Permanent cardiac pacing in pediatric patients

Is the use of gonad protection protectors necessary during infants chest radiography?

INTRODUCTION AND OBJECTIVES

To compare gonad doses with and without a gonad protector and to optimize the use of gonadal protectors in infants thorax radiography.

MATERIALS AND METHODS

Two pediatric anthropomorphic phantoms are used: an X-ray system for KXO-50SS/DRX-3724HD, and a digital radiography system for CALNEO Smart C12, with and without a gonad protector during infants thorax radiography. A real time skin dosimeter is placed on the X-ray system, and a real time skin dosimeter is inserted on the front side of the mammary gland, the front and back sides of the true pelvis level, and on the ovaries and testes. The X-ray system is irradiated 15 times using phantoms with and without a gonad protector. The measured entrance patient doses values of for the real time skin dosimeter are compared for each phantom, with and without the gonad protector.

RESULTS

The medium of measured entrance patient doses values for front side dose of the true pelvis level with and without the protector are 10.00 and 5.00 μGy at newborn, and 10.00 and 0.00μGy at one year, respectively. The medium of measured entrance patient doses values for the back side dose of the true pelvis level with and without the protector are 0.00 and 0.00 μGy at both newborn one year, respectively. The measured entrance patient doses cannot be detected in the ovaries and testes with or without the protector. No significant differences are observed in the measured entrance patient doses values for the front and back side doses of the pelvis, ovaries, and testes at newborn and one year, with and without the protector (p>0.05).

CONCLUSIONS

No significant difference was observed in gonad dose measurements with and without the gonad protector during infants chest radiography. We believe that gonadal protector wearing is not necessary.

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.

Lead Management in Patients with Congenital Heart Disease

Pediatric patients with congenital heart disease present unique challenges when it comes to cardiac implantable electronic devices. Pacing strategy is often determined by patient size/weight and operator experience. Anatomic considerations, including residual shunts, anatomic obstructions and barriers, and abnormalities in the native conduction system, will affect the type of CIED implanted. Given the young age of patients, it is important to have an "eye on the future" when making pacemaker/defibrillator decisions, as one can expect several generator changes, lead revisions, and potential lead extractions during their lifetime.

Percutaneous epicardial pacing in infants using direct visualization: A feasibility animal study

BACKGROUND

Pacemaker implantation in infants and small children is limited to epicardial lead placement via open chest surgery. We propose a minimally invasive solution using a novel percutaneous access kit.

OBJECTIVE

To evaluate the acute safety and feasibility of a novel percutaneous pericardial access tool kit to implant pacemaker leads on the epicardium under direct visualization.

METHODS

A custom sheath with optical fiber lining the inside wall was built to provide intrathoracic illumination. A Veress needle inside the illumination sheath was inserted through a skin nick just to the left of the xiphoid process and angled toward the thorax. A needle containing a fiberscope within the lumen was inserted through the sheath and used to access the pericardium under direct visualization. A custom dilator and peel-away sheath with pre-tunneled fiberscope was passed over a guidewire into the pericardial space via modified Seldinger technique. A side-biting multipolar pacemaker lead was inserted through the sheath and affixed against the epicardium.

RESULTS

Six piglets (weight 3.7-4.0 kg) had successful lead implantation. The pericardial space could be visualized and entered in all animals. Median time from skin nick to sheath access of the pericardium was 9.5 (interquartile range [IQR] 8-11) min. Median total procedure time was 16 (IQR 14-19) min. Median R wave sensing was 5.4 (IQR 4.0-7.3) mV. Median capture threshold was 2.1 (IQR 1.7-2.4) V at 0.4 ms and 1.3 (IQR 1.2-2.0) V at 1.0 ms. There were no complications.

CONCLUSION

Percutaneous epicardial lead implantation under direct visualization was successful in six piglets of neonatal size and weight with clinically acceptable acute pacing parameters.

Evaluation of different lead types and implantation techniques in pediatric populations with permanent pacemakers: Single-center with 10 years' experience

BACKGROUND

Permanent pacemaker (PM) implantation is performed for various indications and by different techniques in children; however, many problems with lead performance are encountered during follow-up. This study aims to evaluate the possible effects of different lead types and implantation techniques on pacing at early and midterm in children with a permanent PM.

PATIENTS AND METHODS

Pediatric patients who underwent permanent PM system implantation at our tertiary cardiac surgery center between January 1, 2010 and January 1, 2020 were evaluated retrospectively. Patients were categorized in the epicardial pacing lead (EP), transvenous pacing lead (TP), and transvenous bipolar lumenless (Select Secure [SS]) lead groups according to the lead implantation technique and lead type with the same manufacturer. Groups were evaluated statistically for demographic features, pacing type and indication for implantation, lead electrical performance, lead failure, complications, and outcome.

RESULTS

Over 10 years, 323 lead implantations were performed on 167 patients (96 males, median age 68 months [5 days-18 years]). Of 323 leads, 213 (66%) were EP, 64 (20%) were TP, and 46 (14%) were SS. Of the total, 136 of the leads were implanted in atria, and 187 were implanted in ventricles. Primary pacing indications were postoperative complete atrioventricular (AV) block (n = 95), congenital AV block (n = 71), sinus node dysfunction (n = 13), and acquired complete AV block (n = 1). Additional cardiac diseases were present in 115 patients (69%). No statistically significant difference was observed in gender, syndrome, or pacing indication (P > .05). Atrial and ventricular capture, threshold, sensing, and lead impedance measurements were not significantly different at the initial and follow-up periods (P > .05). The median follow-up duration was 3.3 years (6 months-10 years). Twenty lead failures were determined in 15 patients (EP: 14 lead failures in 10 patients; TP: two lead failures in two patients; and SS: four lead failures in three patients) during follow-up, and no statistically significant difference was found between groups (P = .466). The 5-year lead survival was 98% for TP, 95% for EP, and 90% for SS; the 10-year lead survival was 90% for TP, 70% for EP, and 70% for SS. There was no mortality related to chronic pacing or due to the procedure of implantation.

CONCLUSIONS

Despite improvements in technology, lead failure is still one of the most critical problems during these patients' follow-up. Early to midterm lead survival rates of all three lead types were satisfactory.

Percutaneous epicardial placement of a prototype miniature pacemaker under direct visualization: An infant porcine chronic survival study

INTRODUCTION

Pacemaker implantation in infants typically consists of surgical epicardial lead placement with an abdominal generator. Here, we describe the chronic performance of our minimally invasive prototype miniature pacemaker implanted under direct visualization in an immature porcine model.

METHODS

Twelve piglets underwent miniature pacemaker implantation. A self-anchoring two-channel access port was inserted into a 1 cm incision in the subxiphoid space, and a thoracoscope was inserted into the main channel to visualize the thoracic cavity under insufflation. The pacemaker leadlet was inserted through a sheath via secondary channel and affixed against the epicardium using a helical side-biting electrode. The miniature pacemaker was tucked into the incision, which was sutured closed. Ventricular sensing, leadlet impedance, and capture thresholds were measured biweekly. A limited necropsy was performed after euthanasia.

RESULTS

Nine piglets were followed for a median of 78 (IQR 52-82) days and gained 6.6 ± 3.2 kg. Three animals were censored from the analysis due to complications unrelated to the procedure. Capture thresholds rose above maximal output after a median of 67 (IQR 40-69) days. At termination, there was a significant decrease in R-wave amplitude (P = .03) and rise in capture thresholds at 0.4 ms (P = .01) and 1.0 ms pulse widths (P = .02). There was no significant change in leadlet impedance (P = .74). There were no wound infections.

CONCLUSIONS

There were no infections following minimally invasive implantation of our prototype miniature pacemaker. Improvements to epicardial fixation are necessary to address diminished leadlet efficacy over time.

Congenital heart block: Pace earlier (Childhood) than later (Adulthood)

Congenital complete heart block (CCHB) occurs in 2-5% of pregnancies with positive anti-Ro/SSA and/or anti-La/SSB antibodies, and has a recurrence rate of 12-25% in a subsequent pregnancy. After trans-placental passage, these autoantibodies attack and destroy the atrioventricular (AV) node in susceptible fetuses with the highest-risk period observed between 16 and 28 weeks' gestational age. Many mothers are asymptomatic carriers, while <1/3 have a preexisting diagnosis of a rheumatic disease. The mortality of CCHB is predominant in utero and in the first months of life, reaching 15-30%. The diagnosis of CCHB can be confirmed by fetal echocardiography before birth and by electrocardiography after birth. Whether early in-utero detection and treatment might prevent or reverse this condition remains controversial. In addition to autoantibody-associated CCHB, there is also an isolated (absent structural heart disease) nonimmune early- or late-onset heart block detected later in childhood that may be associated with specific genetic markers or other pathogenic mechanisms. In isolated immune or non-immune CCHB, cardiac pacemakers are implanted in symptomatic patients, however, data on the natural history of CCHB in the adult life indicate that all patients, even if asymptomatic, should receive a pacemaker when first diagnosed. However, important issues have emerged in these patients wherein life-long conventional right ventricular apical pacing may produce left ventricular dysfunction (pacing-induced cardiomyopathy) necessitating a priori alternate site pacing or subsequent upgrading to biventricular pacing. All these issues are herein reviewed and two algorithms are proposed for diagnosis and management of CCHB in the fetus and in the older individual.

Minimally invasive percutaneous epicardial placement of a prototype miniature pacemaker with a leadlet under direct visualization: A feasibility study in an infant porcine model

BACKGROUND

Pacemaker implantation in infants is limited to epicardial lead placement and an abdominal generator pocket. We propose a minimally invasive solution using a prototype miniature pacemaker with a steroid-eluting leadlet that can affix against the epicardium under thoracoscopy.

OBJECTIVE

The purpose of this study was to evaluate the safety and feasibility of acute implantation of a prototype miniature pacemaker in an infant porcine model.

METHODS

A self-anchoring 2-channel access port was inserted into a 1-cm incision left of the subxiphoid space. A rigid thoracoscope with variable viewing angle was inserted through the main channel to visualize the heart under insufflation. An 18-G needle through the second channel accessed the pericardial space, which was secured with a 7-F sheath. The leadlet was affixed against the epicardium using a distal helical side-biting electrode. The sheath, thoracoscope, and port were removed, and the pacemaker was tucked into the incision. Ventricular sensing, lead impedances, and capture thresholds were measured.

RESULTS

Twelve piglets (weight 4.8 ± 1.9 kg) had successful device implantation. The median time from incision to leadlet fixation was 21 minutes (interquartile range [IQR] 18-31 minutes). The median lead impedance was 510 Ω (IQR 495-620 Ω). The median R-wave amplitude was 5.7 mV (IQR 4.2-7.0 mV). The median capture threshold was 1.63 V (IQR 1.32-2.97 V) at 0.4 ms pulse width and 1.50 V (IQR 1.16-2.38 V) at 1.0 ms pulse width. There were no complications.

CONCLUSION

Minimally invasive epicardial placement of a prototype miniature pacemaker under thoracoscopy was safe and avoided open chest surgery and creation of an abdominal generator pocket.

Transvenous Versus Epicardial Pacing in Fontan Patients

Up to 10% of Fontan patients require pacemakers; an epicardial approach has historically been used. A transvenous approach can be used but carries risk of Fontan obstruction, thromboembolism, and can be technically challenging. The safety and efficacy of these approaches is not well described. The aim of this study was to compare epicardial and transvenous pacemaker outcomes in Fontan patients, specifically, device performance and adverse event rate. A retrospective review was performed on Fontan pacemaker patients followed at a single institution. Thirty-one Fontan pacemaker patients were identified between 1985 and 2017. Twenty-six had an epicardial system, five transvenous, and three converted from epicardial to transvenous. Average atrial lead sensing at placement was 3.23 versus 2.35 mV (p = 0.52) for epicardial and transvenous leads, respectively. Median atrial and ventricular lead longevity was 86.4 versus 98.8 months (p = 0.56) and 73.2 versus 140 months (p = 0.3) with generator longevity of 65.5 versus 73.9 (p = 0.16) months for epicardial versus transvenous systems, respectively. One major complication occurred in a transvenous patient, and two minor complications occurred in epicardial patients. All transvenous patients received warfarin except one, who converted to dabigatran. Epicardial patients received aspirin (n = 20), warfarin (n = 3) or a warfarin/aspirin combination (n = 3). No thromboembolic events occurred. System revision was required in 13 epicardial and 5 transvenous patients. There were two deaths, none related to the pacemaker system. Transvenous pacemakers can be utilized with equal efficacy compared to epicardial pacemakers with trends toward longer lead longevity in transvenous pacemaker systems.

Role of cardiac pacing in congenital complete heart block

INTRODUCTION

Congenital complete heart block affects 1/15,000 live-born infants, predominantly due to atrioventricular nodal injury from maternal antibodies of mothers with systemic lupus erythermatosus or Sjogren's syndrome. The majority of these children will need a pacemaker implanted prior to becoming young adults. This article will review the various patient and technical factors that influence the type of pacemaker implanted, and the current literature on optimal pacing practices. Areas covered: A literature search was performed using PubMed, Embase and Web of Science. Data regarding epicardial versus transvenous implants, pacing-induced ventricular dysfunction, alternative pacing strategies (including biventricular pacing, left ventricular pacing, and His bundle pacing), and complications with pacemakers in the pediatric population were reviewed. Expert commentary: There are numerous pacing strategies available to children with congenital complete heart block. The risks and benefits of the initial implant should be weighed against the long-term issues inherent with a life-time of pacing.

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.

Efficacy of Subcutaneous Electrocardiogram Leads for Synchronous Timing During Chronic Counterpulsation Therapy

Counterpulsation devices (CPDs) require an accurate, reliable electrocardiogram (ECG) waveform for triggering inflation and deflation. Surface electrodes are for short-term use, and transvenous/epicardial leads require invasive implant procedure. A subcutaneous ECG lead configuration was developed as an alternative approach for long-term use with timing mechanical circulatory support (MCS) devices. In this study, efficacy testing was completed by simultaneously recording ECG waveforms from clinical-grade epicardial (control) and subcutaneous (test) leads in chronic ischemic heart failure calves implanted with CPD for up to 30 days. Sensitivity and specificity of CPD triggering by R-wave detection was quantified for each lead configuration. The subcutaneous leads provided 98.9% positive predictive value and 98.9% sensitivity compared to the epicardial ECG leads. Lead migration (n = 1) and fracture (n = 1) were observed in only 2 of 40 implanted leads, without adversely impacting triggering efficacy due to lead redundancy. These findings demonstrate the efficacy of subcutaneous ECG leads for long-term CPD timing and potential use as an alternative method for MCS device timing.

Congenital and childhood atrioventricular blocks: pathophysiology and contemporary management

Atrioventricular block is classified as congenital if diagnosed in utero, at birth, or within the first month of life. The pathophysiological process is believed to be due to immune-mediated injury of the conduction system, which occurs as a result of transplacental passage of maternal anti-SSA/Ro-SSB/La antibodies. Childhood atrioventricular block is therefore diagnosed between the first month and the 18th year of life. Genetic variants in multiple genes have been described to date in the pathogenesis of inherited progressive cardiac conduction disorders. Indications and techniques of cardiac pacing have also evolved to allow safe permanent cardiac pacing in almost all patients, including those with structural heart abnormalities.

CONCLUSION

Early diagnosis and appropriate management are critical in many cases in order to prevent sudden death, and this review critically assesses our current understanding of the pathogenetic mechanisms, clinical course, and optimal management of congenital and childhood AV block.

WHAT IS KNOWN

• Prevalence of congenital heart block of 1 per 15,000 to 20,000 live births. AV block is defined as congenital if diagnosed in utero, at birth, or within the first month of life, whereas childhood AV block is diagnosed between the first month and the 18th year of life. As a result of several different etiologies, congenital and childhood atrioventricular block may occur in an entirely structurally normal heart or in association with concomitant congenital heart disease. Cardiac pacing is indicated in symptomatic patients and has several prophylactic indications in asymptomatic patients to prevent sudden death. • Autoimmune, congenital AV block is associated with a high neonatal mortality rate and development of dilated cardiomyopathy in 5 to 30 % cases. What is New: • Several genes including SCN5A have been implicated in autosomal dominant forms of familial progressive cardiac conduction disorders. • Leadless pacemaker technology and gene therapy for biological pacing are promising research fields. In utero percutaneous pacing appears to be at high risk and needs further development before it can be adopted into routine clinical practice. Cardiac resynchronization therapy is of proven value in case of pacing-induced cardiomyopathy.

Single chamber permanent epicardial pacing for children with congenital heart disease after surgical repair

Background

To analyze the 10-year experience of single chamber permanent epicardial pacemaker placement for children with congenital heart diseases (CHD) after surgical repair.

Methods

Between 2002 and 2014, a total of 35 patients with CHD (age: 26.9 ± 23.2 months, weight: 9.7 ± 5.6 kg) received permanent epicardial pacemaker placement following corrective surgery. Echocardiography and programming information of the pacemaker, as well as major adverse cardiac events (MACE) as heart failure or sudden death, were recorded during follow-up (46.8 ± 33.8 months).

Results

Acute ventricular stimulation threshold was 1.34 ± 0.72 V and no significant increase was observed at the last follow-up as 1.37 ± 0.81 V (p = 0.93). Compared with initial pacemaker implantation, the last follow-up didn’t show significant increases in impedance (p = 0.327) or R wave (p = 0.635). Four patients received pacemaker replacement because of battery depletion. 7/35 (20 %) of patients experienced MACE. Although the age and body weight were similar between patients with and without MACE, the patients with MACE were with complex CHD (100 % vs.55.6 %, p = 0.04).

Conclusion

High-degree iatrogenic atrioventricular block was the primary reason for placement of epicardial pacemaker for patients with CHD after surgical repair. Pacemaker placement with the steroid-eluting leads results in acceptable outcomes, however, the pacemaker type should be optimized for the children with complex CHD.

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.

Pacemaker remote monitoring in the pediatric population: is it a real solution?

BACKGROUND

Clinical utility of remote monitoring of implantable cardiac devices has been previously demonstrated in several trials in the adult population. The aim of this study was to assess the clinical utility of remote monitoring in a pediatric population undergoing pacemakers implantation.

METHODS

The study population included 73 consecutive pediatric patients who received an implantable pacemaker. The remote device check was programmed for every 3 months and all patients had a yearly out-patient visit. Data on device-related events, hospitalization, and other clinical information were collected during remote checks and out-patient visits.

RESULTS

During a mean follow-up of 18 ± 10 months, 470 remote transmissions were collected and analyzed. Two deaths were reported. Eight transmissions (1.7%) triggered an urgent out-patient visit. Twenty percent of transmissions reported evidence of significant clinical or technical events. All young patients and their families were very satisfied when using remote monitoring to replace out-patient visits.

CONCLUSIONS

The ease in use, together with satisfaction and acceptance of remote monitoring in pediatric patients, brought very good results. The remote management of our pediatric population was safe and remote monitoring adequately replaced the periodic out-patient device checks without compromising patient safety.

A Case of Transvenous Pacemaker Implantation in a 10-year-old Patient

Objective: The aim of this report was to discuss the type, timing, and surgical techniques of permanent pacemaker implantation in a juvenile patient.

Patients: A 17-year-old girl with Down syndrome and congenital heart defects comprised of ventricular septal defects (VSD) and patent ductus arteriosus (PDA) suffered from postoperative complete atrioventricular block (AVB) when she was 7 months old.

Methods and Results: An epicardial pacemaker was implanted just after the occurrence of complete AVB. Due to the pacing threshold of a ventricular lead not being good, the battery showed rapid depletion. Her generator had to be exchanged under general anesthesia every 2–3 years. When she was 10 years old, we implanted a permanent pacemaker transvenously by using cutdown, screw-in and subpectoral pocket techniques. She has shown a satisfactory outcome since then.

Conclusion: Transvenous pacemaker implantation was safe and effective in our young patient without any complications. The timing of surgery and surgical technique are quite important for pacemaker implantation in juvenile patients.

Stem cell-based biological pacemakers from proof of principle to therapy: a review

Electronic pacemakers are the standard therapy for bradycardia-related symptoms but have shortcomings. Over the past 15 years, experimental evidence has demonstrated that gene and cell-based therapies can create a biological pacemaker. Recently, physiologically acceptable rates have been reported with an adenovirus-based approach. However, adenovirus-based protein expression does not last more than 4 weeks, which limits its clinical applicability. Cell-based platforms are potential candidates for longer expression. Currently there are two cell-based approaches being tested: (i) mesenchymal stem cells used as a suitcase for delivering pacemaker genes and (ii) pluripotent stem cells differentiated down a cardiac lineage with endogenous pacemaker activity. This review examines the current achievements in engineering a biological pacemaker, defines the patient population for whom this device would be useful and identifies the challenges still ahead before cell therapy can replace current electronic devices.