Pacemaker Implantation In Children Research Articles

Ventricular dysfunction after permanent pacemaker implantation in children - what are the implications?

Abstract Introduction Children (<18 years of age) account for less than 1% of patients requiring permanent pacemaker implantation (PPI), but form a complex subset of population due to technical difficulties, higher prevalence of structural abnormalities and higher rates of reinterventions. Post-pacemaker ventricular dysfunction is seen in around 10-15% and is related to the electrical and mechanical ventricular dyssynchrony. However, similar data is lacking from patients who underwent permanent pacemaker implantation below 18 years of age. Methods We retrospectively analysed 235 patients who underwent PPI below 18 years of age, for development of ventricular systolic dysfunction, defined by ejection fraction below 50% of the systemic ventricle. Results Male: female ratio was 1.1:1, with median age of implantation being 7 years. 43.4% underwent epicardial PPI, and the commonest indication being congenital complete heart block (50.2%) followed by post-operative CHB (28.1%). 65.5% underwent VVI pacemaker implantation. 41.3% had associated congenital heart disease out of which ventricular septal defect was commonest (20.6%) followed by atrial septal defect (18.6%). Over a median follow-up of 8 years, 15 (6.38%) patients developed ventricular dysfunction, with systemic ventricle of RV morphology, younger age at implantation, maternal ANA positivity, presence of post-operative CHB, associated congenital heart disease and epicardial PPI being major predictors. Five (2.1%) patients required hospitalization for heart failure, while 2 underwent upgradation to CRT. Those with ventricular dysfunction had higher mortality than those who had normal ventricular dysfunction (40% vs 1.5%, p <0.01). There was no association of ventricular dysfunction with the duration of pacing (p = 0.25), the percentage of pacing (p = 0.25) or number of chambers paced (p = 0.38). Conclusion Ventricular dysfunction is seen in 6.38% of patients who underwent PPI below 18 years of age, over a median duration of 8 years. It was associated with higher mortality, while younger age at implantation, maternal ANA positivity, presence of post-operative CHB, associated congenital heart disease and epicardial PPI were major predictors for development of ventricular dysfunction.

Pacemaker Implantation in the Pediatric Population: Bosnian and Herzegovinian Experience

Introduction: The development of pediatric arrhythmology, as a segment of pediatric cardiology, is conditioned by surgical correction of congenital heart diseases (CHD). The beginning of pediatric cardiosurgery is also the time of pacemaker implantation. The aim of this article is to present indications and results of pacemaker implantation in children in our conditions from April 1997 to April 2020 in the Clinical Center University of Sarajevo (CCUS). Patients and Methods: The article is descriptive and includes the period from April 1997 to April 2020. The data were extracted from the official medical documentation of patients hospitalized at the Paediatric Clinic, CCUS (protocol of operated CHD in children, register of continuous electrocardiogram [ECG] Holter monitoring, register of implanted pacemakers in children). Results: During this period, 46 pacemakers were implanted, 29 (63%) in male patients, of which 13 (28%) were due to congenital atrioventricular (AV) block, and 33 (71.7%) were mostly in children with a postoperative block. Postoperative block occurred in 28 children (84.8%). Given that 771 children with CHD were operated on in the same period, a complication of postoperative complete heart block arose in 3.6% of children, which had to be tackled immediately after surgery in seven patients (21.2%), and later in 26 patients (78.8%). In regard to the age of pacemaker implantation, the interval was between 7 days and 18 years. The local team implanted 37 (80.4%) pacemakers. Reimplantation was done in four patients (8.7%). In April 2020, we followed 42 patients, four of whom died (three after surgery and one child due to congenital heart block). With the help of continuous ECG Holter monitoring (5,839 registrations and analysis), we recognized second- or third-degree or high-degree AV block, which was the indication for pacemaker implantation in 8.2% of all performed ECG Holter monitorings, with a respective indication for control of implanted pacemaker in 3.2% of ECG Holters. Conclusion: Children with implanted pacemakers require close monitoring, frequent medical examinations, recognition of the right time for generator exchange, as well as reimplantation of the pacemaker. This can be achieved principally with the help of continuous ECG Holter monitoring, with an adequately developed pediatric cardiology/cardiosurgery.

Long-term outcomes of pacemaker implantation in children with univentricular versus complex biventricular surgical repair.

Pacing in a univentricular circulation has been associated with worsened outcomes. We investigated the long-term outcomes of pacing in children with a univentricular circulation compared to a complex biventricular circulation. We also identified predictors of adverse outcomes. A retrospective study of all children with major congenital heart disease who underwent pacemaker implantation under the age of 18 years between November 1994 and October 2017. Eighty-nine patients were included; 19 with a univentricular and 70 with a complex biventricular circulation. A total of 96% of pacemaker systems were epicardial. Median follow up was 8.3 years. The incidence of adverse outcome was similar between the two groups. Five (5.6%) patients died and two (2.2%) underwent heart transplantation. Most adverse events occurred within the first 8 years after pacemaker implantation. Univariate analysis identified five predictors of adverse outcomes in the patients in the biventricular but none in the univentricular group. The predictors of adverse outcome in the biventricular circulation were a right morphologic ventricle as the systemic ventricle, age at first congenital heart disease (CHD) operation, number of CHD operations, and female gender. The nonapical lead position was associated with a much higher risk of an adverse outcome. Children with a pacemaker and a complex biventricular circulation have similar survival to the ones with a pacemaker and a univentricular circulation. The only modifiable predictor was the epicardial lead position on the paced ventricle, emphasizing the importance of apical placement of the ventricular lead.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Executive Summary.

2021 PACES Expert Consensus Statement on the Indications and Management of Cardiovascular Implantable Electronic Devices in Pediatric Patients: Executive Summary.

Complications of epi- and endocardial pacing in children

Abstract Aim To analyze complications of cardiac pacing in children depending on the implantation method. Actuality Recently epicardial lead implantation becomes more and more popular either due to more serious complications of transvenous pacing or due to possibility of choice of hemodynamically optimal pacing zone. Methods and materials 242 patients with pacemakers are under our supervision. Epicardial pacemakers were implanted to 145 patients, endocardial – to 97 patients. In “old era” in most children the primary epicardial implantations were performed at RV free wall. In 27 children, having primary implantation at our Institute lately, the epicardial lead was placed at LV apex, or endocardial – at RV apex. Results The comparative analysis of complications of epi- and endocardial implantation showed the following results: 22% of complications at epicardial stimulation, and at transvenous stimulation – 45%. The most often complications at epicardial stimulation (53%) were connected with hemodynamic disorders – dyssinchronous cardiomyopathy. Hemodynamic complications, connected with dyssinchrony of endocardial RV pacing, were disclosed in 16%. The most often complication of endocardial stimulation was TV insufficiency (32%). Venous vessel thrombosis was diagnosed in 9%. Epicardial and transvenous lead failure was discovered in similar percentage ratio (28%). Infectious complications of transvenous pacing, especially, bacterial endocarditis, took place in 6,8%. Thus, progressive bacterial endocarditis and TV insufficiency (3d deg.) appeared in one patient in 10 years after the primary implantation. Afterwards, elimination of endocardial system by open surgery, TV plasty followed by epicardial pacing implantation are required. Infection of pacing site was disclosed in both types of implantation (1%). Perforation of atrial endocardial lead was found in two cases (4%). A case of mechanical complication (cardiac strangulation) was diagnosed in a child (3%) in four years after the primary implantation of epicardial pacing system. Pericarditis was recorded immediately after the epicardil pacemaker implantation in 9% of cases. Our center performs epicardial lead implantation with the help of midline sternotomy that provides clear approach to right atrium. However, the difficulties of lead fixation at LV apex appear here. It concerns, especially, the patients after CHD correction as the repeated sternotomy in them presents high risk of RV insufficiency. Nevertheless, the given approach is still the best possible with epicardial pacing if there is a “preclude”, sufficient experience of CHD correction. Conclusion The possibility of choice of optimal epicardial pacing site exceeds risks of leads and midline sternotomy. Any primary pacemaker implantation in children of any age with ventricular lead should be epicardial. Funding Acknowledgement Type of funding sources: None.

Video-assisted thoracoscopic pacemaker lead placement in children with atrioventricular block.

Background:The pacemaker lead placement is presented as one of the most appropriate procedures in children with a complete atrioventricular block (AVB). Despite the fact that video-assisted thoracic surgery (VATS) for epicardial lead placement has demonstrated positive results as to the feasibility, safety, and efficacy in adults, its role in pacemaker implantation in children remains unclear.Aim:This study sought to assess the intermediate-term outcomes of video-assisted thoracoscopic pacemaker lead placement in children with complete AVBMaterials and Methods:From May 2017 to November 2019, five children with complete AVB underwent minimally invasive left ventricular (LV) lead placements via thoracoscopic video assistance approach. The procedure was performed under complex intratracheal anesthesia with single-lung ventilation, all pacing parameters were evaluated in perioperative and follow-up periods.Results:The median age of children at implantation was 3 years (range: 2 to 4 years), the median weight was 13 kg (range: 12–15 kg). All procedures were completed successfully, pacing thresholds for the active lead measured 0.3-1.1V, with R-wave amplitude of 8-18 mV and impedance of 560-1478 Ohm.Conclusion:Thoracoscopic pacemaker lead placement may provide a potential alternative to the transthoracic approach of epicardial lead placement in children with AVB.

P512New approaches to pacing in children with atrioventricular block

Abstract Introduction The placement of permanent pacemaker is presented as one of the most appropriate procedures in patients with congenital complete atrioventricular block (AVB). Despite video-assisted thoracic surgery (VATS) for epicardial lead placement has demonstrated positive results concerning the feasibility and freedom of complications in adults, its role in pacemaker implantation in children remains unclear. The study aimed to assess the intermediate-term outcomes of video-assisted thoracic pacing in children with congenital complete AVB. Methods From May 2017 to November 2018, six children with complete idiopathic AVB underwent minimally invasive left ventricular lead placements via thoracoscopic video assistance. The procedure was performed under complex intratracheal anesthesia with single-lung ventilation, median operation time was 180 minutes (120–240). Four incisions were made, three of them were used to place the lead on the left ventricular, and one was needed to place the device. All pacing parameters were evaluated in perioperative and follow-up periods. Results Median age at implantation was 3 years (2 to 15 years), median weight 13 kg (12–46 kg). All procedures were completed successfully, pacing thresholds for the active lead measured 0.5-1.1V, with R-wave amplitude of 8-18 mV and impedance of 404-1478 Ohm. Increasing pacing thresholds in the third month after pacemaker implantation occurred in one patient, so anti-inflammatory therapy was assigned. Satisfactory thresholds and impedances with no significant difference with initial values were obtained at the median follow-up of 21 months (range: 10–28 months). Conclusion Video-assisted thoracic pacing may provide a potential alternative to the transthoracic approach of epicardial lead placement in children with congenital AVB.

Clinical analysis of pacing therapy and treatment of complications during follow-up in children

Objective: To analyze characteristics of permanent pacemaker implantation in children as well as treatment and prognosis of complications. Method: Clinical data of children who underwent endocardial or epicardial permanent pacemaker implantation between April 2000 and June 2016 in Shanghai Xinhua Hospital and Shanghai Children's Medical Center were analyzed retrospectively. These patients were discharged 5 days after implantation. Electrocardiogram, chest X ray, echocardiography and pacemaker programming were performed during follow-up. Treatment regimes, complication management and prognosis were analyzed retrospectively. Result: Data of a total of 193 cases were collected. One hundred and six patients were male and 87 patients were female.The average age was (5.09±4.05) years(0.4-16 years)and the average weight was (20.47±11.62) kg.133(68.9%); patients were implanted with endocardial pacemakers and 60(31.1%)patients were implanted with epicardial pacemakers; 135(69.9%)patients were single-chamber paced with 87 from RVA and 48 from RVOT. fifty-eight(30.1%)patients were dual chamber paced. These included 122(63.2%)postoperative third degree AV block(Ⅲ-AVB), 38 (19.7%)congenital complete AV block (CCAVB), 3(1.6%)post ventricular septal defect (VSD) interventional therapy AV block, 23 (11.9%)sick sinus syndrome (SSS) and 7(3.6%)Ⅲ-AVB after fulminant myocarditis. One hundred and thirty-seven(71%)patients were followed up for an average duration of 5.32 years(0.3-10 years). Pacemaker exchange were performed in 46 patients due to battery exhaustion.The average life of battery was 5.4 years (1-9 years). Sixteen patients underwent lead exchange due to dislocation or separation.One patient underwent lead extraction due to recovery of AV conduction 21 days after surgery for complete transposition of great arteries (D-TGA/VSD). Skin abrasion, infection or dehiscence occured in 6 patients. Heart failure occurred in 2 patients at 6 and 8 years after implantation whose heart functions improved after switching from VVI to DDD or adding ACEI . One patient died suddenly due to ineffective pacing caused by lead fracture. Another patient under DDD pacing was found to have atrial myocardial perforation with normal sensing and pacing so that no intervention was performed. Conclusion: The pacing mode and path through which leads are implanted for permanent pacemaker implantation in children have their peculiar characteristics.Some complications might occur during follow-up with good prognosis if appropriately treated.

Axillary vein puncture for device implantation and use of 4F catheter-delivered pacing leads in children

Summary Background: Contrast-guided axillary vein puncture has gained popularity for pacemaker and implantable cardioverter defi brillator (ICD) implantation in adults owing to its low risk profil e, and could be an alternative to subclavian vein puncture, which is commonly performed in children. The Medtronic 3830 lead is a 4.1F lumenless catheter-delivered lead which may be particularly well-suited for use in the paediatric population because of the reduction in intravascular material and possibility for selective-site lead placement in complex anatomies. Methods: Data on paediatric patients at our institution aged <15 years who underwent transvenous device implantation using contrast-guided axillary vein puncture were retrieved. Contrast-guided axillary vein puncture was performed in all patients as the primary approach under general anaesthesia. Results: We retrieved data from 15 patients (7 males), aged 7.7 ± 4.1 yr (range 2–15 yr) at the time of intervention, and weighing 23.0 ± 9.6 kg (range 11.3 –38.0 kg). Axillary vein puncture was successful in all patients. We placed 9 right atrial leads, 13 right ventricular pacing leads, 1 right ventricular ICD lead and 1 coronary sinus lead. A 3830 lead was successfully implanted in all 12 patients in whom this lead was intended. There were no procedure-related complications and lead electrical parameters were within normal limits in all patients after a mean follow-up of 13 months. Conclusion: Contrast-guided axillary vein puncture is a safe and effective method for pacemaker implantation in children. Furthermore, the thinbodied 3830 lead provides stable pacing parameters while reducing the bulk of intravascular material.

Percutaneous Axillary Vein Approach in Pediatric Pacing: Comparison with Subclavian Vein Approach

The subclavian vein approach has been used for 20 years in our center for pacemaker (PM) implantation in children, but it carries risks of hemothorax/pneumothorax and lead fracture, which could be reduced by axillary vein approach. This is a prospective study enrolling the first 48 consecutive pediatric patients (age: 12.3 ± 4.6 years) who underwent PM/implantable cardioverter-defibrillator leads implantation through axillary vein (guided by contrast venography) between 2009 and 2012 (group I). A comparison was made with the outcomes of the subclavian vein approach (group II) in 41 patients, age 12.3 ± 4.8 years, consecutively enrolled between 2006 and 2011. The two groups showed no significant differences for the variables examined except for follow-up, longer in group II, and for alternative ventricular pacing sites, more frequent in group I. Axillary vein diameter was 7.9 ± 1.7 mm and showed positive correlation with height (r = 0.77). The axillary vein approach was effective in 93.7% of patients. The unsuccessful procedures occurred in patients with significantly lower age and smaller venous diameters. The subclavian vein approach was effective in 100% of patients. Sixty-two leads were implanted in group I, 54 in group II. There were neither intraoperative complications in both the groups, nor significant differences for early and late complications. The axillary vein approach for PM implantation in children is effective and safe for physicians skilled with subclavian vein approach. Younger patients with smaller vein diameters are at low risk for unsuccessful procedure.

症例 幼小児ペースメーカー植え込み術の問題点:特に電極装着法とジェネレーター埋没部位についての検討

症例 幼小児ペースメーカー植え込み術の問題点:特に電極装着法とジェネレーター埋没部位についての検討

A Single Institution Experience with Pacemaker Implantation in a Pediatric Population over 25 Years

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

Transvenous Pacing in Children Weighing Less than 10 Kilograms

Pacemakers are used in small children with increasing frequency for the treatment of life-threatening bradyarrhythmias. The epicardial approach is generally preferred in these patients, to avoid the risks of vessel thrombosis. We examined the feasibility and safety of transvenous pacemaker implantation in children weighing <10 kg, via subclavian puncture, using a 4 Fr sheath introduced after a venogram was performed to evaluate the vein diameter. Progressive dilation with 5, 6, and 7 Fr sheaths preceded the insertion and placement of the endocardial lead. A subaponeurotic pocket was created in the abdominal or pectoral regions, depending upon the patient's size. Between 2001 and 2007, we treated 12 patients (median age = 16 months; range 1-32; median weight = 7.9 kg; range 2.3-10.0; 7 males), of whom four weighed <5 kg. Indications for permanent pacing included postsurgical complete atrioventricular block (n = 8), sinus node dysfunction (n = 2), congenital atrioventricular block (n = 1), and long QT syndrome (n = 1). Single-chamber pacemakers were implanted in 10, and dual-chamber pacemakers in two patients. The patients were evaluated at 48 hours, 10 days, and at 3 and 6 months. The mean follow-up was 31.8 +/- 23.5 months. There were no procedural complications. Lead dislodgment occurred in one patient and required replacement of the ventricular lead. One patient died from septicemia. Endocardial pacemaker implantation was feasible and safe in children weighing <10 kg. This procedure is less invasive than the standard epicardial approach.

Discussion on the methods of pacemaker implantation in children

目的 总结儿童永久性心脏起搏器植入、随访和并发症处理的经验.方法(1)对Ⅲ度房室传导阻滞儿童植入永久性心脏起搏器,术后1周,1、3、6、12个月及此后每年均进行随访,随访时行心电图、胸片、心脏超声心动图检查,并对起搏器参数和起搏阈值进行检测.(2)对随诊中出现的6例并发症(其中囊袋感染2例、固定胶套磨破皮肤感染2例、绝缘层破损1例、重度三尖瓣反流1例)分别进行处理.结果对27例植入永久性心脏起搏器的儿童进行7个月～8年随访,平均(5.2±1.5)年;其中6例并发症经处理后,感知和起搏功能良好,随访6个月～5年无异常.结论(1)儿童安装永久性心脏起搏器要严格掌握适应证,尽量采用生理性起搏;(2)心外膜手术创伤大,术后并发症少,适合超声心动图显示锁骨下静脉内径小于5 mm的患儿;(3)心内膜植入时要注意儿童的心脏结构和生长发育特点。

Postpericardiotomy Syndrome After Permanent Pacemaker Implantation in Children and Young Adults

Background Postpericardiotomy syndrome (PPS) occurs in 10% to 50% of pediatric patients after cardiac surgery. The incidence and outcome of PPS after permanent pacemaker implantation in children is not described. Methods A retrospective analysis was performed of all pediatric patients who underwent isolated placement of a pacemaker between January 1984 and December 2002. Patients who underwent congenital heart surgery at the time of pacemaker implantation were excluded. PPS was diagnosed on the basis of clinical symptoms with echocardiographic confirmation of a pericardial effusion. Results Four hundred and forty-three pacemakers (237 epicardial, 206 transvenous) were implanted in 370 patients (median age 10 years, range 2 months to 24 years). Eight (2%) episodes of PPS (6 epicardial, 2 transvenous) occurred in 7 patients. The median time from implantation to PPS was 12.5 days (range 8 to 22 days). Six (75%) episodes followed primary pacemaker implantation, two occurred after subsequent lead revision. Three patients were initially treated with medical therapy (1 nonsteroidal agents, 2 steroids), and 1 required subsequent pericardiocentesis. Five patients underwent initial pericardiocentesis followed by medication. One patient had echocardiographic recurrence of a pericardial effusion 3 weeks after a nonsteroidal taper, with resolution after nonsteroidal agents were reinitiated. One patient required a pericardial window for a persistent effusion. No pacemaker was explanted. Conclusions PPS occurred in 2% of children undergoing isolated pacemaker implantation of both epicardial and transvenous systems. PPS is usually managed successfully with medical therapy. Patients with medical treatment failure were successfully treated with pericardiocentesis or the surgical creation of a pericardial window.

1051-2 Use of the Internet and World Wide Web for Dissemination and Collection of Midwest Pediatric Pacemaker Registry Information

The Midwest Pediatric Pacemaker registry which provides a large data-base of information concerning pacemaker implantation in children relies upon printed articles and meeting presentations for dissemination of collected information and upon member institutions to complete and mail printed forms for data submission. This process increases the time necessary for data submission and slows dissemination of pooled data to the pediatric pacing community. With increasing Internet access by centers involved in pediatric pacing, and the development of the World Wide Web (WWW), use of the WWW was explored to evaluate its potential for information dissemination and acquisition. Hypertext mark-up language (HTML) documents of composite Registry statistics, patient demographics with initial implantation indication, and generator implantation and electrode utilization information were made available on the Internet by publishing it on the WWW. Documents presented data both in textual and graphical form and were organized by topic on different pages to allow selective access directly the data needed. The graphs presented can be downloaded in GIF format. Use of the easily prepared HTML documents allows for frequent updating of information with rapid access by centers involved in pediatric pacing. In addition utilizing the forms capability of WWW browsers, Pacemaker Registry information can be submitted on-line. The form page is displayed and the information directly entered. Information entry is accomplished byfilling in character fields, check boxes and free text fields. The form is then automatically sent to the WWW server which forwards it to the Registry Director for database entry. It is never stored on the public access WWW server, ensuring patient confidentiality. For users without a forms capable WWW browser, a file containing the submission forms is also provided that can be downloaded. Use of the WWW and Internet provides more rapid dissemination and collection of Registry information shortening the period between data collection and data review by centers involved in pediatric pacing which should improve the quality of care delivered to children requiring permanent pacing. Use of WWW can provide a rapid means of medical data dissemination and communication.

Cardiac Pacing in Children

Advances in pacemaker technology over the last 25 years have made cardiac pacing in infants and children a safe and practical therapy. Some of the technical challenges encountered with the first permanent pacemaker implantation in children during the early 1960s have been solved with miniaturized generators, lithium batteries, noninvasive programmability, and improved placement techniques. This chapter reports common causes of bradydysrhythmias in children, reviews the indications for permanent pacemaker implantation in children, describes current pacing systems appropriate for children, and identifies nursing implications and potential pacemaker complications unique to children.

Transvenous pacing in infants and children with congenital heart disease

A technique for transvenous pacemaker implantation in children with complex heart disease is described. The use of small positive-fixation leads, introducers, retained guidewires, and atrial lead loops to allow for growth all have an important role in management of this often challenging problem.

Pacemakers in children: An update

This report reviews recent pacemaker technological advances as they apply to infants, children, and adolescents. Indications for pacemaker implantation in children have evolved since the 1984 Joint Task Force Guidelines. Recent data show that pacemaker implantation should be strongly considered in patients who have (1) asymptomatic congenital complete AV block with a mean heart rate less than 50 beats/min or other evidence of junctional instability; (2) congenital AV block with long QT interval; or (3) congenital long QT syndrome with bradyarrhythmias, or when conventional beta-blocker therapy is unsuccessful. Permanent pacemaker implantation is not necessarily an effective prophylactic measure against sudden death in patients following their operation who are receiving drug therapy for atrial tachyarrhythmias, and so is not absolutely indicated. New developments in lead technology have made transvenous lead systems more feasible for pediatric use. Because epicardial leads are required for small infants and for cosmetic reasons in some older children, design improvements are needed to enhance epicardial lead performance. Rate-responsive pacing is an acceptable alternative to dualchamber pacing for augmenting exercise tolerance, and for children with sinus node dysfunction it is the preferred pacing mode. Pacemakers with automatic antitachycardia capabilities and with noninvasive electrophysiology features are valuable in children with atrial tachyarrhythmias. New data suggest that chronic atrial pacing also may be effective in controlling atrial tachyarrhythmias. New developments in pacemaker systems for the young parallel those for the older population, but differences between adult and pediatric patients demand ongoing increased participation by pediatric cardiologists.

Marcapasso endocárdico definitivo na primeira década de vida

O implante de marcapasso definitivo em crianças tem-se constituído em desafio, tanto pela incompatibilidade de rigidez dos sistemas de estimulação em relação ao crescimento, quanto pela dificuldade de se alojar o sistema, além de outros importantes problemas técnicos e sociais. Mesmo nos Serviços onde a primeira opção tem sido a via endocárdica, nas crianças de baixo peso a opção tem sido a via epicárdica. No Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da USP, no período de novembro de 1980 a outubro de 1985, foram realizados 21 implantes de marcapasso em pacientes na primeira década de vida, utilizando a via endocárdica. Esta técnica consta da introdução do eletrodo pelo território venoso femoral, deixando-se uma alça no átrio direito, para permitir o crescimento, e da colocação do gerador na fossa ilíaca. Em um segundo tempo, após alguns anos, é realizada liberação do eletrodo dentro da loja do gerador, permitindo-se a utilização do sistema por tempo indeterminado. A idade variou de 2 meses a 10 anos, sendo que 13 crianças tinham idade abaixo de 5 anos e 5 delas, no primeiro ano de vida. A indicação mais comum foi o bloqueio atrioventricular do 3º grau (90%), que teve como etiologia mais freqüente o bloqueio pós-operatório (75%). No seguimento realizado de 3 meses a 63 meses, com média de 26 meses, 3 pacientes morreram por causas não relacionadas ao marcapasso, enquanto que os demais estão assintomáticos. Cinco crianças já foram reoperadas para a liberação do eletrodo no interior da loja do marcapasso, após o crescimento ter desfeito toda a alça atrial. O acompanhamento dessas crianças pode demonstrar a grande superioridade da técnica em relação ao implante epicárdico e ao implante endocavitário convencional. Podemos destacar as seguintes vantagens: 1) grande facilidade técnica, com trauma cirúrgico mínimo e pós-operatório extremamente fácil; 2) não necessita outros tipos de prótese para acomodar o eletrodo; 3) permite o acompanhamento seguro da criança com simples estudo radiológico; 4) preserva o sistema cava superior para a utilização na idade adulta; 5) permite, ainda, a integração social perfeita da criança, que poderá participar de atividades esportiva e de lazer, sem que o marcapasso seja notado pelas outras crianças.