Endocardial and epicardial steroid lead pacing in the neonatal and paediatric age group

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.

Transvenous lead extraction in children with bidirectional rotational dissection sheaths

Objectives

Due to the limited longevity of endovascular leads, children require thoughtful lifetime lead management strategies including conservation of access vessel patency. Consequently, there is an increasing interest in transvenous lead extraction (TLE) in children, however, data on TLE and the use of powered mechanical dissection sheaths is limited.

Methods

We performed a retrospective cohort study analyzing all children <18 years that underwent TLE in our institution from 2015 to 2022. Procedural complexity, results and complications were defined as recommended by recent consensus statements.

Results

Twenty-eight children [median age 12.8 (interquartile range 11.3-14.6) years] were included. Forty-one leads were extracted [median dwell time 85 (interquartile range 52-102) months]. Extractions of 31 leads (76%) in 22 patients (79%) were complex, requiring advanced extraction tools including powered bidirectional rotational dissection sheaths in 14 children. There were no major complications. Complete procedural success was achieved in 18 (64%) and clinical success in 27 patients (96%), respectively. Procedural success and complexity varied between lead types. The Medtronic SelectSecure™ lead was associated with increased odds of extraction by simple traction (p = 0.006) and complete procedural success (p < 0.001) while the Boston Scientific Fineline™ II lead family had increased odds of partial procedural failure (p = 0.017).

Conclusions

TLE with the use of mechanical powered rotational dissection sheaths is feasible and safe in pediatric patients. In light of rare complications and excellent overall clinical success, TLE should be considered an important cornerstone in lifetime lead management in children. Particular lead types might be more challenging and less successful to extract.

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.

In vitro and in vivo studies on the biocompatibility of a self-powered pacemaker with a flexible buckling piezoelectric vibration energy harvester for rats

Background

Scavenging energy from biomechanical motions in vivo by energy converting devices, i.e., implantable harvesters, to obtain sustainable electrical energy is the ideal way to power implantable medical devices which require long term and continuous power supply. A novel self-powered cardiac pacemaker is designed to achieve self-powered pacing. The kinetic energy of the heart was collected by an implanted piezoelectric energy collector and supplied to the cardiac pacemaker, and then the cardiac tissue was stimulated by the pacing electrode pierced from the outside of the heart to realize effective pacing effect and self-powered pacing. In this study, we evaluated the stability and biocompatibility of our previously described flexible buckling piezoelectric vibration energy harvester in vitro and in vivo. The biocompatibility, in vivo stability, and safety of the self-powered pacemaker with a flexible flexion piezoelectric vibratory energy harvesting device prepared were analyzed by performing cell and in vivo animal experiments.

Methods

The MTT(3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to detect the cell proliferation of H9C2 cells and HUVECs at 24, 48, and 72 hours. Computed tomography (CT) and cardiac ultrasound were used to evaluate the position and heart rate of pacemakers 12 weeks after implantation, and the changes of plasma biochemical indexes were detected by a biochemical detector.

Results

At 12 weeks after implantation, CT results showed that there were no changes in the position of the self-powered pacemaker. The device implanted into the thoracic cavity of rats demonstrated certain effects on cardiac function, while it did not have a significant effect on their blood biochemical indexes.

Conclusions

the flexible buckling piezoelectric vibratory energy collector did not produce adverse effects on the myocardial tissue or on the normal proliferation of myocardial cells.

Minimally Invasive Epicardial Pacemaker Implantation in Neonates with Congenital Heart Block

BACKGROUND

Few studies have characterized the surgical outcomes following epicardial pacemaker implantation in neonates with congenital complete atrioventricular block (CCAVB).

OBJECTIVE

This study sought to assess the long-term outcomes of a minimally invasive epicardial approach using a subxiphoid access for pacemaker implantation in neonates.

METHODS

Between July 2002 and February 2015, 16 consecutive neonates underwent epicardial pacemaker implantation due to CCAVB. Among these, 12 (75.0%) had congenital heart defects associated with CCAVB. The patients had a mean age of 4.7 ± 5.3 days and nine (56.3%) were female. Bipolar steroid-eluting epicardial leads were implanted in all patients through a minimally invasive subxiphoid approach and fixed on the diaphragmatic ventricular surface. The pulse generator was placed in an epigastric submuscular position.

RESULTS

All procedures were successful, with no perioperative complications or early deaths. Mean operating time was 90.2 ± 16.8 minutes. None of the patients displayed pacing or sensing dysfunction, and all parameters remained stable throughout the follow-up period of 4.1 ± 3.9 years. Three children underwent pulse generator replacement due to normal battery depletion at 4.0, 7.2, and 9.0 years of age without the need of ventricular lead replacement. There were two deaths at 12 and 325 days after pacemaker implantation due to bleeding from thrombolytic use and progressive refractory heart failure, respectively.

CONCLUSION

Epicardial pacemaker implantation through a subxiphoid approach in neonates with CCAVB is technically feasible and associated with excellent surgical outcomes and pacing lead longevity.

Long-term outcome of transvenous pacemaker implantation in infants: a retrospective cohort study

AIM

Evaluation of long-term outcome of transvenous pacemaker (PM) implantation in infants.

METHODS AND RESULTS

A retrospective analysis of all transvenous PM implantations in infants <10 kg between September 1997 and October 2001 was made. Indications for PM implantation, age at implantation, and determinants of long-term outcome including cardiac function, PM function, and PM (system) complications were noted. Seven patients underwent transvenous VVI(R) PM implantation. Median age at implantation was 3 days (range: 1 day to 14 months), median weight 3.5 kg (range: 2.3-8.7 kg), and median follow-up 14 years (range: 12.3-16.3 years). Pacemaker indications were congenital complete atrioventricular block (n = 4), long QT syndrome with heart block (n = 2), and post-operative complete atrioventricular block with sinus node dysfunction (n = 1). No procedural complications were noted. Today all patients are alive and symptom free with good PM and cardiac function. Two patients underwent PM generator relocation for imminent skin necrosis and skin traction. Two patients suffered from asymptomatic left subclavian vein occlusion and developed thrombosis on the PM electrode. Three patients were converted to an epicardial PM system, due to atrial perforation after upgrading procedure (n = 1), syncope with need for implantable cardioverter defibrillator implantation (n = 1), and systolic dysfunction with development of dilated cardiomyopathy, which normalized under cardiac resynchronization therapy pacing (n = 1). Two patients needed atrioventricular (AV) valve repair for severe insufficiency. Two patients underwent repositioning of dysfunctional PM leads. In five patients, transvenous leads were removed. Indications were elective lead replacement (n = 1), atrial perforation (n = 1), and switch to an epicardial system (n = 3).

CONCLUSION

Transvenous PM implantation in infants (<10 kg) is associated with a high incidence of vascular occlusion, thrombosis, and severe atrioventricular valve regurgitation during long-term follow-up. We advocate an epicardial approach for PM implantation in small children.

Low incidence of complications after cephalic vein cutdown for pacemaker lead implantation in children weighing less than 10 kilograms: A single-center experience with long-term follow-up

BACKGROUND

Only a few studies on the cephalic vein cutdown technique for pacemaker lead implantation in children weighing ≤10 kg have been reported even though the procedure is widely accepted in adults.

OBJECTIVE

The purpose of this study was to prove that cephalic vein cutdown for pacemaker lead implantation is a reliable technique with a low incidence of complications in children weighing ≤10 kg.

METHODS

The study included 44 children weighing ≤10 kg with an endocardial pacemaker. Cephalic, subclavian, and axillary vein diameters were measured by ultrasound before implantation. The measured diameters were used to select either an endocardial or epicardial surgical technique. Regular 6-month follow-up visits included pacemaker interrogation and clinical and ultrasound examinations.

RESULTS

Two dual-chamber and 42 single-chamber pacemakers were implanted. Mean weight at implantation was 6.24 kg (range 2.25-10.40 kg), and mean age was 11.4 months (range 1 day-47 months). In 40 children (90.1%), the ventricular leads were implanted using the cephalic vein cutdown technique, and implantation was accomplished via the prepared right external jugular vein in 4 of the children (9.9%). The atrial leads were implanted using axillary vein puncture and external jugular vein preparations. Mean follow-up was 8.9 years (range 0-20.9 years). Only 1 pacemaker-related complication was detected (a lead fracture near the connector that was successfully resolved using a lead repair kit).

CONCLUSION

The cephalic vein cutdown technique is feasible and reliable in children weighing ≤10 kg, which justifies the application of additional surgical effort in the treatment of these small patients.

Implantation of VVI epicardial pacemaker through mini-sternotomy in a patient with superior vena cava occlusion after radiotherapy

The paper presents a case report of a patient with a superior vena cava occlusion and post-operational (after the implantation of the aortic valve) atrioventricular block, which required constant stimulation. An epicardial VVI pacemaker was implanted through mini-sternotomy in the lower part of the previous operation field with very satisfactory stimulation parameters. Implantation of a screw-in epicardial lead is in some cases the method of choice, which provides efficient and constant heart stimulation.

Prophylactic epicardial left ventricular lead implantation for biventricular pacing during operations

BACKGROUND

Surgical epicardial left ventricular (LV) lead implantation for biventricular pacing has advantages over the transvenous approach in cardiac surgical patients. We investigated the benefit of concomitant prophylactic LV lead implantation during open heart operations and subsequent lead performance after patients with impaired LV function receive a biventricular device.

METHODS

Retrospective data of 4,844 patients undergoing cardiac operations through a sternotomy between January 2001 and December 2011 were analyzed. Of these, 380 patients (7.8%) had severe impairment of LV function (contrast left ventriculogram showing grade 4 estimated ejection fraction or echocardiogram showing LV ejection fraction<0.30). LV lead implantation was performed in patients in whom recovery of LV function was unlikely. Lead performance data were collected at follow-up.

RESULTS

LV lead implantation occurred in 95 patients (25%), and 29 (30.5%) subsequently received a biventricular device. Of patients with impaired LV function, more patients with prophylactic LV leads underwent biventricular implant than those without LV leads (30.5% vs 1.1%, p<0.0001). The median interval from LV lead implantation to connection to a biventricular device was 30 days (interquartile range, 5.5 to 145 days). At a median follow-up of 437.5 days (interquartile range, 13.8 to 1198 days), the mean pacing threshold (1.25±0.46 vs 1.58±0.66 volts, p=0.069) and impedance (383.81±70.33 vs 448.6±200.1 Ohms, p=0.168) remained stable compared with time of biventricular device connection.

CONCLUSIONS

A significant proportion of patients with poor LV function undergoing cardiac operations may benefit from concomitant LV lead implantation. Subsequent lead performance appears satisfactory. Epicardial LV lead placement is easily accomplished during open heart operations and should be considered before the operation.

Cardiac pacing in paediatric patients with congenital heart defects: transvenous or epicardial?

AIMS

Cardiac pacing is a difficult technique in children, particularly in patients with congenital heart defects (CHDs). Few studies to date have addressed this topic.

METHODS AND RESULTS

We performed a retrospective analysis of the results of a single centre. Between 1982 and 2008, 287 patients with CHD, median age of 5 years (25-75%, 1-11) underwent cardiac pacing for sinus node dysfunction (SND) and atrioventricular block (AVB); 97% of patients underwent at least one heart surgery. Endocardial systems (Endo) were implanted in 117 patients, epicardial systems (Epi) in 170, with 595 leads (228 Endo, 367 Epi). Endocardial systems showed a significantly older age group with more frequent SND; Epi a younger age group, with more frequent AVB, greater number of surgical interventions. Perioperative complications were mortality 0.6% (Epi), pericardial effusion 0.6% (Epi), and haemothorax 3.4% (Endo). The median follow-up is 5 (2-10) years: the pacing system failed in 29% of patients, 13% Endo, and 40% Epi (P < 0.0001). Multivariate analysis showed a significantly higher risk of failure for Epi, a lower implant age, greater the number of leads implanted. The risk of malfunction of the leads increases significantly for Epi and the younger age when implanted. The steroid-eluting leads have a lower risk of malfunction (P = 0.05), steroid-eluting Endo leads provide significantly better outcomes than Epi.

CONCLUSION

Cardiac pacing in paediatric patients with CHD shows satisfactory results in the long term. Endocardial systems show significantly better results than Epi systems. A younger age when implanted is a risk factor for complications at follow-up.

Permanent cardiac pacing in pediatric patients

Pediatric pacemaker (PM) implants comprise less than 1 % of all PM implants. This study aimed to investigate permanent cardiac pacing among the pediatric population, identifying different indications and complications of pediatric cardiac pacing, especially focusing on the effect of the pacing sites, the PM lead type, and the indications for pacing. The current work is a cross-sectional study of 103 procedures for permanent PM insertion in pediatric patients between January 2001 and December 2010. The patients were followed up 1, 3, and 6 months after implantation, then every 6 months or as needed. Evaluation included routine clinical examination, electrocardiography, chest X-ray, echocardiography, and a full analysis of the pacing system measurements. The ages of the patients ranged from 0.09 to 12 years (median, 2.3 years). The most common indication for pacing was postoperative complete heart bock, noted in 54 patients (52.4 %). Transvenous endocardial PM insertion was performed in 92 procedures (89.3 %), whereas transthoracic epicardial insertion was performed in 11 procedures (10.7 %). The most common site of pacing was the right ventricular apex (n = 64, 62 %), followed by the right ventricular outflow tract (n = 25, 24.3 %). Transthoracic epicardial PM insertion was associated with a significantly higher percentage and greater severity of complications. In this study, 65 % of the patients with left ventricle (LV) dilation before pacing showed a significant improvement in LV dimensions and function after pacing. This was noted only in those with endocardially inserted PM leads in both the congenital and the postoperative groups regardless of the pacing site. Endocardial PM insertion in children is a safe procedure with fewer complications and a lower ventricular threshold than the epicardial route. Permanent single-chamber right ventricle pacing is safe and can lead to significant improvement in LV function and dimensions. However, long-term follow-up assessment is needed for further evaluation.

Long-term outcome of transvenous bipolar atrial leads implanted in children and young adults with congenital heart disease

AIMS

Atrial leads are often implanted in paediatric patients needing a pacemaker (PM). The aim of this study is the evaluation of their outcome in young patients.

METHODS AND RESULTS

We evaluated transvenous atrial leads outcome in children and young adults from a single centre, with a retrospective analysis. A P< 0.05 was considered significant. Between 1992 and 2008, 110 patients, 75 with congenital heart defects (d-transposition of great arteries status/post, s/p, Mustard 41%, atrioventricular septal defect 11%, tetralogy 9%, ventricular septal defect 8%), aged 13.3 ± 5.3 years, underwent PM implantation with bipolar atrial transvenous leads for sinus node dysfunction (50%), atrioventricular block (38%), cardiomyopathies, and primary ventricular arrhythmias (12%). Leads are steroid-eluting (98%), tined (59%), screw-in (41%), polyurethane-insulated (72%), silicone-insulated (28%), and have been positioned by transcutaneous puncture of subclavian vein into right atrial appendage/remnant (RAA, 50%), right atrial free wall/septum (25%), left atrium (s/p Mustard, 25%). Follow-up duration is 6.4 ± 4.8 (range 0.1-18) years. At multivariate analysis, younger age at implant was a risk factor for lead failure (4 leads, 3.5%) (P= 0.03); 16 leads (14%) dislodged post-implantation and 12 were successfully repositioned, the others extracted or abandoned. Dislocation occurred more frequently with screw-in leads (P= 0.03) positioned outside RAA (P= 0.02). Atrial threshold showed a small but significant increase, 0.002 V/month (P< 0.001), impedance showed a decrease (0.6 Ω/month, P< 0.001), P-wave showed no significant difference.

CONCLUSIONS

Transvenous bipolar atrial leads have good long-term results in young patients, with a very low rate of lead failure. Older age at implant can further reduce this rate. Lead dislodgement is frequent in the post-operative period.

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.

Long-term follow-up after steroid-eluting epicardial pacemaker implantation in young children: a single centre experience

AIMS

The purpose of this paper is the retrospective investigation of the clinical outcome and modes of failure leading to reoperation, as well as the report of the long-term results, in a group of young children who underwent epicardial pacemaker implantation.

METHODS AND RESULTS

Between 2000 and 2008, 45 young children underwent epicardial pacemaker implantation at 3.2 +/- 2.5 years of age for congenital (n = 27) or post-operative (n = 18) atrioventricular block. The follow-up time was 5.7 years +/- 5 months (range: 6 months to 7.3 years). Five lead malfunction events (11%) were detected during the follow-up time, three of which were due to ventricular lead fracture. All revisions could be performed without complications, and all revised pacemakers showed stable pacing and sensing parameters during long-term follow-up. The actuarial freedom from reoperation at 6 years was 88.8 +/- 2%. Median epicardial ventricular and atrial pacing thresholds were stable and excellent at the latest follow-up, with means of 1.1 +/- 0.5 V and 0.7 +/- 0.8 V, respectively.

CONCLUSION

In our patient cohort of 45 young children, epicardial pacing was associated with a satisfactory clinical outcome and acceptable long-term results. The major cause of reoperation in our series was lead fracture. Reoperations were performed at a low risk.

Equivalent performance of epicardial versus endocardial permanent pacing in children: a single institution and manufacturer experience

BACKGROUND

Children requiring permanent pacing have a lifelong need for follow-up. Epicardial leads have traditionally fared worse than endocardial counterparts. We tested the hypothesis that steroid-eluting epicardial and endocardial leads had equivalent outcomes.

METHODS

We reviewed medical records of 148 children, mean age 8.2 +/- 4.8 years, in whom a dual-chamber pacemaker system with steroid-eluting leads from a single manufacturer was implanted. Primary outcome was mortality. Secondary outcomes included freedom from lead failure and pacemaker system reintervention. Loss of capture-sensing, lead displacement-fracture, exit block, and high thresholds constituted lead failure. Reintervention included need for lead revision or generator change.

RESULTS

There was no early mortality. Late mortality occurred once (0.5 +/- 0.5 deaths/1,000 patient-months) and eight times (3.4 +/- 1.2 deaths/1,000 patient-months) in the endocardial and epicardial groups, respectively. The relative hazard of endocardial versus epicardial site for lead failure was 0.408 (p = 0.038) and for reintervention was 0.629 (p = 0.002). Endocardial and epicardial groups differed in important ways: concomitant cardiac surgery 5% (3 of 61) versus 27% (27 of 99); congenital heart disease 33% (20 of 61) versus 90% (89 of 99); single ventricle physiology 13% (8 of 61) versus 52% (51/99); and age (10.5 +/- 4.5 years vs 5.5 +/- 5.2 years). Adjusting for these covariants, the relative hazard for freedom from lead failure for endocardial versus epicardial leads was 0.546 (p = 0.360). The adjusted relative hazard for freedom from reintervention was 0.157 (p = 0.045).

CONCLUSIONS

Technologic advances attenuate important differences in lead failure rates between endocardial and epicardial steroid-eluting pacing leads and thus bridge the performance gap between these fixation modes.

Percutaneous permanent pacemaker implantation via the azygous vein in a patient with superior vena cava occlusion

Occlusion of the superior vena cava (SVCO) makes implantation of permanent pacemakers challenging and difficult. We describe an extended application of a Medtronic Attain (Medtronic Inc., Minneapolis, MN, USA) guide catheter (a tool designed for delivery of left ventricular pacing leads into the coronary sinus) for delivery of a right ventricular pacing lead via the azygous vein in a 72-year-old woman with SVCO secondary to long-term central venous hemodialysis catheters. This approach allowed the use of an endocardial pacing lead, implantation under local anesthesia, and conventional positioning of the pacemaker generator in the pectoral region in a patient with SVCO.

Single-centre experience on endocardial and epicardial pacemaker system function in neonates and infants

AIMS

Endocardial (ENDO) or epicardial (EPI) pacing systems are implanted in infants but it remains unclear which system should be preferred.

METHODS AND RESULTS

We evaluated the results of children <or=1 year who underwent pacemaker (PM) implantation at our centre with a retrospective analysis. Between 1992 and 2004, 56 patients, 37 of whom had other congenital heart defects (CHDs), received a PM at 4.4 +/- 3.8 months of age for atrioventricular block (n = 52) and sinus node dysfunction. Rate-responsive ventricular demand pacing (VVIR) PMs were implanted in 25 patients (19 ENDO), dual-chamber demand pacing (DDD) in 29, and rate-responsive atrial demand pacing (AAIR) in 2 (all EPI). Follow-up (FU) was 4.5 +/- 3.5 (range 0.3-13) years: 15 pacing system failures occurred among the 56 patients (26%) after 4.5 +/- 3.2 years, with a significantly reduced success rate for EPI (21-fold increase of the risk of failure) and complex CHD. Also in patients without surgery for CHD, EPI showed a worse outcome. Among the 91 leads implanted, failures occurred more significantly in EPI (18% of atrial, 24% of ventricular leads) than in ENDO (5% of ventricular leads). No venous occlusion was found at FU.

CONCLUSIONS

Single-lead, VVIR ENDO pacing had higher efficiency and safety than EPI, and it might be the best choice for PM implantation in infants. However, because of small patient numbers and lack of longer FU, these findings should be treated with caution.

Evolution of left ventricular function in paediatric patients with permanent right ventricular pacing for isolated congenital heart block: a medium term follow-up

AIMS

We aimed to assess the evolution of left ventricular (LV) systolic function in children with right ventricular apical (RVA) pacing for isolated congenital heart block (ICHB) and to identify possible predictors of LV function deterioration. Right ventricular apical pacing can be detrimental to LV function in a significant number of adults. Effects in children are still controversial.

METHODS AND RESULTS

Left ventricular shortening fraction (LV SF) and QRS duration were retrospectively assessed in 45 children with RVA pacing for ICHB: before pacemaker (PM) implantation, immediately after and then regularly during a follow-up of 58.69 +/- 45.23 months. Patients were categorized as stable or deteriorators according to an arbitrarily chosen cut-off point of > or =7% decrease in LV SF. Lupus status was unknown. Overall LV SF did not change significantly (41.42% +/- 8.21 before pacing, 39.77% +/- 7.03 immediately after PM implant, 37.43% +/- 9.91 with chronic pacing, P = NS). Deteriorators (n = 13) had significantly higher baseline heart rate (57.5 +/- 8.7 vs. 46.9 +/- 10.5 bpm, P < 0.05) and baseline LV SF (46.17 +/- 8.13 vs. 38.4 +/- 6.4%; P < 0.05), a significantly higher proportion of them being implanted before 2 years of age: 8 of 13 (61.5%) vs. 5 of 25 (20%) in the stable group (P < 0.05). Deteriorators had a higher incidence of an initial epicardial lead and narrower native QRS.

CONCLUSION

Permanent RVA pacing for ICHB does not necessarily affect LV function in children. The risk of deterioration of LV function seems to be higher in children with higher baseline heart rate and better baseline LV SF, especially with pacing at a younger age, a narrower native QRS and RVA epicardial pacing site.

Superior vena cava stenting and transvenous pacemaker implantation (stent and pace) after the Mustard operation

The Mustard operation for transposition of the great arteries is associated with good long-term survival. Typical complications at follow-up include progressive loss of sinus node function requiring permanent pacemaker implantation, and systemic venous pathway obstruction often precluding a transvenous approach to pacing. We report on 7 patients (median age 14.1; range 5-19) with bradyarrhythmia requiring permanent pacemaker implantation with associated stenosis (n = 6) or occlusion (n = 1) of the superior vena cava, in whom stent implantation relieved the obstruction and facilitated subsequent transvenous permanent pacing. In five of them stenting and pacemaker implantation were performed during a single procedure; two patients underwent elective pacemaker implantation 6 weeks later. In one patient the pacemaker had to be explanted due to pacemaker pocket infection. In the others the follow-up has been uneventful, with excellent chronic pacing thresholds and appropriate sensing. Two patients have had their generator replaced electively.We conclude that stenting of the SVC stenosis allows implantation of transvenous pacemaker leads with good intermediate term results in patients with a Mustard operation for transposition of the great arteries.

Transhepatic approach for catheter interventions in infants and children with congenital heart disease

We report on our experience with transhepatic access for catheter interventions in six children (age range 2.5 months-9 years). Three had systemic venous anomalies, and one infant a femoral venous occlusion. In two further patients with bradyarrhythmia after a Fontan operation with an intraatrial Gore-Tex tunnel, transhepatic access was chosen to achieve a perpendicular orientation of the transseptal needle to the atrial baffle, allowing puncture of the Gore-Tex membrane. Two of the patients underwent ablation of an accessory pathway; in one an atrial septal defect was closed. A 2.5 month old baby after Norwood I operation, underwent balloon dilation of the pulmonary arteries. Two patients after prior Fontan surgery underwent DDDR pacemaker implantation. The size of the introducer sheath ranged from 4 F up to two 9 F introducers in the same vein for pacemaker insertion. At the end of the procedure, hemostasis was achieved by external compression.

RESULTS

Transhepatic access could be established in all six patients (using a mirror image approach in children with left atrial isomerism) and the interventional procedures could be performed as planned. In one patient with implantation of a permanent pacemaker, a subcutaneous hematoma occurred, requiring blood transfusion.

CONCLUSION

In selected pediatric patients, transhepatic access for catheter intervention can easily be achieved.

Fractally coated myocardial pacemaker leads in children

We report our single centre experience with a new fractally coated myocardial unipolar lead (ELC35UP; Biotronik) in 96 pediatric patients (59% male, 41% female). Congenital heart disease (CHD) was associated in 89%. The age at implantation ranged between 2 days and 19 years, median for children with CHD 7.8 years, without CHD 4.7 years. Twenty percent of the children were younger than one year at implantation. Mean follow-up was 30 months (1-57 months). We compared our findings with a steroid eluting epicardial lead (CapSure EPI 4968; Medtronic) in 46 children with comparable age and sex-distribution. We found a lead survival of 87% after 57 months in the ELC35UP group (steroid lead: 87% after 129 months). Pacing energy thresholds were equal after 12 months (median 3.0 microjoules), but the sensing characteristics of the fractally coated lead was significantly superior to the steroid eluting lead with median R waves of 7.0 mV (steroid lead: 3.5 mV) after 12 months. Children with myocardial scar tissue requiring pacemaker therapy after surgery of CHD showed no differences in sensing and pacing thresholds in comparison to children with congenital rhythm disorders. The fractally coated screw-in lead offers technical advantages concerning the subxiphoidal implantation procedure.

CONCLUSION

Fractally coated ventricular screw-in leads represent a feasible alternative to the common steroid eluting leads- especially in children requiring pacemaker therapy after surgery for CHD.

Comparison of Modern Steroid-Eluting Epicardial and Thin Transvenous Pacemaker Leads in Pediatric and Congenital Heart Disease Patients

OBJECTIVE

Optimal pacemaker lead choice in pediatric patients eligible for either epicardial or transvenous leads remains unclear. We compared performances of modern thin transvenous (TTV) and steroid-eluting epicardial (SEE) leads in patients followed at one pediatric center.

METHODS

Retrospective review of patients with qualifying leads implanted from August 1997 to March 2004. Threshold energy (TE) at implant and follow-up, sensing thresholds, lead complications, and repeat pacing-related procedures were analyzed. Lead performances were compared using t-tests, Wilcoxon rank-sum tests and Cox regression. Survival curves were plotted using Kaplan-Meier analysis.

RESULTS

A total of 370 implant procedures, 521 leads, and 1549 visits were evaluated. In all, 256 leads were SEE (49%, 184 implants) and 265 were TTV (51%, 186 implants). Median follow-up was 29 months (range 1-80 months). Patients with SEE systems were younger at implant (6 vs. 17 yrs, p < 0.001), and more had congenital heart defects (82% vs. 57%, p < 0.001). At follow-up, ventricular TEs were higher for SEE leads at implant (p < 0.001), 1 month (p < 0.001), and up to 4 years (p = 0.019). When compared across all follow-up durations combined, TTV TEs were significantly lower than SEE TEs for both atrial and ventricular leads (p < 0.001). A total of 70 repeat procedures were performed in 60 patients during the study period, which comprised 18% of SEE and 14% of TTV system patients (p = NS). In all, 18 TTV and 19 SEE leads failed (p = NS). Estimated freedom from lead failure at 1, 3, and 5 years was 97%, 88%, 85% for TTV leads and 96%, 92%, and 58% for SEE leads (log rank P = NS).

CONCLUSIONS

Both SEE and TTV leads showed good mid-term performance and survival in our cohort. Higher TEs seen for SEE leads, especially ventricular and unipolar leads, may result in higher current drain and thus more generator replacements than TTV systems. Lead failure rates were comparable across lead types. TTV leads offer a promising alternative to SEE systems in terms of performance for young patients without intracardiac shunting who do not require open-chest surgery for another indication.

Patient, procedural, and hardware factors associated with pacemaker lead failures in pediatrics and congenital heart disease

OBJECTIVES

To examine outcomes of children with pacemakers over a 22-year period and identify risk factors for lead failure.

BACKGROUND

Small patient size, structural cardiac abnormalities, and growth may complicate pediatric pacemaker management. Better knowledge of risk factors for lead failure in these patients may help improve future outcomes.

METHODS

All pacemaker patients followed at one pediatric center 1980-2002 were included. Lead failures were identified retrospectively as leads repaired, replaced, or abandoned due to fracture, insulation break, dislodgement, or abnormalities in pacing or sensing. Risk factors were identified using logistic regression and Cox analyses.

RESULTS

A total of 1007 leads were implanted in 497 patients during the study period (5175 lead-years). Median age at implant was 9 years (0-55); 64% of patients had structural congenital heart disease. Median follow-up time was 6.2 years (0-22). Lead failure occurred in 155 leads (15%), and 115 patients (23%), with 28% of patients experiencing multiple failures. Significant independent correlates of lead failure included age <12 years at implant, history of structural congenital heart defects, and epicardial lead placement. Younger patients (<12 years) experienced significantly more lead fractures than older children (P = .005), while patients with congenital heart defects experienced more exit block. Epicardial leads were more likely to fail due to fracture or exit block, while transvenous leads failed more due to insulation breaks or dislodgements.

CONCLUSIONS

Pediatric pacing patients have a high incidence lead failures. These occur most commonly in younger patients, structural congenital heart disease, and those with epicardial lead systems. Approaches to pacing system implantation and follow-up in these patients need to be individualized, with special attention to minimizing risk of lead failures. Our findings suggest that expanded utilization of transvenous systems in smaller patients seems justified when anatomy permits.

Emergent permanent pacemaker implantation in a premature 1,502 g neonate

We report a case of an emergent pacemaker implantation in a 1,502 g preterm neonate immediately after birth due to congenital complete atrioventricular block. At a gestational age of 29 weeks the patient was delivered by cesarean section followed by unsuccessful drug treatment of the atrioventricular block. Sixty-five minutes after birth the patient underwent permanent pacemaker implantation. Through a subxyphoid approach, a lead was fixed to the epicardium of the right ventricle, and connected to a pulse generator inserted between the rectus abdominus muscle and posterior rectus sheath. The patient is alive and well 16 months after the operation without pacemaker failure.

Pacing activity, patient and lead survival over 20 years of permanent epicardial pacing in children

BACKGROUND

We report on pediatric epicardial pacing activity, patient and lead survival for more than two decades in a single center.

METHODS

The data cover 96 pacing leads implanted in 59 patients. Median age at implantation was 1.9 years (1 day to 18.2 years). Forty-four percent had structural cardiac disease. Most frequent indications for pacing were postoperative (42%) and congenital complete heart block (42%).

RESULTS

Median activity was 3 pacing leads per year; 326 patient pacing years were observed (median 11.9 years; range, 1.1 to 22 years). Death due to pacemaker failure occurred in a single patient. Lead failure occurred in 33 of 96 leads (median of 28 months postimplantation) with lead fracture the commonest cause (47%). Risk factors for lead failure were decade of implant and nonsteroid eluting leads. Acute implant energy thresholds were significantly lower for steroid than nonsteroid eluting leads but did not predict subsequent lead failure.

CONCLUSIONS

The epicardial approach has offered an effective solution to pacing problems in the pediatric age range. Lead survival has improved with more than 75% of modern steroid eluting leads surviving to 5 years.