SURGICAL TECHNIQUE___________________________________________________________

Intrathoracic Implantation of aDual-Chamber Pacemaker in a PretermInfant with Congenital AV BlockSertac Haydin, M.D.,* Erkut Ozturk, M.D.,y Yakup Ergul, M.D.,y andVolkan Tuzcu, M.D.y*Department of Pediatric Cardiovascular Surgery, Istanbul Mehmet Akif Ersoy Thoracic and

Cardiovascular Surgery Education and Research Hospital, Istanbul, Turkey; and yDivision of

Pediatric Cardiology, Istanbul Mehmet Akif Ersoy Thoracic and Cardiovascular Surgery

Education and Research Hospital, Istanbul, Turkey

ABSTRACT Congenital complete atrioventricular block can be concomitant with congenital heart diseases ormaternal connective tissue disorders like systemic lupus erythematosus and Sjogren’s syndrome. Suchpatients may require implantation of a permanent pacemaker due to ventricular dysfunction. While manymethods of pacemaker implantation have been tested, one that is optimal for low birth weight infantsremains to be determined. We present a preterm infant with maternal Sjogren’s syndrome with congenitalheart block and describe the technique for implantation of an intrathoracic dual-chamber pacemaker.doi: 10.1111/jocs.12068 (J Card Surg 2013;28:196–198)

Complete atrioventricular (AV) block can be congeni-tal or acquired and is characterized by non-propagationof the atrial impulse to the ventricles.1 Congenitalcomplete AV block can be concomitant with congenitalheart diseases or maternal connective tissue disorderslike systemic lupus erythematosus and Sjogren’ssyndrome.2 Early pacemaker implantation is consideredin caseswhen congenital complete AV block has lead tohydrops fetalis, low ventricular rate, and ventriculardysfunction.3

Permanent pacemaker generators are implantedsubcutaneously or submuscularly on the chest or theabdominal wall. In recent years, new techniques likeintradiaphragmatic or extrapleural intrathoracic implan-tation have emerged.4

We describe the technique for intrapleural intratho-racic implantation of a dual-chamber pacemaker gener-ator in a preterm infant with maternal Sjogren’ssyndrome.

PATIENT PROFILE

The patient was the second child of a mother withSjogren’s syndrome, born via Caesarean section in the

34th week of gestation with a weight of 1850 g. Thefirst child of the 30-year-old mother, who had beendiagnosed ten years previously and had been on oralmethylprednisolone treatment for six years, was alsoborn prematurely with congenital complete AV block.That patient was implanted with an intraperitonealpacemaker at three months of age, but died due tosepsis and intestinal obstruction five days later.

The patient developed respiratory distress after birthand was admitted to an other center’s intensive careunit. Chest radiograph findings were consistent withrespiratory distress syndrome (RDS). ECG showedcomplete AV block. No anomalies were seen on theechocardiogram; 24-hour Holter showed an averageheart rate of 60 bpm. Surfactant was given in the sixthpostnatal hour. After four days of mechanical ventila-tion, the patient was extubated, put under an oxygenhood, and received an infusion of isoproterenol at0.02 mcg/kg/min. After his 56th postnatal day, he wasreferred for pacemaker insertion.

Constant monitoring and periodical 24-hour Holterand echocardiography showed no increase in heartrate, a partially damaged sinus node, and ventriculardysfunction (shortening fraction of 22%) despiteisoproterenol. The decision was made to implant apacemaker in DDDR mode on the 60th postnatal day,with the patient weighing 2700 g.

As the family refused implantation inside the abdo-minal cavity, intrapleural intrathoracic implantation wasplanned instead.

Conflict of interest: None.

Address for correspondence: Sertac Haydin, M.D., Istasyon Mah.,

Istanbul Cad., Bezirganbahce Mevkii, Kucukcekmece, Istanbul 34303,

Turkey. Fax: þ90 212 471 94 94; e-mail: sehaydin@hotmail.com

ELECTROPHYSIOLOGY

196 © 2013 Wiley Periodicals, Inc.

SURGICAL TECHNIQUE

The patient was placed in the supine position andfollowing endotracheal intubation, a median sternot-omy was performed and the pericardium and the rightpleura were opened. Bipolar steroid-eluting epicardialleads (CapSure EPI 4968, Medtronic, Inc., Minneapolis,MN, USA) were secured on the right atrium, rightventricular anterior wall, and left ventricular apex. Asubrectal pocket was prepared at the upper rightquadrant and the proximal part of the leads was rolledup and placed in the pocket, whichwould allow for easyretrieval of the leads at time of generator change.P-wave sensing was 3.4 mV, atrial voltage thresholdwas 1 V, R-wave sensing was 7 mV and ventricularvoltage threshold was 1.1 V. Atrial impedance was978 ohms; ventricular impedance was 1.060 ohms.The leads were connected to the pulse generator(Adapta ADDR01

�R, Medtronic, Inc.), which was then

placed posterolaterally in the most suitable area of theright pleural space and anchored to the posterolateralchest wall. Successful AV synchrony was established.The pericardium was closed using interrupted stitches.A 10F drainage catheter was left in the right pleuralspace and the sternotomy was closed in a routinefashion. The postoperative posteroanterior and lateralchest X-rays are shown in Figure 1. He was taken offmechanical ventilation after seven days, monitored fortwomore days, and moved from the ICU into the ward.Echocardiography showed a shortening fraction in-creased from 22% to 34%. The patient was dischargedon the 20th day after admission. In the course of a six-month follow-up period, no complications have beenseen in the improved patient, the lead impedances andsensing and pacing threshold values have been stable.

COMMENT

First defined in 1901 by Morquio, congenital com-plete AV block is a rare disease with an incidence of 1 in20,000 live births and a high mortality and morbidityrisk.1 It can develop secondary to AV septal defect,corrected transposition of the great arteries, left atrialisomerism, and maternal connective tissue diseases.Congenital AV block in a structurally normal heartis mostly seen in maternal systemic lupus erythema-tosus, although it can also be concomitant with

other connective tissue diseases like Sjogren’s syn-drome.1,5,6 While anti-SSA/Ro and anti-SSB/La anti-bodies have been found in 90% of mothers withaffected children, congenital complete AV block hasbeen seen in only 2% of children with motherscarrying these antibodies. The risk of repeated blockin the following pregnancy in maternal connectivetissue diseases has been reported at 10% to 16%.6,7

Our patient was the second child of a mother withSjogren’s syndrome and anti-SSA/Ro and anti-SSB/Laantibodies.

Approximately 60% of patients with congenitalcomplete AV block require a permanent pacemaker.6

Historically, permanent pacemakers have been im-planted in various parts of the body. The idealimplantation site remains to be determined, particularlyin low birth weight infants.3 Intraperitoneal, retroperito-neal, and preperitoneal approaches have led to compli-cation such as dislocation, intestinal injury, ileus, hernia,sepsis, intraperitoneal migration of leads, and respira-tory distress secondary to upper abdominal midlineincision.4,8 Another disadvantage of the retroperitonealapproach is the decubitus position of the patient, whichcomplicates intervention in case of cardiac arrest duringsurgery.

Roubertie et al. described complication-free intra-diaphragmatic implantation of a single-chamber pace-maker in a 1300-g preterm infant.3 Agarwal et al.implanted extrapleural intrathoracic single-chamberpacemakers in six patients who had acquired or con-genital complete AV block and weighed between 1.8and 14 kg, with no complications.4 The advantages ofthis technique are the sufficiency of a single incision,less cutaneous scarring, additional protection fromdamage provided by the rib cage, and ease of access tothe generator, while the disadvantages are possibleextrapleural migration of the device and compromisedpulmonary mechanics.

Kelle et al. implanted dual-chamber pacemakers withunipolar leads in ten newborn patients who ranged insize from 2.0 to 4.2 kg.8

Advantages of dual-chamber pacing include sinusnode responsiveness and maintaining physiologic AVsynchrony. Due to ventricular dysfunction in the patientand as part of our clinic’s general approach to completeAV block, a dual-chamber pacemaker generator was

Figure 1. Postoperative posteroanterior (A) and lateral (B) chest X-rays.

J CARD SURG HAYDIN, ET AL. 1972013;28:196–198 PACEMAKER IMPLANTATION IN A PRETERM INFANT

chosen for implantation in the intrapleural area. Bipolarleads were preferred to unipolar leads due to advan-tages such as low pacing thresholds, less artifact, theoption of switching to unipolar pacing in case of leadbreakage, low energy expenditure, and longer batterylife due to high impedance value. Additionally, placingthe cathode in the left ventricle, like we did, eliminatesthe delay in the left ventricle contraction andmay lead toan increase in left ventricular function. Looping a portionof the leads and leaving them in a prepared subrectalpocket may allow the generator to be placed thereduring the next change. Also,we do notworry about thepossibility of adhesions at the time of generatorreplacement because most likely, there will be a well-defined fibrous capsule and the generator will be easilyenucleated as defined by Agarwal et al.4 The larger dual-chamber generator is more likely to compromisepulmonary mechanics in the early postoperative periodthan a single-chamber one. In the case of our patient,however, this may have been related to pulmonaryparenchymal damage and ventricular dysfunctioncaused by RDS. The patient took one week to recoversufficiently to be taken off mechanical ventilation.Eventually, we were able to implant bipolar AV pacingleads and a dual-chamber generator by using the sameincision. Ventricular dysfunction improved, no woundcomplications were seen, and the patient recovered.

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198 HAYDIN, ET AL. J CARD SURGPACEMAKER IMPLANTATION IN A PRETERM INFANT 2013;28:196–198