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A successfully novel ICD implantation and medical treatment in a child with LQT syndrome and self-limiting ventricular fibrillation

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Beta-blocker is the first line drug therapy for congenital long QT syndrome. However, in some children this drug is ineffective. In a non-responder patient, Shimizu et al. used Mexiletine to suppress the ventricular arrhythmias, obtaining a good
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  Letter to the Editor  A successfully novel ICD implantation and medical treatment in a childwith LQT syndrome and self-limiting ventricular fibrillation Fabrizio Drago a  , Giovanni Fazio a, ⁎ , Massimo Stefano Silvetti a  ,Gianluca Oricchio  b , Guido Michelon  b a   Arrhythmias Service, Pediatric Cardiology Department, Bambino Gesù Hospital, Rome, Italy  b Cardiochirurgic Service, Pediatric Cardiology Department, Bambino Gesù Hospital, Rome, Italy Received 8 December 2006; accepted 3 January 2007Available online 3 April 2007 Abstract Beta-blocker is the first line drug therapy for congenital long QT syndrome. However, in some children this drug is ineffective. In a non-responder patient, Shimizu et al. used Mexiletine to suppress the ventricular arrhythmias, obtaining a good result. In the high risk patient, theICD is necessary. However the implantation of a device in small children can have technical problems. We report a case of a child affected bylong QT syndrome with recurrent episodes of syncope due to self-limiting torsade de point/ventricular fibrillation, successfully treated by anassociation of mexiletin and propanolol, and in whom an ICD was implanted with a new subcutaneous approach.© 2007 Elsevier Ireland Ltd. All rights reserved.  Keywords:  Congenital long QT syndrome; Flecainide; Beta-blockers; ICD 1. Introduction Congenital long QT syndrome (LQTS) is a geneticdisorder characterized by the prolongation of the QT intervalin the ECG and life-threatening cardiac arrhythmias,occurring especially during conditions of increased sympa-thetic activity [1]. Existing therapies are very effective.Mortality is high among untreated, symptomatic individuals.The treatment is step by step [2] and the administration of  beta-blocker therapy is the first line therapy [3,4]. In a report Mexitil was prescribed [5]. Pacemakers for the prevention of  bradycardia-inducedVTcanbeimplanted[6].ICDimplantisrecommended for the prevention of sudden cardiac death [7].We report a case of a child affected by long QTsyndromewith recurrent episodes of syncope due to self-limitingtorsade de point/ventricular fibrillation, successfully treated by an association of mexiletin and propanolol, and in whoman ICD was implanted. 2. Case report A 4-year-old male child was admitted to our Institutionwith a diagnosis of syncope. The patient was 105-centimeter tall and weighed 16 kg. On admission physical examinationwas unremarkable and ECG showed a prolonged QTinterval(QTc 590 ms). A 72-hour Holter monitoring showed manyepisodes of self-limiting torsade de pointes (Fig. 1)/ ventricular fibrillation (Fig. 2), induced by unexpectedawakening or acute sounds. None of the episodes wascorrelated with sinus bradycardia or long pauses (Fig. 3). Theechocardiogram did not show any structural heart defects. International Journal of Cardiology 118 (2007) e108 – e112www.elsevier.com/locate/ijcard ⁎  Corresponding author. Via Santa Maria di Gesu' 25, 90124 - Palermo,Italy.  E-mail address:  Giovanni.fazio-aaaaa@poste.it  (G. Fazio).0167-5273/$ - see front matter © 2007 Elsevier Ireland Ltd. All rights reserved.doi:10.1016/j.ijcard.2007.01.066  Propanolol did not result in a reduction of the arrhythmicepisodes nor in a shortening of the QT (Fig. 4). ThereforeMexitil was prescribed causing a reduction of the arrhythmicepisodes and a shortening of the QT (Fig. 5). Nevertheless, due to the persistence of recurrent episodesof torsade de pointe/VF, an ICD implantation was scheduled.A bipolar epicardial pacing lead (Medtronic 4968) was positioned in the right ventricular apex for ventricular sensing and pacing. The defibrillation catheter (Medtronic6937) was inserted subcutaneously in the left fifth intercostalspace. The two leads were tunneled and connected to agenerator placed on the abdominal muscles (Medtronic). At the moment of implantation, adequate ventricular pacingthreshold (1.5 V/0.4 ms) and sensing values (9.1 mV) wereobtained (Fig. 6). A single shock at 20 joules correctlyinterrupted an induced ventricular fibrillation.Two days after implantation 2 episodes of VF, adequatelyinterrupted by the ICD were observed. For this reason propanolol was added to mexiletin. This medical therapyresulted in a complete resolution of any arrhythmic events inthe next 45 days of follow-up. 3. Discussion Beta-blocker is the first line drug therapy for congenitallong QT syndrome [3 – 9]. However, in some children thesedrugs are unaffected.In 1997, in a non-responder patient, Shimizu andAntzelevitch used Mexitil to suppress the ventricular arrhythmias, obtaining a good result  [5].In the high risk patient, the ICD is necessary [6,7].However the implantation of a device in small children can be a technical problem.In 2004 an elevated incidence of leads dislocation andrupture is reported by Eicken. In this report the authors performed a transvenous conventional implantation, due tothe little dimension of the cardiac chambers. Manyinappropriate shocks are described [10]. Fig. 1. An episode of a self-limiting torsade de pointe.Fig. 2. An episode of self-limiting ventricular fibrillation, did not associate with clinical symptoms.e109  F. Drago et al. / International Journal of Cardiology 118 (2007) e108  –  e112  In the same year Gasparini reported a new approach: twocatheters (one for pacing/sensing and one for defibrillation)were chosen. A bipolar pacing lead was positioned inthe right ventricular apex for ventricular sensing and pacing withintravascular redundancy forming a loop in the IVC, while acaval coil was positioned within the IVC. The defibrillationwavefront propagated from the coil, positioned posteriorly inthe IVC, to the ICD  “ active can ”  implanted in a left pectoral pouch.Antretter et al. described a loss of capture, during afollow-up of 5 years about this approach [14].In an other report, the same Gasparini, described an im- plantationofanICDina13-month-oldpatient:abipolarpacingleadwas positioned in therightventricular apex forventricular sensing and pacing with a loop in the IVC, while the defi- brillation catheter was inserted subcutaneously in the left sixthintercostal space. The two leads were tunneled and connected.In 2005 Stephenson et al. published a series of 11 caseswhen the implant was realized by this technique. During thefollow-up (30 month), 2 ruptures of the coil lead and 3ineffective shocks (with two deaths) were reported.In our patient, propanolol was unaffected (Figs. 3 and 4).So we prescribed Mexitil. The Holters showed an important reduction of the ventricular arrhythmias and a shortening of the QTc (Fig. 5).Although many studies are necessary, like in our case, theassociation with beta-blockers and Mexitil could represent anew important therapeutic option for non-responder patients. Fig. 3. A frame of the basal Holter registration: QTc 0.640 ms.Fig. 4. A frame of the Holter registration during propanolol treatment: QTc 0.660 ms.e110  F. Drago et al. / International Journal of Cardiology 118 (2007) e108  –  e112  For the high risk of sudden death, we implanted an ICD.For the elevated incidence of lead dislocations andruptures with a conventional approach, we did not chosethis one.However in literature there is no information about a possible high risk of cava vein occlusion, forming a loop inthe IVC, due to adhesions between vein and lead, we think that it is very high.For this reasons we preferred the subcutaneous approach.To reduce the possibility of ineffective shock weimplanted the coil lead in a higher position: in the describedcases in fact, during the growing, the heart was exited fromwhere the defibrillation wavefront propagated. 4. Conclusions Although many studies are necessary, like in our case, theassociation withbeta-blockers andMexitilcould representanimportant therapeutic option for the non-responder patients.In the high risk patient, the ICD is necessary [6,7]. Theimplantation of a device in a child can represent a technical problem [11 – 13]. In our opinion the better approach could be to implant the coil lead inserted itself subcutaneously,near the fifth intercostals space. References [1] Schwartz PJ. Management of long QT syndrome. Nat Clin Pract Cardiovasc Med Jul 2005;2(7):346 – 51.[2] Iraqi M, Chevalier P, Raboisson MJ, et al. Long QT syndrome inchildren: analysis of the Lyon series. Arch Mal Coeur Vaiss Feb2006;99(2):134 – 40.[3] Chatrath R, Bell CM, Ackerman MJ. Beta-blocker therapy failures insymptomatic probands with genotyped long-QT syndrome. Pediatr Cardiol Sep – Oct 2004;25(5):459 – 65 [Electronic publication 2004Jul 30].[4] TenHarkelAD,WitsenburgM,deJongPL,JordaensL,WijmanM,WildeAA.Efficacyofanimplantablecardioverter-defibrillatorinaneonatewithLQT3 associated arrhythmias. Europace Jan 2005;7(1): 77 – 84.[5] Shimizu W, Antzelevitch C. Sodium channel block with Mexiletine iseffective in reducing dispersion of repolarization and preventingtorsade de pointes in LQT2 and LQT3 models of the long-QTsyndrome. Circulation Sep 16 1997;96(6):2038 – 47.[6] Fisher JD, Johnston DR, Furman S, Mercando AD, Kim SG. Long-term efficacy of antitachycardia pacing for supraventricular andventricular tachycardias. Am J Cardiol Dec 1 1987;60(16):1311 – 6.[7] Goel AK, Berger S, Pelech A, Dhala A. Implantable cardioverter defibrillator therapy in children with long QT syndrome. Pediatr Cardiol Jul – Aug 2004;25(4):370 – 8.[8] Vyas H, Hejlik J, Ackerman MJ. Epinephrine QT stress testing in theevaluation of congenital long-QTsyndrome: diagnostic accuracy of the paradoxical QT response. Circulation Mar 21 2006;113(11):1385 – 92[Electronic publication 2006 Mar 13].Fig. 5. A frame of the Holter registration during mexiletin treatment: QTc 0.550 ms.Fig. 6.e111  F. Drago et al. / International Journal of Cardiology 118 (2007) e108  –  e112  [9] Zhao F. Relationship between torsades de pointes and QT dispersion inidiopathic long QT syndrome. Di Yi Jun Yi Da Xue Xue Bao Oct 2005;25(10):1312 – 3.[10] Eicken A, Kolb C, Lange S, et al. Implantable cardioverter defibrillator (ICD) in children. Int J Cardiol Feb 8 2006;107(1):30 – 5.[11] Gasparini M, Mantica M, Galimberti P, Coltorti F, Ceriotti C, PrioriSG. Inferior vena cava loop of the implantable cardioverter defibrillator endo-cardial lead: a possible solution of the growth problem in pediatric implantation. Pacing Clin Electrophysiol2000;23:2108 – 12.[12] Gasparini M, Lunati M, Galimberti P, Bloise R, Fiore I, Priori SG.Images in cardiovascular medicine. Endocardial implantation of acardioverter-defibrillator in a 13-month-old child affected by long-QTsyndrome and syndactyly. Circulation Dec 7 2004;110(23):e525 – 7.[13] Stephenson EA, Batra AS, Knilans TK, et al. Berul CIA multicenter experience with novel implantable cardioverter defibrillator config-urations in the pediatric and congenital heart disease population.J Cardiovasc Electrophysiol Jan 2006;17(1):41 – 6.[14] Antretter H, Hangler H, Colvin J, Laufer G. Inferior vena caval loop of an endocardial pacing lead did not solve the growth problem in a child.Pacing Clin Electrophysiol Nov 2001;24(11):1706 – 8 [discussion1709].e112  F. Drago et al. / International Journal of Cardiology 118 (2007) e108  –  e112
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