Background: Ectopic atrial tachycardia (EAT) is a relatively rare form of supraventricular arrhythmia, which, if persistent, may lead to tachycardia-induced cardiomyopathy (TIC), associated with an equally poor prognosis, including the risk of sudden cardiac death, as other dilated cardiomyopathies. The aim of the study was to evaluate the efficacy and course of radiofrequency catheter ablation (RFCA) in the treatment of patients with EAT.
Methods: The study group comprised 33 consecutive patients (16 males and 17 females of mean age 41 &plusmn; 15 years) managed for EAT at our clinic. Each patient underwent an electrophysiological study (EPS) and atrial mapping during an episode of arrhythmia using the CARTO system. Subsequent RFCA was undergone by 32 patients. The procedure was considered successful if the arrhythmia terminated during energy application and remained non-inducible by isoprenaline. The mean follow-up period was 23 &plusmn; 13 months.Results: The ectopic focus was localised in the right atrium in 29 patients (88%) and in the left atrium in 5 patients (15%). In 6 patients more than one ectopic focus was found. The mean duration of the procedure was 159 &plusmn; 67 min and the mean duration of fluoroscopy was 25 &plusmn; 15 min. In 32 patients undergoing RFCA for the first time (the first session), the efficacy was 97%. In 2 patients with a recurrence of tachycardia and in 3 patients with EAT caused by another ectopic focus a re-ablation was performed (the second session) with an efficacy of 80%. The patient in whom re-ablation was unsuccessful underwent a third RFCA (third session). The total efficacy was 97%.
Conclusions: Radiofrequency catheter ablation is an effective and safe treatment in patients with ectopic atrial tachycardia

Kalarus, Zbigniew

Kowalski, Oskar

Kukulski, Tomasz

Lenarczyk, Radosław

Pluta, Sławomir

Pruszkowska-Skrzep, Patrycja

English

Via Medica Journals

ORIGINAL ARTICLEFolia Cardiol.2006, Vol. 13, No. 7, pp. 600–604Copyright © 2006 Via MedicaISSN 1507–4145600 www.fc.viamedica.plThe efficacy of radiofrequency catheterablation in ectopic atrial tachycardiaSławomir Pluta, Oskar Kowalski, Radosław Lenarczyk, Patrycja Pruszkowska-Skrzep,Tomasz Kukulski and Zbigniew Kalarus1st Department of Cardiology, Medical University of Silesia, Zabrze, PolandAbstractBackground: Ectopic atrial tachycardia (EAT) is a relatively rare form of supraventriculararrhythmia, which, if persistent, may lead to tachycardia-induced cardiomyopathy, associatedwith an equally poor prognosis, including the risk of sudden cardiac death, as other dilatedcardiomyopathies. The aim of the study was to evaluate the efficacy and course of radiofre-quency catheter ablation (RFCA) in the treatment of patients with EAT.Methods: The study group comprised 33 consecutive patients (16 males and 17 females ofmean age 41 ± 15 years) managed for EAT at our clinic. Each patient underwent anelectrophysiological study and atrial mapping during an episode of arrhythmia using theCARTO system. Subsequent RFCA was undergone by 32 patients. The procedure was consid-ered as successful if the arrhythmia was terminated during energy application and remainednon-inducible by isoprenaline. The mean follow-up period was 23 ± 13 months.Results: The ectopic focus was localised in the right atrium in 29 patients (88%) and in theleft atrium in 5 patients (15%). In 6 patients more than one ectopic focus was found. Themean duration of the procedure was 159 ± 67 min and the mean duration of fluoroscopy was25 ± 15 min. In 32 patients undergoing RFCA for the first time (the first session), the efficacywas 97%. In 2 patients with a recurrence of tachycardia and in 3 patients with EAT caused byanother ectopic focus a re-ablation was performed (the second session) with an efficacy of 80%.The patient in whom re-ablation was unsuccessful underwent a third RFCA (third session).The total efficacy was 97%.Conclusions: Radiofrequency catheter ablation is an effective and safe treatment in patientswith ectopic atrial tachycardia. (Folia Cardiol. 2006; 13: 600–604)Key words: ectopic atrial tachycardia, radiofrequency catheter ablation, CARTOAddress for correspondence: Dr med. Sławomir Pluta1st Department of CardiologyMedical University of SilesiaSzpitalna 2, 41–800 Zabrze, PolandTel: +48 32 271 34 14, tel./fax: +48 32 271 76 92e-mail: karzab@infomed.slam.katowice.plReceived: 4.05.2006 Accepted: 6.10.2006IntroductionEctopic atrial tachycardia (EAT) is a relativelyrare, yet clinically important form of supraventricu-lar arrhythmia [1]. Paroxysmal EAT may result inpalpitations or racing heartbeat and significantlyreduce exercise tolerance. Persistent EAT may leadto tachycardia-induced cardiomyopathy, which man-ifests itself in heart failure and is associated withan equally poor prognosis, including the risk of601Sławomir Pluta et al., Efficacy of ablation in ectopic atrial tachycardiawww.foliacardiologica.eusudden cardiac death, as dilated cardiomyopathiesof other aetiologies [2, 3]. As demonstrated in thepublished experimental studies, discontinuation ofrapid atrial stimulation results in regression of thetachycardia-incuded cardiomyopathy in the majori-ty of animal models [2, 4]. Clinical studies, on theother hand, demonstrate that an effective treatmentof the tachycardia by surgery, drug therapy or radi-ofrequency catheter ablation (RFCA) results in theresolution of clinical manifestations of heart failureand the regression of signs of dilated cardiomyopa-thy [5–11]. These data point to the considerable im-portance of management of this form of arrhythmia,as its outcome may affect the prognosis.The aim of the study was to evaluate the effi-cacy and course of RFCA in the treatment of pa-tients with ectopic atrial fibrillation.MethodsThe study group comprised 33 consecutivepatients (16 males and 17 females) managed at ourcentre for ectopic atrial fibrillation. The mean ageof the patients was 41 ± 15 years old (range: 16––67 years). The mean ejection fraction in the studygroup was 51 ± 9% (range: 32–60%). Ischaemicheart disease was present in 3 (9%) patients, par-oxysmal atrial flutter was observed in 2 patients(6%), 6 patients (18%) had a history of myocarditisand 6 patients (18%) were hypertensive. Each pa-tient underwent an electrophysiological study(EPS) using two electrodes: a diagnostic electrode,which was introduced through the internal jugularvein and placed into the coronary sinus, and a map-ping/ablation electrode (NaviStar, Biosense/Cordis-Webster), which was used for electroanatomicalmapping and ablation and introduced through theright femoral artery. Bipolar signals recorded fromthe distal rings of the electrode placed in the coro-nary sinus served as reference.Permanent EAT was observed in 23 patients(70%) and in the remaining 10 patients (30%) EATwas induced by programmed stimulation. All thestudy patients underwent a subsequent atrial acti-vation mapping during the episode of arrhythmiausing the electroanatomical system CARTO, dem-onstrating an EAT-specific activation sequence.The mean rate of EAT was 131 ± 15 beats perminute (bpm) (range: 110–170 bpm).Left atrial mapping was performed followinga prior puncture of the interatrial septum, follow-ing the method previously described in [12].A total of 33 patients underwent EPS, result-ing in the localisation of ectopic foci according tothe time of the earliest activation. Of these patients32 (97%) underwent RFCA of the ectopic focus (upto 50°C at up to 40 W). The procedure was consid-ered successful if the arrhythmia was terminatedduring energy application and remained non-induc-ible by isoprenaline.ResultsThe ectopic focus was localised in the rightatrium in 29 patients (88%) and in the left atrium in5 patients (15%). More than one ectopic focus wasrevealed in 6 patients (18%) with two foci in 4 pa-tients and three foci in 2 patients. The localisationof the ectopic foci is shown in Tables 1 and 2. Themean duration of the procedure in the study groupwas 159 ± 67 min (range: 45–330 min). The meanduration of fluoroscopy was 25 ± 15 min (range:3–65 min). The mean duration of follow-up was23 ± 13 months (range: 8–65 months).In 27 patients (96%) in whom the site of ear-liest activation was found in the right atrium andin all the patients with ectopy in the left atrium(n = 5, 100%), RFCA proved to be an effectivetreatment for EAT.In one female patient, following right atrialmapping performed during tachycardia, the site ofearliest activation was found near the atrioventricu-lar node. Because of the high risk of atrioventricu-lar block, ablation was abandoned.Table 1. Localisation of left-sided ectopic foci.Area between the ostia 1 (2%)of the right pulmonary veinsArea near the ostium of the 1 (2%)left superior pulmonary veinArea near the ostium of the 3 (7%)right superior pulmonary veinInteratrial septum from left atrial aspect 1 (2%)Table 2. Localisation of right-sided ectopic foci.Area near the ostium 6 (15%)of the superior vena cavaArea near the ostium 2 (5%)of the inferior vena cavaCrista terminalis 12 (29%)Area near the ostium 7 (17%)of the coronary sinusArea near the atrioventricular junction 7 (17%)Interatrial septum from right atrium side 2 (5%)602Folia Cardiol. 2006, Vol. 13, No. 7www.foliacardiologica.euOf the total of 32 patients undergoing a firstRFCA for EAT (first session) the procedure wassuccessful in 97% (n = 31).In one case (a 16-year-old patient with a histo-ry of surgical closure of ASD II) right atrial map-ping revealed two atrial ectopic foci, one localisedaround the Dacron patch sewn onto the interatrialseptal defect and the other localised near the supe-rior vena cava. While the application of radiofre-quency current at the sites of earliest activationresulted in their resolution, the follow-up 24-hourECG performed during the same hospitalisationrevealed brief episodes of self-limiting EAT of sim-ilar rates. Following drug therapy the patient did notrequire re-ablation.Five patients underwent a second RFCA ses-sion. Re-ablation was successful in all 3 patients inwhom the recurrence of EAT was caused by activa-tion of another ectopic focus (mean time since thefirst ablation: 7.8 ± 7.3 months, range: 1–17 months)and in one of another two patients in whom the ar-rhythmia recurred as a result of reactivation of thesame focus (mean time since the first ablation:9.5 ± 9.2 months, range: 3–16 months). The other pa-tient, in whom the arrhythmia could not be terminat-ed, underwent radiofrequency re-ablation 3 monthslater (a third session). The total efficacy and the effi-cacy of individual sessions are shown in Table 3.In the group taken as a whole one complicationwas observed in patients with EAT who underwentEPS followed by RFCA (3%). The complication wasobserved in a female patient who had been using oralcontraceptives for many years and consisted in sud-den dyspnoea which developed on the first night af-ter successful ablation of two ectopic foci localisednear the superior vena cava and between the ostia ofthe right pulmonary veins. On the basis of laboratoryand imaging studies, including echocardiography andpulmonary artery angiography, a diagnosis of massivepulmonary embolism was established. The treatmentinvolved a selective infusion of tissue plasminogenactivator at a dose of 80 mg into the pulmonary trunkwith a pigtail catheter and fragmentation of the throm-bus. A follow-up angiography performed approximate-ly 1 hour later revealed a partial recanalisation of thepulmonary bed. On the basis of the ultrasound imageof the veins of the lower extremities, deep vein throm-bosis of the right lower extremity was diagnosed.Further management involved heparin followed byacenocoumarol. The patient was discharged in goodgeneral condition and over the 6 months of follow-upno recurrence of EAT or adverse outcomes of thecomplication were observed. In our opinion the pul-monary embolism was linked to deep vein thrombo-sis, for which predisposing factors existed in the formof pressure dressing at the femoral vein puncture siteand the use of oral contraceptives.DiscussionEctopic atrial tachycardia is most prevalent inchildren and young adults. Its underlying mecha-nism is unclear. Some authors point to triggeredactivity and abnormal automatism as the causativefactors [13]. There is also evidence to suggesta genetic aetiology of EAT [14]. Some reports sug-gest the presence of areas predisposing to the de-velopment of ectopic foci within the atrium.In a group of 23 patients free from structuralheart disease with right atrial focal tachycardiaKalman et al. [15] showed that two-thirds of theectopic foci are localised along the crista termina-lis. In our group of patients, some of whom sufferedfrom structural heart disease and had a history ofcardiac surgery, the most common localisation ofectopic foci was also the area along the crista ter-minalis, consistent with the findings of Kalman etal. [15]. The percentage of these localisations, how-ever, was lower and amounted to 29%. The frequentoccurrence of ectopic foci in the area of the cristaterminalis is explained by the extreme anisotropyand evidence of slow conduction in this region,which could be pivotal in generating this type ofarrhythmia. Furthermore, cardiac myocytes in thisregion could demonstrate pacemaker properties orabnormal automatism [16, 17].Ectopic atrial tachycardia may be oligosymp-tomatic until the development of the first symptomsof heart failure, the clinical manifestation of tachy-cardia-incuded cardiomyopathy.Table 3. Results.1st session 2nd session 3rd session TotalNumber of patients undergoing radiofrequency catheter ablation 32 5 1 38Number of successful radiofrequency catheter ablations 31 4 1 37Efficacy 97% 80% 100% 97%603Sławomir Pluta et al., Efficacy of ablation in ectopic atrial tachycardiawww.foliacardiologica.euThere are literature reports of clinical and ex-perimental studies which have demonstrated thereversibility of tachycardia-induced cardiomyopathyfollowing a successful treatment of tachycardia.Early diagnosis and elimination of the arrhythmiamay therefore be advisable. RFCA is the currenttreatment of choice in patients in whom drug thera-py fails [18]. Various methods of localising the siteof ectopy are reported in the literature, such as con-ventional mapping using one or two electrodes, theelectroanatomical system CARTO or the non-con-tact mapping system (EnSite 3000).The available reports on using the three-di-mensional electroanatomical system in the treat-ment of EAT are based on relatively small groupsof patients [19–21].In our group of patients with EAT the use ofthe CARTO electroanatomical mapping proved tobe an effective and safe method for localising ec-topic foci both in the right and in the left atrium.The efficacy of RFCA of ectopic foci was 96% in thecase of right atrial localisation and 100% in the caseof left atrial localisation. The most likely causes offailed procedures seem to include the presence ofmore than one ectopic focus, anatomical changes tothe cardiac chambers caused by previous surgeryand the presence of the focus near the atrioventricu-lar junction.In a group of 42 patients with EAT managed withRFCA using the CARTO system Hoffmann et al. [19]achieved a success rate of 82% in the case of ec-topic foci of left atrial localisation and 85% in thecase of right atrial localisation. The authors point-ed to the application of insufficient energy to ectop-ies localised near the His bundle and the presenceof multiple foci as the possible causes of unsuccess-ful ablation of the right atrial foci. Failure to estab-lish a stable contact between the ablation catheterand the atrial wall, especially in its inferior portion,was considered to be the main cause of failed abla-tions in the left atrium.The publication by Natale et al. [20], based onthe results of treatment of 24 patients with EAT,demonstrated a 100% efficacy of RFCA using theCARTO system, with a mean duration of 110 minfor the procedure and a mean duration of 17 min forfluoroscopy. Our results for the duration of proce-dures and the duration of fluoroscopy are similar tothose published by other authors [19–22].ConclusionRadiofrequency ablation is an effective and safetreatment for ectopic atrial tachycardia.References1. Ganz LI, Friedmann PL. Supraventricular tachycar-dia. N Engl J Med, 1995; 332: 162–173.2. Pak PH, Nuss HB, Tunin RS et al. Repolarisationabnormalities, arrhythmia and sudden death in ca-nine tachycardia-induced cardiomyopathy. J Am CollCardiol, 1997; 30: 576–584.3. Fenelon G, Wijns Andries E, Brugada P. Tachycardio-myopathy: mechanisms and clinical implications.PACE, 1996; 16: 95–106.4. Kajstura J, Zhang X, Liu Y. The cellular basis of pacing--induced dilated cardiomyopathy. Circulation, 1995;92: 2306–2317.5. 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The efficacy of radiofrequency catheter ablation in ectopic atrial tachycardia

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The efficacy of radiofrequency catheter ablation in ectopic atrial tachycardia

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