹ [188.9(99.3-308.18)% vs 158.9(83.3-230)% vs 127.2(95.25-209.35)%, P = 0.022], FⅪ [82.6(63.9-103.6)% vs 69.75(53.8-97.6)% vs 67.3(54.25-98.05)%, P = 0.002], FⅫ [87.6(67.15-102.3)% vs 78.9(63.4-97.05)% vs 81.2(62.15-97.4)%, P < 0.001] decreased at 7 and 30 d after surgery;FⅡ activity [157.9(109.7-245.25)% vs 130(86.8-192.5)% vs 144.8(103.31-185.6)%, P = 0.021] decreased at 7 d and increased at 30 d postoperatively. There were no statistically significant changes in the FVII activity within 30 d after PM placement [182.2(85.1-344.8)% vs 157.2(99.1-259)% vs 108.9(74.9-219.8)%, P = 0.128]. Subgroup analysis revealed similar changes only in patients on anticoagulant therapy. FⅫ activity decreased in patients on antiplatelet therapy [82(65.8-101.9)% vs 79.9(63.3-97.1)% vs 89.7(75.7-102.5)%, P = 0.01] 7 d after surgery, returning to baseline values at 30 d postoperatively.CONCLUSION PM placement and anticoagulant therapy were associated with decreased activity of clotting factors FⅤ, FⅧ, Fⅸ, Fⅹ, FⅪ, FⅫ in the postoperative period. FⅧ activity did not decrease within 30 d after PM placement, which may indicate endothelial injury caused by lead placement.展开更多
Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels in the heart modulate cardiac automaticity via the hyperpolarization-activated cation current ( named Ⅰf, Ⅰh, or Ⅰq). Recent studies have unveiled ...Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels in the heart modulate cardiac automaticity via the hyperpolarization-activated cation current ( named Ⅰf, Ⅰh, or Ⅰq). Recent studies have unveiled the molecular identity of HCN (HCN1-4) channels. HCN isoforms are unevenly expressed in the heart, even in the sinoatrial node. Features of HCN currents have been characterized in cardiac and other types of cells or in cell lines transfected with the HCN isoforms. The factors modulating Ih and the physiological significance of HCN channels in the heart have been extensively investigated in recent years. The hypothesis for transplanting and/or creating biological pacemakers to replace diseased sinoatrial and/or atrioventricular nodes has been postulated and tested in animal models. Local overexpression of HCN2 channels in the left atrium or in the left conductive bundle branch of the left ventricle via gene delivery induced significant Ⅰh and escape rhythms during vagal stimulation in canines. In addition, implantation of human mesenchymal stem cells with overexpression of HCN2 channels to the canine left ventricular wall was associated with formation of spontaneous escape rhythms of left-sided origin during vagal-stimulation-induced sinus arrest. This preliminary data suggest that the use of HCN channels may hold great promise in,the development of biological pacemakers.展开更多
The effect of ischemia like solution and high concentration of isoprenaline and Phenylephrine in that solution on normal pacemaker current If of sheep cardiac Puekinje fibres were observed After perfusing the preparat...The effect of ischemia like solution and high concentration of isoprenaline and Phenylephrine in that solution on normal pacemaker current If of sheep cardiac Puekinje fibres were observed After perfusing the preparations with “ischemia” solution 15, 30, and 60 min, the amplitude of If current at all measured membrane potentials (from -60 to -120 mV) decreased (n=7,p<0.05)and the activation curve of If current shiftea to left side,E0.5 changed from control value -85.0±3.7 mV to -91.7±4.1 mV at 30 min. Isoprenaline 1×10-6mol/L could increase the amplitude of If current in “ischemia” solution (n= 10, P<0.05) and shift the activation curve of If current back to right side, but it could not completely reverse the inhibitory effect of“ ischemia“. In the presence of propranolol 5 ×10-7 mol/L, 5×10-5 mol/L phenylephrine decreased the amplitude of If current further in “ischemia” solution (n= 7, P<0.05-0.01), the activatior curve of If current shifted to left side further. The above results indicate that the normal pacemaker current was inhibited in “ischemia” condition even in the presence of high concentration of beta and alpha adrenoceptor agonists so the genesis of ischemic ventricular arrhythmia is hardly due to the abnormal enhancement of normal ventricular pacemaker activity.展开更多
In patients with heart failure and disordered intracardiac conduction of activation, doctors implant a biven- tricular pacemaker (“cardiac resynchronization therapy”, CRT) to allow adjustment of the relative timings...In patients with heart failure and disordered intracardiac conduction of activation, doctors implant a biven- tricular pacemaker (“cardiac resynchronization therapy”, CRT) to allow adjustment of the relative timings of activation of parts of the heart. The process of selecting the pacemaker timings that maximize cardiac function is called “optimization”. Although optimization—more than any other clinical assessment—needs to be precise, it is not yet conventional to report the standard error of the optimum alongside its value in clinical practice, nor even in research, because no method is available to calculate precision from one optimization dataset. Moreover, as long as the determinants of precision remain unknown, they will remain unconsidered, preventing candidate haemodynamic variables from being screened for suitability for use in optimization. This manuscript derives algebraically a clinically-applicable method to calculate the precision of the optimum value of x arising from fitting noisy biological measurements of y (such as blood flow or pressure) obtained at a series of known values of x (such as atrioventricular or interventricular delay) to a quadratic curve. A formula for uncertainty in the optimum value of x is obtained, in terms of the amount of scatter (irreproducibility) of y, the intensity of its curvature with respect to x, the width of the range and number of values of x tested, the number of replicate measurements made at each value of x, and the position of the optimum within the tested range. The ratio of scatter to curvature is found to be the overwhelming practical determinant of precision of the optimum. The new formulae have three uses. First, they are a basic science for anyone desiring time-efficient, reliable optimization protocols. Second, asking for the precision of every reported optimum may expose optimization methods whose precision is unacceptable. Third, evaluating precision quantitatively will help clinicians decide whether an apparent change in optimum between successive visits is real and not just noise.展开更多
The appropriate preparation of the patient with asymptomatic congenital complete heart block (CCHB) and a narrow QRS complex for elective non-cardiac surgery is controversial. Prophylactic temporary pacemaker insertio...The appropriate preparation of the patient with asymptomatic congenital complete heart block (CCHB) and a narrow QRS complex for elective non-cardiac surgery is controversial. Prophylactic temporary pacemaker insertion is associated with well-defined risks, and less invasive techniques exist to treat transient, hemodynamically significant intraoperative brady-arrhythmias. The present case report details the performance of general anesthesia for arthroscopic knee surgery in an adult patient with this condition without a pacemaker. Documentation of preoperative chronotropic competence with isoproterenol may be of value in deciding whether to proceed without temporary pacing capability in this setting.展开更多
A number of publications have claimed that Mobitz type Ⅱ atrioventricular block(AVB)may occur during sleep.None of the reports defined type Ⅱ AVB and representative electrocardiograms were either misinterpreted or m...A number of publications have claimed that Mobitz type Ⅱ atrioventricular block(AVB)may occur during sleep.None of the reports defined type Ⅱ AVB and representative electrocardiograms were either misinterpreted or missing.Relatively benign Wenckebach type Ⅰ AVB is often misdiagnosed as Mobitz type Ⅱ which is an indication for a pacemaker.Review of the published reports indicates that Mobitz type II AVB does not occur during sleep when it is absent in the awake state.Conclusion:There is no proof that sleep is associated with Mobitz type Ⅱ AVB.展开更多
基金supported by 2023 Liaoning Provincial Department of Education Basic Research Project (General Project)(JYTMS20230815)。
文摘To solve the low power transfer efficiency and magnetic field leakage problems of cardiac pacemaker wireless powering, we proposed a wireless power supply system suitable for implanted cardiac pacemaker based on mu-negative(MNG) and mu-nearzero(MNZ) metamaterials. First, a hybrid metamaterial consisted of central MNG unit for magnetic field concentration and surrounding MNZ units for magnetic leakage shielding was established by theoretical calculation. Afterwards, the magnetic field distribution of wireless power supply system with MNG-MNZ metamaterial slab was acquired via finite element simulation and verified to be better than the distribution with conventional MNG slab deployed. Finally, an experimental platform of wireless power supply system was established with which power transfer experiment and system temperature rise experiment were conducted.Simulation and experimental results showed that the power transfer efficiency was improved from 44.44%,19.42%, 8.63% and 6.19% to 55.77%, 62.39%, 20.81%and 14.52% at 9.6 mm, 20 mm, 30 mm and 50 mm,respectively. The maximum SAR acquired by SAR simulation under human body environment was-7.14 dbm and maximum reduction of the magnetic field strength around the receiving coil was 2.82 A/m. The maximum temperature rise during 30min charging test was 3.85℃,and the safety requirements of human bodies were met.
基金Max-Planck-Society(TANDEM project to Koenen M and Schweizer PA)Ministry of Science,Research and the Arts Baden-Wuerttemberg(Sonderlinie Medizin to Thomas D)+5 种基金German Heart Foundation(Kaltenbach scholarship to Darche FF)German Cardiac Society(Otto-Hess scholarship to Rahm AK)Heidelberg Medical Faculty(Physician Scientist-Programm to Darche FF,Rivinius R and Rahm AK)German Cardiac Society(Research scholarship to Rivinius R)the German Society of Internal Medicine(Clinician-Scientist-Program to Rahm AK)and the German Centre for Cardiovascular Research(DZHK).
文摘BACKGROUND Mesenchymal stem cells(MSC)modified by gene transfer to express cardiac pacemaker channels such as HCN2 or HCN4 were shown to elicit pacemaker function after intracardiac transplantation in experimental animal models.Human MSC derived from adipose tissue(haMSC)differentiate into cells with pacemaker properties in vitro,but little is known about their behavior after intracardiac transplantation.AIM To investigate whether haMSC elicit biological pacemaker function in vivo after transplantation into pig hearts.METHODS haMSC under native conditions(nhaMSC)or after pre-conditioning by medium differentiation(dhaMSC)(n=6 pigs each,5×106 cells/animal)were injected into the porcine left ventricular free wall.Animals receiving PBS injection served as controls(n=6).Four weeks later,total atrioventricular(AV)-block was induced by radiofrequency catheter ablation,and electronic pacemaker devices were implanted for backup stimulation and heart rate monitoring.Ventricular rate and rhythm of pigs were evaluated during a follow-up of 15 d post ablation by 12-lead-ECG with heart rate assessment,24-h continuous rate monitoring recorded by electronic pacemaker,assessment of escape recovery time,and pharmacological challenge to address catecholaminergic rate response.Finally,hearts were analyzed by histological and immunohistochemical investigations.RESULTS In vivo transplantation of dhaMSC into the left ventricular free wall of pigs elicited spontaneous and regular rhythms that were pace-mapped to ventricular injection sites(mean heart rate 72.2±3.6 bpm;n=6)after experimental total AV block.Ventricular rhythms were stably detected over a 15-d period and were sensitive to catecholaminergic stimulation(mean maximum heart rate 131.0±6.2 bpm;n=6;P<0.001).Pigs,which received nhaMSC or PBS presented significantly lower ventricular rates(mean heart rates 47.2±2.5 bpm and 37.4±3.2 bpm,respectively;n=6 each;P<0.001)and exhibited little sensitivity towards catecholaminergic stimulation(mean maximum heart rates 76.4±3.1 bpm and 60.5±3.1 bpm,respectively;n=6 each;P<0.05).Histological and immunohistochemical evaluation of hearts treated with dhaMSC revealed local clusters of transplanted cells at the injection sites that lacked macrophage or lymphocyte infiltrations or tumor formation.Intense fluorescence signals at these sites indicated membrane expression of HCN4 and other pacemaker-specific proteins involved in cardiac automaticity and impulse propagation.CONCLUSION dhaMSC transplanted into pig left ventricles sustainably induced rate-responsive ventricular pacemaker activity after in vivo engraftment for four weeks.The data suggest that pre-conditioned MSC may further differentiate along a pacemakerrelated lineage after myocardial integration and may establish superior pacemaker properties in vivo.
文摘AIM:To determine if there were any interactions between cardiac devices and small bowel capsules secondary to electromagnetic interference (EMI) in patients who have undergone small bowel capsule endoscopy (SBCE).METHODS:Authors conducted a chart review of 20 patients with a cardiac pacemaker (CP) or implantable cardioverter defibrillator (ICD) who underwent continuous electrocardiographic monitoring during their SBCE from 2003-2008.authors searched for unexplained electrocardiogram (ECG) findings,changes in CP andICD set parameters,any abnormality in transmitted capsule data,and adverse clinical events.RESULTS:There were no adverse events or hemodynamically significant arrhythmias reported.CP and ICD set parameters were preserved.The majority of ECG abnormalities were also found in pre-or post-SBCE ECG tracings and the CP behavior during arrhythmias appeared appropriate.Two patients seemed to have episodes of undersensing by the CP.However,similar findings were documented in ECGs taken outside the time frame of the SBCE.One patient was observed to have a low signal encountered from the capsule resulting in lack of localization,but no images were lost.CONCLUSION:Capsule-induced EMI remains a possibility but is unlikely to be clinically important.CPinduced interference of SBCE is also possible,but is infrequent and does not result in loss of images transmitted by the capsule.
基金Thework and the contributions were supported by the project SV4502261/SP2022/98‘Biomedical Engineering systems XVIII’.
文摘The usability assessment of a pacemaker is a complex task where the dedicated programmer for testing programmed algorithms is necessary.This paper provides the outcomes of development and complex testing of the artificial cardiac system to evaluate the pacemaker’s functionality.In this work,we used the modular laboratory platform ELVIS II and created graphical user interface in LabVIEW programming environment.The electrical model of the heart allows signals generation(right atrium,right ventricle)and the monitoring of the stimulation pulses.The LabVIEW user interface allows to set the parameters of the generated signals and the simulation of the cardiac rhythm disorders as well as the monitoring and visualization of the pacemaker behavior in real-time.The results demonstrate the capability of proposed system to evaluate the paced and sensed pulses.The proposed solution allows the scientists to test the behavior of any cardiac pacemaker for its pre-programmed settings and pacing mode.In addition,the proposed system can simulate various disorders and test cardiac pacemakers in different working modes.
文摘Objectives: The purpose of this study is to identify how to manage oversensing of pacemakers in chest CT. Methods: Four different models of pacemakers were examined to select the pacemaker generating oversensing. To the pacemaker with oversensing, intermittent switching X-ray was exposed using ECG-gated CT helical scan system at prospective CTA mode. IVY Model was used to synchronize the ECG. Only during in the alert period that is non-refractory and sensing is available, intermittent switching X-ray (300 msec/sec) was exposed in chest CT. For comparison, the same intermittent switching X-ray (300 msec/sec) was exposed in the refractory period when sensing was not available. Results: Oversensing was detected only in one of the four pacemakers tested. In this pacemaker, oversensing was generated by exposure of the intermittent switching X-ray in the alert (non-refractory) period, but oversensing was not observed in the refractory period. Conclusion: A pacemaker has alert and refractory periods. Oversensing of a pacemaker was found to be inhibited by selective ECG-synchronized exposure in the refractory period. Since all pacemakers have the refractory period, the results of this study can be widely applied to the patients with pacemakers in chest CT, and their chest CT can be operated safely.
文摘Wireless capsule endoscopy is a new endoscopic tool for the diagnosis and management of small bowel diseases. The main indication at present is the evaluation of GI bleeding of obscure origin, Crohn’s disease, coeliac disease and small bowel tumors. Studies suggest that capsule endoscopy is associated with few adverse events. Whether cardiac pacemaker may interfere with capsule endoscopy is still a controversial issue. We here report a case showing that there is a possibility of interference between the two procedures, cardiac pacemaker affecting the proper functioning of capsule endoscopy and that this is related to the distance between the pacemaker and the recorder.
文摘Objective: To inquire into the effect of systematic family nursing guidance on improving the Quality of Life for elderly patients with implanted cardiac pacemaker. Methods: 41 elderly patients in accordance with the corresponding requirements were studied after offering systematic family nursing guidance and surveyed through the questionnaires about the QOL (quality of life) respectively 1 month, 3 months and 6 months after leaving hospital. Results: Compared with that of 1 month and 3 months after the operation, the questionnaire scores for 6 months after the operation were found to have significant improvement, and the differences were statistically significant. Conclusion: Systematic family nursing guidance can effectively improve the QOL for elderly patients with implanted cardiac pacemaker, which makes them spend their old age in comfort and happiness.
文摘In view of the omnipresence of electronic article surveillance (EAS) systems in daily life and the increasing number of patients with active implants, there is concern about adverse electromagnetic interference in particular cardiac pacemakers (CPM) and cardioverter defibrillators (ICD), which due to sensing electrocardial signals are particularly vulnerable. To provide quantitative information interference of monopolar CPM and ICD by EAS systems operating at 8.2MHz radiofrequency electromagnetic fields (EMF) investigations have been performed by exposing numerical anatomical models of pacemaker patients with implants at the conventional left or right pectoral sites and at the abdomen to magnetic fields of a simulated EAS gate source. Investigation of normal position in the centre and worst case with the back next to the gate showed that adverse interference such as inadequate sensing need not be expected at any position. This applies for conventional sensing thresholds even if the exposure span of existing EAS systems is taken into account. However, if full use is made of the newly expanded exposure budget, adverse interference cannot be excluded.
文摘Background:High cost of imported pacemakers is a main obstacle for Chinese patients suffering from bradyarrhythmia,and a domestically developed pacemaker will help lower the burden.This study aimed to evaluate the safety and efficacy ofQinming8631 DR (Qinming Medical,Baoji,China),the first domestically developed dual-chamber pacemaker of China,compared with a commercially available pacemaker Talos DR (Biotronik,Berlin,Germany) in Chinese patients.Methods:A prospective randomized trial was conducted at 14 centers in China.Participants were randomized into trial (Qinming8631 DR) and control (Talos DR) groups.Parameters of the pacing systems were collected immediately after device implantation and during follow-ups.The effective pacing rate at 6-month follow-up was recorded as the primary end point.Electrical properties,magnet response,single-and double-pole polarity conversion,rate response function,and adverse events of the pacing system were analyzed.The Cochran-Mantel-Haenszel Chi-square test,paired t-test,and Wilcoxon signed-rank test were used for measuring primary qualitative outcomes and comparing normally and abnormally distributed measurement data.Results:A total of 225 patients with a diagnosis ofbradyarrhythmia and eligible for this study were randomly enrolled into the trial (n =113) and control (n =112) groups.They underwent successful pacemaker implantation with acceptable postoperative pacing threshold and sensitivity.Effective pacing rates of trial and control groups were comparable both in the full analysis set and the per protocol set (81.4% vs.79.5%,P =0.712 and 95.4% vs.89.5%,P =0.143,respectively).In both data sets,noninferiority of the trial group was above the predefined noninferiority limit(-9.5%).Conclusions:This study established the noninferiority ofQinming8631 DR to Talos DR.The safety and efficacy ofQinming8631 DR pacemaker were comparable to those of Talos DR in treating patients with cardiac bradyarrhythmia.
基金Supported by Foundation of Guizhou Science and Technology Department,No.QIANKEHEZHICHEN[2022]YIBAN 179National Natural Science Foundation of China,No.82160370Guizhou Education Department,No.Qian Jiao He KY Zi[2018]239.
文摘BACKGROUND Pacemaker lead-induced heart perforation is a rare but life-threatening complication of pacemaker implantation,and timely diagnosis remains a challenge for clinicians.Here,we report a case of pacemaker lead-induced cardiac perforation rapidly diagnosed by a“bow-and-arrow”sign on point-of-care ultrasound(POCUS).CASE SUMMARY A 74-year-old Chinese woman who had undergone permanent pacemaker implantation 26 d before suddenly developed severe dyspnea,chest pain,and hypotension.The patient had received emergency laparotomy for an incarcerated groin hernia and was transferred to the intensive care unit 6 d before.Computed tomography was not available due to unstable hemodynamic status,so POCUS was performed at the bedside and revealed severe pericardial effusion and cardiac tamponade.Subsequent pericardiocentesis yielded a large volume of bloody pericardial fluid.Further POCUS by an ultrasonographist revealed a unique“bow-and-arrow”sign indicating right ventricular(RV)apex perforation by the pacemaker lead,which facilitated the rapid diagnosis of lead perforation.Given the persistent drainage of pericardial bleeding,urgent off-pump open chest surgery was performed to repair the perforation.However,the patient died of shock and multiple organ dysfunction syndrome within 24 h post-surgery.In addition,we also performed a literature review on the sonographic features of RV apex perforation by lead.CONCLUSION POCUS enables the early diagnosis of pacemaker lead perforation at the bedside.A step-wise ultrasonographic approach and the“bow-and-arrow”sign on POCUS are helpful for rapid diagnosis of lead perforation.
文摘BACKGROUND Bradyarrhythmias are typically treated with permanent pacemakers(PM). The elimination of bradyarrhythmia by PM implantation improves the patient’s quality of life and prognosis, but it can also result in a number of sequalae. It is still unclear how PM implantation affects the hemostasis system’s parameters and how such parameters relate to different consequences after PM placement.AIM To assess the blood coagulation factor activity in PM patients throughout the perioperative period.METHODS Patients treated in the Department of Surgical Therapy of Cardiac Arrhythmias and Pacing at the Ryazan State "Regional Clinical Cardiology Dispensary" from April 2020 to December 2021 were included in the study. Before surgery, 7 and 30 d after PM placement, peripheral venous blood samples were withdrawn to measure the level of blood coagulation factor Ⅰ(FⅠ) and the activity of blood coagulation factors Ⅱ(FⅡ), Ⅴ(FⅤ), Ⅶ(FⅦ), Ⅷ(FⅧ), ⅸ(Fⅸ), ⅹ(Fⅹ), Ⅺ(FⅪ), Ⅻ(FⅫ). We used an automatic coagulometer Sysmex CA 660(Sysmex Europe, Germany) and reagents from Siemens(Siemens Healthcare Diagnostics Products GmbH, Germany).RESULTS The study included 146 patients. The activity of factors FⅤ [147.7(102.1-247.55)% vs 103.85(60-161.6)% vs 81.8(67.15-130.65)%, P = 0.002], FⅧ [80.4(60.15-106.25)% vs 70.3(48.5-89.1)% vs 63.7(41.6-88.25)%, P = 0.039], Fⅸ [86.2(70.75-102.95)% vs 75.4(59.2-88.3)% vs 73.9(56.45-93.05)%, P = 0.014], Fⅹ [188.9(99.3-308.18)% vs 158.9(83.3-230)% vs 127.2(95.25-209.35)%, P = 0.022], FⅪ [82.6(63.9-103.6)% vs 69.75(53.8-97.6)% vs 67.3(54.25-98.05)%, P = 0.002], FⅫ [87.6(67.15-102.3)% vs 78.9(63.4-97.05)% vs 81.2(62.15-97.4)%, P < 0.001] decreased at 7 and 30 d after surgery;FⅡ activity [157.9(109.7-245.25)% vs 130(86.8-192.5)% vs 144.8(103.31-185.6)%, P = 0.021] decreased at 7 d and increased at 30 d postoperatively. There were no statistically significant changes in the FVII activity within 30 d after PM placement [182.2(85.1-344.8)% vs 157.2(99.1-259)% vs 108.9(74.9-219.8)%, P = 0.128]. Subgroup analysis revealed similar changes only in patients on anticoagulant therapy. FⅫ activity decreased in patients on antiplatelet therapy [82(65.8-101.9)% vs 79.9(63.3-97.1)% vs 89.7(75.7-102.5)%, P = 0.01] 7 d after surgery, returning to baseline values at 30 d postoperatively.CONCLUSION PM placement and anticoagulant therapy were associated with decreased activity of clotting factors FⅤ, FⅧ, Fⅸ, Fⅹ, FⅪ, FⅫ in the postoperative period. FⅧ activity did not decrease within 30 d after PM placement, which may indicate endothelial injury caused by lead placement.
文摘Hyperpolarization-activated cyclic-nucleotide-gated (HCN) channels in the heart modulate cardiac automaticity via the hyperpolarization-activated cation current ( named Ⅰf, Ⅰh, or Ⅰq). Recent studies have unveiled the molecular identity of HCN (HCN1-4) channels. HCN isoforms are unevenly expressed in the heart, even in the sinoatrial node. Features of HCN currents have been characterized in cardiac and other types of cells or in cell lines transfected with the HCN isoforms. The factors modulating Ih and the physiological significance of HCN channels in the heart have been extensively investigated in recent years. The hypothesis for transplanting and/or creating biological pacemakers to replace diseased sinoatrial and/or atrioventricular nodes has been postulated and tested in animal models. Local overexpression of HCN2 channels in the left atrium or in the left conductive bundle branch of the left ventricle via gene delivery induced significant Ⅰh and escape rhythms during vagal stimulation in canines. In addition, implantation of human mesenchymal stem cells with overexpression of HCN2 channels to the canine left ventricular wall was associated with formation of spontaneous escape rhythms of left-sided origin during vagal-stimulation-induced sinus arrest. This preliminary data suggest that the use of HCN channels may hold great promise in,the development of biological pacemakers.
文摘The effect of ischemia like solution and high concentration of isoprenaline and Phenylephrine in that solution on normal pacemaker current If of sheep cardiac Puekinje fibres were observed After perfusing the preparations with “ischemia” solution 15, 30, and 60 min, the amplitude of If current at all measured membrane potentials (from -60 to -120 mV) decreased (n=7,p<0.05)and the activation curve of If current shiftea to left side,E0.5 changed from control value -85.0±3.7 mV to -91.7±4.1 mV at 30 min. Isoprenaline 1×10-6mol/L could increase the amplitude of If current in “ischemia” solution (n= 10, P<0.05) and shift the activation curve of If current back to right side, but it could not completely reverse the inhibitory effect of“ ischemia“. In the presence of propranolol 5 ×10-7 mol/L, 5×10-5 mol/L phenylephrine decreased the amplitude of If current further in “ischemia” solution (n= 7, P<0.05-0.01), the activatior curve of If current shifted to left side further. The above results indicate that the normal pacemaker current was inhibited in “ischemia” condition even in the presence of high concentration of beta and alpha adrenoceptor agonists so the genesis of ischemic ventricular arrhythmia is hardly due to the abnormal enhancement of normal ventricular pacemaker activity.
文摘In patients with heart failure and disordered intracardiac conduction of activation, doctors implant a biven- tricular pacemaker (“cardiac resynchronization therapy”, CRT) to allow adjustment of the relative timings of activation of parts of the heart. The process of selecting the pacemaker timings that maximize cardiac function is called “optimization”. Although optimization—more than any other clinical assessment—needs to be precise, it is not yet conventional to report the standard error of the optimum alongside its value in clinical practice, nor even in research, because no method is available to calculate precision from one optimization dataset. Moreover, as long as the determinants of precision remain unknown, they will remain unconsidered, preventing candidate haemodynamic variables from being screened for suitability for use in optimization. This manuscript derives algebraically a clinically-applicable method to calculate the precision of the optimum value of x arising from fitting noisy biological measurements of y (such as blood flow or pressure) obtained at a series of known values of x (such as atrioventricular or interventricular delay) to a quadratic curve. A formula for uncertainty in the optimum value of x is obtained, in terms of the amount of scatter (irreproducibility) of y, the intensity of its curvature with respect to x, the width of the range and number of values of x tested, the number of replicate measurements made at each value of x, and the position of the optimum within the tested range. The ratio of scatter to curvature is found to be the overwhelming practical determinant of precision of the optimum. The new formulae have three uses. First, they are a basic science for anyone desiring time-efficient, reliable optimization protocols. Second, asking for the precision of every reported optimum may expose optimization methods whose precision is unacceptable. Third, evaluating precision quantitatively will help clinicians decide whether an apparent change in optimum between successive visits is real and not just noise.
文摘The appropriate preparation of the patient with asymptomatic congenital complete heart block (CCHB) and a narrow QRS complex for elective non-cardiac surgery is controversial. Prophylactic temporary pacemaker insertion is associated with well-defined risks, and less invasive techniques exist to treat transient, hemodynamically significant intraoperative brady-arrhythmias. The present case report details the performance of general anesthesia for arthroscopic knee surgery in an adult patient with this condition without a pacemaker. Documentation of preoperative chronotropic competence with isoproterenol may be of value in deciding whether to proceed without temporary pacing capability in this setting.
文摘A number of publications have claimed that Mobitz type Ⅱ atrioventricular block(AVB)may occur during sleep.None of the reports defined type Ⅱ AVB and representative electrocardiograms were either misinterpreted or missing.Relatively benign Wenckebach type Ⅰ AVB is often misdiagnosed as Mobitz type Ⅱ which is an indication for a pacemaker.Review of the published reports indicates that Mobitz type II AVB does not occur during sleep when it is absent in the awake state.Conclusion:There is no proof that sleep is associated with Mobitz type Ⅱ AVB.