ATS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Author home page(s):
Michael Hilker
Hellmut Oelert
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Schmid, F. X.
Right arrow Articles by Oelert, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Schmid, F. X.
Right arrow Articles by Oelert, H.

Ann Thorac Surg 1999;67:1400-1402
© 1999 The Society of Thoracic Surgeons

Original Articles

Cardiac pacing in premature infants and neonates: steroid eluting leads and automatic output adaptation

Franz X. Schmid, MDa, Bernd Nowak, MDb, Christoph Kampmann, MDc, Michael Hilker, MDa, Hellmut Oelert, MD, PhDa

a Department of Cardiothoracic Surgery, Johannes-Gutenberg University Hospitals, Mainz, Germany
b Medical Clinic, Johannes-Gutenberg University Hospitals, Mainz, Germany
c Department of Pediatric Cardiology, Johannes-Gutenberg University Hospitals, Mainz, Germany

Accepted for publication November 3, 1998.

Address reprint requests to Dr Schmid, Department of Cardiovascular and Thoracic Surgery, Johannes Gutenberg-University Hospitals, Langenbeckstr 1, D-55101 Mainz, Germany
e-mail: schmidfx{at}mail.uni-mainz.de


   Abstract
Top
 Abstract
Introduction
 Patients and methods
 Results
 Comment
 References
 
Background. Appropriate generator and lead selection as well as techniques of implantation are most important aspects of cardiac pacing in the extremely young patient. Here we report the clinical results using a new technique with automatic output adaptation based on evoked response in combination with steroid-eluting epicardial leads in small children.

Methods. One neonate and 2 premature infants underwent permanent pacemaker implantation because of congenital high-degree atrioventricular block or postoperative complete heart block, respectively. Steroid-eluting epicardial leads and a multiprogrammable pacemaker with automatic output adaptation were used.

Results. Intermuscular abdominal generator placement and epicardial suture-fixation of the bipolar lead through a subcostal approach was without complications. Serial follow-up examinations revealed safe and consistent pacemaker function up to 12 months after operation.

Conclusions. The technique represents an excellent alternative for permanent cardiac pacing in extremely small patients. We believe that it provides an increase in functional lifetime of the devices and delays the need for battery replacement with its associated complications in this young patient population.


   Introduction
Top
 Abstract
 Introduction
Patients and methods
 Results
 Comment
 References
 
Pacemaker therapy in the pediatric population has markedly improved in recent years. Even permanent endocardial pacing in pediatric patients has become available [1]. The experience with permanent pacemaker implantation in premature and small infants is still limited. Despite the development of smaller pulse generators, the relatively large size of the units, small vein size, and allowance for growth are factors favoring epicardial pacing.

The currently smallest commercially available generator is characterized by a decreased battery capacity. When automatic adaptation of the output pulse amplitude to the prevailing capture threshold is used (autocapture function), the functional lifetime of the battery equals conventional-sized devices. To our best knowledge, only endocardial pacing in combination with automatic output adaptation has been reported so far [2, 3].

Our experience with permanent pacemaker implantation using a rate-adaptive pulse generator with an autocapture algorithm in combination with an epicardial steroid-eluting electrode is presented in this report.


   Patients and methods
Top
 Abstract
 Introduction
 Patients and methods
Results
 Comment
 References
 
During a 12-month period from June 1997 to May 1998, 7 pediatric patients underwent permanent pacemaker implantation because of high-degree atrioventricular block. In 3 of the 7 patients, 2 premature infants and 1 neonate, a combination of a miniaturized pulse generator with automatic output adaptation and an epicardially fixed bipolar lead was used. In 1 of 2 monozygotic twins, fetal echocardiography demonstrated congenital atrioventricular block. At an estimated gestational age of 35 weeks both patients were delivered by cesarean section. One male twin presented with a birth weight of 1,980 g and a heart rate of 40 beats/min. After a short time bradycardia treatment failed, and the baby was temporarily stimulated by a transvenously placed pacing lead. Permanent pacemaker implantation was performed the next day.

The other premature patient was also delivered by means of cesarean section at the end of the 36th week of pregnancy. His birth weight was 2,550 g and his heart rate 45 beats/min in conjunction with high-degree atrioventricular block. After 2 days of temporary pacing, a permanent pacemaker system was implanted.

A 3.0-kg term female infant underwent successful one-stage repair of aortic atresia with ventricular septal defect and normal left ventricle at the age of 2 weeks. After reparative operation, including enlargement of the ventricular septal defect through a median sternotomy, the patient developed complete heart block. Temporary pacing by two epicardial leads for 2 weeks followed by permanent pacemaker implantation was performed.

Pacemaker system
The VVIR pacemaker system (VVI pacemaker with activity sensor) consists of a considerably small multiprogrammable pacemaker and a bipolar epicardial lead. The pulse generator, Microny SR+2425T (Pacesetter AB, Solna, Sweden), is a miniaturized, single-chamber, rate-adaptive cardiac pacemaker with autocapture function. Autocapture means automatic output adaptation based on evoked response and comprises four algorithms: automatic response evaluation of a pacing stimulus, rescue high-output backup pulse in case of no capture, automatic detection and reevaluation of the capture threshold, and subsequent adaptation of the output amplitude to a level of 0.3 V greater than the prevailing capture threshold. The pulse generator weighs 12.8 g, its size is 6 x 33 x 33 mm, and it provides a battery capacity of 0.35 A · h.

The steroid-eluting, bipolar, epicardial lead (CapSure Epi 10366, Medtronic Inc, Minneapolis, MN) consists of a platinum-coated porous surface and a bipolar connector. Each electrode tip is able to elute a maximum of 1.0 mg of dexamethasone-sodium phosphate. The length of the electrode is 35 cm.

Implantation technique
Implantation was performed through a subcostal approach. One patient had the pacemaker insertion through a midsternotomy incision in conjunction with an intracardiac procedure.

The patients were placed in supine position. A subcostal incision from the midline along the costal arch approximately 5 cm in length was performed. The rectus muscle was divided at the tendinous inscriptions to the lower ribs and the pericardium was incised. The limbs of a bipolar electrode were fixed to the epicardium near the apex of the right and left ventricles with nonabsorbable sutures. The pacemaker generator was inserted through the same incision between the rectus abdominis muscle and posterior rectus sheath. Loops of excessive electrode were formed and were left in the pericardium (Fig 1). The muscle, subcutaneous, and subcuticular sutures for wound closure were all absorbable.



View larger version (164K):
[in this window]
[in a new window]
  		Fig 1. Chest and abdominal radiograph after pacemaker system implantation in patient 1. Note loops of excessive electrode placed in the pericardium.

 

   Results
Top
 Abstract
 Introduction
 Patients and methods
 Results
Comment
 References
 
The surgical procedure and the postoperative course after pacemaker implantation was uneventful in all patients. Pulse generator follow-up was performed at 1, 2, 4, and 12 weeks as well as after 6 and 12 months. Satisfactory epicardial pacing has been maintained and the capture threshold remained stable. Patient data collection during follow-up, including capture threshold, evoked response signal, and polarization values, is summarized in Table 1. Postoperative chest roentgenograms showed stable lead and generator positions (Fig 1).


View this table:
[in this window]
[in a new window]
  		Table 1. Data Collection During Implantation and Follow-up in 3 Patients

 

   Comment
Top
 Abstract
 Introduction
 Patients and methods
 Results
 Comment
References
 
Pacemaker implantation in the extremely young patient is associated with technical problems about placement of pulse generators and electrodes. Whereas transvenous endocardial pacing with subcutaneous generator implantation is the preferred technique of permanent pacemaker therapy in adults and older children, not all pediatric patients are suitable for an endocardial system. Small vein size, the potential for growth, and some features of congenital heart malformations require the use of epicardial leads. Epicardial pacing has been reported to be associated with a reduced longevity owing to sensing and pacing problems and threshold changes. Only recently, steroid-eluting electrodes demonstrating stable long-term capture thresholds or even threshold improvement have become available [4]. With respect to the high incidence of lead myocardial interface problems with screw-in electrodes [5] and the encouraging results of the steroid-eluting leads, our current practice is to use epicardial steroid-eluting electrodes in the pediatric population. Moreover, epicardial lead placement offers the advantage of electrode tip fixation anywhere on the heart. This may be essential in most postoperative patients presenting with epicardial thickening and adhesions from previous cardiac surgery. On the basis of our early results with good and stable capture thresholds during follow-up, we anticipate favorable long-term performance with the electrodes we implanted. A length of 35 cm is not adequate for newborns and may result in late problems [6]. More recently, an improved electrode design having a length of 15 cm has become available.

Various techniques for generator placement in children have been suggested. Intrapleural, retroperitoneal, subdiaphragmatic, and intrapelvic placement of these devices provide problems with implantation, generator migration, interference with major organs, and during programming, function control and battery replacement [7]. Invasion of major body cavities for placement of a pacemaker represents an unacceptable approach to us. As a matter of fact, the smaller the patient, the more critical is the size of the pacemaker. Because of limited subcutaneous tissue and thin skin of the neonate, intermuscular implantation in the abdominal wall of a generator as small as possible is advisable. Creation of an adequate pacemaker pocket within the abdominal muscle layers was easy to perform and provided sufficient space to accommodate the generator we have used. The smallest commercially available pacemaker was chosen for our patients. When conventional programming is used, the limited battery capacity of this pacemaker would result in a reduced functional lifetime. This problem is circumvented by using the autocapture function that avoids hardly any energy waste. To our knowledge, there is no information in the literature concerning the use of the autocapture algorithm in conjunction with epicardial electrodes. All our patients demonstrated acceptable and stable threshold data for a period of up to now 1 year after implantation (Table 1). Autocapture function was safe and consistent in all. Unfortunately, at present the autocapture function is not available for atrial pacing. Advancements in pacemaker technology should result in atrioventricular sequential pacing, including autocapture function, in the future.

In conclusion, this technique has been without complications and offers an excellent alternative for permanent cardiac pacing in extremely small patients. However, a larger series of patients and more extensive follow-up are needed to confirm the long-term benefit of this technique.


   References
Top
 Abstract
 Introduction
 Patients and methods
 Results
 Comment
 References
 

  1. Hayes D.L., Holmes D.R., Maloney J.D., Neubauer S.A., Ritter D.G., Danielson G.K. Permanent endocardial pacing in pediatric patients. J Thorac Cardiovasc Surg 1983;85:618-624.[Abstract]
  2. Schüller H., Fahraeus T., Thuesen L., et al. Automatic output adaptation based on evoked response—clinical experience with a new pulse generator. Pacing Clin Electrophysiol 1995;18:1823.
  3. Guerola M., Binner L., Clarke M., et al. Autocapture function in a VVIR pacemaker. A multicentre clinical experience. Eur J Card Pace 1996;6:198.
  4. Hamilton R., Gow R., Bahoric B., et al. Steroid-eluting epicardial leads in pediatrics: improved epicardial thresholds in the first year. Pacing Clin Electrophysiol 1991;14:2066-2072.[Medline]
  5. DeLeon S.Y., Ilbawi M.N., Backer C.L., et al. Exit block in pediatric pacing. Comparison of suture-type and fishhook epicardial electrodes. J Thorac Cardiovasc Surg 1990;99:905-910.[Abstract]
  6. Perry J.C., Nihill M.R., Ludomirsky A., et al. The pulmonary lasso: epicardial pacing lead causing right ventricular outflow obstruction. Pacing Clin Electrophysiol 1991;14:1018-1023.[Medline]
  7. Ohmi M., Tofuhuji M., Sato K., et al. Permanent pacemaker implantation in premature infants less than 2000 grams of body weight. Ann Thorac Surg 1992;54:1223-1225.[Abstract/Free Full Text]



This article has been cited by other articles:


Home page
 EuropaceHome page
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]

Home page
 EuropaceHome page
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]

Home page
 CirculationHome page
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]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to Personal Folders
Right arrow Download to citation manager
Right arrow Author home page(s):
Michael Hilker
Hellmut Oelert
Right arrow Permission Requests
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Schmid, F. X.
Right arrow Articles by Oelert, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Schmid, F. X.
Right arrow Articles by Oelert, H.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
ANN THORAC SURG ASIAN CARDIOVASC THORAC ANN EUR J CARDIOTHORAC SURG
J THORAC CARDIOVASC SURG ICVTS ALL CTSNet JOURNALS