BACKGROUND:The role of atrial arrhythmia inducibility as an endpoint of catheter ablation of atrial fibrillation (AF) has been a controversial subject in many studies. Our goal is to evaluate the significance of inducibility, the impact of multiple sites or protocols of stimulation or the change in inducibility status in a prospective study including patients with AF undergoing first catheter ablation.METHODS:We studied 170 consecutive patients with AF (62.9% paroxysmal) undergoing catheter ablation. All patients underwent two separate stimulation protocols before and after the ablation from the coronary sinus ostium and the left atrial appendage: burst pacing at 300, 250, 200 milliseconds (or until refractoriness) for 10 seconds and ramp decrementing from 300 to 200 milliseconds in increments of 10 milliseconds every three beats for 10 seconds. Inducibility was defined as any sustained AF or organized atrial tachycardia (AT) lasting >30 seconds.RESULTS:We had AF/AT inducibility in 55 patients at baseline compared to 36 following ablation. After a mean of 41, 3 months follow-up, 115 patients were free of AF. Inducibility before or after the ablation or change in inducibility status did not influence AF recurrence. There were no significant differences regarding paroxysmal or persistent patients with AF.CONCLUSIONS:Non-inducibility of atrial arrhythmia or change in inducibility status following pulmonary vein (PV) isolation and substrate modification are not associated with long-term freedom from recurrent arrhythmia. Therefore, the use of induction of an endpoint in AF ablation is limited.

Objective Atrial fibrillation or atrial flutter (AF) and heart failure (HF) often go hand in hand and, in combination, lead to an increased risk of death compared with patients with just one of both entities. Sex-specific differences in patients with AF and HF are under-reported. Therefore, the aim of this study was to investigate sex-specific catheter ablation (CA) use and acute in-hospital outcomes in patients with AF and concomitant HF in a retrospective cohort study. Methods Using International Statistical Classification of Diseases and Related Health Problems and Operations and Procedures codes, administrative data of 75 hospitals from 2010 to 2018 were analysed to identify cases with AF and HF. Sex differences were compared for baseline characteristics, right and left atrial CA use, procedure-related adverse outcomes and in-hospital mortality. Results Of 54 645 analysed cases with AF and HF, 46.2% were women. Women were significantly older (75.4±9.5 vs 68.7±11.1 years, p<0.001), had different comorbidities (more frequently: cerebrovascular disease (2.4% vs 1.8%, p<0.001), dementia (5.3% vs 2.2%, p<0.001), rheumatic disease (2.1% vs 0.8%, p<0.001), diabetes with chronic complications (9.7% vs 9.1%, p=0.033), hemiplegia or paraplegia (1.7% vs 1.2%, p<0.001) and chronic kidney disease (43.7% vs 33.5%, p<0.001); less frequently: myocardial infarction (5.4% vs 10.5%, p<0.001), peripheral vascular disease (6.9% vs 11.3%, p<0.001), mild liver disease (2.0% vs 2.3%, p=0.003) or any malignancy (1.0% vs 1.3%, p<0.001), underwent less often CA (12.0% vs 20.7%, p<0.001), had longer hospitalisations (6.6±5.8 vs 5.2±5.2 days, p<0.001) and higher in-hospital mortality (1.6% vs 0.9%, p<0.001). However, in the multivariable generalised linear mixed model for in-hospital mortality, sex did not remain an independent predictor (OR 0.96, 95% CI 0.82 to 1.12, p=0.579) when adjusted for age and comorbidities. Vascular access complications requiring interventions (4.8% vs 4.2%, p=0.001) and cardiac tamponade (0.3% vs 0.1%, p<0.001) occurred more frequently in women, whereas stroke (0.6% vs 0.5%, p=0.179) and death (0.3% vs 0.1%, p=0.101) showed no sex difference in patients undergoing CA. Conclusions There are sex differences in patients with AF and HF with respect to demographics, resource utilisation and in-hospital outcomes. This needs to be considered when treating women with AF and HF, especially for a sufficient patient informed decision making in clinical practice.

Aims Catheter ablation is an established therapy in patients with symptomatic atrial fibrillation (AF) with increasing popularity. Pericardial effusion requiring intervention (PE) is one of the most threatening adverse outcomes. The aim of this study was to examine rates of PE after catheter ablation in a large 'real-world' data set in a German-wide hospital network. Methods and results Using ICD and OPS codes, administrative data of 85 Helios hospitals from 2010 to 2017 was used to identify AF catheter ablation cases [Helios atrial fibrillation ablation registry (SAFER)]. PE occurred in 0.9% of 21 141 catheter ablation procedures. Patients with PE were significantly older, to a higher percentage female, had more frequently hypertension, mild liver disease, diabetes with chronic complications, and renal disease. Low hospital volume (<50 procedures per year) and radiofrequency ablation (vs. cryoablation) were significantly associated with PE. Using two logistic regression models, age, female gender, hypertension, mild liver disease, diabetes with chronic complications, renal disease, low hospital volume, and radiofrequency ablation remained independent predictors for PE. Conclusion Overall PE rate was 0.9%. Predictors for PE occurrence involved factors ascribed to the patient (age, gender, comorbidities), the type of catheter ablation (radiofrequency), and the institution (low-volume centres).

Aims Atrial fibrillation (AFib) and atrial flutter (AFlut) are common arrhythmias with increased use of invasive procedures. A steady re-evaluation of relevant safety endpoints is recommended and both quality management and pay-for-performance programs are evolving. Therefore, the aims of this study were (i) to investigate and report overall in-hospital mortality and mortality of invasive arrhythmia-related procedures and (ii) to identify mortality predictors in a German-wide hospital network. Methods and results Administrative data provided by 78 Helios hospitals between 2010 and 2017 were examined using International Statistical Classification of Diseases and Related Health Problems- and Operations and Procedures-codes to identify patients with AFib or AFlut as main discharge diagnosis or secondary diagnosis combined with invasive arrhythmia-related interventions. In 161 502 patients, in-hospital mortality was 0.6% with a significant decrease from 0.75% to 0.5% (P < 0.01) during the observational period. In multivariable analysis, age [odds ratio (OR) 2.69, 95% confidence interval (CI) 2.36-3.05; P < 0.01], high centre volume (OR 0.57, 95% CI 0.50-0.65; P < 0.01), emergency hospital admission (OR 1.57, 95% CI 1.38-1.79; P < 0.01), and Charlson Comorbidity Index (CCI, OR 4.95, 95% CI 4.50-5.44; P < 0.01) were found as independent predictors of in-hospital mortality. Mortality rates were 0.05% for left atrial catheter ablation (CA, n = 21 744), 0.3% for right atrial CA (n = 9972), and 0.56% for implantation of a left atrial appendage occluder (n = 2309), respectively. Conclusion We analysed for the first time in-hospital mortality rates of patients with atrial arrhythmias in a German-wide, multi-centre administrative dataset. This allows feasible, comparable, and up-to-date performance measurement of clinically important endpoints in a real-world setting which may contribute to quality management programs and towards value-based healthcare.

AIMS:A discordant left ventricular (LV) lead position can be responsible for cardiac resynchronization therapy (CRT) non-response. In this study, tailored optimization of the individual LV wall motion was evaluated for the outcome in these patients.METHODS AND RESULTS:Two hundred and forty-six CRT outpatients were screened for non-response due to a discordant LV lead. In 17 patients, three-dimensional data of fluoroscopic rotation scan and echocardiography were integrated to analyse the individual LV wall motion with respect to the LV lead position. Optimization was guided by the systolic dyssynchrony index (SDI) and LV ejection fraction (LVEF) during different interventricular (VV)-delay programming. If re-programming failed, implantation of a second LV lead was performed. A discordant or partly concordant LV lead position was found in nearly all patients (16/17, 94%), which contributed to an unchanged baseline amount of LV dyssynchrony with either CRT on or off (SDI 11.3 vs. 11.0%; P = 0.744). In the majority of patients, VV-delay re-programming achieved better resynchronization, 4/17 patients needed implantation of a second LV lead. After 3 months, significant improvement of NYHA functional class (1 class; P = 0.004), peak oxygen consumption (10 vs. 13 mL/min/kg; P = 0.008), LVEF (27 vs. 39%; P = 0.003), and SDI (11.0 vs. 5.8; P = 0.02) was observed. Clinical and echocardiographic responses were found in 77 and 59%, respectively, with even good results on long-term follow-up.CONCLUSION:Tailored optimization of the individual LV wall motion can lead to significant clinical and echocardiographic improvements in previous CRT non-responders with a discordant LV lead position.

AIMS Non-responder rates for cardiac resynchronization therapy (CRT) vary from 11% to 46%. Retrospective data imply a better outcome with stimulation of the latest contracting left ventricular (LV) region. Our study analysed the feasibility, safety and clinical outcome of prospectively planned LV lead placement at the site of latest mechanical activation. METHODS AND RESULTS Thirty-eight heart failure patients with CRT indication were assessed by three-dimensional (3D) transoesophageal echocardiography and rotation angiography of the coronary sinus (CS). Both images were merged into a single 3D-model to identify CS target veins close to the site of latest mechanical activation. Subsequently, LV lead deployment was attempted at the desired target position. Patients were clinically and echocardiographically evaluated at baseline, after 3 and 6 months. The area of latest mechanical activation covered 6 ± 2 segments (38 ± 13% of LV surface) and was found lateral in 24 of 37 (65%), anterior in 11 of 37 (30%), inferior in 2 of 37 (5%), and septal in 1 of 37 (3%) patients. In 36 of 37 (97%) patients an appropriate target vein was identified and successful implantation could be performed in 34 of 37 (92%) patients. Among those patients clinical and echocardiographic response was observed in 91% and 81%, respectively. CONCLUSION Individualized lead placement at the latest contracting LV site can be performed safely and successfully in the majority of patients. Initial clinical outcome data are encouraging. Identification of target sites requires multimodality integration between LV wall motion data and CS anatomy. Future developments need to improve those technologies and require randomized data on clinical outcome parameters.

IntroductionVentriculoatrial (VA) conduction and related pacemaker-mediated tachyarrhythmias (PMT) have not been systematically investigated in a large cohort of patients implanted for symptomatic atrioventricular (AV) block.Methods and resultsTwo hundred fifty consecutive patients (71±14years, 63% male) implanted for symptomatic second- or third-degree AV block were screened for retrograde VA conduction and related PMTs including endless loop tachycardia (ELT) and repetitive nonreentrant VA synchrony (RNRVAS). After a mean post-implantation period of 38±12months, AV block was persistent in 137 (55%) and variable in 113 (45%) patients. Retrograde 1:1 conduction was present in 76 patients (30%) with a mean VA conduction time of 258±65ms. The incidence of VA conduction varied considerably according to the presence and type of anterograde conduction block. Retrograde conduction was present in 24 of 137 patients (18%) with persistent AV block. Fifteen of the 76 patients (20%) with VA conduction had ≥1 documented PMT. The recorded arrhythmias were ELT in 11 and RNRVAS in 4 patients. VA conduction time was significantly longer in patients with than without PMT (297±64 vs. 249±62ms, resp., P<0.01). None of the patients without VA conduction had documented PMTs.ConclusionsRetrograde VA conduction and related PMTs are not uncommon in patients implanted for symptomatic AV block. Testing for retrograde conduction should therefore be performed in all patients with AV block in order to optimize device programming and prevent PMTs.

Exercise-related palpitations, vertigo, and syncope may be caused by benign etiologies but can also herald life-threatening arrhythmias. The precise diagnosis of these findings is therefore essential and potentially life saving but often is a challenge for sports physicians and cardiologists. Leadless, ambulatory HR monitors with chest strap transmitters have been designed to steer exercise intensity in athletes with a baseline sinus rhythm. However, they also can capture arrhythmias. Presented here are three cases of varying arrhythmias: atrial fibrillation, atrioventricular nodal reentrant tachycardia, and ectopic atrial tachycardia that demonstrate the utility of HR monitors designed for athletic purposes in facilitating the diagnosis of arrhythmias and guiding appropriate treatment.

Long‐Term Efficacy of Single Procedure Remote Magnetic Catheter Navigation. Background: Remote magnetic navigation (RMN) aims to reduce some inherent limitations of manual radiofrequency (RF) ablation. However, data comparing the effectiveness of both methods are scarce. This study evaluated the acute and long‐term success of RMN guided versus manual RF ablation in patients with ischemic sustained ventricular tachycardia (sVT). Methods: One hundred two consecutive patients (age 68 ± 10 years, LVEF 32 ± 12%, 88 men) with ischemic sVT were ablated with RMN (Stereotaxis; 49%) or manually (51%) using substrate and/or activation mapping (Carto) and open‐irrigated‐tip catheters. All received implantable defibrillators or loop recorders. Acute success was defined as noninducibility of any sVT at the end of the ablation procedure and long‐term success as freedom from VT upon follow‐up. Results: There was no difference in the baseline characteristics between the groups. Three patients died in hospital. Acute success rate was similar for RMN and manual ablation (82% vs 71%, P = 0.246). RMN was associated with significantly shorter fluoroscopy time (13 ± 12 minutes vs 32 ± 17 minutes, P = 0.0001) and RF time (2337.59 ± 1248.22 seconds vs 1589.95 ± 1047.42 seconds, P = 0.049), although total procedure time was similar (157 ± 40 minutes vs 148 ± 50 minutes, P = 0.42). There was a nonsignificant trend toward better long‐term success in RMN group: after a median of 13 (range 1–34) months, 63% in the RMN and 53% in the manual ablation group were free from VT recurrence (P = 0.206). Conclusion: RMN guided RF ablation of ischemic sustained VT is equally efficient compared with manual ablation in terms of acute and long‐term success rate. These results are achieved with a significantly reduced fluoroscopy time and shorter RF time. (J Cardiovasc Electrophysiol Vol. 23, pp. 499‐505, May 2012)

BACKGROUND Atrial septal pacing (ASP) has been shown to shorten P-wave duration (PWD) and reduce recurrence of atrial fibrillation (AF) in patients with bradyarrhythmias. However, variability of interatrial connections and atrial conduction properties may explain ASP's modest clinical benefit. The aim of this study was to assess the effect of ASP site on the duration of the paced P wave. METHODS AND RESULTS Atrial septal pacing at high atrial septum (HAS), posterior septum behind the fossa ovalis (PSFO), and coronary sinus ostium (CSo) was performed in 69 patients admitted for electrophysiological study (52 ± 16 years, 41 men). Twelve-lead electrocardiogram was recorded at baseline and during pacing, signal-averaged for analysis of PWD and P-wave shortening achieved by ASP (ΔPWD = paced PWD-baseline PWD). Baseline PWD was 128 ± 15 ms. The shortest PWD during pacing was achieved at CSo (112 ± 15 ms) followed by HAS (122 ± 14 ms, P< 0.001 vs. CSo) and PSFO (124 ± 21 ms, P< 0.001 vs. CSo). P wave was shortened during pacing in patients with baseline PWD of > 120 ms (n= 50), whereas those with PWD of ≤ 120 ms showed PWD lengthening (n= 19) when paced at HAS (8 ± 17 vs. -12 ± 15 ms, P< 0.001), PSFO (15 ± 17 vs. -12 ± 26 ms, P< 0.001) and CSo (6 ± 16 vs. -25 ± 18 ms, P< 0.001). CONCLUSION Pacing at CSo is associated with the shortest PWD. P-wave shortening is greatest in patients with baseline PWD of > 120 ms regardless of the pacing site. The results may have implications on the selection of candidates for ASP and the placement of the atrial septal lead, and warrant further evaluation in cases of permanent pacing in patients with paroxysmal AF.

Pacing and Clinical ElectrophysiologyVolume 34, Issue 11 p. 1573-1575 DEVICE ROUNDS The A Wave Method—An alternative Approach for Determining the Atrial Pacing Threshold ANDREAS MÜSSIGBRODT M.D., ANDREAS MÜSSIGBRODT M.D. Department of Electrophysiology, Heart Center, University of Leipzig, Leipzig, GermanySearch for more papers by this authorSERGIO RICHTER M.D., SERGIO RICHTER M.D. Department of Electrophysiology, Heart Center, University of Leipzig, Leipzig, GermanySearch for more papers by this authorULRIKE WETZEL M.D., ULRIKE WETZEL M.D. Department of Electrophysiology, Heart Center, University of Leipzig, Leipzig, GermanySearch for more papers by this authorGERHARD HINDRICKS M.D., GERHARD HINDRICKS M.D. Department of Electrophysiology, Heart Center, University of Leipzig, Leipzig, GermanySearch for more papers by this authorARASH ARYA M.D., ARASH ARYA M.D. Department of Electrophysiology, Heart Center, University of Leipzig, Leipzig, GermanySearch for more papers by this author ANDREAS MÜSSIGBRODT M.D., ANDREAS MÜSSIGBRODT M.D. Department of Electrophysiology, Heart Center, University of Leipzig, Leipzig, GermanySearch for more papers by this authorSERGIO RICHTER M.D., SERGIO RICHTER M.D. Department of Electrophysiology, Heart Center, University of Leipzig, Leipzig, GermanySearch for more papers by this authorULRIKE WETZEL M.D., ULRIKE WETZEL M.D. Department of Electrophysiology, Heart Center, University of Leipzig, Leipzig, GermanySearch for more papers by this authorGERHARD HINDRICKS M.D., GERHARD HINDRICKS M.D. Department of Electrophysiology, Heart Center, University of Leipzig, Leipzig, GermanySearch for more papers by this authorARASH ARYA M.D., ARASH ARYA M.D. Department of Electrophysiology, Heart Center, University of Leipzig, Leipzig, GermanySearch for more papers by this author First published: 31 March 2011 https://doi.org/10.1111/j.1540-8159.2011.03088.x Address for reprints: Andreas Müssigbrodt, M.D., Department of Electrophysiology, Heart Center, University of Leipzig, Strümpellstr 39, 04289 Leipzig, Germany. Fax: 49-341-8651460; e-mail: [email protected] Conflict of interest: None. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume34, Issue11November 2011Pages 1573-1575 RelatedInformation

AIMS To compare the acute and the 6 month outcome of catheter ablation of atrial fibrillation (AF) using irrigated tip magnetic catheter and remote magnetic cathter navigation (RMN) with manual catheter navigation (MCN) in patients with paroxysmal and persistent AF. METHODS AND RESULTS In this retrospective analysis 356 patients (235 male, mean age: 57.9 ± 10.9 years) with AF (70.5%, paroxysmal) who underwent catheter ablation between August 2007 and May 2008 using either RMN (n = 70, 46 male, mean age: 57.9 ± 10.1 years, 50% paroxysmal) or MCN (n = 286, 189 male, mean age: 58.0 ± 13.9 years, 75.5% paroxysmal) were included. All patients completed an intensive follow-up strategy. Complete pulmonary vein isolation was achieved in 87.6 and 99.6% of patients in RMN and MCN groups, respectively (P < 0.05). The procedure, fluoroscopy, and radiofrequency application times were 223 ± 44 vs. 166 ± 52 min (P < 0.0001), 13.7 ± 7.8 vs. 34.5 ± 15.1 min (P < 0.0001), and 75.4 ± 20.9 vs. 53.2 ± 21.4 min (P < 0.0001) in RMN and MCN groups, respectively. Seven (10.0%) and 28 (9.8%) patients in RMN and MCN groups received antiarrhythmic medications during the follow-up (P = 0.96). All the patients completed the 6 month follow-up. Freedom from AF at 6 months was achieved in 57.8 and 66.4% of the patients in RMN and MCN groups, respectively (P = 0.196). In patients without previous AF catheter ablation procedure the freedom from AF at 6 months were 68.2 and 60.5% in the MCN and RMN groups, respectively (P = 0.36). CONCLUSION Catheter ablation using irrigated tip magnetic catheter and RMN is an effective and safe method for catheter ablation of AF. Compared to manual catheter navigation, the procedure and radiofrequency application times were longer and fluoroscopy time was shorter in the RMN group compared with the MCN group.

O27 Effects of atrial septal pacing sites on the P-wave duration correlated with baseline P-wave duration and morphology Yan Huo, Fredrik Holmqvist, Jonas Carlson, Arash Arya, Ulrike Wetzel, Andreas Bollmann, Pyotr Platonov Arrhythmia Clinic, Skane University Hospital and Center for Integrative Electrocardiology at Lund University (CIEL), Lund, Sweden Department of Electrophysiology, Leipzig Heart Center, Leipzig University, Leipzig, Germany

BACKGROUND:Steerable sheath technology is designed to facilitate catheter access, stability, and tissue contact in target sites of atrial fibrillation (AF) catheter ablation. We hypothesized that rhythm control after interventional AF treatment is more successful using a steerable as compared with a nonsteerable sheath access.METHODS AND RESULTS:One hundred thirty patients with paroxysmal or persistent drug-refractory AF undergoing their first ablation procedure were prospectively included in a randomized fashion in 2 centers. Ablation was performed by 10 operators with different levels of clinical experience. Treatment outcome was measured with serial 7-day Holter ECGs and additional symptom-based arrhythmia documentation. Single procedure success (freedom from AF and/or atrial macroreentrant tachycardia) was significantly higher in patients ablated with a steerable sheath (78% versus 55% after 3 months, P=0.005; 76% versus 53% after 6 months, P=0.008). Rate of pulmonary vein isolation, procedure duration, and radiofrequency application time did not differ significantly, whereas fluoroscopy time was lower in the steerable sheath group (33±14 minutes versus 45±17 minutes, P<0.001). Complication rates showed no significant difference (3.2% versus 5%, P=0.608). On multivariable analysis, steerable sheath usage remained the only powerful predictor for rhythm outcome after 6 months of follow-up (hazard ratio, 2.837 [1.197 to 6.723]).CONCLUSIONS:AF catheter ablation using a manually controlled, steerable sheath for catheter navigation resulted in a significantly higher clinical success rate, with comparable complication rates and with a reduction in periprocedural fluoroscopy time.CLINICAL TRIAL REGISTRATION:URL: http://clinicaltrials.gov. Unique identifier: NCT00469638.

Catheter ablation of atrial fibrillation has evolved towards a serious therapeutical option with reproducible success rates and a reasonable risk profile in selected patients. In terms of efficacy, catheter ablation is clearly superior to antiarrhythmic drugs today. The technical approach has constantly been developed in order to further increase long-term success rates, to reduce the rate of reinterventions, to minimize complication rates, to simplify the procedure, and to limit procedure duration. Examples of these technologic and strategic refinements comprise targeted integration of CT reconstructions into electro-anatomic mapping systems, improved lesion deployment and validation using the Pace-and-Ablate strategy, more efficient energy transfer into the tissue by using steerable transseptal sheaths as well as electrical contact technology, and refined deployment of strategic linear lesion concepts for left atrial macro- reentrant tachycardias by creation of colour-coded entrainment maps. These innovations of the ablation procedure have been shown to be effective, and consequently have been integrated into the daily routine of interventional electrophysiology in the Heart Center Leipzig recently.

Catheter ablation of Atrial Fibril- lation - New Technologies and Strategies. Catheter ablation of atrial fibrillation has evolved towards a serious therapeutical option with reproducible success rates and a reason- able risk profile in selected patients. In terms of efficacy, catheter ablation is clearly superior to antiarrhythmic drugs today. The technical ap- proach has constantly been developed in order to further increase long-term success rates, to reduce the rate of reinterventions, to minimize

Role of ECG in Localization of OT‐VT. Background: Different kinds of the surface ECG limb electrode positions may affect the limb lead vector and therefore the accuracy of the 12‐lead ECG in localization of outflow tract ventricular tachycardia (OTVT). This study was intended to evaluate and compare the accuracy of the standard and the modified 12‐lead ECG for localization of OTVT using the current published criteria. Methods and Results: Twenty consecutive patients (10 men, mean age, 51.6 ± 13.4 years) with OT‐VT were included. A standard ECG with the distal placement of the limb lead electrodes and a modified ECG with the limb electrodes placed on the torso were recorded during the OT‐VT and were used for localization by 2 electrophysiologists who were blinded to the successful ablation site to compare the accuracy of the 2 ECGs. The R wave amplitude during OT‐VT in lead I of the standard 12‐lead ECG was significantly higher compared to the modified surface ECG (0.225 ± 0.145 mV vs 0.139 ± 0.111 mV, P = 0.032). The S wave in aVR during OT‐VT was significantly more negative compared to the modified surface ECG (−0.682 ± 0.182 mV vs −0.527 ± 0.228 mV, P = 0.017). The rate of accurate localization of the successful ablation sites in the anterior versus posterior outflow tract by the 2 observers using standard ECG (70% and 80%) were higher compared to modified ECG (50% and 60%, P = 0.042). Conclusion: The R wave amplitude in lead I and the depth of the S wave amplitude in lead aVR of the standard surface ECG during OT‐VT is significantly larger compared to the modified surface ECG. As the QRS morphology of the OT‐VT is usually the first clue to the possible site of successful ablation, the standard 12‐lead ECG should be used for more accurate localization of the origin of the OT‐VT. (J Cardiovasc Electrophysiol, Vol. 22, pp. 886‐891, August 2011)

Aims Implantable loop recorders (ILRs) with specific atrial fibrillation (AF) detection algorithms (ILR-AF) have been developed for continuous AF monitoring. We sought to analyse the clinical value of a new AF monitoring device and to compare it to serial 7-day Holter. Methods and results Sixty-four consecutive patients suffering from paroxysmal AF were included in this prospective analysis and received an ILR-AF. Manual electrogram analysis was performed for each automatically detected episode and each was categorized into one of three possible diagnoses: ‘no AF', ‘definite AF', and ‘possible AF' (non-diagnostic). Analysis was performed separately before and after a software upgrade that was introduced during the course of the study. A subgroup of patients (51 of 64) underwent AF catheter ablation with subsequent serial 7-day Holter in comparison with the ILR-AF. A total of 333 interrogations were performed (203 before and 130 after software upgrade). The number of patients with AF misdetection was significantly reduced from 72 to 44% following the software upgrade (P= 0.001). The number of patients with non-diagnostic interrogations went from 38 to 16% (P= 0.001). Compared with serial 7-day Holter, the ILR-AF had a tendency to detect a higher number of patients with AF recurrences (31 vs. 24%; P = 0.125). Conclusions The rate of AF detection on ILR-AF may be higher compared with standard AF monitoring. However, false-positive AF recordings hamper the clinical value. Developements in device technology and device handling are necessary to minimize non-diagnostic interrogations.