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To the Editor: Increased levels of C-reactive protein (CRP) have been demonstrated to be an independent predictor of atrial fibrillation (AF) and to correlate with AF burden ([1,2][1]). In addition, inflammation and endothelial activation have been described as risk factors for adverse events in AF

Background— In the meantime, catheter ablation is widely used for the treatment of persistent atrial fibrillation (AF). There is a paucity of data about long-term outcomes. This study evaluates (1) 5-year single and multiple procedure success and (2) prognostic factors for arrhythmia recurrences after catheter ablation of persistent AF using the stepwise approach aiming at AF termination. Methods and Results— A total of 549 patients with persistent AF underwent de novo catheter ablation using the stepwise approach (2007–2009). A total of 493 patients were included (Holter ECGs ≥every 6 months). Mean follow-up was 59±16 months with 2.1±1.1 procedures per patient. Single and multiple procedure success rates were 20.1% and 55.9%, respectively (80% off antiarrhythmic drug). Antiarrhythmic drug–free multiple procedure success was 46%. Long-term recurrences (n=171) were paroxysmal AF in 48 patients (28%) and persistent AF/atrial tachycardia in 123 patients (72%). Multivariable recurrent event analysis revealed the following factors favoring arrhythmia recurrence: failure to terminate AF during index procedure (hazard ratio [HR], 1.279; 95% confidence interval [CI], 1.093–1.497; P =0.002), number of procedures (HR, 1.154; 95% CI, 1.051–1.267; P =0.003), female sex (HR, 1.263; 95% CI, 1.027–1.553; P =0.027), and the presence of structural heart disease (HR, 1.236; 95% CI, 1.003–1.524; P =0.047). AF termination was correlated with a higher rate of consecutive procedures because of atrial tachycardia recurrences ( P =0.003; HR, 1.71; 95% CI, 1.20–2.43). Conclusions— Catheter ablation of persistent AF using the stepwise approach provides limited long-term freedom of arrhythmias often requiring multiple procedures. AF termination, the number of procedures, sex, and the presence of structural heart disease correlate with outcome success. AF termination is associated with consecutive atrial tachycardia procedures.

Intracardiac echocardiography (ICE) has emerged as an adjunctive tool during electrophysiological procedures. The objective of this study was to validate ICE for assessing atrial mechanical function in patients with atrial fibrillation (AF) by comparing the parameters of atrial mechanical function assessed by transoesophageal echocardiography (TOE) versus ICE. This study enrolled 23 patients (20 men; mean (SD) age 56 (12) years) undergoing ablation of symptomatic drug refractory AF: 11 patients with paroxysmal and 12 with persistent AF of > 6 months’ duration. The left anteroposterior atrial size was 45 (8) mm and left ventricular ejection fraction was 63 (13)%. All patients were prospectively enrolled after providing written informed consent. TOE was performed on the day of the ablation procedure with a Hewlett Packard Sonos 2500 or 5000 or an Acuson Sequoia workstation connected to a multiplane 5–7.5 MHz probe. ICE imaging was performed at the start of the ablation procedure. A 10 French ICE catheter with a 5–10 MHz probe was connected to an Acuson Sequoia workstation. In five patients without adequate imaging of the left atrial appendage (LAA) from the right atrium, the catheter was advanced into the left atrium through a patent foramen ovale or a transseptal puncture. All parameters were measured according to established clinical laboratory practice and were recorded on videotape or digitally for offline analysis. The following parameters were determined by TOE and ICE: LAA emptying velocity (LAAEV); maximum mitral E wave velocity; left …

AVNRT in the Elderly. Introduction: Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common regular supraventricular tachycardia in the general population as well as in elderly patients. The purpose of thestudy was to investigate the success and complication rate particularly regarding the induction of an atrioventricular (AV) block by radiofrequency (RF) ablation in elderly patients with and without a preexisting AV block. Methods and Results: Between February 1998 and July 2004, all patients with symptomatic AVNRT referred for slow-pathway ablation in our institution were included and divided into two groups: group 1 patients younger than 75 years (n = 508) and group 2 patients >75 years (n = 70). A preexisting prolonged PR interval was present in 17 (3.3%) patients of group 1 and in 26 (37%, P < 0.0001) patients of group 2. Following successful slow-pathway ablation (follow-up time group 1: 37 ′ 22, group 2: 37 ′ 24 months) no induction of an AV block was observed in group 2 but in four patients of group 1 (0.79%) a complete heart block was induced requiring a pacemaker implantation. In group 1, 15 (2.95%) patients with a recurrence of AVNRT were readmitted for a repeat ablation procedure. No recurrences occurred in group 2. Conclusion: Despite a higher incidence of preexisting prolonged PR intervals slow-pathway ablation in elderly patients is both effective and safe and should be considered as the first line therapy also in this patient population.

Implantable cardioverter defibrillators (ICD) may have the capacity to provoke or worsen ventricular tachyarrhythmias (VT). It has been reported that ICD shocks by itself can increase mortality. This study aimed to determine the role of back-up pacing-induced VT (PIT) in the overall ICD shock burden by avoiding pause-related ventricular back-up pacing.A population of 550 single-chamber ICD patients was studied. Of them, 17 (3%, 69 ± 16 years, 14 male) patients had documented episodes of PIT. A total of 431 VT episodes were documented including 89 (21%) due to PIT. In 3 patients, VT events were exclusively PITs. After ≥2 documented PITs, the pacing output for VVI pacing was set to a subthreshold level resulting in noncapturable ventricular back-up pacing. All other device parameters remained unchanged to prove a potential proarrhythmic effect of pause related back-up pacing. During a follow-up of 99 ± 39 months after reducing the pacing output to a subthreshold level, no further episodes of PIT were observed (P0.001). Moreover, with the prevention of PITs, the ICD shock burden decreased significantly (pre: 150 vs. post: 18, P0.001). However, a single event of pause-induced VT occurred due to missing back-up pacing.PIT is a frequent mechanism of VTs in ICD patients resulting in a substantially increased shock burden. Elimination of pause-related back-up pacing by subthreshold pacing output effectively abolishes PIT and thus significantly reduces ICD shock burden.

The procedural end point of electrical isolation of the pulmonary veins (PVs) for the treatment of atrial fibrillation (AF) has been debated extensively. After identifying the PVs as the dominant arrhythmogenic site of paroxysmal AF, 2 fundamentally different approaches to the interventional treatment of AF were introduced. Haissaguerre et al developed a technique to electrically isolate the PVs by targeting electrophysiological (EP) breakthroughs from the left atrium to the PVs guided by a circular mapping catheter. In contrast, Pappone et al implemented an anatomical approach that used circumferential ablation lines around the PVs guided by a 3-dimensional mapping system. This latter approach used the procedural end point of local electrogram amplitude reduction on the line and assessment of voltage maps within the encircled area but not the demonstration of PV isolation. For a considerably long time, these 2 different approaches separated the EP community in terms of AF ablation into 2 fractions according to their affinity to either of these techniques. Subsequently, 2 independent groups performed each a prospective randomized trial comparing the 2 approaches. However, these 2 studies ultimately did not clarify which one of the approaches is the more effective and therefore more appropriate technique. In contrast, the completely divergent results of the 2 studies further heated up this debate. Interestingly, although no additional clarifying data were published afterward, the 2007 Heart Rhythm Society/European Heart Rhythm Association/European Cardiac Arrhythmia Society consensus documents recommended for the first time that in AF ablation approaches targeting the PVs, complete electrical isolation should be the goal. With this statement, discussions on whether electrical isolation should be used as the EP end point of PV ablation abated subsequently. The contemporary approach to PV isolation consolidates the combination of both techniques, a wide circumferential linear ablation around the ipsilateral PVs with the end point of electrical isolation guided by a circular PV mapping catheter. Recently, the German Gap-AF (AFNET 1) study demonstrated

Catheter ablation (CA) has emerged as a widespread therapeutic option in the treatment of atrial fibrillation (AF). Currently, no safety data with regard to the impact of the underlying structural heart diseases (SHD) are available. We sought to assess the risk for acute and long-term complications during CA of AF in relation to underlying SHD.We included 6,211 patients in a prospective registry undergoing CA of AF in 41 nationwide centers. All patients were divided into 4 groups according to the underlying heart disease: No SHD (69.4%), hypertensive heart disease (HHD) (12.0%), coronary artery disease (CAD) (15.1%), and cardiomyopathy (CM) (3.6%). In univariate analysis, patients with HHD had an overall complication rate of 7.28%, whereas patients without an SHD had a significantly lower rate of 6.01% (P0.01). Multivariate analysis revealed that HHD (adjusted odds ratio [OR]: 1.97 [95% confidence interval (CI): 1.02-3.83], P = 0.0442) and age (years; OR: 1.04 [95% CI: 1.01-1.07], P = 0.0155) were independent predictors of severe, nonfatal complications and death. Other SHD including CAD (OR: 1.48 (0.73-3.00), P = 0.2797) and CM (OR: 2.37 [0.70-7.99], P = 0.1630) failed to reach statistical significance. Male sex was protective (OR: 0.47 [95% CI: 0.27-0.81], P = 0.0062).In general, CA of AF has a low number of severe complications. In our prospective registry HHD emerged as an independent predictor of severe, nonfatal complications during AF ablation but other SHD including CAD and CM did not. The influence of HHD on the complication rate should be considered in patient selection.

This study was conducted to determine if an additional procedural endpoint of unexcitability (UE) to pacing along the ablation line reduces recurrence of atrial fibrillation (AF) or atrial tachycardia (AT) after radiofrequency catheter ablation.AF/AT recurrence is common after pulmonary vein isolation (PVI).We included 102 patients from 2 centers (age 63 ± 10 years; 33 women; left atrium 38 ± 7 mm; left ventricular ejection fraction 61 ± 6%) with symptomatic paroxysmal AF. A 3-dimensional mapping system and circumferential mapping catheter were used in all patients for PVI. In group 1 (n = 50), the procedural endpoint was bidirectional block across the ablation line. In group 2 (n = 52), additional UE to bipolar pacing at an output of 10 mA and 2-ms pulse width was required. The primary endpoint was freedom from any AF/AT (30 s) after discontinuation of antiarrhythmic drugs.Procedural endpoints were successfully achieved in all patients. Procedure duration was significantly longer in group 2 (185 ± 58 min vs. 139 ± 57 min; p 0.001); however, fluoroscopy times were not different (23 ± 9 min vs. 23 ± 9 min; p = 0.49). After a follow-up of 12 months in all patients, 26 patients (52%) in group 1 versus 43 (82.7%) in group 2 were free from any AF/AT (p = 0.001) after a single procedure. No major complications occurred.The use of pacing to ensure UE along the PVI line markedly improved near-term single-procedure success, compared with demonstration of bidirectional block alone. This additional endpoint significantly improved patient outcomes after PVI. (Unexcitability Along the Ablation as an Endpoint for Atrial Fibrillation Ablation; NCT01724437).

Background The presence of impaired left atrial appendage (LAA) function identifies patients who are prone to thrombus formation in the LAA and therefore being at high risk for subsequent cardioembolic stroke. LAA function is typically assessed by measurements of LAA emptying velocities using transesophageal echocardiography (TEE) in clinical routine. This study aimed at evaluating the feasibility of assessing LAA emptying by velocity encoded (VENC) cardiovascular magnetic resonance (CMR). Methods This study included 30 patients with sinus rhythm (n = 18) or atrial fibrillation (n = 12). VENC-CMR velocity measurements were performed perpendicular to the orifice of the LAA. Peak velocities were measured of passive diastolic LAA emptying (e-wave) in all patients. Peak velocities of active, late-diastolic LAA emptying (a-wave) were assessed in patients with sinus rhythm. Correlation and agreement was analyzed between VENC-CMR and TEE measurements of e- and a-wave peak velocities. Results A significant correlation and good agreement was found between VENC-CMR and TEE measurements of maximal e-wave velocities (r = 0.61, P Conclusions The assessment of active and passive LAA emptying by VENC-CMR is feasible. Further evaluation is required of potential future clinical applications such as risk stratification for cardioembolic stroke.

Marfan syndrome (MFS) is a variable, autosomal-dominant disorder of the connective tissue. In MFS serious ventricular arrhythmias and sudden cardiac death (SCD) can occur. The aim of this prospective study was to reveal underlying risk factors and to prospectively investigate the association between MFS and SCD in a long-term follow-up.77 patients with MFS were included. At baseline serum N-terminal pro-brain natriuretic peptide (NT-proBNP), transthoracic echocardiogram, 12-lead resting ECG, signal-averaged ECG (SAECG) and a 24-h Holter ECG with time- and frequency domain analyses were performed. The primary composite endpoint was defined as SCD, ventricular tachycardia (VT), ventricular fibrillation (VF) or arrhythmogenic syncope.The median follow-up (FU) time was 868 days. Among all risk stratification parameters, NT-proBNP remained the exclusive predictor (hazard ratio [HR]: 2.34, 95% confidence interval [CI]: 1.1 to 4.62, p=0.01) for the composite endpoint. With an optimal cut-off point at 214.3 pg/ml NT-proBNP predicted the composite primary endpoint accurately (AUC 0.936, p=0.00046, sensitivity 100%, specificity 79.0%). During FU, seven patients of Group 2 (NT-proBNP ≥ 214.3 pg/ml) reached the composite endpoint and 2 of these patients died due to SCD. In five patients, sustained VT was documented. All patients with a NT-proBNP214.3 pg/ml (Group 1) experienced no events. Group 2 patients had a significantly higher risk of experiencing the composite endpoint (logrank-test, p0.001).In contrast to non-invasive electrocardiographic parameter, NT-proBNP independently predicts adverse arrhythmogenic events in patients with MFS.

Catheter ablation of atrial fibrillation has evolved as a widely accepted therapy approach and is now also incorporated in the current guidelines.A major limitation consists of the limited three-dimensional visualization of the complex three-dimensional structures in the left atrium since most procedures have routinely been performed using fluoroscopy alone. Another unsolved problem is the limited durability of lesions sets performed with radiofrequency ablation and therefore somewhat disappointing long-term ablation results besides fluoroscopy exposition for patient and operator as required for safe catheter manipulation.In the recent years we have gained substantial insight with respect to arrhythmia mechanism. At the same time new techniques and developments have become available to improve catheter ablation results.The present article summarizes the available opportunities with respect to three-dimensional mapping including CT/MRI image integration and gives an overview of the robotic and magnetic systems available for catheter ablation.

Intravenous Electrolytes Increase Success Rate of Cardioversion. Background: External biphasic electrical cardioversion (CV) is a standard treatment option for patients suffering from acute symptoms of atrial fibrillation (AF). Nevertheless, CV is not always successful, and thus strategies to increase the success rate are desirable. Objective: The purpose of this study was to evaluate the effect of intravenously administered K/Mg solution on the biphasic CV energy threshold and success rate to restore sinus rhythm (SR) in patients with AF. Methods: The study consisted of 170 patients with persistent AF. The patients were randomly assigned to undergo biphasic CV either with (n = 84) or without (n = 86) pretreatment with K/Mg solution. An energy step-up protocol of 75, 100, and 150 W (J) was used. Results: Biphasic CV of AF was effective in 81 (96.4%) patients in the pretreatment and 74 (86.0%) patients in the control group (P = 0.005). The effective energy level required to achieve SR was significantly lower in the pretreated group (140.8 ± 26.9 J vs 182.5 ± 52.2 J, P = 0.02). No K/Mg-solution-associated side effects such as hypotension or bradycardia were observed. Conclusion: Administration of K/Mg solution positively influences the success rate of CV in patients with persistent AF. Furthermore, significantly less energy is required to successfully restore SR and therefore K/Mg pretreatment may facilitate SR restoration in patients undergoing CV for AF. (J Cardiovasc Electrophysiol, Vol. 23, pp. 54-59, January 2012)

Growing attention has been recently paid to the assessment of active LA emptying in patients after ablation of atrial fibrillation. Measurements of active LA emptying are typically performed by echocardiography in clinical routine. However, little is known about the role of cardiac MRI for this purpose. The present study evaluated the relative merits of biplane long-axis cine- and VENC-MRI for the assessment of active LA emptying.

The presence of reduced LAA flow velocities indicates patients who are prone to thrombus formation in the LAA and therefore being at high risk for subsequent cardioembolic stroke. LAA flow velocities are typically assessed by TEE in clinical routine. VENC-MRI is an established tool for the quantification of transvalvular flow, but the feasibility of LAA flow measurements by VENC-MRI has not been studied so far.

To describe a technique to facilitate passage and stable deployment of thoracic stent-grafts in patients with multiple tortuous aortic segments that may hamper endograft delivery or precise placement because of an unstable position in the aortic arch.The technique of a transseptal through-and-through guidewire is demonstrated in a patient with a ruptured thoracic aneurysm with severe tortuosity of the aorta and a right-sided, severely angulated aortic arch. The transseptal through-and-through guidewire stabilization technique allowed successful passage and deployment of a thoracic stent-graft after debranching of the right common carotid and subclavian arteries. The ruptured thoracic aneurysm was excluded, while the proximal graft edge lined up with the origin of the aberrant left innominate artery.An externalized transseptal guidewire can facilitate endograft passage in tortuous aortic anatomies and optimize control in most severely angulated aortic arches. It may obviate the use of proximal bare stents because the proximal stent-graft is actively conformed to the inner curve of the aortic arch by the stabilizing wire. Transseptal access to the ascending aorta has the potential to become an important tool for endovascular treatment, especially for catheterization of branches and fenestrations in aortic arch stent-grafts.

Pulmonary veins (PVs) usually drain into the left atrium (LA) and are frequently targeted for electrical isolation, since it became evident that PVs may trigger and maintain paroxysmal atrial fibrillation (AF). We present a patient with right-sided PVs anomalously connecting to the right atrium with lack of electrical PV-atrial connection. Therefore, isolation of the left veins was performed resulting in freedom from AF as shown during a midterm follow-up. These findings indicate that PV connection to the LA may be a prerequisite for the arrhythmogenic properties of the PVs causing AF.

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°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.

Reduced Fluoroscopy in PVI Using RN. Background: Recently, a nonmagnetic robotic navigation system (RN, Hansen-Sensei™) has been introduced for remote catheter manipulation. Objective: To investigate the influence of RN combined with intuitive 3-dimensional mapping on the fluoroscopy exposure to operator and patient during pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (PAF) in a prospective randomized trial. Methods: Sixty patients were randomly assigned to undergo PVI either using a RN guided (group 1; n = 30, 20 male, 62 ± 7.7 years) or conventional ablation approach (group 2; n = 30, 14 male, 61 ± 7.6 years). A 3-dimensional mapping system (NavX™) was used in both groups. Results: Electrical disconnection of the ipsilateral pulmonary veins (PVs) was achieved in all patients. Use of RN significantly lowered the overall fluoroscopy time (9 ± 3.4 vs 22 ± 6.5 minutes; P < 0.001) and reduced the operator's fluoroscopy exposure (7 ± 2.1 vs 22 ± 6.5 minutes; P < 0.001). The difference in fluoroscopy duration between both groups was most pronounced during the ablation part of the procedure (3 ± 2.4 vs 17 ± 6.3 minutes; P < 0.001). The overall procedure duration tended to be prolonged using RN without reaching statistical significance (156 ± 44.4 vs 134 ± 12 minutes, P = 0.099). No difference regarding outcome was found during a midterm follow-up of 6 months (AF freedom group 1 = 73% vs 77% in group 2 [P = 0.345]). Conclusion: The use of RN for PVI seems to be effective and significantly reduces overall fluoroscopy time and operator's fluoroscopy exposure without affecting mid-term outcome after 6-month follow-up. (J Cardiovasc Electrophysiol, Vol. 21, pp. 6–12, January 2010)

External cardioversion is an established and very important tool to terminate symptomatic atrial flutter. The superiority of the biphasic waveform has been demonstrated for atrial flutter, but whether electrode position affects the efficacy of cardioversion in this population is not known. The aim of this trial was to evaluate whether anterior-lateral (A-L) compared with anterior-posterior (A-P) electrode position improves cardioversion results. Of 130 screened patients, 96 (72 men, mean age 62 +/- 12 years) were included and randomly assigned to a cardioversion protocol with either A-L or A-P electrode position. In each group, 48 patients received sequential biphasic waveform shocks using a step-up protocol consisting of 50, 75, 100, 150, or 200 J. The mean energy (65 +/- 13 J for A-L vs 77 +/- 13 J for A-P, p = 0.001) and mean number of shocks (1.48 +/- 1.01 for A-L vs 1.96 +/- 1.00 for A-P, p = 0.001) required for successful cardioversion were significantly lower in the A-L group. The efficacy of the first shock with 50 J in the A-L electrode position (35 of 48 patients [73%]) was also highly significantly greater than the first shock with 50 J in the A-P electrode position (18 of 48 patients [36%]) (p = 0.001). In conclusion, the A-L electrode position increases efficacy and requires fewer energy and shocks in external electrical cardioversion of common atrial flutter. Therefore, A-L electrode positioning should be recommended for the external cardioversion of common atrial flutter.

Interventional treatment for atrial fibrillation (AF) has been introduced as a therapeutic option soon after the pulmonary veins (PV) have been discovered as the dominant sources of paroxysmal atrial fibrillation (PAF). Elimination of PV conduction is the initial goal during catheter ablation in this setting. The success rate after the initial procedure varies between 60% and 85%, with80% after subsequent interventions. Supported by the current guidelines, interventional treatment of AF is indicated in case of symptomatic arrhythmias refractory to antiarrhythmic treatment. The introduction of the combined, stepwise approach has been another important breakthrough with regard to the treatment of chronic persistent atrial fibrillation (CAF). This strategy includes the combination of all conventional ablation strategies (pulmonary vein isolation [PVI], defragmentation, linear ablation) with the goal of AF termination by radiofrequency current. The first procedure for CAF treatment is quite frequently also only the first step toward stable sinus rhythm with a favorable outcome after AF termination (80% sinus rhythm). In more than half of the patients predominantly atrial arrhythmias other than AF have to be targeted in a second procedure. This approach is currently under clinical investigation and so far not "clinically established" due to the fact that it is a quite time-consuming and challenging procedure even in experienced centers. Future studies may help to identify predictors for procedure failure (e.g., left atrial size, AF duration, atrial cycle length) in order to improve patient selection. Additionally, it has to be underscored, that in PAF the relatively high recurrence rate after the first procedure still is the subject of further investigations. This aspect might be improved by the introduction of novel strategies (i.e., testing of concealed PV conduction after ablation with adenosine) or technologies (i.e., robotic navigation) for PAF ablation.

Aims Beneficial effects of atrial fibrillation (AF) ablation have been demonstrated in patients with congestive heart failure (CHF) and significantly impaired left ventricular ejection fraction (LVEF). However, the impact of pulmonary vein isolation (PVI) on cardiac function in patients with paroxysmal AF and impaired LVEF remains under discussion. This study aimed to evaluate the impact of PVI for paroxysmal AF on cardiac function in patients with impaired LVEF using cardiac magnetic resonance imaging (CMRI). Methods and results A total number of 70 patients with paroxysmal AF and episodes � 24 h were scanned on a 1.5-T-CMRI before and 6 months after PVI during sinus rhythm. End-diastolic volume, end-systolic volume, and LVEF were determined by epicardial and endocardial measurements. Patients were categorized into two groups regarding cardiac function as assessed by CMRI: group 1 patients (n ¼ 18) with an LVEF , 50% and patients with an LVEF . 50% (group 2, n ¼ 52). Group 1 patients demonstrated a significant lower success rate than patients of group 2 after a follow-up of 152+ 40 days (50 vs. 73%, P , 0.05). Cardiac magnetic resonance imaging in group 1 patients demonstrated a significant improvement in cardiac function after AF ablation (41+ 6v s. 51+ 12%, P ¼ 0.004), whereas group 2 patients did not show significant differences (60+ 6v s. 59+ 9%, P ¼ 0.22) after a 6 months follow-up. Conclusion Pulmonary vein isolation improves cardiac function in patients with paroxysmal AF and impaired LVEF. These data suggest that an impaired LV function can be partially attributed to AF with short-lasting paroxysms.

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.

AP localization can be predicted by analyzing the polarity of the delta wave, QRS polarity, and R/S ratio in patients with Wolff-Parkinson-White syndrome. However, the estimation of AP location is limited in patients with concealed pathways during atrioventricular reentrant tachycardias (AVRT). Thus, we analyzed retrograde P-wave polarity during orthodromic AVRT and developed an algorithm to predict the localization of concealed accessory pathways (AP).A total number of 131 patients with a single AP and inducible orthodromic AVRT were included. The initial 61 patients were analyzed retrospectively for algorithm development, whereas 70 patients were evaluated prospectively. The retrograde P-wave polarity was analyzed by subtracting the superimposing T-wave during orthodromic AVRT using custom-designed software. Four leads of the surface electrocardiogram (ECG) were identified to accurately distinguish AP locations assigned to four different regions around each AV annulus: I, aVR, aVL, and V(1). Lead V(1) was used to differentiate right (negative or isoelectric) from left (solely positive) APs. Retrograde P-wave in lead I was negative in left posterior APs exclusively and became more positive with an AP location shifting towards right anterior. P-wave polarity in lead aVR demonstrated a shift from a positive polarity from left APs to isoelectric in right APs. The opposite direction (shift from positive to isoelectric) was observed for lead aVL. The subsequently developed algorithm for concealed AP localization using these surface ECG leads demonstrated a high sensitivity, specificity, and positive predictive value particularly for common AP localizations (left posterior and inferior, and right septal) when applied in a prospective fashion.Concealed AP localization can be accurately predicted by the analysis of retrograde P-wave polarity during orthodromic AVRT using the algorithm derived from the presented study.

Our purpose was to investigate the impact of short-lasting atrial fibrillation (AF) on the electrophysiological properties of the atria and pulmonary veins (PVs) in patients devoid of AF.The presence of AF is associated with electrical remodeling processes that promote a substrate for arrhythmia maintenance in the atria, which has been termed "AF begets AF." However, it is unclear whether those electrical alterations also occur in the PVs.Thirty-five patients with a left-sided accessory pathway and without a prior history of AF were included. After successful ablation, the effective refractory periods (ERPs) and conduction times of the right atrium (RA), left atrium (LA), and the PVs were determined. Afterwards, AF was induced and maintained for a period of 15 min. Thereafter, the stimulation protocol was repeated.At baseline, the PVs had significantly longer ERPs than the atria. After exposure to AF, the ERPs of both the atria and the PVs decreased significantly. The ERPs of the PVs, however, decreased by a significantly greater extent than the ERPs of the atria (PVs: 248 +/- 27 ms vs. 211 +/- 40 ms, p0.001; LA: 233 +/- 23 ms vs. 214 +/- 20 ms, p = 0.004; RA: 226 +/- 29 ms vs. 188 +/- 20 ms; p = 0.003). After AF exposure, the PVs demonstrated a significant conduction slowing whereas the atria did not (PVs: 125 +/- 33 ms vs. 159 +/- 37 ms, p0.001; LA: 129 +/- 26 ms vs. 130 +/- 24 ms, p = NS; RA: 192 +/- 36 ms vs. 196 +/- 32 ms, p = NS). Finally, AF was more frequently induced after the presence of AF, particularly by pacing in the PVs (14% vs. 49%, p = 0.001).New-onset, short-lasting AF creates electrical characteristics similar to those of patients with AF. However, these alterations are pronounced in the PVs compared with the atria, indicating that "AF begets AF in the PVs" (Electrophysiological Properties of the Pulmonary Veins; NCT00530608).

Pulmonary vein (PV) arrhythmogenicity underlying the maintenance of atrial fibrillation (AF) may be explained by three mechanisms: enhanced automaticity, triggered activity, and reentry. There are only a few reports describing sustained PV tachycardias (PVT) following electrical disconnection from the left atrium, in which the electrophysiological features are most consistent with a reentrant mechanism. We describe the case of a patient with paroxysmal AF demonstrating PVT within an isolated PV with high-density mapping revealing two different PVTs interacting in a "ping-pong" manner.

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.

Background The accuracy of three-dimensional mapping systems is affected by cardiac contraction and respiration. Objective The study sought to determine relative motion of cardiac and thoracic structures to assess positional errors and guide the choice of an optimized spatial reference. Methods Motion of catheters placed at the coronary sinus (CS), pulmonary vein (PV) ostia, left atrial (LA) isthmus and roof, cavotricuspid isthmus (CTI), and right atrial appendage (RAA) were recorded for 30 patients using Ensite-NavX. The right subclavian vein, left brachiocephalic vein, azygos vein, pulmonary arteries, and a static reference were included. The displacement from a mean position was calculated for each pair of sites. Respiration effects were assessed by the shift of the motion curve during in- and expiration phases. Results The PVs showed a mean interpair displacement of 4.1 ± 0.2 mm and a shift of 5.0 ± 0.5 mm. Proximal CS references for all LA structures (4.0 ± 1.1 mm) were superior to the static reference (4.9 ± 0.7 mm; P = .01). In addition, the shift due to respiration was less pronounced at 3.5 ± 0.8 mm versus 4.9 ± 0.5 mm ( P = .004), respectively. Motion of extracardiac vessels was influenced by a mean shift of 6.8 ± 1 mm. The remote subclavian and brachiocephalic veins were more affected (7.6 ± 0.7 mm) than the pulmonary arteries (5.9 ± 0.4 mm; P = .002). For the CTI, a minimized mean displacement of less than 4.6 ± 2.0 mm relative to the proximal CS, RAA, and azygos vein was found. Conclusion Respiration is the major source of relative motion, which increases with distance from the heart. For LA procedures, a proximal CS reference position is superior to a static reference position.

Isolated Areas of Atrial Fibrillation. Introduction: Nonpulmonary vein sources have been implicated as potential drivers of atrial fibrillation (AF). This observational study describes regions of fibrillating atrial tissue isolated inadvertently from the left atrium (LA) following linear catheter ablation for AF. Methods and Results: We report four patients with persistent/permanent AF who underwent pulmonary vein isolation with additional linear lesions and who presented with recurrent AF (mean AF cycle length [AFCL] 175-270 ms). Further catheter ablation resulted in the inadvertent electrical isolation of significant areas of the LA in which AF persisted at the same AFCL as was measured prior to disconnection, despite the restoration of sinus rhythm (SR) in all other left and right atrial areas, strongly suggesting that these islands were driving the remaining atria into fibrillation. The disconnected areas were located in the lateral LA, including the left atrial appendage (LAA) in three patients (limited to the LAA in one) and in the posterior LA in one patient. These isolated fibrillating regions represented 15-24% of the global LA surface, as estimated by electroanatomic mapping. Conclusion: Fibrillation can be maintained within electrically isolated regions of the LA following catheter ablation of AF, demonstrating the importance of atrial drivers in the maintenance of AF. Further mapping of these drivers is needed to characterize their mechanism and thereby allow for a more specific ablation strategy.

The LocaLisa mapping system provides an economical means of continuous online monitoring of multiple catheters, the annotation of anatomic structures, and the tagging of previously ablated regions. These features significantly reduce the fluoroscopic exposure and procedural duration associated with PV isolation and linear substrate modification for AF.

Atrial fibrillation (AF) and congestive heart failure (CHF) are closely related conditions. While CHF promotes the development of AF, the presence of AF may exacerbate or, in some cases, cause left ventricular (LV) dysfunction, with symptoms of CHF as a consequence [1, 2]. In addition, each disease adversely affects the prognosis of the other [3, 4]. Cardiomyopathy due to rapid uncontrolled ventricular response has been implicated as the main mechanism by which AF results in LV dysfunction [5]. However, in the absence of a rapid ventricular rate during AF, LV dysfunction can still occur as a result of impaired atrial contractile function, loss of atrioventricular synchrony, or an irregular ventricular rhythm [58].

Treatment options for atrial fibrillation (AF) have evolved from simple, fluoroscopy-guided pulmonary vein isolation for those patients with paroxysmal AF to complex, multi-modality procedures targeting not only anatomic structures but also electrophysiologic phenomena including complex fractionated electrograms, sites of dominant frequency and local non-venous drivers in patients with persistent and permanent AF. The stepwise ablation approach is a novel technique whereby structures contributing to initiation and maintenance of AF are sequentially targeted by radiofrequency ablation. Broadly divided into pulmonary veins, left atrial (LA) roof, left atrium (incorporating all anatomic regions of the chamber), mitral isthmus and non-LA structures, each region is targeted in sequence and the impact of ablation upon the global fibrillatory process assessed by measurement of AF cycle length (AFCL) at a site remote from the ablation target. In addition to pulmonary vein electrical disconnection and demonstrable complete conduction block across the roof and mitral isthmus lines (when performed), ablation is performed at those sites displaying continuous electrical and complex fractionated activity, with the endpoint of local organization, as well as at sites displaying electrograms consistent with focal sources driving AF. Ablation is accompanied by a cumulative increase in the AFCL prior to termination of AF by conversion either directly to sinus rhythm or to an atrial tachycardia which is then mapped conventionally and ablated. There is a ceiling of ablation within the LA beyond which further ablation is unlikely to result in a clinical benefit and should prompt evaluation of the contribution of the right atrium to maintenance of AF. The stepwise approach benefits from the integration of anatomic and electrophysiologic information to achieve a high level of success in termination of chronic AF by catheter ablation.

Aims Paroxysmal atrial fibrillation (PAF) is predominantly triggered by focal ectopies located within the pulmonary veins (PV). The BITMAP Study (Breakthrough and Isolation Trial: Mapping and Ablation of Pulmonary Veins) investigated prospectively the safety and efficacy of a catheter design with circumferential mapping and ablation electrodes. We report the phenomenon of ST-segment-elevation during catheter placement in the left atrium (LA) and superior PVs in this multi-centre study. Methods and results Forty-three patients (57 + 10 years) with PAF were included in this study. Radiofrequency catheter (RFC) ablation supported by the 4F REVELATION Helix microcatheter (Cardima Inc., Freemont, CA, USA) with eight distal-coiled microelectrodes for bipolar mapping and ablation. RFC was applied at the ostial region of PV (30 W, 45–508C) with a maximum of four RFC applications per electrode. In four of the 43 patients from three centres, we recorded the occurrence of ST-segmentelevation greater than 0.2 mV and accompanying left thoracic discomfort. The ECG changes and the symptoms started abruptly and lasted for 4.2+ 2.2 min. Pericardial effusion could instantaneously be excluded by echocardiography in all cases. Coronary angiograms were performed in three patients with the longest episodes; no thrombotic material or air emboli were present. The symptoms and the ECG changes resolved completely in all patients. Conclusion The phenomenon of ST-segment-elevation during LA- and PV-mapping in patients with PAF may be a common occurrence. In this prospective multi-centre trial, we demonstrated the reversibility of this phenomenon; no cardiovascular or cerebral damage was reported during both the procedure and the follow-up. Although the mechanism is still unclear, vasospasm may contribute to this phenomenon because of autonomic dysregulation.

Background— Endocardial mapping of localized sources driving atrial fibrillation (AF) in humans has not been reported. Methods and Results— Fifty patients with AF organized by prior pulmonary vein and linear ablation were studied. AF was considered organized if mapping during AF showed irregular but discrete atrial complexes exhibiting consistent activation sequences for >75% of the time using a 20-pole catheter with 5 radiating spines covering 3.5-cm diameter or sequential conventional mapping. A site or region centrifugally activating the remaining atrial tissue defined a source. During AF with a cycle length of 211±32 ms, activation mapping identified 1 to 3 sources at the origin of atrial wavefronts in 38 patients (76%) predominantly in the left atrium, including the coronary sinus region. Electrograms at the earliest area varied from discrete centrifugal activation to an activity spanning 75% to 100% of the cycle length in 42% of cases, the latter indicating complex local conduction or a reentrant circuit. A gradient of cycle length (>20 ms) to the surrounding atrium was observed in 28%. Local radiofrequency ablation prolonged AF cycle length by 28±22 ms and either terminated AF or changed activation sequence to another organized rhythm. In 4 patients, the driving source was isolated, surrounded by the atrium in sinus rhythm, and still firing at high frequency (228±31 ms) either permanently or in bursts. Conclusions— AF associated with consistent atrial activation sequences after prior ablation emanates mostly from localized sources that can be mapped and ablated. Some sources harbor electrograms suggesting the presence of localized reentry.

Background The relative contributions of different atrial regions to the maintenance of persistent atrial fibrillation (AF) are not known. Methods Sixty patients (53 +/- 9 years) undergoing catheter ablation of persistent AF (17 +/- 27 months) were studied. Ablation was performed in a randomized sequence at different left atrial (LA) regions and comprised isolation of the pulmonary veins (PV), isolation of other thoracic veins, and atrial tissue ablation targeting all regions with rapid or heterogeneous activation or guided by activation mapping. Finally, linear ablation at the roof and mitral isthmus was performed if sinus rhythm was not restored after addressing the above-mentioned areas. The impact of ablation was evaluated by the effect on the fibrillatory cycle length in the coronary sinus and appendages at each step. Activation mapping and entrainment maneuvers were used to define the mechanisms and locations of intermediate focal or macroreentrant atrial tachycardias. Results AF terminated in 52 patients (87%), directly to sinus rhythm in 7 or via the ablation of 1-6 intermediate atrial tachycardias (total 87) in 45 patients. This conversion was preceded by prolongation of fibrillatory cycle length by 39 +/- 9 msec, with the greatest magnitude occurring during ablation at the anterior LA, coronary sinus and PV-LA junction. Thirty-eight atrial tachycardias were focal (originating dominantly from these same sites), while 49 were macroreentrant (involving the mitral or cavotricuspid isthmus or LA roof). Patients without AF termination displayed shorter fibrillatory cycles at baseline: 130 +/- 14 vs 156 +/- 23 msec; P = 0.002. Conclusion Termination of persistent AF can be achieved in 87% of patients by catheter ablation. Ablation of the structures annexed to the left atrium-the left atrial appendage, coronary sinus, and PVs-have the greatest impact on the prolongation of AF cycle length, the conversion of AF to atrial tachycardia, and the termination of focal atrial tachycardias.

ObjectivesThe aim of the present study was to assess the feasibility of identifying sites of focal atrial activity by localized high-density endocardial mapping during atrial fibrillation (AF).BackgroundSites of focal activity in the left atrium have been demonstrated by epicardial mapping during AF.MethodsTwenty-four patients (15 with paroxysmal, 3 with persistent, and 6 with permanent AF) underwent endocardial mapping during AF. A 20-pole catheter with five radiating spines was used to map both atria for 30 s in each of 10 pre-determined segments. A focal activity was defined as ≥3 atrial cycles with activation spreading from center to periphery of the mapping catheter. Catheter ablation was performed independent of the mapping results.ResultsSpontaneous focal activities were observed in 13 sites in the left atrium (9%; anterior 1, roof 2, posterior 6, inferior 4) in 12 patients (9 paroxysmal, 3 persistent). Focal activity was observed continuously (two sites) or intermittently (11 sites, median 5 episodes), and associated with shortening of the cycle length (from 183 ± 33 ms to 172 ± 29 ms; p < 0.05). The mean duration of an intermittent episode was 1.5 s (range 0.4 to 7.1 s). Atrial fibrillation terminated without ablation at the foci in all of 12 patients, but in 2 of them, re-initiated arrhythmia was successfully ablated at these foci. Nine of these 12 patients (75%) were arrhythmia-free without antiarrhythmic drugs during a follow-up period of 7.0 ± 3.1 months.ConclusionsTermination of AF without ablation at the sites of atrial focal activity suggests that this activity may be triggered by impulses originating from other regions, such as the pulmonary veins.

The purpose of this study was to characterize the occurrence of phrenic nerve injury (PNI) and its outcome after radiofrequency (RF) ablation of atrial fibrillation (AF).It is recognized that extra-myocardial damage may develop owing to penetration of ablative energy.Between 1997 and 2004, 3,755 consecutive patients underwent AF ablation at five centers. Among them, 18 patients (0.48%; 9 male, 54 +/- 10 years) had PNI (16 right, 2 left). The procedure consisted of pulmonary vein (PV) isolation in 15 patients and anatomic circumferential ablation in 3 patients, with additional left atrial lesions (n = 11) and/or superior vena cava (SVC) disconnection (n = 4).Right PNI occurred during ablation of right superior PV (n = 12) or SVC disconnection (n = 3). Left PNI occurred during ablation at the left atrial appendage. Immediate features were dyspnea, cough, hiccup, and/or sudden diaphragmatic elevation in 9, and in the remaining the diagnosis was made after ablation owing to dyspnea (n = 7) or on routine radiographic evaluation (n = 2). Four patients (22%) were asymptomatic. Complete recovery occurred in 12 patients (66%). Recovery occurred within 24 h in the two patients with left PNI and in one patient with right PNI occurring with SVC disconnection. In the other nine patients, right PNI recovery occurred after 4 +/- 5 months (1 to 12 months) with respiratory rehabilitation. After a mean follow-up of 36 +/- 33 months, six patients have persistent PNI (three with partial and three with no recovery).In this multicenter experience, PNI was a rare complication (0.48%) of AF ablation. Ablation of the right superior PV, SVC, and left atrial appendage were associated with PNI. Complete (66%) or partial (17%) recovery was observed in the majority.

Background Areas of complex fractionated atrial electrograms (CFAEs) have been implicated in the atrial substrate of atrial fibrillation (AF). The mechanisms underlying CFAE in humans are not well investigated. Objectives The purpose of this study was to investigate the regional activation pattern associated with CFAE using a high-density contact mapping catheter. Methods Twenty patients with paroxysmal AF were mapped using a high-density multielectrode catheter. CFAE were mapped at 10 different sites (left atrium [LA]: inferior, posterior, roof, septum, anterior, lateral; right atrium [RA]: anterior, lateral, posterior, septum). Local atrial fibrillation cycle length (AFCL) was measured immediately before and after the occurrence of CFAE, and the longest electrogram duration (CFAE max ) was assessed. Results Longer electrogram durations were recorded in the LA compared with the RA (CFAE max 118 ± 21 ms vs 104 ± 23 ms, P = .001). AFCL significantly shortened before the occurrence of CFAE max compared with baseline (LA: 174 ± 32 ms vs 186 ± 32 ms, P = .0001; RA: 177 ± 31 ms vs 188 ± 31 ms, P = .0001) and returned to baseline afterwards. AFCL shortened by ≥10 ms in 91% of mapped sites. Two different local activation patterns were associated with occurrence of CFAE max : a nearly simultaneous activation in all spines in 84% indicating passive activation, and a nonsimultaneous activation sequence suggesting local complex activation or reentry. Conclusion Fractionated atrial electrograms during AF demonstrate dynamic changes that are dependent on regional AFCL. Shortening of AFCL precedes the development of CFAE; thus, cycle length is a major determinant of fractionation during AF. High-density mapping in AF may help to differentiate passive activation of CFAE from CFAE associated with an active component of the AF process.

Background Pulmonary vein (PV) isolation and linear lesions are effective in eliminating paroxysmal atrial fibrillation (AF), but linear lesions probably are not required in all patients. Noninducibility of AF has been shown to be associated with freedom from arrhythmia in 87% of patients. Objectives The purpose of this study was to prospectively evaluate the role of noninducibility in guiding a stepwise approach tailored to the patient. Methods In 74 patients (age 53 ± 8 years) with paroxysmal AF, PV isolation was performed during induced or spontaneous AF. If AF was inducible after PV isolation, one to two additional linear lesions were placed at the mitral isthmus and/or left atrial roof, with the endpoint of noninducibility of AF or atrial flutter. Inducibility (AF/atrial flutter, lasting ≥10 minutes) was assessed using burst pacing at an output of 20 mA down to refractoriness from the coronary sinus and both atrial appendages. Results In 42 patients (57%), PV isolation restored sinus rhythm and rendered AF noninducible. In the 32 patients with persistent or inducible AF after PV isolation, a single linear lesion achieved noninducibility in 20, whereas two linear lesions were required in 12 and resulted in conversion to sinus rhythm and noninducibility in 10. Using this stepwise approach, a total of 69 patients (93%) were rendered noninducible. During follow-up of 18 ± 4 months, 67 patients (91%) were free from arrhythmia without antiarrhythmic drugs. Repeat procedures were performed in 23 patients: repeat ablation was required to consolidate prior targets in 15 patients (20%), and "new" linear lesions, which were not predicted by inducibility during the index procedure, were required in 8 (11%). Conclusion Noninducibility can be used as an endpoint for determining the subset of patients with paroxysmal AF who require additional linear lesions after PV isolation. This tailored approach is effective in 91% of patients while preventing delivery of unnecessary linear lesions.

Pierre Jais, Meleze Hocini, Prashanthan Sanders, Li-Fern Hsu, Martin Rotter, Frederic Sacher, Yoshihide Takahashi, Thomas Rostock, Philippe Le Metayer, Jacques Clementy, Michel Haissaguerre