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.     

Ventricular pacing threshold variations in the young

Ventricular Capture Management (VCM) is a Medtronic Kappa pacemakers (PM) feature that automatically measures pacing threshold through detection of the evoked response after a pacing stimulus. The aim of this study was to evaluate the range of variation of ventricular pacing threshold in pediatric patients with endocardial and epicardial pacing leads. Thirty-one patients (median age 6.5 years) were implanted with a Kappa 901 PM for atrioventricular block or sinus node dysfunction. Congenital heart defects (CHD) were present in 58% of patients. Ventricular leads were epicardial in 52% of patients. VCM was programmed to automatically measure threshold every 2 hours. In a median follow-up of 12 months, 27,110 threshold measurements, 72% of which were successful, have been taken in 94% of patients. Measurement success was 99% in the endocardial leads group (age at implantation 12 +/- 6 years) and 31% in epicardial leads (age 4 +/- 5 years) (P < 0.05). Main reasons for unsuccessful measurements were high heart rate and, in a patient with an endocardial lead, competition with intrinsic rhythm. Undersensing or oversensing of the evoked responses was not detected. In all successful VCM measurements, epicardial pacing and CHD contributed to stability of thresholds (multivariate analysis). Pacing threshold showed specific circadian patterns: higher thresholds were found between 00.00 and 06.00 a.m., but the variation was low, 0.03 +/- 0.01 V. In conclusion, children and young patients show stable ventricular thresholds, especially in presence of CHD, and epicardial leads are at least as stable as endocardial leads. Ventricular pacing threshold showed a circadian variability similar to that described in adults, that does not seem to influence VCM functioning and PM programming.     

Single Pass Lead VDD Pacing in Children and Adolescents

Implantation of permanent pacemakers in children and adolescents is possible but usually is limited to single chamber generators. The natural growth of these patients may require physiological pacing, but until recently two leads were required for this type of pacing. The single pass lead VDD pacing mode makes posible physiological pacing by using only one lead, for both atrial sensing and ventricular sensing and pacing. The feasibility of VDD pacing using endocardial lead was evaluated in 16 children and adolescents with congenital or postsurgical atrioventricular block. Their mean age was 7.9 ± 4.9 years (range 1-16 years) and the smallest patient's weight was 8.2 kg. In all the patients, a single pass pacing lead with atrial sensing rings and bipolar ventricular pacing and sensing capability was implanted through the left or right subclavian vein. The pacemaker generator was implanted in a rectopectoral position. The mean atrial electrogram during the implantation was 4.2 ± 2.1 mV and 2.6 ± 1.9 mV after a mean of 1 week. The ventricular pacing threshold was 0.5 ± 0.2 V; the ventricular pacing impedance was 560 ± 95 Ω and the ventricular electrogram amplitude was 9.9 ± 2.1 mV. This is a first report to demonstrate the feasibility of atrial synchronous ventricular endocardial pacing using a single pass lead in a relatively large group of children and adolescents.     

The Subpectoral Pocket: The Preferred Implant Site for Pediatric Pacemakers

Implantation technique for pediatric pacemaking has evolved from predominantly epicardial to predominantly endocardial. One of the potential problems with endocardial pacing in children is their very thin subcutaneous tissue, which can result in an unpleasant cosmetic result. The superficialness of the pacemaker pulse generator also may render it more susceptible to erosion and infection. A series is presented of pediatric patients who underwent implantation of a transvenous bipolar pacing system in the pediatric catheterization laboratory. The pacemaker was implanted under the pectoralis major muscle after a muscle spreading incision was made. The lead was also introduced into the subclavian vein under the pectoralis muscle. No complications resulted, and the cosmetic result was judged to be good to excellent by the parents and physicians. No infections or erosions occurred. The subpectoral pocket is recommended as the preferred site for implantation of transvenous pacemakers in pediatric patients.     

Acute and Chronic Cycle Length Dependent Increase in Ventricular Pacing Threshold

Several factors have been shown to influence ventricuJar pacing threshold in humans, including pacing lead location (endocardial vs epicardial), lead maturation, and antiarrhythmic agents. To determine whether ventricuJar pacing rate has a significant influence on acute and chronic pacing thresholds, we measured pacing thresholds in 16 patients receiving an implantafaleantitachycardia pacemaker cardioverter defibrillator (Cadence?). Ventricular pacing thresholds were determined using the device programmer at cycle lengths of GOO, 400, and 300 msec at the time of implantation; prior to hospital discharge at 3-14 days; and during follow-up outpatient visits at 6-8 weeks, 3 months, and 6 months to 1 year. Eleven patients had an epicardial lead system and five an endocardial lead system. Eleven patients were being treated with antiarrhythmic drug therapy. Device output ranged from 1-10 V and was adjustable in 1-V increments (pulse width was held constant at 1 msec). A cycle length dependent increase in pacing threshold (defined as a ≤ 1-V increase in threshold at 400 or 300 msec relative to 600 msecj was observed in 10/16 patients during 12/72 pacing trials at 400 msec, and in 15/16 patients during 31/67 trials at 300 msec. In trials in which an increase in pacing threshold occurred, the magnitude of the increase at 400 msec relative to 600 msec was only 1 V in all 12 trials, but at 300 msec the increase ranged from 4–9 V in 7/31 (23%) trials. There was an equal percentage (67%) of patients demonstrating a cycle length dependent increase in threshold with measurements made at the time of device implantation and at the 6 month to 1 year follow-up period. Two-way analysis of variance showed a significant effect of cycle length and time from implantation on mean pacing thresholds at the three cycle lengths. In conclusion, a cycle length dependent increase in pacing threshold occurred in virtually all patients during follow-up of up to 12 months and, thus, its presence was independent of lead location, presence of antiarrhythmic agents, and the state of lead maturation. These findings suggest that pacing thresholds measured at rates just above the sinus rate may not always apply to the faster rates utilized for antitachycardia pacing and indicates the need for threshold measurement at the designed pacing rate.     

The Use of Active Fixation Electrodes for Permanent Endocardial Pacing Via a Persistent Left Superior Vena Cava

Two patients underwent permanent endocardial pacing for complete atrioventricular block. In each case a persistent left superior vena cava was either suspected or known to be present. An active fixation electrode was passed down the left superior vena cava and the tip positioned in the apex of the right ventricle. Stable ventricular pacing was achieved for the follow-up period of approximately six months. With the availability of such active fixation electrodes the presence of a persistent left superior vena cava no longer mandates insertion of an endocardial electrode via the right superior vena cava. when present, or implantation of an epicardial pacing system. (PACE, Vol. 5, March-April, 1982)     

Comparison of the efficacy of two surgical alternatives for cardiac resynchronization therapy: trans-apical versus epicardial left ventricular pacing

Background: Epicardial pacing lead implantation is the currently preferred surgical alternative for left ventricular (LV) lead placement. For endocardial LV pacing, we developed a fundamentally new surgical method. The trans‐apical lead implantation is a minimally invasive technique that provides access to any LV segments. The aim of this prospective randomized study was to compare the outcome of patients undergoing either trans‐apical endocardial or epicardial LV pacing. Methods: In group I, 11 end‐stage heart failure (HF) patients (mean age 59.7 ± 7.9 years) underwent trans‐apical LV lead implantation. Epicardial LV leads were implanted in 12 end‐stage HF patients (group II; mean age 62.8 ± 7.3 years). Medical therapy was optimized in all patients. The following parameters were compared during an 18‐month follow‐up period: LV ejection fraction (LVEF), LV end‐diastolic diameter (LVEDD), LV end‐systolic diameter, and New York Heart Association (NYHA) functional class. Results: Nine out of 11 patients responded favorably to the treatment in group I (LVEF 39.7 ± 12.5 vs 26.0 ± 7.8%, P < 0.01; LVEDD 70.4 ± 13.6 mm vs 73.7 ± 10.5 mm, P = 0.002; NYHA class 2.2 ± 0.4 vs 3.5 ± 0.4, P < 0.01) and eight out of 12 in group II (LVEF 31.5 ± 11.5 vs 26.4 ± 8.9%, P = < 0.001; NYHA class 2.7 ± 0.4 vs 3.6 ± 0.4, P < 0.05). During the follow‐up period, one patient died in group I and three in group II. There was one intraoperative LV lead dislocation in group I and one early postoperative dislocation in each group. None of the patients developed thromboembolic complications. Conclusions: Our data suggest that trans‐apical endocardial LV lead implantation is an alternative to epicardial LV pacing. PACE 2012; 35:124–130)     

Preliminary results with the simultaneous use of implantable cardioverter defibrillators and permanent biventricular pacemakers: implications for device interaction and development

We report our preliminary experience with the combined use of implantable cardioverter defibrillators (ICD) and biventricular pacemakers in six patients with heart failure and malignant ventricular arrhythmia. Two patients underwent ICD implantation for malignant ventricular arrhythmia after previous biventricular pacemaker implantation. One patient underwent biventricular pacemaker insertion for NYHA Class III heart failure after previous ICD implantation. Two patients underwent single device implantation. In the sixth patient, a combined implantation failed due to an inability to obtain a satisfactory left ventricular pacemaker lead position. The potential for device interaction was explored during implantation. In two patients a potentially serious interaction was discovered. Subsequent alterations in device configuration and programming prevented these interactions with long-term use. No complication of combined device use has been demonstrated during a mean follow-up of 2 months (range 1-4 months). Satisfactory ICD and pacemaker function has also been demonstrated. We conclude that combined device implantation may be feasible with currently available pacing technology and that further prospective studies are required in this area.     

Endocardial Biventricular Pacing

Simultaneous righ t and left ventricular pacing was performed in a 73-year-old man with coronary artery disease end-stage congestive heart failure and a DDD pacemaker implanted for sick sinus syndrome. An endocardial LV lead was introduced transseptally after unsuccessful attempts to enter the coronary sinus. This new approach for multisite pacing offers an alternative to epicardial LV from the coronary sinus or by thoracotomy.     

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

Summary 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.     

Is Epicardial Dual Chamber Pacing a Realistic Alternative to Endocardial DDD Pacing? Initial Results of a Prospective Study

Seventeen patients, in whom an epicardial (n = 7) or a transvenous DDDM pacemaker system had been implanted between June 1988 and October 1990, were followed up for pacemaker and lead related complications, pacemaker longevity, and electrophysiological lead parameters. The mean follow-up interval was 18 +/- 12 months, maximum 34 months. There were no differences in chronic atrial and ventricular sensing thresholds between epicardial and endocardial stimulation, nor were there any differences concerning lead related complications between the two pacing modalities. However, atrial as well as ventricular chronic stimulation thresholds were significantly higher with epicardial stimulation resulting in a twofold increase in atrial energy consumption and a threefold increase in the ventricular energy consumption. Thus, in one patient with an epicardial DDD system, the pacemaker had to be replaced prematurely because of battery depletion. It is concluded that epicardial DDD stimulation can be reliably performed as far as atrial and ventricular sensing is concerned, but that the energy requirements of available myocardial leads are not satisfactory for making optimal use of modern pacemaker capability.     

Transvenous Pacemaker Implantation Via a Unilateral Left Superior Vena Cava

A 72-year-old man with a unilateral left superior vena cava and anomalous drainage of the inferior vena cava required permanent pacing. The anomalies were verified by venography and cardiac catheterization. Difficulties in implantation of a temporary and permanent pacemaker are described. A transvenous endocardial lead was placed in a stable position in the right ventricle. The pacemaker system has now functioned normally for 32 months.     

The Pulmonary Artery Lasso: Epicardial Pacing Lead Causing Right Ventricular Outflow Obstruction

Permanent pacing in small children may require placement of an epicardial pacing system. This report describes a young child who underwent pacemaker implantation with epicardial ventricular lead placement in infancy as an adjunct to antiarrhythmic therapy for congenital junctional ectopic tachycardia. At 5 years of age, a harsh systolic murmur was detected for the first time. Evaluation by catheterization and transluminal echocardiography showed right ventricular outflow obstruction (pressure gradient 40 mmHg) secondary to extrinsic compression by the epicardial lead. Surgical removal of the lead relieved the obstruction.     

Stability of permanent transvenous dual-chamber pacing electrodes during cardiopulmonary resuscitation

For long-term dual-chamber permanent pacing, atrial and ventricular lead stability is essential. In our overall experience with such pacing systems, four patients suffered cardiac arrest at a time distant from their pacemaker implantation. Since all four patients received prolonged closed chest cardiopulmonary resuscitation, we analyzed these events to determine whether dual-chamber endocardial electrodes would remain stable in such traumatic conditions. Reliable atrial and ventricular lead position was confirmed at autopsy in the three patients whose resuscitation attempts were unsuccessful and, in the fourth patient, by continued normal lead position and pacing function post-resuscitation. The keys to this stability include the use of tined atrial and ventricular endocardial leads and specific maneuvers at the time of implantation to verify fixation. Long-term stability of presently available endocardial leads in dual-chamber pacing systems can thus be anticipated.     

The Combined Transvenous Implantation of Cardioverter Defibrillators and Permanent Pacemakers

We developed criteria for implantation and programming of permanent endocardial pacemakers in patients with a nonthoracotomy ICD system. These criteria were prospectively used in 10 patients who recieved an ICD prior to (n = 5) or following (n = 5) implantation of a dual chamber (n = 6) or ventricular (n = 4) pacemaker with a unipolar (n = 4) or bipolar (n = 6) lead configuration. All patients were tested for interactions or malfunctions. Undersensing of ventricular fibrillation by the atrial sense amplifier and inadequate atrial pacing occurred in one patient with a unipolar dual chamber system programmed to AAIR but didn't impair ICD sensing. Transient or permanent loss of capture or sensing of the pacemaker was not observed after ICD shocks with the output programmed to double pulse width and voltage of stimulation threshold and the sensitivity to 50% of the detected R wave. One episode of transient reprogramming occurred without clinical consequences. One unipolar ventricular pacemaker lead had to be exchanged against a bipolar lead because of oversensing of the pacing artifact by the ICD. There was no failure of an ICD to detect ventricular arrhythmias due to inadequate pacemaker activity. During a follow-up period of 21 ± 11 months, a total of 78 ventricular arrhythmias were effectively treated in six patients. Thus, a combined use of transvenous ICD and pacemaker is possible despite the close vicinity of pacing and defibrillations leads. Optimized programming different to the common settings is required. As interactions occurred only in unipolar pacemaker leads bipolar systems should be used in these patients.     

Ventricular Pacing in Children

Ventricular pacing in children. Ventricular pacing was performed in forty-one children ranging from one day to twenty years of age (median age = 10). Weight of the recipient at implant ranged from 2 kg. to 86 kg. Indications included presyncope, syncope, dyspnea on exertion, congestive heart failure, postoperative infra-Hisian heart block, and inadequate cardiac rate during pharmacotherapy. Four patients died during follow-up, but no deaths were attributable to pacemaker management. In contrast, 66% of the patients required more than one pacemaker related-operative procedure, and 43% of leads implanted failed by 48 hours. Indications for permanent cardiac pacing in this population at this time are symptomatic congenital AV block, symptomatic sinus node disease, and AV block in the postoperative period. Technological developments which might reduce complications seen in this population and electrophysiologic techniques which may better define indications for pacing in children are also reviewed.     

Stability of Permanent Transvenous Dual-Chamber Pacing Electrodes During Cardiopulmonary Resuscitation

For long-term dual-chamber permanent pacing, atrial and ventricular lead stability is essential. In our overall experience with such pacing systems, four patients suffered cardiac arrest at a time distant from their pacemaker implantation. Since all four patients received prolonged closed chest cardiopulmonary resuscitation, we analyzed these events to determine whether dual-chamber endocardial electrodes would remain stable in such traumatic conditions. Reliable atrial and ventricular lead position was confirmed at autopsy in the three patients whose resuscitation attempts were unsuccessful and, in the fourth patient, by continued normal lead position and pacing function post-resuscitation. The keys to this stability include the use of tined atrial and ventricular endocardial leads and specific maneuvers at the time of implantation to verify fixation. Long-term stability of presently available endocardial leads in dual-chamber pacing systems can thus be anticipated.     

Permanent transfemoral pacemaker: a single-center series performed with an easier and safer surgical technique

Introduction: When venous access via the upper venous tree is not possible, the usual approach is to proceed to epicardial lead placement.
Material and Methods: This report presents a consecutive series of 12 permanent pacemaker systems utilizing the right femoral vein for venous access implanted between May 2001 and October 2004.
Results: A modification of the previously reported surgical technique was used with a mean implant time of 52 minutes. Five were dual-chamber systems and seven were VVIR. All the leads implanted were active fixation. There was a 0% dislodgment rate and a mean follow-up of 18 months. During this time, three patients required revision or treatment of a pocket complication. All systems remained in the pacing mode as originally programmed with stable low sensing and pacing thresholds. There was no clinical evidence for acute or chronic venous thrombosis and no evidence of asymptomatic venous obstruction in eight patients who underwent echo-duplex studies.
Conclusion: We believe that the permanent femoral implant utilizing the technical modifications described in this article, offers an alternative to epicardial lead placement when the usual upper venous tree access is not available.     

Use of Radiofrequency Perforation for Lead Placement in Biventricular or Conventional Endocardial Pacing after Mustard or Senning Operations for D-Transposition of the Great Arteries

Background: Endocardial pacemaker lead placement can be challenging after Mustard and Senning operations for transposition of the great arteries (D-TGA), if there is atresia of the systemic venous pathways and because the coronary sinus cannot be used for cardiac resynchronization therapy. Radiofrequency (RF)-assisted perforation techniques have been used in congenital heart disease but have not been reported for use in pacemaker implantation.
Methods and Results: We describe RF perforation of an atretic superior systemic venous pathway and systemic venous baffles in three patients after Senning and Mustard operations to implant endocardial pacing systems to achieve conventional or biventricular pacing.
Conclusions: RF-energy-assisted perforation is feasible and effective tool to facilitate endocardial lead placement during dual-chamber and biventricular pacemaker implantation in patients with Mustard or Senning operations for D-TGA.     

Achieving Permanent Left Ventricular Pacing—Options and Choice

Cardiac resynchronization therapy (CRT) requires permanent left ventricular (LV) pacing. Coronary sinus (CS) lead placement is the first line clinical approach but can be difficult or impossible; may suffer from a high LV pacing threshold, phrenic nerve stimulation, and dislodgement; and produces epicardial LV pacing, which is less physiological and hemodynamically effective and potentially more proarrhythmic than endocardial LV pacing. CS leads can usually be extracted with direct traction but may require use of extraction sheaths. Half of CS side branches previously used for lead placement may be unusable for the same purpose after successful lead extraction, and 30% of CS lead reimplantation attempts may fail due to exhaustion of side branches. Surgical epicardial LV lead placement is the more invasive second line approach, produces epicardial LV pacing, and has a lead failure rate of ≈15% in 5 years. Transseptal endocardial LV lead placement is the third line approach, can be difficult to achieve, but produces endocardial LV pacing. The major concern with transseptal endocardial LV leads is systemic thromboembolism, but the risk is unknown and oral anticoagulation is advised. Among the new CRT recipients in the United States and Western Europe between 2003 and 2007, 22,798 patients may require CS lead revisions, 9,119 patients may have no usable side branches for CS lead replacement, and 1,800 patients may require surgical epicardial LV lead revision in the next 5 years. The CRT community should actively explore and develop alternative approaches to LV pacing to meet this anticipated clinical demand.