Comparison of Antero-Lateral Versus Antero-Posterior Electrode Position for Biphasic External Cardioversion of Atrial Flutter

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  • Comparison of Antero-Lateral Versus Antero-Posterior ElectrodePosition for Biphasic External Cardioversion of Atrial Flutter

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    miThducautreatment for atrial flutter is the restoration of sinus rhythm,which can be achieved by the administration of antiarrhyth-mi 9tratieelethadetigthepro(Auseatrgreatris

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    000doic drugs, overdrive stimulation, catheter ablation, andnsthoracic electrical cardioversion.10 For a defined pa-nt population (e.g., acute symptomatic patients), externalctrical cardioversion is a substantial first-line treatmentt is commonly available. Cardioversion techniques and

    vices for different rhythm disorders are clinically inves-ated.1113 Among these, the allocation of the electrodes isfocus of interest. Different electrode positions have beenposed; the anterior-posterior (A-P) and anterior-lateral

    -L) electrode positions are the most recommended andd variants.1316 Trials of the electrical cardioversion of

    ial fibrillation have shown that the A-P position hasater efficacy than the A-L position.15,16 For commonial flutter, the optimal position for placing the electrodesyet unknown. This prospective trial was designed to

    compare the efficacy of the A-P electrode position to that ofthe A-L electrode position in the electrical cardioversion ofcommon atrial flutter. We screened 130 patients in ouroutpatient clinic, emergency room, intensive care unit, orwards. Patients were eligible for the study if, according tocurrent guidelines, the electrical cardioversion of atrial flut-ter was indicated by, for example, imminent cardiac decom-pensation, hypotension, or angina pectoris. Patients wereineligible for this trial if they aged 18 years, pregnant, orplanned for cardioversion of arrhythmias other than com-mon atrial flutter. All patients underwent diagnostic proce-dures and eventual treatment for the prevention of embolicstroke and systemic embolism according to actual guide-lines14 for the management of patients with atrial fibrillationor flutter. After cardioversion, all patients were required tobe anticoagulated for 4 weeks.14 The local ethics com-mittee approved the study, and the study was in compliancewith the Declaration of Helsinki. All patients gave writteninformed consent. The study was registered at ClinicalTrials.gov (protocol record UKE-2383). The hypothesis was that 1of 2 (A-L vs A-P) electrode positions would have greaterefficacy than the other for the cardioversion of atrial flutter.The efficacy of the 2 different electrode positions was theprimary end point. As secondary end points, we defined the

    University Hospital Hamburg-Eppendorf, Heart Center, Department ofdiology, Hamburg, Germany. Manuscript received March 23, 2009;ised manuscript received and accepted July 2, 2009.*Corresponding author: Tel: 49-40-74105-4120; fax: 49-40-74105-2967.E-mail address: risius@uke.uni-hamburg.de (T. Risius). This study was presented in part at the 28th Annual Scientific Sessionhe Heart Rhythm Society, Denver, Colorado, May 9 to 12, 2007.

    2-9149/09/$ see front matter 2009 Elsevier Inc. All rights reserved. www.AJConline.org:10.1016/j.amjcard.2009.07.027Tim Risius, MD*, Kai Mortensen, MD, TjarkHanno U. Klemm, MD, Rodolfo Ventura, MD

    Thomas Rostock, MD, Thomas Mein

    External cardioversion is an established andatrial flutter. The superiority of the biphasicflutter, but whether electrode position affecttion is not known. The aim of this trial wacompared with anterior-posterior (A-P) electOf 130 screened patients, 96 (72 men, mean agassigned to a cardioversion protocol with egroup, 48 patients received sequential biphasconsisting of 50, 75, 100, 150, or 200 J. The mfor A-P, p 0.001) and mean number of shocp 0.001) required for successful cardioversThe efficacy of the first shock with 50 J in[73%]) was also highly significantly greaterelectrode position (18 of 48 patients [36%])position increases efficacy and requires fewcardioversion of common atrial flutter. Therecommended for the external cardioversionInc. All rights reserved. (Am J Cardiol 2009

    Common atrial flutter is a highly prevalent atrial arrhyth-a1,2 caused by trapped excitation in the right atrium.3,4romboembolic stroke57 and uncontrolled ventricular ratee to loss of atrial function are common complications andse morbidity and mortality in affected patients.1,8 Thehwemer, MD, Muhammet A. Aydin, MD,im Barmeyer, MD, Boris Hoffmann, MD,MD, and Stephan Willems, MD

    portant tool to terminate symptomaticeform has been demonstrated for atrialfficacy of cardioversion in this popula-evaluate whether anterior-lateral (A-L)position improves cardioversion results.12 years) were included and randomly

    A-L or A-P electrode position. In eachveform shocks using a step-up protocolenergy (65 13 J for A-L vs 77 13 J8 1.01 for A-L vs 1.96 1.00 for A-P,ere significantly lower in the A-L group.-L electrode position (35 of 48 patientsthe first shock with 50 J in the A-P

    0.001). In conclusion, the A-L electrodeergy and shocks in external electricale, A-L electrode positioning should bemmon atrial flutter. 2009 Elsevier5471550)

    termine the efficacy of the different electrode positions ingroup of patients with symptomatic atrial flutter withications for acute electrical cardioversion.

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    1548 The American Journal of Cardiology (www.AJConline.org)an energy requirement, the mean number of cardiover-n shocks, and cumulative cardioversion efficacy. Directlyfore cardioversion, patients were randomized in a 1:1io to undergo cardioversion in either the A-P or A-Lctrode position by computer-generated randomization.r all cardioversion procedures, a Zoll M-Series deviced Zoll MFE self-adhesive pads (Zoll Medical, Chelms-d, Massachusetts) were used. Patients were sedated withpofol and/or midazolam at the physicians discretion.rdioversion was done under general anesthesia in thestabsorptive state. Successful cardioversion was definedconversion from atrial flutter to sinus rhythm for 30onds.The shock protocol and starting energies were based onfindings of Kerber et al16 and Kerber.17 Patients receiveduential shocks of increasing energy of 50, 75, 100, 150,200 J as necessary for successful cardioversion. A cross-er between electrode positions was planned in case of a

    le 1ient characteristics

    iable All A-P A-L pValue(n 96) (n 48) (n 48)

    e (years) 62 12 62 12 62 13 0.14n 72 (75%) 37 (77%) 35 (73%) 0.63vious cardioversions 15 (16%) 7 (14%) 8 (17%) 0.21ration of atrial flutter

    (hours)48 48 (50%) 24 (50%) 24 (50%) 1.0048 48 (50%) 24 (50%) 24 (50%) 1.00

    dy mass index (kg/m2) 25 4.7 26 5.0 24 4.3 0.38y surface area (m2) 2 0.2 2 0.2 1.9 0.2 0.38

    York HeartAssociationclassification

    16 (17%) 8 (17%) 8 (17%) 1.0034 (35%) 17 (35%) 17 (35%) 1.00

    I 36 (38%) 19 (40%) 17 (35%) 0.8310 (10%) 4 (8%) 6 (12%) 0.73

    edian II II IIpertension 41 (39%) 21 (44%) 20 (42%) 0.83onary artery disease 30 (31%) 11 (23%) 19 (39%) 0.08vular disease 16 (17%) 5 (10%) 11 (23%) 0.17ial septal defect 10 (10%) 3 (6%) 7 (14%) 0.31diomyopathy (dilatative,

    ischemic, etc.)5 (5%) 1 (2%) 4 (8%) 0.35

    t ventricular functionormal 68 (70%) 36 (75%) 32 (67%) 0.50ild dysfunction 7 (7%) 3 (6%) 4 (8%) 0.69oderate dysfunction 17 (18%) 8 (17%) 9 (19%) 0.78

    evere dysfunction 4 (4%) 1 (2%) 3 (6%) 0.29edian Normal Normal Normal

    tiarrhythmic drugs atcardioversion

    miodarone 12 (12%) 5 (10%) 7 (15%) 0.75lecainide 10 (10%) 5 (10%) 5 (10%) 1.00blockers 23 (24%) 12 (25%) 11 (23%) 0.80

    otalol 6 (6%) 1 (2%) 5 (10%) 0.20ata are expressed as mean SEM or as number (percentage). Theree no significant differences in the clinical characteristics between theups.ile shock of 200 J for a final second shock of 200 J withalternative electrode position.

    negroAll continuous variables are expressed as mean SD.e primary end point was the efficacy of the differentctrode positions. Differences were compared using Stu-nts t test, the Mann-Whitney U test, and the chi-squaret. Multivariate regression analysis was performed tontify predictors of the need for high energy for successfuldioversion. Statistical significance was accepted at p0.05.SS version 13.0 (SPSS, Inc., Chicago, Illinois) was used

    analysis. The sample size was calculated using theample Students t test ( 0.05, 2 sided; 0.2 for

    % statistical power) as 90 patients/group. An interim anal-s was planned after the inclusion of 45 patients/group%); statistical significance was accepted at p 0.05.ring interim analysis, 96 patients had already been in-ded in the study. After interim analysis, the study wasmaturely terminated.

    sults

    One hundred thirty patients were screened for possiblerticipation in this study. Ninety-six patients (72 men,an age 62 12 years) were eligible and gave writtenormed consent for participation in the study. Clinicalaracteristics are listed in Table 1. The 2 groups showed nonificant differences in anthropometric data and underly-cardiac disease (e.g., hypertension or the use of medi-

    ions). Table 2 lists the reasons for exclusion from thedy. All 96 patients could be successfully cardioverted tous rhythm. In both the A-P and A-L groups, 2 patients

    96 Patientswith common-type Atrial Flutter included

    48 Patientscardioverted with