Revista Española de Cardiología (English Edition) Revista Española de Cardiología (English Edition)
Rev Esp Cardiol. 2018;71:48-51 - Vol. 71 Num.01 DOI: 10.1016/j.rec.2017.02.036

Endocardial Pacing in Infants and Young Children Weighing Less Than 10 Kilograms

Aldo Campos-Quintero a, José Antonio García-Montes a, Rubén Cruz-Arias a, Carlos Zabal-Cerdeira a, Juan Calderón-Colmenero a, Juan Pablo Sandoval a,

a Departamento de Cardiología Pediátrica y Hemodinámica e Intervención en Cardiopatías Congénitas, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico

Article

To the Editor,

Permanent pacemaker implantation is a challenge in pediatric patients, who account for less than 1% of all patients who undergo this procedure.1 Widespread pacemaker use in children is limited by the absence of devices tailored to this population. Epicardial pacemaker placement used to be the preferred option for young patients, as the size of generators and endocardial leads were considered to be inappropriate and even dangerous for young children. Today, however, endocardial pacemakers are being increasingly used in the pediatric population as they offer several advantages, such as lower sensing and pacing thresholds and a reduced risk of lead fractures.2

We report our experience with permanent pacemaker implantation in patients weighing less than 10 kg at our hospital between January 2006 and March 2015. The procedure was performed in 25 patients with a median age of 17 months (range, 6-40 months) and a median weight of 7 kg (range, 4.4-10.0 kg). The indication for pacing in 22 (88%) of the patients was complete atrioventricular block (AVB) after surgery (Table). The AVB had occurred after closure of a ventricular septal defect in all cases except one. The median time between surgery and implantation was 23 days (range, 9-40 days). The pacing leads were inserted by puncturing the right (n = 15) or left (n = 10) subclavian vein. The atrial or ventricular leads, measuring 52 cm in length and 2 mm in diameter, were inserted through 7-Fr introducer sheaths. Bipolar active-fixation leads were used in all cases. For dual chamber pacemakers, a right atrial loop measuring approximately 4 to 6 cm in length was created (Figure). Details of the generator models, implantation sites, pacing mode, and electrical parameters during implantation and follow-up are given in the Table. The generator was placed in a subpectoral pocket. The implantation procedure was completed without complications in most of the patients. One patient developed supraventricular tachycardia without repercussions during fixation of the atrial leads. In another patient, the atrial lead needed to be replaced due to malfunction caused by dislodgement on day 2 after the procedure. Twenty-two of the patients (88%) were followed up for a median of 48 months (range, 1-102 months). Generator replacement due to battery depletion was necessary in 2 children and there was no evidence of venous thrombosis during replacement in either case. Leads were extracted due to pocket-site infection in 3 patients (12%) at 8, 25, and 27 months. There had been no evidence of hematoma at the implantation site in any of the cases. Once the infection had cleared, the lead was removed using an epicardial surgical approach and replaced in 2 patients and was repositioned percutaneously on the contralateral side in the third. All the patients, including those who required lead extraction, were in good clinical health.

Clinical and Electrical Characteristics of Permanent Endocardial Pacemaker Implantation in Young Children

Patient Congenital heart disease Generator Implantation site Pacing mode Electrical parameters during implantation
      Atrium Ventricle   Atrium Ventricle Heart rate, max/min (bpm)
            Sensitivity (mV) Pacing treshold (mV) Impedance (Ω) Sensitivity (mV) Pacing threshold (mV) Impedance (Ω)  
1 ASD+ VSD St Jude
Microny II
------ Apex VVIR ------- ------- ------- N/A N/A N/A 185/90
2 CoAo + PDA + VSD Guidant Insignia
I Entra
Posterior wall Apex DDDR N/A N/A 464 N/A N/A 512 150/80
3 Double discordance + VSD Vitatron Posterior wall Apex of LV DDD N/A 0.2 450 N/A 0.4 598 170/90
4 AVC defect St. Jude
Microny II
----- RVOT VVIR ------- ------- ------ N/A N/A 415 185/90
5 VSD + PDA Guidant Insignia
I Entra
Atrial appendage RVOT DDDR N/A N/A 610 N/A N/A 530 180/80
6 Supracardiac-type TAPVC in SVC Guidant Insignia
I Entra
Posterior wall Apex DDD 3.5 0.4 420 3.5 0.4 430 180/90
7 Dextrocardia, situs inversus, DORV Guidant Insignia
I Entra
Posterior wall Apex DDD 0.75 0.6 447 8.6 0.9 464 150/90
8 Structurally healthy heart Guidant Insignia
I Entra
Posterior wall Apex DDDR 1.5   530 8.0   490 185/90
9 TGA + VSD + subpulmonary ring Guidant Insignia
I Entra
Lateral wall Apex DDDR 2.0 1.0 400 10 1.25 700 185/110
10 VSD + PDA Medtronic Atrial appendage RVOT DDDR 0.19 2.4 866 15 2.1 952 180/80
11 VSD + PDA Boston Scientific
Altrua
Atrial appendage RVOT DDD 1.0 0.75 470 6.0 0.5 440 185/70
12 Structurally healthy heart + paralysis of right atrium Boston Scientific
Altrua
Posterior wall RVOT DDDR N/A N/A 420 8.5 N/A 480 185/90
13 VSD + PDA Boston Scientific
Altrua
Atrial appendage RVOT DDDR 2.0 1.6 610 15 1.2 530 180/70
14 VSD + PDA Boston Scientific
Altrua
Posterior wall RVOT DDDR 3.6 1.5 636 20.7 0.9 870 185/100
15 Juxtaposed atrial appendages Medtronic Interatrial septum Apex DDD 1.0 0.6 764 6.8 1.1 697 185/100
16 VSD + PDA Boston Scientific
Altrua
Atrial appendage RVOT DDDR 1.5 0.9 430 2.5 0.5 480 180/80
17 AVC defect Boston Scientific
Altrua
Lateral wall RVOT DDDR 1.2 0.5 780 7.0 0.8 640 185/100
18 ASD + VSD Boston Scientific
Altrua
Posterior wall RVOT DDDR 1.2 0.4 560 6.0 0.7 538 185/70
19 VSD Boston Scientific
Altrua
Roof Apex DDDR 0.75 0.8 413 2.5 0.4 445 180/80
20 VSD + PDA Boston Scientific
Altrua
Lateral wall Apex DDDR 0.75 1.2 534 2.5 1.2 568 180/80
21 Intracardiac-type TAPVC in coronary sinus + VSD Boston Scientific
Altrua
Atrial appendage RVOT DDDR 0.5 0.9 474 2.5 0.5 540 185/90
22 DORV Boston Scientific
Altrua
Roof RVOT DDDR 0.8 1.3 568 3.0 1.4 620 185/70
23 CoAo + VSD Boston Scientific
Ingenio MRI
Atrial appendage RVOT DDDR 1.0 1.5 610 6.5 0.7 740 185/100
24 VSD Boston Scientific
Ingenio MRI
Atrial appendage RVOT DDDR 0.75 0.6 468 2.5 0.8 534 185/90
25 ASD + DORV Boston Scientific
Ingenio MRI
Atrial appendage RVOT DDDR 0.75 0.4 788 2.5 0.4 753 185/110

Patient Electrical parameters during follow-up
  Atrium Ventricle Pacing % AV interval
  Sensitivity (mV) Pacing threshold (mV) Impedance (Ω) Sensitivity (mV) Pacing threshold (mV) Impedance (Ω) Atrial Ventricular SAV PAV
1 ----- ----- ----- N/A N/A N/A NF NF NF NF
2 N/A N/A N/A N/A N/A N/A NF NF NF NF
3 1.75 2.5 650 N/A 0.75 450 29 99 NA NA
4 ----- ----- ----- N/A N/A N/A ----- NA ----- -----
5 1.2 3.25 310 8.6 5.0 380 6 100 NA NA
6 N/A N/A N/A N/A N/A N/A NF NF NF NF
7 2.0 0.1 470 N/A 2.5 500 57 100 NA NA
8 4.2 1.75 470 N/A 1.5 520 0 100 150 80
9 N/A N/A N/A N/A N/A N/A 13 98 NA NA
10 4.0 1.75 460 7.7 5.1 383 21 100 80 140
11 2.0 0.05 370 N/A 0.05 410 0 100 NA NA
12 2.5 1.16 490 4.4 4.1 490 100 73 NA NA
13 0.75 0.75 460 N/A 2.5 420 1 99 NA NA
14 N/A 2.0 410 N/A 1.75 520 97 100 NA 150
15 1.4 1.25 522 N/A 1.25 470 1 100 120 150
16 2.4 1.24 610 N/A 1.25 480 4 100 NA NA
17 2.2 1.75 420 N/A 1.5 420 19 100 NA NA
18 0.5 1.5 420 N/A 1.5 420 14 100 NA NA
19 N/A 2.0 380 N/A 1.75 410 2 100 NA NA
20 1.0 1.25 530 N/A 1.75 430 40 100 NA NA
21 0.32 8.75 560 6.5 1.5 440 14 92 NA NA
22 2.4 1.25 410 N/A 1.25 460 57 100 NA NA
23 1.9 1.25 400 N/A 1.5 460 11 100 NA NA
24 0.9 6.25 N/A 12 2.0 N/A 7 2 NA NA
25 N/A N/A N/A N/A N/A N/A 56 100 80 160

ASD, atrial septal defect; AVC, atrioventricular canal; bpm, beats per minute; CoAo, coarctation of the aorta; DORV, doublet outlet right ventricle; LV, left ventricle; N/A, not applicable; NA, not available; NF, not followed up; PAV, paced AV; SAV, sensed AV; PDA, patent ductus arteriosus; RVOT, right ventricular outflow tract; SVC, superior vena cava; TAPVC, total anomalous pulmonary venous connection; TGA, transposition of the great arteries; VSD, ventricular septal defect.

Two-year-old patient weighing 9 kg with congenital atrioventricular block. Note the position of the leads in both the atrium and at the right ventricle apex (A). The same patient aged 8 years old and weighing 25 kg (B). Note the minimum displacement of the leads despite the significant somatic growth.

Figure. Two-year-old patient weighing 9 kg with congenital atrioventricular block. Note the position of the leads in both the atrium and at the right ventricle apex (A). The same patient aged 8 years old and weighing 25 kg (B). Note the minimum displacement of the leads despite the significant somatic growth.

A number of factors need to be considered when placing an endocardial pacemaker in young children. Lead displacement caused by growth can interfere with pacing, requiring the insertion of new leads within a relatively short period. Use of a longer atrial lead can prevent this from happening. Gheissari et al.3 calculated that a right loop of 8 cm would allow a child to grow for 6 to 12 years without the need for reoperation and that approximately 10 mm of lead per year should accommodate for somatic growth. Other authors, however, have warned that a surplus lead of this length could be displaced into the right ventricular outflow tract, possibly causing lung failure.4 In our experience, a loop length of approximately 4 to 6 cm is adequate. We have detected no problems to date, although we acknowledge that larger series and longer follow-up times are necessary. Another important issue with pacemaker placement in young children is the thinness of the subcutaneous tissue layer, as the generator tends to exert tension against the tissue and can cause lesions. This increases the risk of infection and the need for extraction, as has been previously indicated.5 The use of subpectoral pockets has been associated with a lower risk of infection in such cases.6 Subpectoral placement is preferred not only for cosmetic reasons but also because of the greater protection provided by the pectoral muscle in young patients.

In conclusion, although patients require close lifetime follow-up due to the risk of venous thrombosis and the possible need for lead extraction, we consider that endocardial pacing in pediatric patients weighing less than 10 kg is a reasonably safe and effective option in hospitals with experience.

Corresponding author: juanpablo.sandoval@cardiologia.org.mx

Bibliography

1. McLeod KA. Cardiac pacing in infants and children. Heart. 2010;96:1502-8.
2. Welisch E, Cherlet E, Crespo-Martínez E, et al. A single institution experience with pacemaker implantation in a pediatric population over 25 Years. Pacing Clin Electrophysiol. 2010;33:1112-8.
3. Gheissari A, Hordof A, Spotnitz H. Transvenous pacemaker in children: relation of lead lengthtoanticipatedgrowth. Ann Thorac Surg. 1991;52:118-21.
4. Antretter H, Colvin J, Schweigmann U, et al. Special problems of pacing in children. Indian Pacing Electrophysiol J. 2003;3:23-33.
5. Robledo-Nolasco R, Ortiz-Avalos M, Rodríguez-Diez G, et al. Transvenous pacing in children weighingless than 10 kilograms. Pacing Clin Electrophysiol. 2009;32:177-81.
6. Baddour L, Epstein A, Erickson C, et al. Update on cardiovascular implantable electronic device infections and the management: a scientific statement from the American Heart Association. Circulation. 2010;121:458-77.

1885-5857/© 2018 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved

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