Permanent Pacing System Research Articles

History of cardiac resynchronization therapy : 30years of electrotherapeutic management for heart failure

The first permanent biventricular pacing system was implanted more than 30years ago. In this article, the historical development of cardiac resynchronization therapy (CRT), starting with the pathophysiological concept, followed by the initial "proof of concept" studies and finally the large prospective-randomized studies that led to the implementation of CRT in heart failure guidelines, is outlined. Since the establishment of CRT, both an expansion of indications, e.g., for patients with mild heart failure and atrial fibrillation, but also the return to patients with broad QRS complex and left bundle branch block who benefit most of CRT has evolved. New techniques such as conduction system pacing will have major influence on pacemaker therapy in heart failure, both as an alternative or adjunct to CRT.

830 Surgical Management of a Patient with Triple Carcinoid Heart Valve Disease

Abstract Background Carcinoid heart disease is an uncommon manifestation of carcinoid syndrome that can present to a cardiac surgeon as a complex constellation of structural problems. Patients develop progressive valve disease, more commonly of the right-sided heart valves but sometimes involving the left, which will in turn impact cardiac function. Without intervention, carcinoid heart disease portends a dismal prognosis. Given the rarity with which these cases are encountered, in conjunction with their complexity, it is important for the cardiac surgeon to be equipped with the knowledge of how to operate on these patients and the challenges likely to be faced. Case A 72-year-old man, who had previously undergone small bowel resection for multifocal neuroendocrine tumours, was referred to our centre with significant symptomatic carcinoid heart valvulopathy affecting the tricuspid, mitral and aortic valves. He successfully underwent triple valve replacement and permanent epicardial pacing system implantation along with coronary artery bypass grafting. He was discharged after an inpatient stay of two weeks and is well at follow-up. Discussion Triple valve replacement is infrequently performed in the UK, but all centres ought to be prepared to offer this treatment in a select group of patients. In this report we describe the technicalities of performing such an operation and the relevant surgical anatomy, the rationale and technique of pre-emptive epicardial pacing system implantation, and both the pre- and post-operative management of such patients.

Impact and Modifiers of Ventricular Pacing in Patients With Single Ventricle Circulation

BackgroundPalliation of the single ventricle (SV) circulation is associated with a burden of lifelong complications. Previous studies have identified that the need for a permanent ventricular pacing system (PPMv) may be associated with additional adverse long-term outcomes. ObjectivesThe goal of this study was to quantify the attributable risk of PPMv in patients with SV, and to identify modifiable risk factors. MethodsThis international study was sponsored by the Pediatric and Congenital Electrophysiology Society. Centers contributed baseline and longitudinal data for functionally SV patients with PPMv. Enrollment was at implantation. Controls were matched 1:1 to PPMv subjects by ventricular morphology and sex, identified within center, and enrolled at matched age. Primary outcome was transplantation or death. ResultsIn total, 236 PPMv subjects and 213 matched controls were identified (22 centers, 9 countries). Median age at enrollment was 5.3 years (quartiles: 1.5-13.2 years), follow-up 6.9 years (3.4-11.6 years). Median percent ventricular pacing (Vp) was 90.8% (25th-75th percentile: 4.3%-100%) in the PPMv cohort. Across 213 matched pairs, multivariable HR for death/transplant associated with PPMv was 3.8 (95% CI 1.9-7.6; P < 0.001). Within the PPMv population, higher Vp (HR: 1.009 per %; P = 0.009), higher QRS z-score (HR: 1.19; P = 0.009) and nonapical lead position (HR: 2.17; P = 0.042) were all associated with death/transplantation. ConclusionsPPMv in patients with SV is associated with increased risk of heart transplantation and death, despite controlling for increased associated morbidity of the PPMv cohort. Increased Vp, higher QRS z-score, and nonapical ventricular lead position are all associated with higher risk of adverse outcome and may be modifiable risk factors.

Mejora progresiva de los umbrales de captura auricular y ventricular, detección e impedancias en los cables de estimulación epicárdica en adultos jóvenes que se someten a conversión de Fontan.

Objectives:Patients with univentricular hearts who require permanent pacing systems typically require placement of epicardial leads. It is frequently difficult to find a position with good thresholds due to epimyocardial fibrosis or fat. The goal of the study is to assess the progression of capture thresholds (CT), sensing parameters (P waves and R waves), and impedances (imp) of steroid eluting epicardial pacing leads in young adults who underwent Fontan conversion and a pacemaker implant.Methods:All patients undergoing Fontan conversion in two institutions were retrospectively identified. Demographic data, congenital heart defects, pacing leads used, and pacing parameters were analyzed at implant, at 6 weeks and 12 months after implant.Results:Twenty patients were identified (twelve males); mean age at conversion was 24.9 ± 5.4 years (range 18-35). Epicardial bipolar steroid eluting leads were used. The site of implant both in the atria and the ventricles varied depending on the parameters. At implant, mean atrial and ventricular impedances were 617 ± 171 W and 1061 ± 771 W, respectively, mean P wave amplitude was 2 ± 0.7 mV, and mean R wave amplitude was 12.5 ± 7.7 mV. Mean CT was 1.7 ± 0.8 V at 0.5 ms for the atrium and 2.2 ± 1.2 V at 0.5 ms for the ventricle. Ventricular CT and impedance showed an improvement within the first 12 months after implant, with four patients having a decrease in threshold of more than 2 V.Conclusion:In patients undergoing Fontan conversion, implant ventricular CT and impedances are frequently higher than expected but typically improve during follow-up. Acceptance of higher initial threshold values may be a potential strategy in this patient population.

Efficacy and safety of temporary permanent pacemaker: A single-center experience

Temporary cardiac pacing is commonly indicated for the treatment of symptomatic bradycardia and various types of reversible symptomatic heart block. Conventional transvenous temporary cardiac pacing therapy is widely used. This technique is associated with a number of limitations and complications, compared to permanent pacing system. The aim of our study was to identify the indications, complications and outcomes of transvenous semi-permanent pacing. A retrospective study was conducted in our cardiology department from 2017 to 2019. We investigated semi-permanent transvenous pacing system. Were included all patients presenting symptomatic heart block potentially reversible or in a context of severe infection, and patients hospitalized for alcohol septal ablation. A total of 18 patients were implanted, aged between 47 and 92 years. Seven were enrolled for STEMI with symptomatic atrioventricular block, 4 for alcohol septal ablation for hypertrophic cardiomyopathy, 1 for hyperkaliemia, 1 for myocarditis with atrioventricular block and 5 for symptomatic sinus bradycardia or atrioventricular block with infection circumstances. The venous access was sub clavicular in 17 patients (94%) and internal jugular in just 1 patient. After a median follow-up of 14.5 ± 9.63 months, the total duration of hospital stay was 13.5 ± 10.14 days. The duration of temporary pacing was 10 ± 6.27 days. A total of 12 patients (67%) were definitely implanted of dual chamber pacemaker (75%), cardio resynchronization therapy pacemaker (17%) or defibrillator (8%). One patient died with the semi-permanent pacing system in situ. No major or minor intra-operative or postoperative complication occurred. Temporary permanent pacemaker with bipolar active fixation leads and epicutaneous pulse generators provide a cost effectiveness option for prolonged temporary pacing as a bridge to permanent system implantation or recovery.

Temporary pacing: an overview

This article will review pacing in the context of acute care, with a focus on temporary pacing. Beginning with an overview of the heart's intrinsic electrical conduction system and its function, the discussion moves on to pacing, acute clinical presentations and indications for pacing. This includes an overview of temporary pacing, with the different approaches being percussion, transcutaneous, transvenous and epicardial. There are specific cardiac patient groups at high risk of developing bradyarrhythmias and, in the absence of other measures, potentially requiring emergency pacing. These groups include patients who have experienced a myocardial infarction following cardiac surgery and post transcatheter aortic valve implant. Nurses providing care for patients with temporary transvenous wires need an understanding of the potential complications and to recognise indications for moving on to a permanent pacing system.

The potential of electrocardiography for cardiac risk prediction in chronic and end-stage kidney disease.

Cardiovascular mortality is very high in chronic and end-stage kidney disease (ESKD). However, risk stratification data are lacking. Sudden cardiac deaths are among the most common cardiovascular causes of death in these populations. As a result, many studies have assessed the prognostic potential of various electrocardiographic parameters in the renal population. Recent data from studies of implantable loop recordings in haemodialysis patients from five different countries have shed light on a pre-eminent bradyarrhythmic risk of mortality. Importantly, heart block addressed by permanent pacing system was detected in a proportion of patients during the prolonged recording periods. Standard electrocardiogram is inexpensive, non-invasive and easily accessible. Hence, risk prediction models using this simple investigation tool could easily translate into clinical practice. We believe that electrocardiographic assessment is currently under-valued in renal populations. For this review, we identified studies from the preceding 10 years that assessed the use of conventional and novel electrocardiographic biomarkers as risk predictors in chronic and ESKD. The review indicates that conventional electrocardiographic markers are not reliable for risk stratification in the renal populations. Novel parameters have shown promising results in smaller studies, but further validation in larger populations is required.

Analytical Modeling for Computing Lead Stress in a Novel Epicardial Micropacemaker.

Implantation and maintenance of a permanent cardiac pacing system in children remains challenging due to small patient size, congenital heart defects and somatic growth. We are developing a novel epicardial micropacemaker for children that can be implanted on the epicardium within the pericardial space via a minimally-invasive technique. The key design configurations include a novel open-coiled lead in which living tissue replaces the usual polymeric support for the coiled conductor. To better understand and be able to predict the behavior of the implanted lead, we performed a radiographic image-based modeling study on a chronic animal test. We report a pilot study in which two mechanical dummy pacemakers with epicardial leads were implanted into an adult pig model via a minimally invasive approach. Fluoroscopy was obtained on the animal on Post-Operative Days #9, #35 and #56 (necropsy). We then constructed an analytic model to estimate the in vivo stress conditions on the open-coil lead based on the analysis of orthogonal biplane radiographic images. We obtained geometric deformation data of the implanted lead including elongation magnitudes and bending radii from sequenced films of cardiac motion cycles. The lead stress distribution was investigated on each film frame and the point of maximum stress (Mean Stress=531.4MPa; Alternating Stress=±216.4MPa) was consistently where one of the leads exited the pericardial space, a deployment that we expected to be unfavorable. These results suggest the modeling approach can provide a basis for further design optimization. More animal tests and modeling will be needed to validate whether the novel lead design could meet the requirements to withstand ~200 million cardiac motion cycles over 5years.

Twenty-Seven Years Experience With Transvenous Pacemaker Implantation in Children Weighing

Epicardial pacemaker implantation is the favored approach in children weighing <10 kg in many units. The high incidence of premature failure and fractures with earlier epicardial leads led our unit to undertake transvenous pacemaker implantation in neonates and infants from 1987. To date there have been no long-term follow-up reports of what is for many a controversial strategy. Between 1987 and 2003, 37 neonates and infants-median age 6.7 months (1 day to 3 years) and median weight 4.6 kg (2.7-10 kg)-had a permanent transvenous pacing system implanted. Pacing leads were placed into the right ventricular apex/outflow tract through a subclavian vein puncture with a redundant loop in the atrium. Three patients were lost to follow-up, 4 patients died from complications of cardiac surgery, and 2 patients had their system removed. At long-term follow-up in 28 patients at a median of 17.2 (range, 11.2-27.4) years, 10 patients have a single chamber ventricular pacemaker, 14 a dual chamber pacemaker, 3 a biventricular pacemaker, and 1 has a single chamber implantable cardioverter defibrillator. Subclavian vein patency was assessed in 26 patients. The overall subclavian vein occlusion rate was 10 of 13 (77%) <5 kg and 2 of 13 (15%) >5 kg during long-term follow-up. After a median of 14.3 (range, 13.4-17.6) years of pacing, 7 patients continue with their original lead. Transvenous pacing in infants <10 kg results in encouraging short- and long-term clinical outcomes. Subclavian vein occlusion remains an important complication, occurring predominantly in those weighing <5 kg.

Przypadek niedrożności żyły bezimiennej — wpływ na wybór postępowania zabiegowego w stałej elektroterapii serca

Successful transvenous insertion of cardiac pacing leads during pacemaker implantation is contingent on the patency of consecutive vessels. Vessel obstruction can be detected during either first-time or subsequent procedures associated with the need to introduce additional pacing leads. Venous thrombosis is the most common cause for vessel occlusion, and the main occlusion site along the venous route used for cardiac lead insertion is the subclavian vein, in contrast to the innominate vein or the superior vena cava, whose occlusion rates are much lower. The patient presented here developed venous thrombosis in the left brachiocephalic vein (BCV) also known as the innominate vein 5 years after a first-time permanent cardiac pacing system implantation. Contrast-enhanced vascular imaging conducted during a subsequent procedure intended to introduce a new lead revealed the location and extent of BCV occlusion. Out of 2,258 procedures requiring cardiac lead insertion and performed within a 5-year period (2010–2014) at the Clinic (including 68 cases of adding a lead to the existing device) this was the only case of BCV occlusion of this aetiology. Literature reports on BCV emphasize the uncommonness of this type of occlusion and discuss its effect on the course of the procedure.

Infection of permanent pacing system with negative inflammatory markers

Infection of permanent pacing system with negative inflammatory markers

Left ventricular endocardial leadless pacing brings new hope to patients with heart failure

Cardiac resynchronization therapy (CRT) provides prognostic and symptomatic benefits for patients with heart failure and left ventricular (LV) dyssynchrony. It requires the implantation of an LV lead, usually placed in a tributary of the coronary sinus. Despite important progress made in the development of dedicated instrumentation, challenges still remain, and the procedure may even be unsuccessful for various reasons, including CS occlusion, dissection, abnormal ostium of the CS, coronary vein stenosis, lead instability, high threshold, or phrenic nerve stimulation. Even if the procedure is successful, about 30% of patients receiving CRT do not respond to treatment [1]. Although the underlying reasons for the lack of CRT response in some patients are undoubtedly multifactorial, some problems have been identified and may have the potential to be ameliorated. Firstly, limitations imposed by coronary venous anatomy on the selection of the site for LV stimulation are thought to be a major contributor to the lack of CRT response. Secondly, stimulation is epicardial, which leads to delayed electrical activation of the LV in comparison to endocardial stimulation, and has been shown to provide less hemodynamic benefit [2]. Additionally, pacing leads are the most frequent cause of complications related to permanent pacing systems and CRT complication rates for coronary vein leads are ~11–12% [3]. An alternative approach of delivering left ventricular endocardial leadless pacing (LVELP) offers a number of potential advantages, including greater choice of LV lead position, possibly more rapid LV activation, and reducing lead-related complications. The feasibility of a new technology using energy transfer from an ultrasound transmitter to a receiver electrode to achieve cardiac stimulationwithout theuseof apacing leadhas been reportedpreviously [4]. A novel implantable cardiac pacing systembased on this concept has recently been developed for the treatment of heart failure (Wireless Cardiac Stimulation-LVSystem,WiCS®-LV, EBRSystems, Inc., Sunnyvale, CA, USA) and a clinical trial using the WiCS®-LV system is ongoing in Europe. The study titled Wireless Stimulation Endocardially for CRT (WiSE-CRT) is evaluating the safety and feasibility in specific subsets of patients with CRT-eligible heart failure. LVLEPwill maybe become an effective approach for LV pacing in CRT. In this letter we discuss the potential advantages and disadvantages of this method. LVLEP provides several potential advantages, including:

Surgical Placement of Permanent Epicardial Pacing Systems in Very Low-Birth Weight Premature Neonates

Few studies have characterized the surgical outcomes following epicardial pacemaker placement in very low-birth weight infants with congenital complete heart block. This study was undertaken to review the surgical experience with this patient population based on data from a large multi-institutional registry. The Pediatric Cardiac Care Consortium (PCCC) multi-institutional database was retrospectively reviewed to identify premature, low-birth weight neonates that underwent surgical placement of an epicardial pacing system for heart block. We reviewed 179 patients with birth weights less than 1.5 kg that underwent a major operative procedure. Of these, 10 patients underwent surgical placement of an epicardial pacing system for heart block. Patients had heart block in otherwise structurally normal hearts (n = 6) or heart block associated with complex structural congenital cardiac anomalies (n = 4). There were no deaths directly related to the surgical placement of the epicardial pacing system. There were no immediate complications with either lead or generator placement. One generator pocket was revised three months following placement. Survival to discharge was 60%. The four deaths occurred at a mean of 11 days (range 1-45 days) following the procedure. Neonates born with prematurity and congenital heart block represent a challenging subset of patients with significant mortality. Generator pocket breakdown and infection have been considered barriers to optimal short- and long-term outcomes. Among cases in the PCCC, there were no deaths or major complications that could be attributed to permanent epicardial pacemaker placement. These data suggest that an aggressive surgical strategy may be justified.

Cardiac Magnetic Resonance Imaging of a Patient with an Magnetic Resonance Imaging Conditional Permanent Pacemaker

Cardiac magnetic resonance imaging (MRI) is increasingly used as the optimum modality for cardiac imaging. An aging population and rising numbers of patients with permanent pacemakers means many such individuals may require cardiac MRI scanning in the future. Whilst the presence of a permanent pacemaker is historically regarded as a contra-indication to MRI scanning, pacemaker systems have been developed to limit any associated risks. No reports have been published regarding the use of such devices with cardiac MRI in a clinical setting. We present the safe, successful cardiac MRI scan of a patient with an MRI-conditional permanent pacing system.

Cranial Vena Caval Thrombosis Associated With Endocardial Pacing Leads in Three Dogs

Three dogs were examined several years following implantation of transvenous, single-lead, endocardial, right-ventricular permanent pacing systems for signs consistent with cranial vena caval syndrome. Angiograms performed in all dogs revealed filling defects within the cranial vena cava and, in some instances, intracardiac filling defects. Medical therapy was instituted in two dogs, with one surviving several weeks. One dog underwent surgery to address intra-cardiac thrombosis but did not survive the immediate postoperative period. Postmortem examinations were performed in two dogs and confirmed cranial vena caval and intracardiac thrombosis. Cranial vena caval thrombosis associated with transvenous pacing leads appears to carry significant morbidity and mortality.

Long-Term Follow-Up of Permanent Transvenous Pacing Systems Preserved During Tricuspid Valve Replacement

Patients undergoing tricuspid valve replacement who already have a transvenous pacemaker system in the right ventricle are often recommended to have the ventricular lead removed and an epicardial system implanted. However, as a rule, the reliability of endocardial transvenous pacemaker leads has been superior to epicardial systems. Therefore, if the pacemaker lead in the ventricle is still performing well, it may be preferable to leave it in place. In this communication, we present the long-term follow-up results leaving the pacer lead in place by securing it in a position outside the prosthetic valve without interfering with the function of the prosthetic valve.

Heart Rate Turbulence and Heart Rate Variability in Patients with Atrial Synchronous Ventricular Pacing

Heart rate turbulence (HRT) and heart rate variability (HRV) have been shown to be independent and powerful predictors of mortality in a specific group of cardiac patients. Pacing has unfavorable effects on autonomic function. Our aim is to investigate autonomic responses to atrial synchronous ventricular pacing (VDD) by evaluating HRT and HRV parameters. The study groups comprised 12 control and 12 patients without organic heart disease and with normal sinus function who were implanted with a permanent VDD pacing system for high-degree atrioventricular block. The HRV and HRT analysis were assessed from a 24-hour Holter recording. There was no statistically significant difference between the two groups for HRV parameters. When HRT parameters were compared, turbulence onset was significantly higher in the cardiac paced group than the controls group (2.729 +/- 8.818 vs -1.565 +/- 8.301, P = 0.006), but no statistically significant difference was found between the two groups for turbulence slope (11.166 +/- 10.034 vs 31.675 +/- 28.107, P = 0.68). The number of patients who had abnormal HRT onset was significantly higher in the paced group than controls (9 vs 2, P = 0.004). Atrial synchronous pacing has unfavorable effects on autonomic function. Altered ventricular depolarization sequence may lead to changes in autonomic response. Although we found no difference in HRV parameters between the control and VDD patient groups, the HRT onset and number of patients with abnormal HRT onset was significantly higher in VDD patients. HRT onset can be a better way of noninvasive autonomic response predictor in VDD patients.

Permanent Endovenous Pediatric Pacing: Absence of Lead Failure—20 Years Follow‐Up Study

The aim of the study was to analyze endovenous pacing lead survival in pediatric population implanted by cephalic cut down, or by axillary vein puncture. All implantations were performed in total endotracheal anesthesia, by the same surgeon. Implantations of ventricular leads were performed by cephalic vein cut down or by external jugular vein preparation. In dual-chamber pacing, atrial leads were implanted via cephalic vein (along with ventricular lead), by axillary vein puncture or via external jugular vein. All implanted leads were secured by resorbable suture. Over the 20-year follow-up period, 105 children of 5.7 years average age (range 1 day-15 years) were implanted with a permanent endovenous pacing system for congenital or postsurgical complete atrioventricular block or sinus node disease. Within the group, 27 patients (25.7%) weighed less than 10 kg on implantation. A total of 121 endovenous leads were implanted. All ventricular leads were with a passive fixation mechanism, and most of them unipolar (87.6%) and steroid eluting (94.2%). Leads implanted in atrial position were 82% bipolar, predominantly with active fixation (94%), and all steroid eluting. The most frequently used mode of stimulation was VVIR (66.6%). No acute or chronic lead displacement, exit block, sensing problem, lead conductor fracture, insulation defect or infections were observed during the total follow-up of 709 pacing years (average 6.9, range 0-20 years). Implantation of the endovenous leads by preparation of the cephalic or puncture of the axillary vein, with lead fixation by resorbable suture represents a method of choice.

Cardiac Resynchronization Therapy for Mitral Systolic Anterior Motion in a Child

We describe the successful use of cardiac resynchronization therapy for treatment of mitral valve systolic anterior motion with left ventricle outflow tract obstruction after re-excision of a subaortic membrane and septal myectomy in a 12-year-old child. In the recovery phase, a total atrioventricular block persisted. Therefore a permanent atrioventricular pacing system was implanted.

Physiologic Pacing in Patients With Obstructive Sleep Apnea: A Prospective, Randomized Crossover Trial

This study was designed to assess the impact of prevention of bradycardia with physiologic pacing on the severity of obstructive sleep apnea. Apneic episodes during sleep are associated with slowing of the heart rate during apnea and tachycardia with subsequent arousal. Patients with permanent pacemakers may have reduced episodes of sleep apnea when their pacemaker rate is set faster than their spontaneous nocturnal heart rate. We conducted a prospective, randomized, single-blind crossover trial of temporary atrial pacing in obstructive sleep apnea to reduce the apnea hypopnea index (AHI). Fifteen patients (age 60 +/- 13 years, 12 men) with moderate to severe obstructive sleep apnea (AHI 34 +/- 14) underwent insertion of an externalized atrial permanent pacing system via the left subclavian vein. Patients underwent overnight respiratory sleep studies in hospital, during atrial pacing at 75 beats/min, and with pacing turned off. The order of pacing mode was randomized, with crossover the subsequent night to the other mode. Patients were blinded to pacing mode, and the analysis of sleep recordings was blind to pacing mode. Pacing was tolerated without complications in all patients. Overnight physiologic pacing did not affect the AHI (pacing 39 +/- 21/h vs. control 42 +/- 21/h, p = 0.23, 95% confidence interval -9.3 to 2.5 for difference), desaturation time (pacing 3.8 +/- 6.0% vs. control 3.5 +/- 4.3%, p = 0.70), or the minimum SaO(2) (pacing 75 +/- 10% vs. control 77 +/- 11%, p = 0.38). There was a borderline significant reduction in circulatory time with pacing (pacing 23.4 +/- 3.2 s vs. control 25.5 +/- 4.4 s, p = 0.09). Temporary atrial pacing does not appear to improve respiratory manifestations of obstructive sleep apnea. Permanent atrial pacing in this patient population does not appear to be justified.