HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bauersfeld, U. Articles by Schüller, H. Search for Related Content PubMed PubMed Citation Articles by Bauersfeld, U. Articles by Schüller, H.

Ann Thorac Surg 1999;68:1380-1383
© 1999 The Society of Thoracic Surgeons

---

Original Articles: Cardiovascular

Low-energy epicardial pacing in children: the benefit of autocapture

^a Division of Pediatric Cardiology, Children’s University Hospital, Zurich, Switzerland
^b II Medical Clinic, Johannes Gutenberg University, Mainz, Germany
^c Department of Cardiothoracic Surgery, University Hospital, Lund, Sweden

Address reprint requests to Dr Bauersfeld, Division of Pediatric Cardiology, Children’s University Hospital, Steinwiesstr 75, 8032 Zurich Switzerland
e-mail: bauersfe{at}kispi.unizh.ch

	Abstract

Top Abstract Introduction Patients and methods Results Comment References

 
Background. Permanent cardiac pacing in children results commonly in augmented energy consumption because of the high pacing rates and the ample stimulation safety margin applied in children. Cardiovascular anatomy and limited venous access sometimes preclude the otherwise preferred endocardial approach. In this multicenter patient series, we studied the feasibility, safety, and energy saving obtained by a combination of steroid-eluting epicardial leads with autocapture devices capable of ongoing adjustment of the stimulation output to the prevailing threshold.

Methods. Autocapture devices (Pacesetter Microny SR+ and Regency SR+; Pacesetter, Solna, Sweden) and steroid-eluting epicardial pacing leads (Medtronic CapSure Epi 10366; Medtronic, Inc, Minneapolis, MN) were implanted in 14 children. Thresholds, telemetry data, evoked response, and polarization signals were obtained at discharge and follow-up, and battery service life was calculated.

Results. During a median follow-up of 6.5 months, autocapture pacing was applied in 12 of 14 children. The automatically adjusted pulse amplitude of autocapture devices demonstrated low-energy pacing with no significant changes between discharge and 6 months follow-up (1.1 ± 0.3 versus 0.9 ± 0.3 V). Autocapture-programmed pacemakers had calculated life spans of 7.8 ± 1.4 years (Microny) and 21.0 ± 1.6 years (Regency). No adverse effects were noted.

Conclusions. Autocapture-controlled pacing with bipolar epicardial pacing leads is feasible and safe in children. Autocapture programming results in substantial energy savings and extends battery life markedly.

	Introduction

Top Abstract Introduction Patients and methods Results Comment References

 
The main indication for permanent cardiac pacing in children is for treatment of severe bradycardia and prevention of Stokes-Adams attacks [1–3]. Absolute or relative pacemaker dependency forces one to program the stimulation output for high safety margins. An additional cause of higher energy consumption and accelerated battery depletion is the higher stimulation rates used in children. Modern endocardial steroid-eluting leads allow for lower long-term output settings and are now used even in smaller children. However cardiovascular anatomy and vascular access, as well as concerns about the risk of venous occlusions, often preclude the use of transvenous pacing leads [4–8]. Recently, steroid-eluting epicardial pacing leads have shown encouraging results and so has the clinical use of autocapture devices connected to endocardial leads [9–14]. The autocapture function provides ongoing capture verification by evoked response signal detection with access to back-up pulses on a beat-to-beat basis. Automatic ongoing output adjustment 0.3 V above the actual threshold results in substantial battery current savings without any hazards regarding stimulation safety. This protocol has been used with transvenous leads in adult patients but it has not been used with epicardial lead systems in children.

	Patients and methods

Top Abstract Introduction Patients and methods Results Comment References

 
Fourteen infants and children who received a bipolar steroid-eluting epicardial pacing lead and a pacemaker with autocapture function between December 1996 and May 1998 were enrolled in the study. Patient demographics, clinical characteristics, and indications for pacing are described in Table 1. Epicardial pacing systems rather than transvenous systems were chosen because of cardiovascular anatomy in 7 children and small patient size in another 7 children, with the intention of preserving venous access for future approaches. All patients were hemodynamically stable in a VVI or VVIR pacing mode. Eight patients had previous cardiac operations.

Implantation procedure
Standard implant techniques were used, and surgical access, lead, and pacemaker position are given in Table 1. A pulse generator was replaced with an autocapture device in one patient, with the lead already in place for 4 years. Lead impedance, ventricular pacing, and sensing thresholds were determined intraoperatively to confirm adequate lead positioning. Postoperative care included continuous electrocardiographic monitoring for at least 24 hours in all patients and Holter analysis in 11 ambulatory children.

Data collection
Pacemaker telemetry data, pacing thresholds, R wave, evoked-response signals, and polarization signals were obtained before discharge and at 1, 3, and 6 months postimplant and thereafter at 6-month intervals. Pacemakers were programmed to collect autocapture-determined pacing thresholds continuously to provide trend data at follow-up. Battery service life calculations were performed assuming 100% pacing, stable thresholds, and a mean rate of 100 beats per minute in VVIR pacing mode. A mean heart rate of 100 beats per minute was chosen for analysis as Holter-determined mean heart rates were approximately 100 beats per minute in our investigated patients. Six months follow-up data were also collected from an age-matched control group (mean age, 35 ± 10 months) comprising 11 children who had various VVIR devices attached to the same epicardial lead (Medtronic CapSure Epi 10366). The output voltage of the pulse generators in the control group were programmed with high safety margins to guarantee capture in case of physiologic or nonphysiologic threshold variations.

Statistical analyses
The descriptive statistics are, if not otherwise stated, presented as mean ± standard error of the mean. Appropriate t tests were used to analyze the difference between paired variables. A p value less than 0.05 was considered statistically significant. For statistical analysis, data for up to 6 months follow-up (n = 7) were used although some patients had 18 months of follow-up, for a total observation time of 126 months. Statistical analysis regarding energy consumption between autocapture devices and conventional devices was not done because of the differences in intrinsic current drain in the different models.

	Results

Top Abstract Introduction Patients and methods Results Comment References

 
Autocapture function
The autocapture function could be applied in 12 patients. Evoked-response signals, polarization signals, and R wave amplitudes remained stable over time and showed no statistically significant differences between discharge and 6 months follow-up (Table 2). No adverse effect of VVI mode pacing or autocapture was noted in any patient, with 3 patients being paced in VVI and 11 in VVIR mode, respectively. No loss of capture was documented or suspected clinically in any patient with applied autocapture feature for up to 18 months of follow-up. Activation of the autocapture function was not feasible in 2 patients because of low evoked-response signals. One of those patients had a concurrent high pacing threshold. Autocapture had to be programmed off in one patient 1 year after pacemaker implant because of an increase in pacing threshold. The threshold trend in this patient showed marked fluctuations from 1.5 to 4.5 V/0.49 ms, with an overall threshold increase that necessitated high-output pacing with conventional programming. The rare intermittent need for pacing in a child with paroxysmal complete heart block resulted in multiple pseudofusion beats that compromised adequate detection of evoked response. The subsequent unnecessary back-up pulses and automatic output increase initiated the abandonment of the autocapture function and conversion to conventional program settings.

	Comment

Top Abstract Introduction Patients and methods Results Comment References

 
There will always be need for epicardial pacing systems in children for anatomic reasons. High pacing rates are usually required in pediatric patients together with substantial safety margins of stimulation output that will increase the energy consumption considerably. Thus, fast battery depletion necessitating generator replacements frequently occurs in children, which increases the inconvenience and morbidity of permanent pacing because of numerous reoperations. The autocapture principle not only regulates output automatically but also assures capture by detection of an evoked response with ongoing access to back-up pulses in case of exit block. Consequently, the autocapture principle results in marked energy savings as well as increased patient safety. The critical function of the autocapture principle is based on evoked response signal detection and low polarization signals.

This study evaluated the feasibility of the autocapture principle in combination with an epicardial pacing lead in a series of children. For as long as 18 months of follow-up autocapture pacing could be applied to 12 of 14 study patients. Measured data from autocapture-programmed pacemakers showed stable evoked-response and polarization signals, as well as low pulse energy and battery current values. Although evoked-response signals were similar, battery current values of autocapture-programmed pacemakers were slightly higher in our study compared with those of a multicenter study using transvenous leads in adult patients [14]. However, when compared with an age-matched control group with various conventional VVIR devices connected to the same epicardial lead, the autocapture devices had impressive stimulation energy savings with very low battery current drain. Besides constant low energy consumption for up to 18 months of follow-up, the fact that one lead was implanted for more than 4 years and functioned well indicates that energy consumption remains low for many years. Battery service life calculations showed a markedly prolonged battery life, with some life expectancies beyond 20 years with Regency generators and 9 years with Microny generators, which is about two to four times longer than with conventional output settings. Thus, the energy savings of autocapture enables small generators with reasonable battery life expectancies to be implanted in preterm infants [15]. However, the service life calculations did not account for changes in lead impedance, pacing thresholds, or heart rates and therefore, represent rough estimations of what could theoretically be attainable as maximum battery service life. Assuming a two- to threefold safety margin with conventional output programming, patients with relatively high stimulation thresholds have even more benefit from autocapture than patients with a low stimulation threshold. The maximum autocapture-controlled output is limited to 4.5 V/0.49 ms. High stimulation thresholds therefore preclude the use of autocapture and require conventional output program settings. Inadequate low evoked response and relatively high polarization signals that precluded autocapture programming were detected in only 2 of 14 children. In addition one child had a threshold increase, with desired safety margins beyond the back-up pulse settings, which required conventional reprogramming. However back-up pulses, while still programmed with autocapture settings, prevented loss of capture. This had been the case with conventional settings because of the low stimulation threshold determined at earlier pacemaker follow-up. Autocapture was not beneficial in one child with intermittent complete heart block. While most children were completely pacemaker dependent, no adverse effect of autocapture was seen and no loss of capture was documented or suspected.

In conclusion, autocapture-controlled pacing is feasible in most children with bipolar epicardial pacing leads. Inadequate evoked response and high polarization signals or high pacing thresholds occasionally precluded the activation of autocapture programs. Autocapture programming resulted in substantial energy savings and extended battery service life markedly; therefore, children would require fewer pulse generator replacements. In addition, back-up pulses yield an increase in safety by accounting for varying thresholds resulting from physiologic or nonphysiologic factors. The medium-term results with steroid-eluting bipolar epicardial leads are encouraging, and substantial benefits from the use of the autocapture function can be expected. Although the epicardial approach is sometimes mandatory for anatomic reasons, more extensive use of it in infants without cardiac malformations appears to be feasible to preserve their venous system.

	References

Top Abstract Introduction Patients and methods Results Comment References

 

1. Gregoratos G., Cheitlin M., Conill A., et al. ACC/AHA guidelines for implantation of cardiac pacemakers and antiarrhythmia devices. Circulation 1998;97:1325-1335.[Free Full Text]
2. Beder S., Hanisch D., Cohen M., Van Heeckeren D., Ankeney J., Riemenschschneider T. Cardiac pacing in children. Am Heart J 1985;109:152-156.[Medline]
3. Gillette P., Zeigler V., Winslow A., Kratz J. Cardiac pacing in neonates, infants, and preschool children. PACE 1992;15:2046-2049.
4. Gillette P., Shannon C., Blair H., Garson A., Porter C., McNamara D. Transvenous pacing in pediatric patients. Am Heart J 1983;105:843-847.[Medline]
5. Kratz J., Gillette P., Crawford F., Sade R., Zeigler V. Atrioventricular pacing in congenital heart disease. Ann Thorac Surg 1992;54:485-489.[Abstract]
6. Figa F., McCrindle B., Bigras J., Hamilton R., Gow R. Risk factors for venous obstruction in children with transvenous pacing leads. Pacing Clin Electrophysiol 1997;20:1902-1909.[Medline]
7. Goto Y., Abe T., Sekine S., Sakurada T. Long-term thrombosis after transvenous permanent pacemaker implantation. PACE 1998;21:1192-1195.
8. Silka M., Rice M. Paradoxic embolism due to altered hemodynamic sequencing following transvenous pacing. PACE 1991:499-503.
9. Mond H., Stokes K. The electrode-tissue interface. PACE 1992;15:95-107.
10. Hamilton R., Gow R., Bahoric B., Griffiths J., Freedom R., Williams W. Steroid-eluting epicardial leads in pediatrics. PACE 1991;14:2066-2072.
11. Johns J., Fish F., Burger J., Hammon J. Steroid-eluting epicardial pacing leads in pediatric patients. J Am Coll Cardiol 1992;20:395-401.[Abstract]
12. Bauersfeld U., Schönbeck M., Candinas R., Von Sägesser L., Turina M. Initial experiences with a new steroid-eluting bipolar epicardial pacing lead. [Abstract]. European Journal of Cardiac Pacing and Electrophysiology 1996;6:222.
13. Schüller H, Lindgren A. Principles and utility of autocapture. VI Asian-Pacific Symposium on Cardiac Pacing and Electrophysiology 1997. Oct 25–28, 1998, New Delhi, India. Bologna: Monduzzi, 1997:187–92.
14. Clarke M., Liu B., Schüller H. Automatic adjustment of pacemaker stimulation output correlated with continuously monitored capture thresholds. PACE 1998;21:1567-1575.
15. Nowak B., Kampmann C.H., Schmid F.X., et al. Schrittmachertherapie bei Frühgeborenen mit AV-Block. Herzschr Elektrophys 1998;9:120-121.

This article has been cited by other articles:

				M. Tomaske, B. Gerritse, L. Kretzers, R. Pretre, A. Dodge-Khatami, M. Rahn, and U. Bauersfeld A 12-Year Experience of Bipolar Steroid-Eluting Epicardial Pacing Leads in Children Ann. Thorac. Surg., May 1, 2008; 85(5): 1704 - 1711. [Abstract] [Full Text] [PDF]

				J. Odim, B. Suckow, B. Saedi, H. Laks, and K. Shannon Equivalent Performance of Epicardial Versus Endocardial Permanent Pacing in Children: A Single Institution and Manufacturer Experience Ann. Thorac. Surg., April 1, 2008; 85(4): 1412 - 1416. [Abstract] [Full Text] [PDF]

				M. S. Silvetti, A. De Santis, S. Marcora, T. De Santo, N. Grovale, and F. Drago Circadian pattern of atrial pacing threshold in the young Europace, February 1, 2008; 10(2): 147 - 150. [Abstract] [Full Text] [PDF]

				M. Tomaske, P. Harpes, R. Pretre, A. Dodge-Khatami, and U. Bauersfeld Long-term experience with AutoCapture(R)-controlled epicardial pacing in children Europace, August 1, 2007; 9(8): 645 - 650. [Abstract] [Full Text] [PDF]

				N. C. Aellig, C. Balmer, A. Dodge-Khatami, M. Rahn, R. Pretre, and U. Bauersfeld Long-Term Follow-Up After Pacemaker Implantation in Neonates and Infants Ann. Thorac. Surg., April 1, 2007; 83(4): 1420 - 1423. [Abstract] [Full Text] [PDF]

				M. S. Silvetti, F. Drago, G. Grutter, A. De Santis, V. Di Ciommo, and L. Rava Twenty years of paediatric cardiac pacing: 515 pacemakers and 480 leads implanted in 292 patients Europace, July 1, 2006; 8(7): 530 - 536. [Abstract] [Full Text] [PDF]

				A. Çeliker, N. Ceviz, and O. Küçükosmanoglu Long-term results of endocardial pacing with AutocaptureTM threshold tracking pacemakers in children Europace, January 1, 2005; 7(6): 569 - 575. [Abstract] [Full Text] [PDF]

				M. I. Cohen, K. Buck, R. E. Tanel, V. L. Vetter, L. A. Rhodes, J. Cox, T. Sheldon, and L. Ruetz Capture management efficacy in children and young adults with endocardial and unipolar epicardial systems, Europace, January 1, 2004; 6(3): 248 - 255. [Abstract] [Full Text] [PDF]

				J.-H. Nurnberg, H. Abdul-Khaliq, P. Ewert, and P. E. Lange Antibradycardia pacing in patients with congenital heart disease: experience with automatic threshold determination and output regulation (AutocaptureTM) Europace, January 1, 2003; 5(2): 199 - 205. [Abstract] [PDF]

				C. Balmer, M. Fasnacht, M. Rahn, L. Molinari, and U. Bauersfeld Long-term follow up of children with congenital complete atrioventricular block and the impact of pacemaker therapy Europace, January 1, 2002; 4(4): 345 - 349. [Abstract] [PDF]

				M. I. Cohen, D. M. Bush, V. L. Vetter, R. E. Tanel, T. S. Wieand, J. W. Gaynor, and L. A. Rhodes Permanent Epicardial Pacing in Pediatric Patients : Seventeen Years of Experience and 1200 Outpatient Visits Circulation, May 29, 2001; 103(21): 2585 - 2590. [Abstract] [Full Text] [PDF]

				E. Valsangiacomo, L. Molinari, M. Rahn-Schonbeck, and U. Bauersfeld DDD pacing mode survival in children with a dual-chamber pacemaker Ann. Thorac. Surg., December 1, 2000; 70(6): 1931 - 1934. [Abstract] [Full Text] [PDF]

				J. S. Sachweh, J. F. Vazquez-Jimenez, F. A. Schondube, S. H. Daebritz, H. Dorge, E. G. Muhler, and B. J. Messmer Twenty years experience with pediatric pacing: epicardial and transvenous stimulation Eur. J. Cardiothorac. Surg., April 1, 2000; 17(4): 455 - 461. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bauersfeld, U. Articles by Schüller, H. Search for Related Content PubMed PubMed Citation Articles by Bauersfeld, U. Articles by Schüller, H.