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Aims: Oesophageal fistula represents a rare but dreadful complication of atrial fibrillation catheter ablation. Data on its incidence, management and outcome are sparse., Methods and Results: This international multicenter registry investigates the characteristics of oesophageal fistulae after treatment of atrial fibrillation by catheter ablation. A total of 553,729 catheter ablation procedures (radiofrequency: 62.9%, cryoballoon: 36.2%, other modalities: 0.9%) were performed at 214 centers in 35 countries. In 78 centers 138 patients (0.025%, radiofrequency: 0.038%, cryoballoon: 0.0015% (p<0.0001)) were diagnosed with an oesophageal fistula. Periprocedural data were available for 118 patients (85.5%). Following catheter ablation, the median time to symptoms and the median time to diagnosis were 18 (7.75, 25; range: 0-60) days and 21 (15, 29.5; range: 2-63) days, respectively. The median time from symptom onset to oesophageal fistula diagnosis was 3 (1, 9; range: 0-42) days. The most common initial symptom was fever (59.3%). The diagnosis was established by chest computed tomography in 80.2% of patients. Oesophageal surgery was performed in 47.4% and direct endoscopic treatment in 19.8%, and conservative treatment in 32.8% of patients. The overall mortality was 65.8%. Mortality following surgical (51.9%) or endoscopic treatment (56.5%) was significantly lower as compared to conservative management (89.5%) (odds ratio 7.463 (2.414, 23.072) p<0.001)., Conclusions: Oesophageal fistula after catheter ablation of atrial fibrillation is rare and occurs mostly with the use of radiofrequency energy rather than cryoenergy. Mortality without surgical or endoscopic intervention is exceedingly high., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aims: Clinical practice guidelines restrict rhythm control therapy to patients with symptomatic atrial fibrillation (AF). The EAST-AFNET 4 trial demonstrated that early, systematic rhythm control improves clinical outcomes compared to symptom-directed rhythm control., Methods and Results: This prespecified EAST-AFNET 4 analysis compared the effect of early rhythm control therapy in asymptomatic patients (EHRA score I) to symptomatic patients. Primary outcome was a composite of death from cardiovascular causes, stroke, or hospitalization with worsening of heart failure or acute coronary syndrome, analyzed in a time-to-event analysis. At baseline, 801/2633 (30.4%) patients were asymptomatic [mean age 71.3 years, 37.5% women, mean CHA2DS2-VASc score 3.4, 169/801 (21.1%) heart failure]. Asymptomatic patients randomized to early rhythm control (395/801) received similar rhythm control therapies compared to symptomatic patients [e.g. AF ablation at 24 months: 75/395 (19.0%) in asymptomatic; 176/910 (19.3%) symptomatic patients, P = 0.672]. Anticoagulation and treatment of concomitant cardiovascular conditions was not different between symptomatic and asymptomatic patients. The primary outcome occurred in 79/395 asymptomatic patients randomized to early rhythm control and in 97/406 patients randomized to usual care (hazard ratio 0.76, 95% confidence interval [0.6; 1.03]), almost identical to symptomatic patients. At 24 months follow-up, change in symptom status was not different between randomized groups (P = 0.19)., Conclusion: The clinical benefit of early, systematic rhythm control was not different between asymptomatic and symptomatic patients in EAST-AFNET 4. These results call for a shared decision discussing the benefits of rhythm control therapy in all patients with recently diagnosed AF and concomitant cardiovascular conditions (EAST-AFNET 4; ISRCTN04708680; NCT01288352; EudraCT2010-021258-20)., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Recent innovations have the potential to improve rhythm control therapy in patients with atrial fibrillation (AF). Controlled trials provide new evidence on the effectiveness and safety of rhythm control therapy, particularly in patients with AF and heart failure. This review summarizes evidence supporting the use of rhythm control therapy in patients with AF for different outcomes, discusses implications for indications, and highlights remaining clinical gaps in evidence. Rhythm control therapy improves symptoms and quality of life in patients with symptomatic AF and can be safely delivered in elderly patients with comorbidities (mean age 70 years, 3-7% complications at 1 year). Atrial fibrillation ablation maintains sinus rhythm more effectively than antiarrhythmic drug therapy, but recurrent AF remains common, highlighting the need for better patient selection (precision medicine). Antiarrhythmic drugs remain effective after AF ablation, underpinning the synergistic mechanisms of action of AF ablation and antiarrhythmic drugs. Atrial fibrillation ablation appears to improve left ventricular function in a subset of patients with AF and heart failure. Data on the prognostic effect of rhythm control therapy are heterogeneous without a clear signal for either benefit or harm. Rhythm control therapy has acceptable safety and improves quality of life in patients with symptomatic AF, including in elderly populations with stroke risk factors. There is a clinical need to better stratify patients for rhythm control therapy. Further studies are needed to determine whether rhythm control therapy, and particularly AF ablation, improves left ventricular function and reduces AF-related complications., (© The Author(s) 2019. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aims: To analyse outcomes of supraventricular tachycardia (SVT) ablations performed within a prospective German Ablation Quality Registry., Methods and Results: Data from 12 566 patients who underwent catheter ablation of SVT between January 2007 and January 2010 to treat atrial fibrillation (AFIB, 37.2% of procedures), atrial flutter (AFL, 29.9%), atrioventricular nodal re-entrant tachycardia (AVNRT, 23.2%), atrioventricular re-entrant tachycardia (6.3%), and focal atrial tachycardia (AT, 3.4%) were prospectively collected. Patients were followed for at least 1 year. The periprocedural success rate was 96.3%, ranging from 84.3% (focal AT) to 98.9% (AVNRT). Kaplan-Meier mortality estimate at 1 year was 1.4% overall, and as high as 2.6% in the AFL group and 2.8% in the focal AT group. Recurrence of ablated or another symptomatic SVT was observed in 3783 (32.6%) of patients, ranging from 17.2% (AVNRT) to 45.6% (AFIB). Repeat ablation was performed in 12.0% of patients. After 1 year, 74.1% of survivors perceived ablation therapy as successful, 15.7% as partly successful, and 9.6% as unsuccessful. Even in those patients with arrhythmia recurrence, 76.0% perceived ablation as successful or partly successful and 89.6% would still undergo repeat ablation in the same institution., Conclusion: Ablation therapy for SVT is a safe procedure bringing symptomatic improvement and satisfaction to three quarters of patients after 1 year. Even in patients with arrhythmia recurrence, a high satisfaction level and adherence to the ablating institution could be documented. Strikingly high mortality and stroke rates in follow-up were observed in AFL patients, who apparently need consistent long-term anticoagulation and more medical attention., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.)

Aims: Human autopsy, animal, and cell culture studies together have merged in a concept suggesting participation of mast cells (MCs) in the generation of atherosclerotic plaques. More specifically, these studies have suggested MC-induced intraplaque neovascularization as one mechanism by which MCs may render the plaques vulnerable. The present study was designed to assess the association between MC numbers and neovascularization in human atherosclerotic plaques, and to relate the abundance of plaque MCs to the occurrence of adverse cardiovascular events during the follow-up., Methods and Results: Atherosclerotic plaques of 270 patients suffering from carotid artery stenosis were stained for the presence of MCs (MC tryptase). Furthermore, during a follow-up of 3 years, cardiovascular-related endpoints were assessed in 253 patients. On average a high number of MCs were observed per plaque cross-section [median 108 (55-233) cells per section]. Plaques with high MC numbers revealed an unstable lipid-rich inflammatory phenotype and were associated with symptomatic patients. In addition, MC numbers were positively associated with microvessel density (r = 0.416, P < 0.001). Patients with high intraplaque MC numbers showed significantly more cardiovascular events during the follow-up (58/142 vs. 31/111 events, P = 0.029). In a multivariate analysis with correction for the main risk factors of cardiovascular diseases, MCs remained independently associated with adverse cardiovascular events (P = 0.025)., Conclusion: Mast cells are highly prevalent in human carotid atherosclerotic lesions and associated with plaque microvessel density. Furthermore, intraplaque MC numbers associate with future cardiovascular events.

Aims: We investigated the feasibility of real-time magnetic resonance imaging (RTMRI) guided ablation of the cavotricuspid isthmus (CTI) by using a MRI-compatible ablation catheter., Methods and Results: Cavotricuspid isthmus ablation was performed in an interventional RTMRI suite by using a novel 7 French, steerable, non-ferromagnetic ablation catheter in a porcine in vivo model (n = 20). The catheter was introduced and navigated by RTMRI visualization only. Catheter position and movement during manipulation were continuously visualized during the entire intervention. Two porcine prematurely died due to VT/VF. Anatomical completion of the CTI ablation line could be achieved after a mean of 6.3+/-3 RF pulses (RF energy: 1807+/-1016.4 Ws/RF pulse, temperature: 55.9+/-5.9 degrees C) in n = 18 animals. In 15 of 18 procedures (83.3%) a complete CTI block was proven by conventional mapping in the electrophysiological (EP) lab., Conclusion: Completely non-fluoroscopic ablation guided by RTMRI using a steerable and non-ferromagnetic catheter is a promising novel technology in interventional electrophysiology.

Atrial fibrillation (AF) causes important mortality and morbidity on a population-level. So far, we do not have the means to prevent AF or AF-related complications adequately. Therefore, over 70 experts on atrial fibrillation convened for the 2nd AFNET/EHRA consensus conference to suggest directions for research to improve management of AF patients (Appendix 1). The group defined three main areas in need for research in AF: 1. better understanding of the mechanisms of AF; 2. Improving rhythm control monitoring and management; and 3. comprehensive cardiovascular risk management in AF patients. The group put forward the hypothesis that successful therapy of AF and its associated complications will require comprehensive therapy. This applies e.g. to the "old" debate of "rate versus rhythm control", since rhythm control is generally added to underlying (continued) rate control therapy, but also to the emerging debate of "antiarrhythmic drugs versus catheter ablation", of which both may be needed in most patients to maintain sinus rhythm, but also to therapy of conditions that predispose to AF and contribute to cardiovascular complications such as stroke, cognitive decline, heart failure, and acute coronary syndromes. We call for research initiatives aiming at a better understanding of the different causes of AF and its complications, and at development and validation of mechanism-based therapies. The future of AF therapy may require a combination of management of underlying and concomitant conditions, early and comprehensive rhythm control therapy, adequate control of ventricular rate and cardiac function, and continuous therapy to prevent AF-associated complications (e.g. antithrombotic therapy). The reasons for these suggestions are detailed in this paper.

Aims: Rhythm follow-up after catheter ablation of atrial fibrillation (AF ablation) is mainly based on Holter electrocardiogramm (ECG), tele-ECG or on patients symptoms. However, studies using 7-day Holter or tele-ECG follow-up revealed a significant number of asymptomatic recurrences. Thus, the aim of this study was to analyse continuous atrial recordings in pacemaker patients with an incorporated Holter function before and after AF ablation in order to determine all AF recurrences and thereby the 'real' success rates., Methods and Results: The study comprised 37 patients (64.6 +/- 10 years) with prior pacemaker/implantable cardioverter defibrillator (ICD) implantation including an atrial Holter function referred for AF ablation. Holter data were obtained and correlated to patients' symptoms before and every 3-month after AF ablation. AF recurrence was defined as an atrial high frequency episode of less than 330 ms (180 b.p.m.) lasting longer than 30 s. The ablation procedure consisted of pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (PAF, n = 20) and additional substrate modification aiming arrhythmia termination in patients with persistent or inducible AF after PVI as well as in patients with a history of long-lasting persistent AF (PersAF, n = 17). The mean atrial Holter monitoring period was 7.4 +/- 3.3 months before and 13.5 +/- 4.2 months after ablation with an overall AF burden of 33.7% prior to ablation. During follow-up, AF burden decreased from 17.3-0.65% (P = 0.001) in PAF patients and from 57.4 to 13.9% (P = 0.024) in patients with PersAF. Complete AF freedom was observed in 85% (17 patients) of PAF patients and 59% (10 patients) in patients with PersAF. The absence of symptoms correlated well with documented freedom of AF., Conclusion: In the present study we could show, that freedom from AF can be achieved by catheter ablation in a high percentage of patients even with PersAF. Continuous atrial monitoring reveals AF ablation success rates comparable with those assessed by clinical evaluation. Symptomatic freedom of AF correlated well with the actual freedom of AF at least in this highly symptomatic patient cohort.

Aims: In the setting of right ventricular outflow tract-tachycardia (RVOT-T), data about long-term follow-up (FU) with respect to the therapeutic strategies are missing. All patients (pts) referred to our institution during the last 20 years for the treatment of RVOT-T were studied in a retrospective analysis to assess mortality and efficacy of treatment., Methods and Results: One hundred and thirty-three patients (77 female; 39+/-13 years) with sustained RVOT-T were included in this study. At the time of first presentation, diagnosis of RVOT-T was made by complete invasive and non-invasive diagnostic assessment, including electrophysiology study and two-dimensional echocardiography. After 135+/-68 months (median 136, range 29-248), patients were invited to undergo clinical assessment. Of the 133 pts, 127 (95%) survived and six (5%) died from non-cardiac disease. Anti-arrhythmic (AA) drugs were given to 62 of the 133 pts (47%); of them 32 (52%) had recurrences during follow-up. The mean time to recurrence was 10.02 years (95% CI 7.46-12.59). The other 71 study patients (53%) underwent catheter ablation. The procedure was successful in 58 pts (82%). During follow-up, 30 (52%) of the 58 successfully treated patients had recurrences of RVOT-T. The mean time to recurrence was 6.28 years (95% CI 4.96-7.6). RVOT-T recurrences were similar in morphology to those treated previously in 33% and different in 67% of cases., Conclusions: Long-term follow-up in patients with RVOT-T is favourable. Catheter ablation is effective in this setting. However, late recurrences with similar or different morphology may arise in half of the patients after initially successful treatment. AA drug therapy is a valid initial therapeutic option, since it is effective in about half of the patients.

Aims: To investigate the effectiveness of additional substrate modification (SM) by left atrial (LA) linear lesions as compared with pulmonary vein isolation (PVI) alone in patients with persistent atrial fibrillation (AF) in a prospective randomized study. Percutaneous PVI has evolved as an accepted treatment for paroxysmal AF but seemed to be less effective in patients with persistent AF. The benefit of PVI alone and additional linear lesions has not been validated in a randomized study so far., Methods and Results: Sixty-two patients with persistent AF (median duration 7, range 1-18 months) were randomly assigned to either PVI alone (n = 30) or additional SM (n =32) consisting of a roof line connecting both left superior and right superior PV and LA isthmus ablation between left inferior PV and mitral annulus. Procedures including SM were performed using a three-dimensional mapping system (EnSite NavX, St Jude Medical, St Paul, MN, USA). Anti-arrhythmic drugs were discontinued within 8 weeks after ablation in both groups. Follow-up included daily trans-telephonic ECG transmitted irrespective of the patient's symptoms. PVI was successful in 98% of all targeted veins in both groups. Additional SM did not increase fluoroscopy time (72.1+/-18.7 vs. 72.9+/-17.3 min, P=0.92) because of the use of three-dimensional navigation in the PVI+SM group. AF recurrences within the first 4 weeks following ablation were more common after PVI alone (77%) than additional SM (44%, P=0.002). After a follow-up time of 487 (429-570) days, only 20% of patients undergoing stand alone PVI remained in sinus rhythm when compared with 69% following PVI combined with SM (P=0.0001). Two patients assigned to PVI+SM experienced procedure-related complications (cardiac tamponade and minor stroke) which resolved without sequelae., Conclusion: PVI alone is insufficient in the treatment of persistent AF. However, additional left linear lesions increase the success rate significantly. Early AF-relapses are associated with a negative outcome after PVI alone but not following additional SM.

Aim: Sub-threshold stimulation (STS) applied during atrioventricular nodal re-entrant tachycardia (AVNRT) of the common (slow-fast) type has been shown to effectively characterise target sites suitable for slow pathway (SP) ablation but has not been investigated in the setting of fast-slow and slow-slow variants., Methods and Results: Seventeen consecutive patients (52+/-16 years, 12 female) with sustained uncommon type AVNRT (fast-slow: n = 13, slow-slow: n = 4) were investigated. Mapping of the SP was started postero-septally close to the coronary sinus ostium and continued toward mid-septal sites, if required. Target sites for STS were selected according to established criteria including the recording of the earliest retrograde atrial activation during AVNRT. Long duration (5 s) constant current STS during AVNRT variants was performed in a stepwise manner (max 5 mA) at each site eligible for SP ablation until termination or capture occurred. Radiofrequency current (RFC) was delivered following successful STS termination of tachycardia (65 degrees C, 60 s) and exclusion of catheter dislodgement. Uncommon AVNRT with a mean cycle length of 405+/-70 ms was induced without spontaneous termination in all patients. Interruption of AVNRT variants due to selective STS-induced block of the retrograde (n = 12) or anterograde (n =2) SP occurred without capture in 14/17 (82%) patients. This was exclusively observed at sites with successful subsequent RFC application. AVNRT was rendered non-inducible in all patients after a median of 1 (1-11) RFC pulses without complications., Conclusions: Uncommon AVNRT can be interrupted by STS delivered at subsequently successful target sites for SP ablation in most patients (82%). The high positive and negative concordance between the effects of STS and following RFC application indicates that STS-mapping is also useful in the setting of AVNRT variants.

Aims: Anatomical and electrogram-guided techniques have been used separately for slow pathway ablation in atrioventricular nodal reentrant tachycardia. The aims of the present study were to analyse electrogram characteristics of target sites and biophysical parameters using a combined anatomical and electrogram-guided technique for temperature-controlled radiofrequency catheter ablation of the slow pathway., Methods and Results: Using a temperature-controlled (pre-selected 60 degrees C) catheter system, 53 patients with atrioventricular nodal reentrant tachycardia underwent slow pathway radiofrequency ablation. Mapping was started posteroseptally near the coronary sinus ostium and continued towards the midseptal area if needed. The longest and latest atrial electrograms with an atrioventricular ratio of < or = 0.5 were targeted. After a median of two pulses (mean 2.36 +/- 1.33), atrioventricular nodal reentrant tachycardia was rendered non-inducible in all patients without complications. Successful sites had longer atrial electrograms (78.8 +/- 9.8 vs 67.6 +/- 13.3 ms, P < 0.003) and larger ventricular electrogram amplitudes (92.4 +/- 51.2 vs 63.1 +/- 28.8 mV, P < 0.05) than the failed sites, but had a similar atrioventricular ratio, P-A interval and atrial electrogram amplitude. Overall, an atrial electrogram duration of > or = 70 ms was associated with effective radiofrequency delivery, with 86% sensitivity and 62% specificity. The achieved temperature maximum was 62.3 +/- 9.8 degrees C at successful and 58.8 +/- 9.0 degrees C at unsuccessful sites (ns). There was no significant difference between successful and unsuccessful applications with respect to power output, impedance and total delivery energy. During a pre-discharge study, three patients with inducible atrioventricular nodal reentrant tachycardia underwent a repeat ablation. During 12.3 +/- 2.5 (6-15) months of follow-up, three others had a clinical recurrence of atrioventricular nodal reentrant tachycardia., Conclusions: The combined approach for slow pathway ablation is highly effective, requiring a low number of radiofrequency pulses. Long atrial activation time seems to be the most powerful predictor of success. Similar catheter tip temperature levels during successful and unsuccessful radiofrequency applications indicate that suboptimal selection of target sites rather than ineffective heating due to poor catheter tissue coupling is responsible for unsuccessful energy delivery.

Objectives: The primary objectives of this study were to assess the feasibility of temperature-controlled radiofrequency catheter ablation of left and right sided manifest accessory pathways in patients with Wolff-Parkinson-White syndrome and to gain more insights into biophysical aspects of temperature-controlled catheter ablation in humans., Background: The electrode-tissue interface temperature and other biophysical parameters are among important variables determining the efficacy and safety of radiofrequency ablation of accessory pathways. Experimental studies have shown that radiofrequency-induced tissue necrosis can be accurately predicted by monitoring of catheter tip temperature., Methods: 38 consecutive patients (14 f, 24 m; aged 42 +/- 12 years) with anterograde conducting accessory pathways (left sided: n = 22; right sided: n = 16) underwent temperature-controlled radiofrequency ablation (HAT 200S, Dr Osypka, Germany). The electrode temperature was monitored via a thermistor embedded into a 4 mm catheter tip. Power output was adjusted automatically during energy delivery in a closed loop system (preselected temp.: 70.1 +/- 5.8 degrees C)., Results: Accessory pathway conduction was successfully abolished in all patients after the delivery of 2.3 +/- 2.1 radiofrequency pulses (range: 1-9, median: 2). Interruption of the accessory pathway as evidenced by loss of preexcitation occurred after 5.9 +/- 5.4 s. At the time of the interruption of the accessory pathway the catheter tip temperature measured 54.2 +/- 11.2 degrees C in patients with left and 44.9 +/- 5.0 degrees C in patients with right sided accessory pathways, respectively (P < 0.008). Higher temperature levels during left sided applications did not shorten the time it took for the effect to appear (left sided accessory pathway: 7.5 +/- 6.3 s, right sided accessory pathway: 3.7 +/- 2.9 s; ns). The catheter tip temperature was significantly higher during left compared to right sided applications after 5 (52.1 +/- 3.1 degrees C vs 47.2 +/- 4.3 degrees C) and 10 s (61.5 +/- 6.2 degrees C vs 52.7 +/- 4.2 degrees C) following initiation of the impulse (P < 0.005). Power output and delivered energy did not differ significantly at the time of accessory pathway abolition. Peak values of delivered power (45.1 +/- 10.9 W vs 41.3 +/- 10.6 W; P < 0.05) and total delivered energy (2452 +/- 1335 J vs 1392 +/- 762 J; P < 0.02) were significantly higher in the group of right sided pathways compared to left sided applications. The peak temperature measured 77.1 +/- 13 degrees C during effective and 69.9 +/- 14 degrees C during ineffective energy applications (P < 0.05). The time it took for the effect to appear was significantly longer in transiently effective pulses (10.4 +/- 7.2 s) compared to permanently effective applications (5.9 +/- 5.4 s; P < 0.02). Despite temperature control, an abrupt rise in impedance was observed in 10 of 89 (11%) energy applications. No procedure-related complications occurred., Conclusions: Temperature-controlled radiofrequency ablation of manifest accessory pathways is highly effective and safe. The temperature response is faster and significantly higher in left-sided energy applications compared to right-sided pulses. Peak temperature levels measured at the electrode tip are significantly higher during effective than ineffective pulses. Sudden rises in impedance are not completely prevented during temperature-controlled radiofrequency ablation of accessory pathway, although no procedure-related complications were noted in this patient cohort.

Objective: The aim of this prospective study was to analyse the yield of programmed ventricular stimulation at the right ventricular apex compared with the outflow tract., Methods: A stepwise randomized cross-over protocol of programmed ventricular stimulation with alternating stimulation at both sites was used in 66 patients who were studied because of sustained ventricular tachycardia (n = 30), ventricular fibrillation (n = 7), or non-sustained ventricular tachycardia and/or syncope (n = 29)., Results: There were no significant differences between the results of stimulation from either right ventricular site with regard to the presence or absence of structural heart disease, spontaneous arrhythmia, ejection fraction or effective refractory periods. Overall, monomorphic ventricular tachycardia was inducible in 33 patients (50%); in 25 patients (75.8%), this arrhythmia was induced from both sites. However, in only 17 of these 25 patients (68%) did the induced monomorphic ventricular tachycardias have the same morphologies and similar (+/- 50 ms) cycle lengths. Ventricular fibrillation was inducible in 11 patients (17%), mostly by three extrastimuli (n = 8; 73%)., Conclusions: (1) stimulation from at least two right ventricular sites is desirable because of their independent contribution to the induction of ventricular tachyarrhythmias, (2) the non-inducibility or inducibility at one ventricular site does not predict the effect at another stimulation site, (3) the effective refractory period at the right ventricular apex and outflow tract do not differ, (4) the inducibility of multiple ventricular tachycardia morphologies emphasizes the importance of documenting the cause of spontaneous arrhythmias with multiple electrocardiographic leads to ensure the correct interpretation of arrhythmias induced by programmed stimulation, (5) clinical or haemodynamic features cannot predict whether one or more stimulation sites will be required for induction of ventricular tachycardia. These results are important for the diagnostic evaluation and assessment of pharmacological or non-pharmacological interventions.

Up to now there have been no descriptions in the literature of endocardial catheter mapping and successful radiofrequency catheter ablation of the right sided accessory pathway during sustained atrial fibrillation. We attempted ablation of a right posterolateral and a right lateral accessory pathway during sustained atrial fibrillation with rapid anterograde conduction over the accessory pathway in two patients with Wolff-Parkinson-White syndrome. In both patients (aged 47 and 52 years), sustained atrial fibrillation occurred during the electrophysiological study to assess accessory pathway conduction properties. The mean ventricular rate during atrial fibrillation was 180 and 170 beats.min-1, respectively. Both patients were successfully ablated with a single radiofrequency impulse. At the successful ablation sites, a potential of the accessory pathway was consistently recorded preceding the onset of preexcitation in the surface electrogram, by 25 ms in patient 1 and 30 ms in patient 2. The unipolar electrogram recorded from the ablation catheter showed a QS morphology and the accessory pathway potential preceded the intrinsic deflection by 10 ms in both patients. Onset of the ventricular electrogram (patient 1: -20 ms; patient 2: -15 ms) and its activation time (patient 1: -15 ms; patient 2: +5 ms) in relation to the onset of preexcitation in the surface electrocardiogram also indicated the close proximity of the ablation catheter to the accessory pathway. Preexcitation disappeared within 2 s after energy application in both patients. Thus, radiofrequency catheter ablation of right sided accessory pathways during sustained atrial fibrillation is feasible and may obviate the need for medical or electrical cardioversion.(ABSTRACT TRUNCATED AT 250 WORDS)

Introduction: Radiofrequency catheter ablation has been demonstrated to be an effective and safe therapy in patients with so-called idiopathic ventricular tachycardia, whereas the benefit/risk profile for ablation of ventricular tachycardia in patients with chronic myocardial infarction and severely compromised left ventricular function still needs to be determined. The present report describes the unintended induction of transient third-degree atrioventricular block in a patient with remote myocardial infarction who underwent radiofrequency catheter ablation of ventricular tachycardia., Methods and Results: Endocardial catheter mapping and radiofrequency ablation were performed in a 57-year-old patient with chronic recurrent ventricular tachycardia, who had previously suffered from anterior and posterior wall myocardial infarction. Additionally, the patient presented with complete right bundle branch block during sinus rhythm. Radiofrequency energy applied to a critical site of the reentrant tachycardia at the left ventricular basal septum during sinus rhythm induced third-degree atrioventricular block after 20 s of current delivery, which lasted for 24 h. At this site, a presumable left bundle branch potential was recorded during sinus rhythm., Conclusions: Radiofrequency current application for ablation of ventricular tachycardia may induce third-degree atrioventricular block in patients with remote myocardial infarction. When current is delivered to target sites at the left ventricular basal septum, radiofrequency energy should be applied during sinus rhythm to allow continuous monitoring of atrioventricular conduction. Special caution should be given to patients with right bundle branch block during sinus rhythm.

The role of programmed ventricular stimulation (PVS) in patients at high risk of sudden death related to idiopathic dilated cardiomyopathy (DCM) is still controversial. The possible reason is that most study series have been too small or that only a few patients had documented sustained ventricular tachyarrhythmias. This study therefore, looked at PVS performed in 102 patients with DCM and documented sustained ventricular tachycardia (VT; n = 63) or ventricular fibrillation (VF; n = 39). Sustained VT was induced in 27 of 63 patients (43%) with documented sustained VT and in 14 of 39 patients (36%) with documented VF (ns). VF was induced in nine patients (14%) with a history of sustained VT and in seven (18%) with a history of VF (ns). At a mean follow-up of 32 +/- 15 months, sudden death occurred in 14 (14%) patients, a rate similar in both patients with documented VT and VF (ns). Incidence of sudden death at 36 months was 6% in patients with inducible sustained VT/VF compared to 29% in patients without inducible VT/VF (P < 0.05). A favourable drug regimen (response to drug and no intolerable side effects) was obtained by serial drug testing in 25 of all 102 patients (25%). A cardioverter defibrillator (ICD) was implanted in 32 patients, in 63% of whom discharges were observed during 18 +/- 11 months of follow-up; only one patient (3%) died suddenly. Thus, in patients with DCM, there was no relationship between documented and inducible ventricular tachyarrhythmias, and initiation of sustained VT or VF had little prognostic value for the prediction of subsequent sudden death. Wherever antiarrhythmic drug therapy was of limited value, implantation of an ICD may improve the prognosis of these high risk patients.