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Journal of the American College of Cardiology Vol. 43, No. 9, 2004© 2004 by the American College of Cardiology Foundation ISSN 0735-1097/04/$30.00Published by Elsevier Inc. doi:10.1016/j.jacc.2003.12.042

Congenital Heart Disease

eversible Atrioventricular Blockssociated With Closure of Atrialeptal Defects Using the Amplatzer Deviceenji Suda, MD,* Marie-Josee Raboisson, MD,† Eric Piette, Nagib S. Dahdah, MD, FACC,‡

oaquim Miro, MD, FRCP‡enri, Japan; Lyon, France; and Montreal, Canada

OBJECTIVES We sought to determine the incidence, nature, and predisposing factors of atrioventricularblock (AVB) associated with closure of atrial septal defects (ASDs) using the Amplatzerseptal occluder (ASO).

BACKGROUND In our institution, 162 patients underwent ASD closure using ASO between December 1997and December 2001. This includes small children with large defects.

METHODS Electrocardiographic tracings during ASO implantation and at follow-up visits werereviewed. Anatomic characteristics and device size were assessed as potential risk factors forAVB.

RESULTS Ten patients (6.2%) presented with new-onset (n � 9) or aggravation of preexisting(n � 1) AVB. Atrioventricular block occurred during the procedure (n � 3) or was first notedone day to one week later (n � 7). Patients had first-degree (n � 4), second-degreeWenckebach (n � 4), or third-degree (n � 2) AVB, with no symptoms or hemodynamiccompromise. First-degree AVB persisted in two patients at 12 and 33 months of follow-up,whereas most recovered normal AV conduction within one (n � 7) or six months (n � 1).A larger shunt (Qp/Qs ratio 2.8 � 0.9 vs. 2.1 � 0.8, p � 0.01) and device size (24 � 5 vs.19 � 6 mm, p � 0.01) were the only determinant factors for AVB. A device size �19 mmwas used in 90% (9 of 10) of patients who developed AVB, as compared with 49% of thosewithout AVB (p � 0.02).

CONCLUSIONS Closure of ASDs using the large ASO can be associated with the development of AV blockand mandate a closer follow-up. In our series, however, all AVBs resolved or improvedspontaneously, with no recurrence at mid-term follow-up. (J Am Coll Cardiol 2004;43:1677–82) © 2004 by the American College of Cardiology Foundation

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ercutaneous closure of ostium secundum atrial septalefects (ASDs) has been widely accepted and is becomingne of the standard treatments of this malformation (1–6).mong these devices, the Amplatzer septal occluder (ASO;GA Medical Corp., Golden Valley, Minnesota) seems torovide the highest level of effectiveness and safety (1,7–10).owever, some complications have been reported with the

se of the ASO, such as arrhythmia, embolization, throm-us formation, pericardial effusion, and transient ischemicttack (4–6,10). Because of the close proximity between theiscs of the device and the atrioventricular (AV) node (11),trioventricular block (AVB) is a likely complication. How-ver, limited data are available concerning AVB associatedith ASD closure using the ASO (4–6,10,12). Therefore, the

im of this study was to determine the incidence, evolution,nd predisposing factors of AVB associated with ASD closuresing the ASO in a single-institution experience.

From the *Division of Pediatric Cardiology, Department of Pediatrics, Tenriospital, Tenri, Japan; †Department of Cardiology, Hopital Louis Pradel, Lyon,

rance; and ‡Division of Cardiology, Hopital Sainte-Justine, University of Montreal,ontreal, Canada. This work was completed at Hopital Sainte-Justine, University ofontreal, Montreal, Canada.Manuscript received July 30, 2003; revised manuscript received October 1, 2003,

ccepted December 9, 2003.

ETHODS

rom December 1, 1997, to December 31, 2001, 162atients with ASDs underwent ASD closure using the ASOt Sainte-Justine Hospital, Montreal. Before August 2000,ome patients were referred for surgical closure without anyttempt to close the defect via catheterization (n � 16) orfter a failed attempt (n � 2). Since August 2000, allatients with an isolated secundum ASD underwent suc-essful ASD closure using the ASO, regardless of the defectnatomy (size, number of defects, or rim characteristics) orhe patient’s size and age. Among these patients, multipleSDs were closed using a single device in 40 patients andsing two devices in one patient with distant defects.All patients had an electrocardiogram (ECG) before and

uring closure and at one day, one week, one month, threeonths, and yearly after the procedure, according to our

rotocol. Patients with second- or third-degree AVB wereurther evaluated on a daily or weekly basis until 1:1onduction was restored. All ECG tracings, includinghythm strips during the procedure, 12-lead ECGs duringisits, and 24-h ambulatory ECGs before closure and atollow-up visits were reviewed.

In this study, patients with new-onset AVB or aggrava-

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1678 Suda et al. JACC Vol. 43, No. 9, 2004AV Conduction Disturbances in ASD Closure Using ASO May 5, 2004:1677–82

ion of a pre-existing AV conduction disturbance weredentified and defined as patients with AVB. A PR intervalxceeding the upper normal limits for a given age and heartate was defined as first-degree AVB (13).

To determine the predisposing factors of AVB, weompared the following variables between patients with andithout AVB: demographic data, ECG findings beforeSD closure (heart rate and PR interval), size of primarySD, number of multiple ASDs, procedure time, device

ize, device size indexed to body height (device/height), andulmonary to systemic flow ratio (Qp/Qs).In addition, to evaluate the relationship between device

isc and AV node, we measured the distance between theight atrial disc and the tricuspid annulus in a standardchographic apical four-chamber view immediately afterricuspid valve closure. Results were compared between theix patients who received a device �19 mm and developedVB and a randomly selected group of 23 patients who

eceived a device �19 mm but did not develop AVB.rotocol of ASD closure. The full description of the ASOnd the protocol of device closure were reported previously2,3). In short, all procedures were done under generalnesthesia with continuous transesophageal echocardio-raphic monitoring. A complete hemodynamic study andight pulmonary vein angiography were performed. Trans-sophageal echocardiography was performed to evaluate theumber, position, and size of ASDs and surrounding rims.he defects were balloon-sized using either the Meditechcclusion Balloon Catheter (Boston Scientific Corp., Wa-

ertown, Massachusetts) until June 1999 or the Amplatzerizing Balloon (AGA Medical Corp.) thereafter. An oc-luder was chosen and implanted as reported (2,3). Written,

Abbreviations and AcronymsASD � atrial septal defectASO � Amplatzer septal occluderAV � atrioventricularAVB � atrioventricular blockECG � electrocardiogram or electrocardiographicQp/Qs � pulmonary to systemic flow ratio

able 1. Biometric and Atrial Septal Defect Characteristics of Pa

PatientAge(yrs)

Weight(kg)

Height(cm)

Number ofASDs

Primary ASDSize by TEE

(mm)

1 10.1 28.5 138.0 Fenestrated 4.02 3.1 15.2 96.7 1 17.83 4.3 14.8 109.8 1 14.04 6.9 26.3 106.5 Fenestrated 10.85 15.0 62.5 163.0 1 16.06 6.8 19.1 122.0 1 16.07 2.6 12.4 92.5 1 16.58 7.3 15.9 120.3 1 20.59 4.9 16.2 106.0 3 5.2

10 5.3 17.4 109.1 1 24.0

˙ ˙

SD � atrial septal defect; Qp/Qs � pulmonary to systemic flow ratio; TEE � transesop

nformed consent was obtained from all patients and/orheir guardians.tatistical analysis. Data are expressed as the mean value

SD or median value (range) for continuous and categor-cal data, respectively. The unpaired t test was used toompare continuous data (demographic, ECG parametersefore procedure, ASD size, number of ASDs, device size,evice/height ratio, fluoroscopic time, and procedure time),nd the Mann-Whitney U test was used in case of non-ormal distribution. Data distribution was evaluated withhe Kolmogorov-Smirnov normality test. The Fisher exactest was used for comparison of categorical data (frequenciesf multiple ASDs, device size �19 mm, and indexed size0.18 mm/cm). A value of p � 0.05 was considered

ignificant. All calculations were performed using the sta-istical package Stat View version 5.0 (SAS Institute Inc.,ary, North Carolina).

ESULTS

mong the 162 patients, 10 (6.1 %) developed new-onsetVB (n � 9) or aggravation of pre-existing first-degreeVB (n � 1). Among those, 6 (3.6%) developed second- or

hird-degree AVB (Table 1).In three patients (Patients 1 to 3), second- or third-

egree AVB was noted during the procedure. Normal AVonduction resumed spontaneously before the cathetersere withdrawn in two cases and one month after therocedure in the third case, after resuming 1:1 conductionith first-degree AVB during the procedure (Figs. 1 and 2).

n the remaining seven patients (Patients 4 to 10), AVB wasrst noted between one day and one week after therocedure. The AVB was characterized as first-, second-, orhird-degree in four, two, and one patient, respectively. Inhese patients, normal AV conduction was restored withinne month (n � 4) and six months (n � 1). Two patientsersisted in first-degree AVB at 12- and 33-monthollow-up visits. In both cases, however, the PR interval hadmproved compared with its immediate postproceduralalue (Table 2).

The minimum heart rate in the six patients with second-

s With Atrioventricular Conduction Disturbance

ASDalloon Size

(mm)

DeviceSize

(mm)

Device/HeightRatio

Qp/QsRatio

AssociatedConditions

11.0 18 0.13 0.9 Ebstein’s anomaly27.0 26 0.27 3.221.0 20 0.18 2.7 S/p neuroblastoma20.8 20 0.19 2.7 Trisomy 2128.6 34 0.21 1.823.5 24 0.20 3.223.0 22 0.24 3.4 Pulmonary stenosis29.3 30 0.25 4.115.0 19 0.18 2.824.9 28 0.26 2.8

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1679JACC Vol. 43, No. 9, 2004 Suda et al.May 5, 2004:1677–82 AV Conduction Disturbances in ASD Closure Using ASO

r third-degree AVB ranged from 39 to 80 beats/min (withn effective junctional escape rhythm for the two patients inhird-degree AVB) on 24-h ambulatory ECG monitoringbtained one to seven days after the procedure. No patientresented with symptoms or hemodynamic compromisehat required removal of the device or pacemaker implan-ation.

Seven other patients presented with first-degree AVBefore ASD closure. Atrioventricular conduction remainednchanged after the procedure and therefore was notncluded in the AVB group, as defined earlier. No patientas documented to have sinus node dysfunction or second-r third-degree AVB before the procedure. Five of the seven

igure 2. Echocardiographic apical four-chamber view of the same patients in Figure 1. Note the close proximity of the right atrial disc of themplatzer device (A) to the tricuspid annulus at the atrioventricular

unction (arrow).

igure 1. Complete atrioventricular block (ventricular rate 74 beats/min) innd normal atrioventricular conduction at one-month follow-up (b).

o

atients remained in first-degree AVB and two were inormal AV conduction at final follow-up of 10 to 51onths. Interestingly, four of these five patients who

emained in first-degree AVB had an underlying disease,ncluding Steinert myopathy or Holt-Oram syndrome.

There was no significant difference in age, weight, height,CG findings before the procedure, size of primary ASD,

requency of multiple ASDs, fluoroscopic time, and proce-ure time between patients with and without AVB (Table). However, the device size (25 � 5 vs. 19 � 6 mm),evice/height ratio (0.21 � 0.05 vs. 0.17 � 0.05 mm/cm),nd Qp/Qs (2.8 � 1.0 vs. 2.1 � 0.8) were significantlyigher in patients with AVB than in those without AVBTable 3). Among the 10 patients who developed AVB, 990%), including all 7 who did so after the procedure,eceived a device �19 mm. In comparison, 49% of thoseithout AVB received a device �19 mm (p � 0.02).imilarly, 9 of 10 of patients with AVB and all sevenatients who did so after the procedure had a device/heightatio �0.18 mm/cm, compared with 44% of patients with-ut AVB (p � 0.01).Transthoracic echocardiographic follow-up showed com-

lete ASD closure or a trivial residual shunt in 87% ofatients immediately after and in 93% at one and threeonths after ASO implantation. In this respect, there was

o difference between patients with or without AVB. Inatients in whom a device �19 mm was implanted, thereas no significant difference in distance between the right

trial disc and the tricuspid valve among patients with versushose without AVB (6.6 � 2.0 vs. 6.3 � 2.5 mm, p � NS)

ISCUSSION

ur retrospective study of a large consecutive series in aingle institution indicates that ASD closure using the ASOan be associated with AVB, which can occur during therocedure or immediately after and mandates close ECGollow-up. Because hemodynamic compromise was not

year-old patient 24 h after implantation of a 28-mm Amplatzer device (a)

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1680 Suda et al. JACC Vol. 43, No. 9, 2004AV Conduction Disturbances in ASD Closure Using ASO May 5, 2004:1677–82

r improvement was observed in all, we advocate closebservation rather than systematic removal of the device.Atrioventricular block has been reported after ASD

losure with most of the devices currently or recently in useTable 4), such as the Cardio-Seal, ASDOS, Angel-Wings,nd ASO (4,5,10,12,14–16). Although none of those stud-es was looking specifically at the association of AVB withevice closure, this occurrence seems to be particularlyrequent with the ASO, a finding confirmed in our study.his comparison is difficult to interpret, however, as it isidely accepted that the ASO allows the closure of largerefects than the other devices do. Thus, it might benappropriate to conclude whether the characteristics of theSO (material, shape, size of disks for a specific ASDiameter) alone are responsible for the increased occurrencef AVB with the ASO.Hill et al. (12) systematically obtained 24-hour ambula-

ory ECG monitoring in 41 patients before and after ASDlosure with the ASO and found second- or third-degreeVB in two patients (4.9%). Given the retrospective naturef our study, 24-h Holter recordings were not obtainedccording to standard protocol. This may represent a limi-ation of our study. Nevertheless, the frequency of AVB inur study (6.1%, of which 3.7% was second- or third-degreeVB) is comparable, despite the larger size devices used inur group of patients. Demkow et al. (5) found one patient2%) with transient AVB of 50 adult patients who had largeSDs closed using the ASO. The lower frequency of AVB

n their series might be explained by the larger size ofatients, which logically would decrease the device/heightatio, an identified risk factor in our study. Chan et al. (4)eported one patient with transient AVB in a 100-patienteries, but the mean size of the device in that study (14.6m by our calculation) was much smaller than that in this

tudy (19.3 mm).Indeed, the size of the device can be a predisposing factor

able 3. Comparison Between Patients With and Thoseithout Atrioventricular Conduction Disturbance

PatientsWith AVB

(n � 10)

PatientsWithout AVB

(n � 152)

ge (yrs) 6.6 � 3.7 8.3 � 7.2ody weight (kg)* 22.9 � 14.9 27.4 � 18.1ody height (cm) 116 � 21 121 � 27ultiple ASDs (%) 3 (30%) 36 (23.7%)ain ASD size (mm) 14.6 � 6.5 14.0 � 5.8

˙ p/Qs ratio* 2.8 � 0.9† 2.1 � 0.8evice size (mm) 24 � 5† 19 � 6evice/height ratio (mm/cm) 0.21 � 0.04† 0.17 � 0.05rocedure time (min)* 87 � 26 79 � 33eart rate (beats/min) 109 � 27 103 � 24R interval (ms) 148 � 41 145 � 40RS duration (ms) 85 � 12 82 � 15

Mann-Whitney U test used. †p � 0.01 compared with patients without atrioven-ricular block. Data are presented as the mean value � SD or number (%) of patients.

Abbreviations as in Tables 1 and 2.

of AVB after ASD closure. In our study, patients with AVBT *

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1681JACC Vol. 43, No. 9, 2004 Suda et al.May 5, 2004:1677–82 AV Conduction Disturbances in ASD Closure Using ASO

eceived significantly larger devices than did patients with-ut AVB, with the device/height ratio being significantlyigher. Nine (11%) of 83 patients who received devices �19m and 9 (12%) of 75 patients with a device/height ratio0.18 developed AVB during or after implantation, com-

ared with one (1.2%) of 79 and one (1.1%) of 87 patients,espectively (p � 0.05 each). Thus, patients meeting thoseriteria need closer hemodynamic and ECG monitoring ofheir AV conduction immediately after the procedure.welve-lead ECG periodically and 24-h Holter recordings

re necessary later on, whereas exercise testing may beequired for selected patients. Chessa et al. (10) reportedhat a patient who showed third-degree AVB with implan-ation of an 18-mm device had restored normal sinushythm after the device was replaced with a 14-mm device.his again strongly suggests that device size may be an

ndependent risk for AV conduction after ASO implanta-ion. This emphasizes the importance of the precise sizingf the ASD to avoid placement of oversized devices.On the other hand, Du et al. (6) and Hill et al. (12)

eported on the same one patient with preexisting sinusode dysfunction who developed complete AVB after ASDlosure using a 24-mm ASO and subsequently requiredacemaker implantation (Table 4). To our knowledge, thiss the only reported case requiring pacemaker implantationfter ASO implantation so far. Pacemaker implantationaises the question of device retrieval to alleviate AVB. Oneay suggest retrieval in case of second- or third-degree

lock, which occurs during the procedure without sponta-eous conversion to 1:1 conduction within 30 min. Implan-ation of a smaller device may then be attempted. This hasot proven necessary in any of our three patients wither-procedural AVB, who all improved rather rapidly.atients with new-onset AVB that first appears after therocedure has been completed may be observed in theospital until hemodynamic instability is ruled out oregression of AVB is observed. Subsequent ambulatoryollow-up with Holter monitoring may be appropriate inase of proven hemodynamic stability. In our experience, allatients with second- or third-degree AVB presented with

able 4. Reported Atrioventricular Conduction Disturbance Asso

DeviceNumber of

PatientsMean Age

(yrs)Stretched

Size

ardio-Seal (13) 50 15.9SDOS (14) 41 7.8 � 1.9 14.7 � 2ngel Wings (15) 75 28.3 11.9mplatzer (4) 93 13.3 � 13.9 14.6 (devmplatzer (12)* 41 9.2†

mplatzer (5) 50 40 � 15.5 18.5mplatzer (6)* 423 18.1 � 19.3 17.8 � 6mplatzer‡ 162 8.2 � 7.0 18.4 � 5

Reported the same patient. †Median value. ‡Our study. Data on mean age and ASAbbreviations as in Tables 1 and 2.

n adequate escape rate, suggesting an intact lower AV node o

unction. On the other hand, conversion to 1:1 AV con-uction has taken up to two weeks in one of our patients.The mechanism of AVB secondary to ASO implantationight be partly attributable to continuous pressure or

riction of atrial discs on the AV node, inducing transientdema leading to AVB, as suggested by Hill et al. (12).owever, in our patients in whom devices �19 mm were

mplanted, there was no significant difference in distanceetween the right atrial disc and the tricuspid valve amongatients with versus those without AVB. Assessment of theeal spatial relationship between atrial discs and the AVode using other diagnostic modalities, such as three-imensional magnetic resonance imaging, may give us morensight on this issue.

Preexisting sinus node dysfunction or AV conductionisturbance should not be ignored, especially in the case of

arge ASDs requiring large devices. It is well known thatSDs may be associated with subclinical ECG abnormali-

ies, including sinus node dysfunction, conduction delay,nd AV block (17–19). In such cases, thorough ECGcreening, including 24-h ambulatory ECG monitoring,efore closure of larger ASDs, may be valuable. Use oforticosteroids to enhance AV conduction recovery is notupported by experimental data or controlled studies. How-ver, we used them in our patient with postproceduralhird-degree AVB. Rapid improvement to second-degreeVB and subsequent full recovery was observed within twoeeks. Whether or not this was a spontaneous or

orticosteroid-enhanced recovery remains uncertain. Like-ise, the indication for and timing of device retrieval are not

vailable in the literature. If selected because of unstableVB, device retrieval may not necessarily avoid pacemaker

mplantation.onclusions. Closure of ASDs using the large ASO can be

ssociated with transient AVB, which occurs during the firsteek of ASD closure and mandates close follow-up. Device

ize �19 mm or indexed size �0.18 mm/cm seems to be theajor predisposing factor. The absence of hemodynamic

ompromise and spontaneous resolution in all our patientsay justify close observation rather than systematic removal

d With Device Closure of Atrial Septal Defects

Atrioventricular Block Intervention

Transient first-degree AVB � 1 NoneTransient AVB � 4 (third-degree AVB � 1) NoneTransient third-degree AVB � 3 (4%) NoneTransient AVB � 1 NoneTransient second-degree AVB � 1,

third-degree AVB � 1Pacemaker*

Transient second-degree AVB � 1 NoneThird-degree AVB � 1 Pacemaker*Transient second-degree AVB � 4,

third-degree AVB � 2None

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1682 Suda et al. JACC Vol. 43, No. 9, 2004AV Conduction Disturbances in ASD Closure Using ASO May 5, 2004:1677–82

een favorable in our series, this issue needs to be discussedhile obtaining consent from patients with large defects.

eprint requests and correspondence: Dr. Nagib S. Dahdah,opital Sainte-Justine, Department of Cardiology, 3175 Cote St.atherine, Montreal QC H3T1C-5, Canada. E-mail: ndahdah@ol.net.

EFERENCES

1. Rocchini AP, Lock JE. Umbrella devices (technology, methodology inatrial septal defect, ventricular septal defect, fenestrated Fontan, PDA,others). In: Lock JE, Keane JF, Perry SB, editors. Diagnostic andInterventional Catheterization in Congenital Heart Disease. 2nd ed.Norwell, MA: Kluwer Academic, 2000:179–98.

2. Masura J, Gavora P, Formanek A, Hijazi ZM. Transcatheter closureof secundum atrial septal defects using the new self-centering Am-platzer septal occluder: initial human experience. Cathet CardiovascDiagn 1997;42:388–93.

3. Fisher G, Krammer HH, Stieh J, Harding P, Jung O. Transcatheterclosure of secundum atrial septal defects with the new self-centeringAmplatzer septal occluder. Eur Heart J 1999;20:541–9.

4. Chan KC, Godman MJ, Walsh K, Wilson N, Redington A, Gibbs JL.Transcatheter closure of atrial septal defect and interatrial communi-cations with a new self expanding nitinol double disc device (Am-platzer septal occluder): multicentre UK experience. Heart 1999;82:300–6.

5. Demkow M, Ruzyllo W, Konka M, et al. Transvenous closure ofmoderate and large secundum atrial septal defects in adults using theAmplatzer septal occluder. Cathet Cardiovasc Intervent 2001;52:188–93.

6. Du Z-D, Hijazi ZM, Keinman CS, Silverman NH, Larntz K, for theAmplatzer Investigators. Comparison between transcatheter and sur-gical closure of secundum atrial septal defect in children and adults.J Am Coll Cardiol 2002;39:1836–44.

7. Formigari R, Santoro G, Rossetti L, Rinelli G, Guccione P, BalleriniL. Comparison of three different atrial septal defect occlusion devices.Am J Cardiol 1998;82:690–2.

8. Walsh KP, Tofeig M, Kitchiner DJ, et al. Comparison of the Siderisand Amplatzer septal occlusion device. Am J Cardiol 1999;83:933–6.

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