A 12-Year Experience of Bipolar Steroid-Eluting Epicardial Pacing Leads in Children

Epicardial Versus Endocardial Pacing in Paediatric Patients with Atrioventricular Block or Sinus Node Dysfunction: A Systematic Review and Meta-analysis

Pacing indications in children are clearly defined, but whether an epicardial (EPI) or an endocardial (ENDO) pacemaker performs better remains to be elucidated. This systematic review and meta-analysis aimed to directly compare the incidence of pacemaker (PM) lead-related complications, mortality, hemothorax and venous occlusion between EPI and ENDO in children with atrioventricular block (AVB) or sinus node dysfunction (SND). Literature search was conducted in MEDLINE (via PubMed), Scopus by ELSEVIER, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, and OpenGrey databases until June 25, 2022. Random-effects meta-analyses were performed to assess the pacing method's effect on lead failure, threshold rise, post-implantation infection and battery depletion and secondarily on all-cause mortality, hemothorax and venous occlusion. Several sensitivity analyses were also performed. Of 22 studies initially retrieved, 18 were deemed eligible for systematic review and 15 for meta-analysis. Of 1348 pediatric patients that underwent EPI or ENDO implantation, 542 (40.2%) had a diagnosis of congenital heart disease (CHD). EPI was significantly associated with higher possibility of PM-lead failure [pooled odds ratio (pOR) 3.00, 95% confidence interval (CI) 2.05-4.39; I2 = 0%]; while possibility for threshold rise, post-implantation infection and battery depletion did not differ between the PM types. Regarding the secondary outcome, the mortality rates between EPI and ENDO did not differ. In sensitivity analyses the results were consistent results between the two PM types. The findings suggest that EPI may be associated with increased PM-lead failure compared to ENDO while threshold rise, infection, battery depletion and mortality rates did not differ.

A survival analysis of bipolar steroid-eluting and unipolar nonsteroid-eluting epicardial leads

INTRODUCTION

Epicardial pacemakers are known as an alternative for endocardial pacemakers in some cases such as heart block, and complex congenital heart diseases. Considering recent advances and improvement of epicardial lead subtypes, it is essential to investigate the long-term function of them. In this study, we aimed to assess the sensing and pacing characteristics, and survival of bipolar steroid-eluting and unipolar nonsteroid-eluting epicardial pacemakers.

METHODS

We conducted an entirely concentrated search on the documents of all patients who had undergone epicardial lead implantation in the Shaheed Rajaie Cardiovascular, Medical & Research Center during 2015-2018. Implant, and follow-up data were extracted. Kaplan-Meier analysis and Weibull regression hazards model were applied for the survival analysis.

RESULTS

Eighty-nine leads were implanted for 77 patients. Of the total leads, 52.81%, 53.93%, and 47.19% were implanted in children (under 18-year-old), females, and patients with congenital heart diseases, respectively. Bipolar steroid-eluting leads comprised 33.71% of 89 leads. The pacing threshold of unipolar nonsteroid-eluting leads that were implanted on the left ventricle and right atrium increased significantly during the follow-up to greater records than bipolar steroid-eluting leads. Survival analysis also revealed that bipolar steroid-eluting leads are significantly better in 48-month survival (Weibull hazard ratio [HR]: 0.13 (95% confidence interval [CI]: 0.02-0.99), p = .049). Age, ventricular location of the lead, and acute pacing characteristics were not associated with survival.

CONCLUSIONS

Bipolar steroid-eluting epicardial leads have an acceptable survival compared with unipolar nonsteroid-eluting, without a significant difference regarding patients age. Therefore, they could be an excellent alternative for endocardial ones.

A Review of the Recent Advances of Cardiac Pacemaker Technology in Handling Complications

The total number of annual pacemaker implantations continues to grow globally, and help patients with heart rhythm disorders with an improved quality of life and reduced mortality. The first implantable pacemakers appeared in 1965, characterized by their bulkiness, short battery life, and a single pacing mode. Innovation led to the modern pacemaker: a smaller system with improved battery life and capacity, and innovation in lead technology. Certain arrhythmia conditions may also qualify for leadless pacemaker implantation, thus eliminating the spectrum of complications that could occur with leads. Adverse events can be divided into acute (perforation, lead dislodgement, infection) and long-term (lead fractures, device infection, insulation failure). Traditional long-term complications with leads occur in 10% of patients, compared with device-related adverse effects observed in 6.7% of leadless pacemakers. Furthermore, cardiac pacemaker implantation results in quality of life improvements across all age groups. Large cardiac rehabilitation studies have demonstrated the effectiveness of exercise in reducing the physical complications involved with pacemaker implantation. Of the three randomized controlled trials examined, all of them reported some benefit of exercise in the intervention group compared with the control. The following review aims to discuss the multitude of pacemaker options potentially available for the clinician, complications, their course of management, and the path forward with innovations arising out of previous research within the field.

Permanent epicardial pacing in neonates and infants less than 1 year old: 12-year experience at a single center

BACKGROUND

Permanent epicardial pacing is the primary choice for neonates and infants with bradyarrhythmia. We reviewed mid-term outcomes after epicardial permanent pacemaker (EPPM) implantation in this age group.

METHODS

From Dec 1, 2008 to Dec 1, 2019, children who underwent EPPM implantation within the first year of life were included in our study. Patients were followed up for as long as 12 years, until Jun 11, 2021, for all-cause mortality and pacemaker reoperation. Kaplan-Meier and log-rank tests were used for analysis.

RESULTS

Of 31 consecutive patients [18 boys (58.1%) and 2 neonates (6.5%)] included in this study, 30 (96.8%) were discharged alive and assessed at a median follow-up of 3.9 years [interquartile range (IQR) 4.7]. The median age and weight of the patients were 156 days (IQR 217) and 5.3 kg (IQR 3.5), respectively, at the time of their operation. Twenty-five (80.6%) patients had congenital heart disease, and the main indication for pacing was postoperative atrioventricular block (AVB) in 21 (67.7%) patients. During follow-up, 3 (9.7%) patients died and there were a total of 9 pacing lead failures in 7 (22.6%) patients. The median longevity of leads (unipolar steroid-eluting) was 2.9 years (IQR 3.6). Freedom from lead reoperation was 90.3%, 72.0%, 65.5% and 49.1% at 1, 3, 5, and 8 years, respectively. The median longevity of the pacing generators was 3.3 years (IQR 2.8). Freedom from generator reoperation was 90.3%, 75.6%, 52.4% and 43.6% at 1, 3, 5 and 6 years, respectively.

CONCLUSIONS

The mid-term outcome of EPPM implantation in neonates and infants was acceptable. Neonates and infants with EPPM implants face the risk of repeated reoperations and all-cause death. A patient's prognosis can depend on regular follow-up, type of pacing lead and the presence of congenital heart malformations, especially complex congenital heart disease.

Mini right axillary thoracotomy for congenital heart defect repair can become a safe surgical routine

OBJECTIVE

Owing to its obvious cosmetic appeal, minimal invasive repair of congenital heart defects (CHDs) through the mini right axillary thoracotomy is becoming routine in many centres. Besides cosmesis, and before becoming a new norm, it is important to establish its outcomes as safe compared to repairs through traditional median sternotomy.

METHODS

Between 2013 and 2021, 116 consecutive patients underwent defect repairs through mini right axillary thoracotomy. Patient, operative data, and hospital outcomes were compared to contemporary mini right axillary thoracotomy and sternotomy series.

RESULTS

There was no mortality or need for approach conversion (mean age 4.3 years, range 0.17-17, mean weight 18.6 kg, range 4.8-74.4) in 118 repairs for atrial septal defect, ventricular septal defect, partial anomalous pulmonary venous return, partial atrioventricular canal with mitral cleft, scimitar syndrome, double-chambered right ventricle, cor triatriatum, and tricuspid valve repair. Protocol included on-table extubation, achieved in 97 children, with 23 outliers leading to 0.7 average hours of mechanical ventilation (range 0-66 hours), indwelling chest drain time of 2.6 days (range 1-9 days), intensive care stay of 1.8 days (range 1-10 days), and hospital stay of 3.9 days (range 2-18 days). Late revisions were required in one patient after scimitar repair for scimitar vein stenosis at 2 weeks, and in another for repair of superior caval vein stenosis after a Warden operation at 2 months; reoperations (5/116 = 4.3%) were successfully performed through the same mini right axillary incision.

CONCLUSIONS

While providing obvious cosmetic advantages, the minimally invasive right axillary thoracotomy approach for the surgical repair of common CHDs yields excellent results and is safe compared to the benchmark median sternotomy approach.

Etiology and device therapy in complete atrioventricular block in pediatric and young adult population: Contemporary review and new perspectives

Complete atrioventricular block (CAVB) is a total dissociation between the atrial and ventricular activity, in the absence of atrioventricular conduction. Several diseases may result in CAVB in the pediatric and young-adult population. Permanent right ventricular (RV) pacing is required in permanent CAVB, when the cause is neither transient nor reversible. Continuous RV apical pacing has been associated with unfavorable outcomes in several studies due to the associated ventricular dyssynchrony. This study aims to summarize the current literature regarding CAVB in the pediatric and young adult population and to explore future treatment perspectives.

Cardiac Implantable Electronic Devices in Hemodialysis and Chronic Kidney Disease Patients-An Experience-Based Narrative Review

Cardiovascular implantable electronic devices (CIEDs) are a standard therapy utilized for different cardiac conditions. They are implanted in a growing number of patients, including those with chronic kidney disease (CKD) and end-stage kidney disease (ESKD). Cardiovascular diseases, including heart failure and malignant arrhythmia, remain the leading cause of mortality among CKD patients, especially in ESKD. CIED implantation procedures are considered minor surgery, typically with transvenous leads inserted via upper central veins, followed by an impulse generator introduced subcutaneously. A decision regarding optimal hemodialysis (HD) modality and the choice of permanent vascular access (VA) could be particularly challenging in CIED recipients. The potential consequences of arteriovenous access on the CIED side are related to (1) venous hypertension from lead-related central vein stenosis and (2) the risk of systemic infection. Therefore, when creating permanent vascular access, the clinical scenario may be complicated by the CIED presence on one side and the lack of suitable vessels for arteriovenous fistula on the contralateral arm. These factors suggest the need for an individualized approach according to different clinical situations: (1) CIED in a CKD patient; (2) CIED in a patient on hemodialysis CIED; and (3) VA in a patient with CIED. This complex clinical conundrum creates the necessity for close cooperation between cardiologists and nephrologists.

Evaluation and Management of the Child and Adult With Fontan Circulation: A Scientific Statement From the American Heart Association

It has been 50 years since Francis Fontan pioneered the operation that today bears his name. Initially designed for patients with tricuspid atresia, this procedure is now offered for a vast array of congenital cardiac lesions when a circulation with 2 ventricles cannot be achieved. As a result of technical advances and improvements in patient selection and perioperative management, survival has steadily increased, and it is estimated that patients operated on today may hope for a 30-year survival of >80%. Up to 70 000 patients may be alive worldwide today with Fontan circulation, and this population is expected to double in the next 20 years. In the absence of a subpulmonary ventricle, Fontan circulation is characterized by chronically elevated systemic venous pressures and decreased cardiac output. The addition of this acquired abnormal circulation to innate abnormalities associated with single-ventricle congenital heart disease exposes these patients to a variety of complications. Circulatory failure, ventricular dysfunction, atrioventricular valve regurgitation, arrhythmia, protein-losing enteropathy, and plastic bronchitis are potential complications of the Fontan circulation. Abnormalities in body composition, bone structure, and growth have been detected. Liver fibrosis and renal dysfunction are common and may progress over time. Cognitive, neuropsychological, and behavioral deficits are highly prevalent. As a testimony to the success of the current strategy of care, the proportion of adults with Fontan circulation is increasing. Healthcare providers are ill-prepared to tackle these challenges, as well as specific needs such as contraception and pregnancy in female patients. The role of therapies such as cardiovascular drugs to prevent and treat complications, heart transplantation, and mechanical circulatory support remains undetermined. There is a clear need for consensus on how best to follow up patients with Fontan circulation and to treat their complications. This American Heart Association statement summarizes the current state of knowledge on the Fontan circulation and its consequences. A proposed surveillance testing toolkit provides recommendations for a range of acceptable approaches to follow-up care for the patient with Fontan circulation. Gaps in knowledge and areas for future focus of investigation are highlighted, with the objective of laying the groundwork for creating a normal quality and duration of life for these unique individuals.

A Stretchable and Flexible Cardiac Tissue-Electronics Hybrid Enabling Multiple Drug Release, Sensing, and Stimulation

Replacement of the damaged scar tissue created by a myocardial infarction is the goal of cardiac tissue engineering. However, once the implanted tissue is in place, monitoring its function is difficult and involves indirect methods, while intervention necessarily requires an invasive procedure and available medical attention. To overcome this, methods of integrating electronic components into engineered tissues have been recently presented. These allow for remote monitoring of tissue function as well as intervention through stimulation and controlled drug release. Here, an improved hybrid microelectronic tissue construct capable of withstanding the dynamic environment of the beating heart without compromising electronic or mechanical functionality is reported. While the reported system is enabled to sense the function of the engineered tissue and provide stimulation for pacing, an electroactive polymer on the electronics enables it to release multiple drugs in parallel. It is envisioned that the integration of microelectronic devices into engineered tissues will provide a better way to monitor patient health from afar, as well as provide facile, more exact methods to control the healing process.

Bioprosthetic tricuspid valve dysfunction in patients with transvalvular or epicardial pacing leads

BACKGROUND

Dysfunction of native tricuspid valves due to transvenous pacing leads is well described. Patients with bioprosthetic tricuspid valve (BTV) who need ventricular pacing are often advised epicardial lead placement to avoid potential damage to the BTV although there are no data to support this.

OBJECTIVE

The aim of the study was to assess the frequency of BTV dysfunction in patients with permanent transvenous right ventricular pacemaker lead and compare it to patients with epicardial leads.

METHODS

A retrospective review of patients with BTV with ventricular pacing lead was conducted. Demographics, lead, BTV, and echocardiographic data were collected. Frequency of BTV dysfunction (moderate or severe) regurgitation or stenosis was compared between epicardial and transvalvular lead groups.

RESULTS

Forty-six patients with BTV and ventricular pacing lead (20 transvalvular and 26 epicardial leads) were identified. Mean age was 46 years with the majority being female (85%) and with rheumatic heart disease (87%). Both groups were similar in age, sex, and indications for BTV. Mean echocardiographic follow-up was for 5.5 years (±4.1 years). BTV dysfunction was similar between the transvalvular group with six (30%) patients and the epicardial group with five (19.2%) patients. The incidence of BTV dysfunction was greater in patients in sinus rhythm compared to patients in atrial fibrillation (50% vs 10%, P  =  0.004).

CONCLUSION

Development of BTV dysfunction is similar in patients with transvalvular ventricular leads and epicardial leads. The incidence of BTV dysfunction was higher in patients with sinus rhythm compared to atrial fibrillation.

Surgical Outcomes of Permanent Epicardial Pacing in Neonates and Young Infants Less Than 1 Year of Age

BACKGROUND

Open surgical implantation of epicardial leads in neonates and infants remains the first option of treatment. We reviewed the long-term outcomes after epicardial pacemaker implantation in neonates and infants.

METHODS

From 1989 to 2016, 48 patients (16 neonates) underwent pacemaker implantation within the first year of life. Their median age and weight were 66.5days (range: 0∼319 days), and 4.2kg (range: 1.9∼9.3kg), respectively, at the time of first pacemaker implantation. The indications for pacemaker implantation were postoperative or congenital atrioventricular block, sinus node dysfunction, and/or myocarditis-induced atrioventricular block. Forty-six (46) unipolar epicardial leads (non-steroid-eluting: 22; steroid-eluting: 24) and two bipolar leads (steroid-eluting) were inserted using a median sternotomy or subxiphoid approach.

RESULTS

The mean follow-up duration was 8.5±7.9years. The most commonly used generator mode at first implantation was VVI (n=24, 50.0%). Eleven (11) generator mode changes from the initial VVI or VVIR to dual-chamber pacing were made at a mean of 7.0±6.2years after the first implantation for better inter-chamber synchrony and ventricular function. Freedom from reoperation for generator change after the first implantation was 95.3, 70.6, and 21.9% at 1, 5, and 10 years. Eighteen (18) lead malfunction events (34.1%) were detected. Freedom from reoperation for lead change was 97.8, 76.2, and 46.3% at 1, 5, and 10 years. The lead replacement rate was significantly higher in patients with non-steroid-eluting than steroid-eluting leads (p=0.045).

CONCLUSIONS

Neonates and infants require more frequent changes in pacemaker generator and leads than the older population. The use of steroid-eluting leads increased lead longevity and reduced the need for surgical re-interventions.

Multi-site multi-polar left ventricular pacing through persistent left superior vena cava in tricuspid valve disease

Multi-site multi-polar left ventricular pacing through the coronary sinus (CS) may be preferred over endocardial right ventricular or surgical epicardial pacing in the presence of tricuspid valve disease. However, the required lead placement can be difficult through a persistent left superior vena cava (PLSVC), as the CS tends to be hugely dilated and side branches tend to have sharp angulations (>90°) when approached from the PLSVC. Pre-shaped angiography catheters and techniques used for finding venous grafts from the ascending aorta post coronary bypass surgery may help with lead placement in such a situation.

Epicardial left ventricular leads via minimally invasive technique: a role of steroid eluting leads

Background

We retrospectively assessed two types of sutureless screw-in left ventricular (LV) leads (steroid eluting vs. non-steroid eluting) in cardiac resynchronization therapy (CRT) implantation with regards to their electrical performance.

Methods

Between March 2008 and May 2014 an epicardial LV lead was implanted in 32 patients after failed transvenous LV lead placement using a left-sided lateral minithoracotomy or video-assisted thoracoscopy (mean age 64 ± 9 years). Patients were divided into two groups according to the type of implanted lead. Steroid eluting (SE) group: 21 patients (Myodex™ 1084 T; St. Jude Medical) and non-steroid eluting (NSE) group: 11 patients (MyoPore® 511,212; Greatbatch Medical).

Results

All epicardial leads could be placed successfully, without any intraoperative complications or mortality. With regard to the implanted lead following results were observed: sensing (mV): SE 8.8 ± 6.1 vs. NSE 10.1 ± 5.3 (p = 0.380); pacing threshold (V@0.5 ms): SE 1.0 ± 0.5 vs. NSE 0.9 ± 0.5 (p = 0.668); impedance (ohms): SE 687 ± 236 vs. NSE 790 ± 331 (p = 0.162). At the follow-up (2.6 ± 1.9 years) the following results were seen: sensing (mV): SE 8.7 ± 5.0 vs. NSE 11.2 ± 6.6 (p = 0.241), pacing threshold (V@0.5 ms): SE 1.4 ± 0.5 vs. NSE 1.0 ± 0.3 (p = 0.035), impedance (ohms): SE 381 ± 95 vs. NSE 434 ± 88 (p = 0.129).

Conclusions

Based on the results no strong differences have been found between the both types of epicardial LV leads (steroid eluting vs. non-steroid eluting) in CRT implantation in short- and midterm.

Robotic-Assisted Left Ventricular Lead Placement

Robot-assisted left ventricular lead implantation for cardiac resynchronization therapy is a feasible and safe technique with superior visualization, dexterity, and precision to target the optimal pacing site. The technique has been associated with clinical response and beneficial reverse remodeling comparable with the conventional approach via the coronary sinus. The lack of clinical superiority and a residual high nonresponder rate suggest that the appropriate clinical role for the technique remains as rescue therapy.

Robotic-Assisted Left Ventricular Lead Placement

Robot-assisted left ventricular lead implantation for cardiac resynchronization therapy is a feasible and safe technique with superior visualization, dexterity, and precision to target the optimal pacing site. The technique has been associated with clinical response and beneficial reverse remodeling comparable with the conventional approach via the coronary sinus. The lack of clinical superiority and a residual high nonresponder rate suggest that the appropriate clinical role for the technique remains as rescue therapy.

Complications and Risk Assessment of 25 Years in Pediatric Pacing

BACKGROUND

Children who require cardiac pacemaker implantation have presented a small patient sub-population since the breakthrough of this technology in the 1950s and 1960s. Their small bodies result in a technical challenge for the operating surgeon and put the patient at risk for a series of specific complications. Our study aims to analyze complications and to identify risk factors of endocardial and epicardial pacemaker systems in children.

METHODS

All pacemaker-related operations in pediatric patients up to the age of 18 years from 1985 through 2010 were retrospectively evaluated. Demographic data including age, height, and weight were recorded. Idiopathic and postoperative dysrhythmias were analyzed separately.

RESULTS

A total of 149 pacemaker operations were performed in 73 patients. Thirty-two patients did not have a previous cardiac operation. Indications for revision included box exchange, lead-related problems, pacemaker pocket complications, impaired left ventricular function, and pectoral muscle stimulation. Increased pacing thresholds occurred in 17.2% of the patients with epicardial leads compared with 2.9% in the endocardial group. Aside from threshold-related revision, lead problems are more common in the endocardial group (30.4% vs 17.2%). Venous thrombosis occurred in 13.7% of the patients (only endocardial), preferentially (25%) in the weight group less than 15 kg and in idiopathic patients (15.6% vs 10.5% with prior cardiac surgery).

CONCLUSIONS

Cardiac pacing is particularly challenging in the pediatric patient population facing a large number of reoperations during their lifetime. The lack of clear superiority of either epicardial or endocardial pacing systems requires an individual concept.

Femoral approach: an exceptional alternative for permanent pacemaker implantation

The classic transvenous implantation of a permanent pacemaker in a pectoral location may be precluded by obstruction of venous access through the superior vena cava or recent infection at the implant site. When these barriers to the procedure are bilateral and there are also contraindications or technical difficulties to performing a thoracotomy for an epicardial approach, the femoral vein, although rarely used, can be a viable alternative. We describe the case of a patient with occlusion of both subclavian veins and a high risk for mini-thoracotomy or videothoracoscopy, who underwent implantation of a permanent single-chamber pacemaker via the right femoral vein.

Long-term follow-up shows excellent transmural atrial lead performance in patients with complex congenital heart disease

BACKGROUND

Many patients with congenital heart disease require permanent pacing for rhythm management but cannot undergo transvenous lead placement. In others, epicardial scarring prohibits adequate sensing and pacing thresholds using epicardial leads. This study describes long-term lead performance using a transmural atrial (epicardial to endocardial) pacing approach in patients with congenital heart disease.

METHODS AND RESULTS

For transmural atrial (TMA) lead access, a bipolar, steroid-eluting transvenous lead was placed from the epicardium via purse-string incision or atriotomy and affixed to atrial endocardium. Records were reviewed for patient data and acute and long-term lead performance for TMA leads placed 1998 to 2004. Forty-two of 48 TMA leads remain active at last follow-up. Two leads fractured, 4 were functional at >5-year follow-up but no longer active. Freedom from lead failure 98% (95% confidence interval, 86%-100%) at mean follow-up 7.8 years. TMA leads gave excellent sensing and pacing characteristics at implant and chronically. Median acute and chronic sensing thresholds were 3 and 2.8 mV, respectively; median acute and chronic pacing thresholds at 0.5 ms were 0.9 and 0.7 V, respectively. TMA leads performed similarly in Fontan patients. Overdrive pacing for intra-atrial re-entrant tachycardia was successful in 7 of 8 patients. One patient with high baseline risk died of stroke 7 years after implant. No lead-associated thrombi were observed.

CONCLUSIONS

TMA pacing leads had excellent longevity, initial, and chronic functional properties and provide an alternative to epicardial leads in patients with congenital heart disease. Patients who cannot receive transvenous leads, have epicardial scarring or have intra-atrial re-entrant tachycardia could benefit most from routine use of this technique.

Performance of steroid eluting bipolar epicardial leads in pediatric and congenital heart disease patients: 15 years of single center experience

Objective

Cardiac pacing is sometimes required for patients with congenital heart disease for various reasons. Because of complex anatomy, repetitive previous heart surgery and patient size, epicardial leads are of special importance in these patients. Using epicardial leads has been discussed controversly regarding pacing performance and lead survival. The aim of this study was to review the long-term data on pacing performance as well as lead survival of epicardial leads implanted in our center.

Methods

Retrospective chart review and review of the literature.

Results

82 consecutive pediatric patients or adult patients with congenital heart disease with 158 epicardial leads (Medtronic 4968, bipolar, steroid - eluting) were included. We found 1.2% pacemaker-related early postoperative complications. The incidence of lead dysfunction was 7.5% (12/158) for primary (i.e. directly related to the lead itself) lead dysfunction and 3.2% (5/158) of lead abandonment for reasons not directly related to the lead itself. Primary lead dysfunction occured after a median of 3.83 years. Lead survival at 2, 5 and 10 years was 98.7%, 93% and 92.4%. There were no infections reported. Stable median measurements for impedance (RA/RV/LV of 577/483/610 Ohm), sensing threshold (RA/RV/LV of 2.0/11.0/10.0 mV) and pacing threshold (RA/RV/LV of 0.75 V at 0.4 ms/1.0 V at 0.49 ms/1.0 V at 0.45 ms) indicated a good mid- to longterm performance. The only risk factor for primary lead dysfunction was young age at implantation.

Conclusion

The use of epicardial leads in pediatric and adult patients with congenital heart disease shows good longterm outcomes in terms of pacing performance and lead survival. The authors encourage using epicardial leads in patients with congenital heart disease based on the patient‘s individual characteristics.

Drug release mechanisms of steroid eluting rings in cardiac pacemaker lead electrodes

This paper reports on the drug release mechanisms of silicone structures with embedded steroids applied in pacing leads. Different derivatives of the steroid dexamethasone, which is associated with the reduction of acute stimulation thresholds, were evaluated together with different matrix based release control mechanisms with the target to potentially match optimal drug release rates during the first month after implantation. By incorporating dexamethasone-21-dihydrogen phosphate in silicone matrices in combination with release rate adaption layers, almost continuous release rates were obtained under physiological test settings.

Failure of epicardial pacing leads in congenital heart disease: not uncommon and difficult to predict

AIMS

We evaluate the incidence of epicardial lead failure and try to identify risk factors in patients with congenital heart disease.

METHODS

All patients with a congenital heart defect and an epicardial pacing system, implanted within a timeframe of 25 years, were included in this study. Patients' medical records and lead data were reviewed. Lead failure was defined as the primary endpoint.

RESULTS

In total 198 active epicardial leads (atrial 40, ventricular 158) were implanted in 93 patients (median age at implantation 4.4 years (range 0-58.6)). During a total follow-up of 1235 lead-years, 29 lead failures (14.6%, 4 atrial, 25 ventricular) were documented in 22 patients (23.7%). Lead failure occurred at a median time period of 4.8 years (range 1.2-24.1) after implantation. Five-year freedom of lead failure was 88%. The only independent predictor for lead failure was the age at implantation (HR 0.44; 95%CI 0.20-0.97, p = 0.04), other characteristics failed to predict lead failure. Sudden cardiac death occurred in four patients (4.3%), in one a lead failure was documented.

CONCLUSION

A high incidence of epicardial lead failures is found in patients with congenital heart disease. Unfortunately, it is difficult to predict this potentially life-threatening complication.

Permanent epicardial pacing in children: long-term results and factors modifying outcome

AIMS

To evaluate the results of permanent epicardial pacing in children.

METHODS AND RESULTS

All consecutive patients from one country (n = 119, period 1977-2009) undergoing permanent epicardial pacemaker implantation at <18 years of age (median 1.8 years, inter-quartile range 0.3-6.4 years) were studied retrospectively. Median patient follow up was 6.4 years (inter-quartile range 2.9-11.1 years); 207 generators, 89 atrial and 153 ventricular pacing leads were implanted. The probability of absence of any pacing system dysfunction was 70.1 and 47.2% at 5 and 10 years after implantation, respectively. Overall probability of continued epicardial pacing was 92.8 and 76.1% at 5 and 10 years, respectively, and increased in the recent implantation era (post-2000, P = 0.04). The use of steroid-eluting leads decreased the risk of exit block with a hazard ratio (HR) of 0.20 [95% confidence interval (CI) 0.09-0.44, P < 0.001)]. The use of bipolar Medtronic 4968 leads reduced the risk of surgical reintervention because of fracture, insulation break, outgrowth or exit block in comparison to the unipolar 4965 lead design (HR 0.12, 95% CI 0.04-0.40, P < 0.001). The AutoCapture™ feature (HR 0.08, 95% CI 0.02-0.36, P < 0.001) and steroid-eluting leads (HR 0.30, 95% CI 0.11-0.84, P = 0.021) decreased the risk of battery depletion.

CONCLUSION

The probability of continued epicardial pacing in children was 76% at 10 years after implantation, increased for implantation in recent years, and allowed transvenous pacing to be deferred to a significantly greater age. The use of bipolar steroid-eluting leads and of a beat-to-beat capture tracking feature significantly increased pacing system longevity and decreased the need for surgical reinterventions.

Discovery and management of diaphragmatic hernia related to abandoned epicardial pacemaker wires in a pregnant woman with {S,L,L} transposition of the great arteries

Epicardial pacemaker leads placed during childhood are often not removed when transvenous systems are placed later in life. The risk of complications related to retained pacemaker leads and generators is not clear but is generally considered low. We report the case of a 23-year-old pregnant woman who presented with left upper quadrant pain at 20 weeks gestation. The patient was born with {S,L,L} transposition of the great arteries and had high-grade conduction disease in infancy compelling epicardial pacemaker placement. A standard transvenous pacemaker was placed at age 9 years, without removal of the epicardial system. The patient's abdominal pain was attributed to herniation of abdominal contents through a diaphragmatic defect at the site of the abandoned epicardial pacing wire. Her pain improved spontaneously but worsened later in pregnancy leading to repair of the diaphragmatic hernia via anterolateral thoracotomy at 30 weeks gestation. The procedure was well tolerated by mother and fetus. At 38 3/7 weeks gestation, the patient underwent uneventful delivery by cesarean section for breech presentation. This case illustrates the importance of multidisciplinary collaboration in the care of women with congenital heart disease.

A single institution experience with pacemaker implantation in a pediatric population over 25 years

BACKGROUND

With the development of new technical devices and software more appropriate for pediatric patients, pacemaker implantations in children and young adults have increased over time. It is necessary to monitor the mid- and long-term consequences. The decision for the implantation of a cardiovertor defibrillator (ICD) in children remains challenging despite technical improvements.

OBJECTIVE

To assess the safety of pacemaker implantation in children, to review old and new indications, and to point out changes of management over time.

PATIENTS AND METHODS

Between 1984 and 2009, 181 patients required the implantation of a pacemaker or an ICD device at the Heart and Diabetes Centre in Bad Oeynhausen, Germany. Their charts have been reviewed pro- and retrospectively for indications, complications, longevity of the device, and the natural course.

RESULTS

Indications have been high-degree atrioventricular block in 65% (postoperative 55%) and sinus node dysfunction in 24% (postoperative 90%), including three patients with vasovagally mediated significant bradycardia. Eleven percent required the implantation of an ICD device secondary to significant ventricular arrhythmias. The indication was class II in one-third of all patients. Complications requiring revision occurred in six patients (3.3%); one of them required removal of the device due to an infection. Ten patients died, but none related to pacemaker implantation.

CONCLUSION

Pacemaker implantation even in young pediatric patients is generally safe. No complication led to the death of a patient. The number of class II indications has been increasing. The future aim is to improve pediatric algorithms and to prevent unnecessary pacing.

Ventricular pacing-induced loss of contractile function and development of epicardial inflammation

Perturbations in the normal sequence of ventricular activation can create regions of early and late activation, leading to dysynchronous contraction and areas of dyskinesis. Dyskinesis occurs across the left ventricular (LV) wall, and its presence may have important consequences on cardiac structure and function in normal and failing hearts. Acutely, dyskinesis can trigger inflammation and, in the long term (6 wk and above), leads to LV remodeling. The mechanisms that trigger these changes are unknown. To gain further insight, we used a canine model to evaluate transumural changes in myocardial function and inflammation induced by epicardial LV pacing. The results indicate that 4 h of LV suprathreshold pacing resulted in a 30% local loss of endocardial thickening. Assessment of neutrophil infiltration showed a significant approximately fivefold increase in myeloperoxidase activity in the epicardium versus the midwall/endocardium. Matrix metalloproteinase-9 activity increased ∼2 fold in the epicardium and ROS generation increased ∼2.5-fold compared with the midwall/endocardium. To determine the effects that electrical current alone has on these end points, a group of animals was subjected to subthreshold pacing. Significant increases were observed only in epicardial myeloperoxidase levels. Thus, the results indicate that transmural dyskinesis induced by suprathreshold epicardial LV activation triggers a localized epicardial inflammatory response, whereas subthreshold stimulation appears to solely induce the trapping of leucocytes. Suprathreshold pacing also induces a loss of endocardial function. These results may have important implications as to the nature of the mechanisms that trigger the inflammatory response and possibly long-term remodeling in the setting of dysynchrony.

Fontan "Ten Commandments" revisited and revised

Choussat's "Ten Commandments," which describes the components of an ideal Fontan candidate, was first published in 1977. Despite the wisdom in these commandments, it is clear from a historic perspective that total compliance with all criteria does not necessarily portend excellent long-term survival. I believe the end point of the original commandments should be modified to include improvement in long-term survival. I suggest the following single commandment: "Thou Shalt Be Perfect."

Future Developments in Nonsurgical Epicardial Therapies

The unique anatomic position of the pericardium in juxtaposition to central cardiac structures enables it to serve as the ideal vantage point for the delivery of novel cardiovascular therapies. Development of new tools to permit delivery of therapy in the closed pericardial space holds promise for near-surgical access to the heart, without open surgical morbidity. Early observations raise hope for the availability of epicardial leads to enhance cardiac resynchronization therapy designed for subxiphoid nonsurgical percutaneous delivery. Emerging technologies for left atrial appendage ligation may offer new strategies for preventing stroke.

Permanent atrial pacing lead implant route after Fontan operation

BACKGROUND

Atrial pacing is indicated for sinus node dysfunction (SND) after Fontan surgery; preferred lead implantation technique is debated. We compare outcomes of transvenous (TV) and epicardial (Epi) atrial lead implants in this population.

METHODS

Retrospective review of Fontan patients undergoing atrial lead implant between 1992 and 2007. Demographics, lead performance data, and outcomes were analyzed.

RESULTS

78 patients had 90 leads implanted: 25 via TV route and 65 via Epi route. Median follow-up was 1.6 years (TV) and 3.6 years (Epi). TV leads were implanted in older patients (23.1 vs 9.3 years, P < 0.001) and at longer intervals after Fontan (15.2 vs 4.9 years, P < 0.001). Pacing indication for most TV leads was SND, while Epi leads were also indicated for atrioventricular block. Acute complication rates were similar (8% TV vs 19% Epi, P = 0.23), but median hospital stay was shorter for TV (2 vs 5 days, P = 0.03). Thrombus was observed in five patients (two in TV; three in Epi), but no thromboembolic events were observed. Mean lead survival was similar (TV 9.9 vs Epi 7.8 years, P = NS). Energy threshold was lower at implant for TV leads (0.9 vs 2.2 microJ, P = 0.049), but similar at follow-up (1.2 vs 2.6 microJ, P = 0.35). Atrial sensing was unchanged over time for TV (2.2 to 2.1 mV, P = NS), but decreased for Epi (3.3 to 2.5 mV, P = 0.02).

CONCLUSIONS

Compared to epicardial leads, transvenous atrial pacing leads may be placed in Fontan patients with lower procedural morbidity and equivalent expectation of lead performance and longevity.

Intra-diaphragmatic pacemaker implantation in very low weight premature neonate

Implantation of a pacemaker (PM) in very low weight premature neonates can be a challenging procedure because of the actual dimension of generators. Ideal placement of the PM is still controversial. We describe a technique of intra-diaphragmatic PM implantation in a 1.3 kg neonate.