Search

Background: Patients may develop atrial tachycardia (AT) after left atrial (LA) ablation of persistent atrial fibrillation (AF)., Methods: The population consisted of 101 consecutive patients (age = 64.3 ± 8.7 years, 70 males (69%), LA = 4.6 ± 0.8 cm, ejection fraction = 48.5 ± 16%) undergoing their initial procedure for persistent AF. After pulmonary vein isolation, patients either underwent posterior LA isolation (n = 50; study group) or linear ablation at the LA roof with verification of conduction block (n = 51; control group)., Results: A repeat procedure was performed in 17 (34%) and 28 (55%) patients in the study and control groups, respectively (p = 0.02). Patients in the study group were less likely to develop AT (9/50 [18%] vs. 18/51 [35%]; p = 0.02), roof-dependent (1/50 [2%] vs. 8/51 [16%]; p = 0.008), and multi-loop AT (6/50 [12%] vs. 14/51 [27%]; p = 0.03) as compared to controls. Among various factors, only posterior LA isolation was associated with a lower likelihood of AT recurrence and roof tachycardia at redo procedure (OR, 0.37; 95% CI, 0.1 to 1.00, p = 0.05, and OR, 0.1, 95% CI, 0.01 to 0.96; p < 0.05, respectively)., Conclusions: In patients with persistent AF, posterior LA isolation is associated with a lower risk of a redo procedure, roof-dependent macro-reentry, and post-ablation AT in general as compared to controls who only received roof ablation. Posterior LA isolation also obviates the need for pacing maneuvers, and may be a more definitive endpoint than linear ablation at the LA roof., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

In the last three decades, ablation of atrial fibrillation (AF) has become an evidence-based safe and efficacious treatment for managing the most common cardiac arrhythmia. In 2007, the first joint expert consensus document was issued, guiding healthcare professionals involved in catheter or surgical AF ablation. Mounting research evidence and technological advances have resulted in a rapidly changing landscape in the field of catheter and surgical AF ablation, thus stressing the need for regularly updated versions of this partnership which were issued in 2012 and 2017. Seven years after the last consensus, an updated document was considered necessary to define a contemporary framework for selection and management of patients considered for or undergoing catheter or surgical AF ablation. This consensus is a joint effort from collaborating cardiac electrophysiology societies, namely the European Heart Rhythm Association, the Heart Rhythm Society, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society ., Competing Interests: Conflict of interest: All members provided disclosure statements to assess potential conflicts of interest. Details are available in the Supplementary material., (This article has been co-published with permission in Europace, HeartRhythm, Journal of Arrhythmia and Journal of Interventional Cardiac Electrophysiology. © 2024 Heart Rhythm Society, the European Society of Cardiology, the Asia Pacific Heart Rhythm Society, and the Latin American Heart Rhythm Society The articles are identical except for minor stylistic and spelling differences in keeping with each journal's style. Any citation can be used when citing this article.)

Introduction: Incidental left atrial appendage (LAA) isolation may occur during radiofrequency ablation of persistent atrial fibrillation (AF). The study aims to describe the mechanisms and long-term thromboembolic risk related to incidental LAA isolation., Methods: Patients who experienced incidental LAA isolation after AF ablation were included. Culprit sites where ablation resulted in LAA isolation were identified. Thromboembolic risk despite oral anticoagulation (OAC) was compared to that in a propensity-matched control group without LAA isolation., Results: Forty-one patients with LAA isolation, and 82 matched patients without LAA isolation were included. The patient age, ejection fraction, LA diameter, and CHA 2 DS 2 -VASc score were 64 ± 11 years, 55 ± 12%, 45.0 ± 7 mm and 2.62 ± 1.5, respectively. Culprit sites included the LAA base, mitral isthmus, inferior LA, Bachmann's bundle, coronary sinus, and Marshall vein. After 4.2 ± 3.6 years follow-up, thromboembolism occurred in 7 of 41 patients (17%) with LAA isolation versus 3 of 82 patients (4%) without isolation (log rank p < .009, HR 5.14, 95% CI [1.32-19.94], p = .02). Patients with and without thromboembolism had similar CHA 2 DS 2 -VASc scores (2.65 ± 1.3 vs. 2.71 ± 0.76, p = .89). Thromboembolism occurred during noncompliance with or temporary discontinuation of OAC in four of the seven patients., Conclusions: Incidental LAA isolation may occur during ablation of atrial arrhythmias in the vicinity of, or even at sites remote from the appendage. Patients with incidental LAA isolation had higher rates of thromboembolism compared to patients without isolation. Since thromboembolism may occur despite prescription for OAC, the risks of LAA isolation must be weighed against clinical benefit and appendage occlusion devices should be considered in vulnerable patients., (© 2023 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Introduction: Transseptal puncture (TSP) is routinely performed for left atrial ablation procedures. The use of a three-dimensional (3D) mapping system or intracardiac echocardiography (ICE) is useful in localizing the fossa ovalis and reducing fluoroscopy use. We aimed to compare the safety and efficacy between 3D mapping system-guided TSP and ICE-guided TSP techniques., Methods: We conducted a prospective observational study of patients undergoing TSP for left atrial catheter ablation procedures (mostly atrial fibrillation ablation). Propensity scoring was used to match patients undergoing 3D-guided TSP with patients undergoing ICE-guided TSP. Logistic regression was used to compare the clinical data, procedural data, fluoroscopy time, success rate, and complications between the groups., Results: Sixty-five patients underwent 3D-guided TSP, and 151 propensity score-matched patients underwent ICE-guided TSP. The TSP success rate was 100% in both the 3D-guided and ICE-guided groups. Median needle time was 4.00 min (interquartile range [IQR]: 2.57-5.08) in patients with 3D-guided TSP compared to 4.02 min (IQR: 2.83-6.95) in those with ICE-guided TSP (p = .22). Mean fluoroscopy time was 0.2 min (IQR: 0.1-0.4) in patients with 3D-guided TSP compared to 1.2 min (IQR: 0.7-2.2) in those with ICE-guided TSP (p < .001). There were no complications related to TSP in both group., Conclusions: Three-dimensional mapping-guided TSP is as safe and effective as ICE-guided TSP without additional cost., (© 2022 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Introduction: Monitored anesthesia care (MAC) or general anesthesia (GA) can be used during catheter ablation (CA) of atrial fibrillation (AF). However, each approach may have advantages and disadvantages with variability in operator preferences. The optimal approach has not been well established. The purpose of this study was to compare procedural efficacy, safety, clinical outcomes, and cost of CA for AF performed with MAC versus GA., Methods: The study population consisted of 810 consecutive patients (mean age: 63 ± 10 years, paroxysmal AF: 48%) who underwent a first CA for AF. All patients completed a preprocedural evaluation by the anesthesiologists. Among the 810 patients, MAC was used in 534 (66%) and GA in 276 (34%). Ten patients (1.5%) had to convert to GA during the CA., Results: Although the total anesthesia care was longer with GA particularly in patients with persistent AF, CA was shorter by 5 min with GA than MAC (p < 0.01). Prevalence of perioperative complications was similar between the two groups (4% vs. 4%, p = 0.89). There was no atrioesophageal fistula with either approach. GA was associated with a small, ~7% increase in total charges due to longer anesthesia care. During 43 ± 17 months of follow-up after a single ablation procedure, 271/534 patients (51%) in the MAC and 129/276 (47%) patients in the GA groups were in sinus rhythm without concomitant antiarrhythmic drug therapy (p = 0.28)., Conclusion: With the participation of an anesthesiologist, and proper preoperative assessment, CA of AF using GA or MAC has similar efficacy and safety., (© 2022 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Purpose: We aim to describe the long-term safety and efficacy of catheter ablation (CA) in young patients (<30 years) with atrial fibrillation (AF)., Methods: This was a retrospective study of patients aged 18-30 who underwent CA for AF, and clinical characteristics and long-term outcomes are reported. Survival analyses were performed between the study group and a propensity-matched older cohort (>30 years, mean age: 58±10 years)., Results: From January 2000 to January 2019, a 1st CA (radiofrequency energy n=72, cryoballoon n=10), was performed in 82 patients (mean age 26±4 years, paroxysmal n=61, persistent n=14, longstanding persistent n=7), among 6336 consecutive patients with AF. During a follow-up of 5±5 years, 56% and 30% of the patients with paroxysmal and non-paroxysmal AF were arrhythmia free without antiarrhythmic drug (AAD) therapy after a single CA (P=0.02). After 1.5±0.8 CA procedures, 76% and 75% of the patients with paroxysmal AF and non-paroxysmal AF were arrhythmia free without AADs (P=0.54). Compared to a propensity-matched group of older patients, young patients were as likely to remain in sinus rhythm after CA (P=0.47), however after fewer repeat CAs (1.5±0.8 vs 1.9±0.9, P<0.009). There were no long-term adverse outcomes associated with CA., Conclusions: CA is a safe and effective treatment of AF in young patients with comparable outcomes to the older patients, however after fewer procedures., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

Atrial tachycardias are commonly encountered in patients undergoing catheter ablation of persistent atrial fibrillation (AF). Unlike typical atrial flutter that can be readily recognized and ablated, these post-AF tachycardias can arise from a wide variety of locations and involve a multiplicity of mechanisms. Apart from diagnostic challenges, radiofrequency ablation to eliminate the tachycardias may require multiple approaches. In addition, specialized techniques such as epicardial and chemical ablation may be required for definitive treatment. This review describes the various mechanisms and approaches to mapping and ablation of these challenging tachycardias., (© 2021 Wiley Periodicals LLC.)

Background: Electrical isolation of the left atrial appendage (LAA) improves outcomes of patients with persistent atrial fibrillation (AF) but may increase the risk of thromboembolism., Objective: The purpose of this study was to describe a method to map and ablate appendage drivers without complete electrical isolation., Methods: One hundred thirteen patients underwent an ablation procedure for persistent AF. The procedure was performed during AF and consisted of pulmonary vein and posterior LA isolation as well as ablation of the LAA. The right atrium (RA) was targeted in patients with a right-to-left gradient in cycle length (CL). The end point of appendage ablation was CL slowing or AF termination but not complete isolation., Results: Among the 113 patients (mean age 64.6 ± 8.6 years; ejection fraction 54% ± 13%; LA diameter 46 ± 6.5 mm), radiofrequency ablation terminated AF in 51 patients (45%). RA ablation was performed in 41 patients (36%) at the index or repeat procedure. The mean AF CL in the RA appendage (RAA) was shorter than that in the LAA (160 ± 32 ms vs 186 ± 29 ms; P < .01) in these patients. The most frequent target in the RA was the RAA (CLs approaching 50-60 ms). Discontinuing radiofrequency ablation upon AF termination or conduction slowing prevented LAA isolation. After a mean follow-up of 24 ± 15 months, 89 patients (78%) remained arrhythmia-free without antiarrhythmic medications., Conclusion: An ablation strategy guided by the AF CL addresses LAA drivers without complete electrical isolation and also helps identify the RAA as a source of persistent AF., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Diabetes mellitus (DM) is a risk factor for atrial fibrillation (AF). The effect of antidiabetic medications on AF or the outcomes of catheter ablation (CA) has not been well described. We sought to determine whether metformin treatment is associated with a lower risk of atrial arrhythmias after CA in patients with DM and AF., Methods and Results: A first CA was performed in 271 consecutive patients with DM and AF (age: 65 ± 9 years, women: 34%; and paroxysmal AF: 51%). At a median of 13 months after CA (interquartile range: 6-30), 100/182 patients (55%) treated with metformin remained in sinus rhythm without antiarrhythmic drug therapy, compared with 36/89 patients (40%) not receiving metformin (p = .03). There was a significant association between metformin therapy and freedom from recurrent atrial arrhythmias after CA in multivariable Cox hazards models (hazard ratio [HR]: 0.66; ±95% confidence interval [CI]: 0.44-0.98; p = .04) that adjusted for age, sex, body mass index, AF type (paroxysmal vs. nonparoxysmal), antiarrhythmic medication, obstructive sleep apnea, chronic kidney disease, coronary artery disease, left ventricular ejection fraction, and left atrial diameter. A Cox model that also incorporated other antidiabetic agents and fasting blood glucose demonstrated a similar reduction in the risk of recurrent atrial arrhythmias with metformin treatment (HR: 0.63; ±95% CI: 0.42-0.96; p = .03)., Conclusions: In patients with DM, treatment with metformin appears to be independently associated with a significant reduction in the risk of recurrent atrial arrhythmias after CA for AF. Whether this effect is due to glycemic control or pleiotropic effects on electroanatomical mechanisms of AF remains to be determined., (© 2021 Wiley Periodicals LLC.)

Background: It is not clear if antiarrhythmic drug therapy (AAD) after catheter ablation (CA) of atrial fibrillation (AF) increases mortality., Objective: To determine whether there is an association between AAD therapy and mortality after CA of AF., Methods: There were 3624 consecutive patients with AF (mean age: 59 ± 11 years, women: 27%, paroxysmal AF: 58%). An AAD was used in 2253 patients (62%, AAD group) for a mean duration of 1.3 ± 0.8 years, during a mean follow-up of 6.7 ± 2.2 years after CA of AF. Using propensity score matching, with every 2 patients using an AAD matched to 1 patient who did not use AAD (NO-AAD group), Cox regression models were utilized to assess the association between AAD use (as a time-variable covariate) and all-cause mortality., Results: There were a total of 50 deaths (2.2%) in the AAD and 62 deaths (4.5%) in the NO-AAD groups, respectively (P = .02). At the time of death, 46 of 50 patients (92%) who died in the AAD cohort were still using an AAD (P = .21, compared to baseline use). On multivariate analysis, although the risk of death was not statistically significant between the AAD and NO-AAD cohorts, there was a trend towards mortality benefit with AAD therapy (hazard ratio [HR]: 0.66, 95% confidence interval [CI]: 0.43-1.00, P = .05), regardless of the rhythm or anticoagulation status., Conclusion: AAD use after CA of AF is not associated with an increased risk of mortality, suggesting that when carefully chosen and monitored, AADs appear to be safe after CA of AF., (Copyright © 2019 Heart Rhythm Society. All rights reserved.)

Background: The role of cryoballoon ablation (CBA) for antral pulmonary vein isolation (APVI) has not been well established in persistent atrial fibrillation (PerAF). Isolation of the left atrial posterior wall (BOX) after APVI has been suggested to improve the efficacy of radiofrequency catheter ablation (RFA) in PerAF., Objective: The purpose of this study was to compare characteristics and clinical outcomes of APVI by CBA vs APVI + BOX by contact force-guided RFA (CF-RFA) in patients with PerAF., Methods: APVI was performed in 167 consecutive patients with PerAF (mean age 64 ± 9 years; left atrial diameter 46 ± 6 mm) using CBA (n = 90) or CF-RFA (n = 77). After APVI, a roofline was created in 33 of 90 patients (37%) in the CBA group and BOX was performed in all 77 patients in the CF-RFA group., Results: During 21 ± 10 months of follow-up after a single ablation procedure, 37 of 90 patients (41%) in the CBA group (APVI) and 39 of 77 (51%) in the CF-RFA group (APVI + BOX) remained in sinus rhythm without antiarrhythmic drugs (AADs) (P = .22). During repeat ablation, APVI + BOX using CF-RFA was performed in 20 of 90 patients (22%) and in 18 of 77 patients (23%) who initially underwent CBA or CF-RFA, respectively. At 19 ± 10 months after repeat ablation, sinus rhythm was maintained in 55 of 90 patients (61%) and 52 of 77 patients (68%) in the CBA and CF-RFA groups without AADs, respectively (P = .39)., Conclusion: In PerAF, an initial approach of APVI by CBA or APVI + BOX by CF-RFA has a similar efficacy of 40%-50% without AADs. After repeat ablation for APVI + BOX by CF-RFA in ∼25%, sinus rhythm is maintained in 60%-70% of patients without AADs., (Copyright © 2018 Heart Rhythm Society. All rights reserved.)

Purpose: The endpoint for radiofrequency catheter ablation (RFA) of cavo-tricuspid isthmus (CTI)-dependent atrial flutter (AFL) is complete conduction block along the CTI. The purpose of this study is to evaluate the utility of the temporal relationship between the P wave and the local atrial electrograms in determining complete CTI block., Methods: RFA of CTI was performed in 125 patients (age 63 ± 11 years). During pacing from the coronary sinus (CS), the intervals from the peak of the P wave (P peak ) in lead V 1 to the second component of the local atrial electrogram (A 2 ) along the ablation line (P peak -A 2 ) and from the end of the P wave (P end ) to A 2 (P end -A 2 ) were investigated before and after complete block in the first 100 patients (training set). In the next 25 patients (validation set), P peak -A 2 and P end -A 2 intervals were prospectively assessed to determine CTI block., Results: The mean P peak -A 2 and P end -A 2 immediately before complete block were - 15±24 and - 39±23 ms compared to 49 ± 17 and 21 ± 16 ms after CTI block (P < 0.0001). P peak -A 2 ≥ 20 ms and P end -A 2 ≥ 0 ms predicted CTI block with 98% sensitivity and 95% specificity and 96% sensitivity and 100% specificity, respectively. In the validation set, the positive and negative predictive values of P peak -A 2 ≥ 20 ms or P end -A 2 ≥ 0 ms were 100 and 96%, respectively. The diagnostic accuracy was 98%., Conclusions: During pacing from the CS, the temporal relationship between the P wave in lead V 1 and A 2 is a simple and reliable indicator of complete block during RFA of CTI-AFL.

Background: There are no randomized controlled studies of the efficacy and safety of protamine to reverse anticoagulant effects of heparin after catheter ablation (CA) of atrial fibrillation (AF)., Objective: The purpose of this study was to determine the efficacy and safety of protamine to expedite vascular hemostasis and ambulation after CA of AF., Methods: CA to eliminate AF (n = 139) or left atrial flutter (n = 11) was performed in 150 patients using radiofrequency catheter ablation (n = 112) or cryoballoon ablation (n = 38). CA was performed under uninterrupted anticoagulation with warfarin in 28 patients or after skipping a single dose of a novel oral anticoagulant in 122 patients who were randomized to receive protamine (n = 77) or to the control group (n = 73). Baseline and procedural characteristics were similar between the 2 groups. Hemostasis was achieved manually once the activated clotting time returned to preprocedural values., Results: The maximum activated clotting time during CA was 359 ± 31 and 359 ± 29 seconds in the protamine and control groups, respectively (P = .91). The time to hemostasis was 123 ± 95 minutes in the protamine group and 260 ± 70 minutes in the control group (P < .001). The time to ambulation was 316 ± 80 and 480 ± 92 minutes in the protamine and control groups, respectively (P < .001). There were no differences in the rates of major or minor vascular access complications or thromboembolic events (P > .05)., Conclusion: Protamine expedites vascular hemostasis and time to ambulation by ∼3 hours after CA of AF without an increase in the risk of vascular or thromboembolic complications., (Copyright © 2018 Heart Rhythm Society. All rights reserved.)

Introduction: Although noninferiority of cryoballoon ablation (CBA) and radiofrequency catheter ablation for antral pulmonary vein isolation (APVI) has been reported in patients with paroxysmal atrial fibrillation (PAF), it is not clear whether contact force sensing (CF-RFA) and CBA with the second-generation catheter have similar procedural costs and long-term outcomes. The objective of this study is to compare the long-term efficacy and cost implications of CBA and CF-RFA in patients with PAF., Methods and Results: A first APVI was performed in 146 consecutive patients (age: 63 ± 10 years, men: 95 [65%], left atrial diameter: 42 ± 6 mm) with PAF using CBA (71) or CF-RFA (75). Clinical outcomes and procedural costs were compared. The mean procedure time was significantly shorter with CBA than with CF-RFA (98 ± 39 vs. 158 ± 47 minutes, P < 0.0001). Despite a higher equipment cost in the CBA than the CF-RFA group, the total procedure cost was similar between the two groups (P = 0.26), primarily driven by a shorter procedure duration that resulted in a lower anesthesia cost. At 25 ± 5 months after a single ablation procedure, 51 patients (72%) in the CBA, and 55 patients (73%) in the CF-RFA groups remained free from atrial arrhythmias without antiarrhythmic drug therapy (P = 0.84)., Conclusions: The procedure duration was approximately 60 minutes shorter with CBA than CF-RFA. The procedural costs were similar with both approaches. At 2 years after a single procedure, CBA and CF-RFA have similar single-procedure efficacies of 72-73%., (© 2017 Wiley Periodicals, Inc.)

Background: The role of the ligament of Marshall (LOM) in patients with atrial fibrillation (AF) has not been well defined., Objective: The purpose of this study was to describe the role of the LOM in patients with AF and related arrhythmias., Methods: Fifty-six patients (mean age 63 ± 11 years; persistent AF in 48 [86%]; ejection fraction 0.49 ± 0.13; left atrial diameter 4.7 ± 0.6 cm) with LOM-mediated arrhythmias were included., Results: A LOM-pulmonary vein (PV) connection was present in 18 patients (32%) and was eliminated with radiofrequency (RF) ablation at the left lateral ridge or crux (n = 12), at the mitral annulus (n = 3), or with alcohol/ethanol (EtOH) ablation of the vein of Marshall (VOM; n = 3). A LOM-mediated atrial tachycardia (AT) was present in 13 patients (23%). Thirty-one patients with refractory mitral isthmus conduction were referred for potential EtOH ablation. In the 6 patients in whom VOM was injected during perimitral reentry, EtOH resulted in slowing in 3 patients and termination in 1 patient. In others, EtOH infusion resulted in complete isolation of the left-sided PVs and left atrial appendage. Repeat RF and adjunctive EtOH ablation of the VOM tended to be more effective in creating conduction block across the mitral isthmus than RF ablation alone (P = .057)., Conclusion: The LOM is responsible for a variety of arrhythmia mechanisms in patients with AF and atrial tachycardia. It may be ablated at any point along its course, at the mitral annulus, at the lateral ridge/PV antrum, and epicardially in the coronary sinus and the VOM itself. EtOH ablation of the VOM may be an adjunctive strategy in patients with refractory perimitral reentry., (Copyright © 2017. Published by Elsevier Inc.)

Background: Frequent premature ventricular complexes (PVCs) have been associated with increased mortality. However, the optimal approach to the risk stratification of these patients is unclear., Objective: The purpose of this study was to prospectively assess the use of cardiac magnetic resonance imaging (MRI) and programmed ventricular stimulation to identify patients with PVCs undergoing radiofrequency ablation at risk for adverse long-term outcomes., Methods: A total of 321 consecutive patients (52 ± 15 years; 157 men [49%]; left ventricular ejection fraction 51% ± 12%) underwent PVC ablation between 2004 and 2015, preceded by cardiac MRI to assess for structural heart disease (SHD). Programmed stimulation was performed at the time of the ablation procedure. If ventricular tachycardia (VT) was induced in the presence of SHD, an implantable cardioverter-defibrillator (ICD) was implanted., Results: SHD was identified by MRI in 64 patients (20%), and sustained monomorphic VT was inducible in 15 patients (5%). Fourteen patients had both SHD and inducible VT, and received an ICD after the procedure. The primary endpoint of VT/ventricular fibrillation or death was met in 15 patients after a median 20 months of follow-up. The combination of SHD by MRI and VT inducibility conferred independently an increased risk of adverse outcome (multivariate hazard ratio 25.73, 95% confidence interval 6.74-98.20; P <.001)., Conclusion: Preablation cardiac MRI and programmed stimulation can be useful for risk stratification in patients with frequent PVCs. Patients with inducible VT in the setting of SHD may benefit from ICD implantation after ablation regardless of left ventricular ejection fraction., (Copyright © 2017 Heart Rhythm Society. All rights reserved.)

Background: Adenosine can reveal dormant pulmonary vein (PV) conduction after PV isolation (PVI) in patients with paroxysmal atrial fibrillation (AF). However, the impact of elimination of adenosine-provoked dormant PV conduction after PVI has not been formally evaluated., Objective: The purpose of this study was to determine whether ablation of PV reconnections unmasked by adenosine improves outcomes., Methods: Patients with paroxysmal AF (n = 129) were randomized to receive either adenosine (n = 61) or no adenosine (n = 68) after PVI. Dormant conduction revealed by adenosine after PVI was ablated until all adenosine-mediated reconnections were eliminated. Thereafter, both groups received isoproterenol., Results: Acute reconnection was seen in 23 patients (37%) in the adenosine group. There was a significant difference between the number of PVs reconnected if patients were given adenosine >60 minutes after initial PVI compared to those who received adenosine <60 minutes after initial PVI (3/32 [9.4%] vs 24/32 [75%], P <.0001). Patients who did not receive adenosine had more PV reconnections after isoproterenol infusion compared to patients in the adenosine group (17/68 [25.0%] vs 5/61 [8.2%], P = .018). There was no difference in the rate of AF recurrence in patients who received adenosine (24/61 [39%]) compared to control patients (23/68 [34%], log-rank P = .83)., Conclusion: Adenosine can reveal dormant conduction in more than one-third of patients with paroxysmal AF undergoing PVI. However, adenosine administration, and additional ablation of the resultant connections, does not improve long-term outcomes compared to a protocol that includes isoproterenol infusion., (Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Frequent idiopathic premature ventricular complexes (PVCs) can result in PVC-induced cardiomyopathy. Frequent PVCs can also aggravate ischemic cardiomyopathy., Objective: The purpose of this study was to investigate the impact of frequent PVCs on nonischemic cardiomyopathy., Methods: This was a consecutive series of 30 patients (mean age 59.1 ± 12.1; 18 men; mean ejection fraction [EF] 38% ± 15%) with structurally abnormal hearts based on the presence of scar on cardiac magnetic resonance imaging and/or a history of cardiomyopathy before the presence of frequent PVCs who were referred for ablation of frequent PVCs., Results: Ablation was successful in 18 of 30 patients (60%), resulting in an increase of mean EF from 33.9% ± 14.5% to 45.7% ± 17% (P < .0001) during mean follow-up of 30 ± 28 months. The PVC burden in these patients was reduced from 23.1% ± 8.8% to 1.0% ± 0.9% (P < .0001). Mean EF did not change in patients with a failed ablation procedure (44.4 ± 16 vs 43.5 ± 21, P = .85). The PVC site of origin was in scar tissue in 14 of 18 patients with a successful ablation procedure. Mean New York Heart Association functional class improved from 2.3 ± 0.6 to 1.1 ± 0.2 (P < .0001) in patients with a successful outcome and remained unchanged in patients with an unsuccessful outcome (1.9 ± 0.9 vs 1.9 ± 0.7, P = 1)., Conclusion: In patients with frequent PVCs and nonischemic cardiomyopathy, EF and functional class can be improved but not always normalized by successful PVC ablation. In most patients with an effective ablation, the arrhythmogenic substrate was located in scar tissue., (Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Atrial fibrillation (AF) is associated with a significant increase in the risk of stroke and mortality. It is unclear whether maintaining sinus rhythm (SR) after radiofrequency ablation (RFA) is associated with an improvement in stroke risk and survival., Objective: The purpose of this study was to determine whether SR after RFA of AF is associated with an improvement in the risk of cerebrovascular events (CVEs) and mortality during an extended 10-year follow-up., Methods: RFA was performed in 3058 patients (age 58 ± 10 years) with paroxysmal (n = 1888) or persistent AF (n = 1170). The effects of time-dependent rhythm status on CVEs and cardiac and all-cause mortality were assessed using multivariable Cox models adjusted for baseline and time-dependent variables during 11,347 patient-years of follow-up., Results: Independent predictors of a higher arrhythmia burden after RFA were age (estimated beta coefficient [β] = 0.017 per 10 years, 95% confidence interval [CI] 0.006-0.029, P = .003), left atrial (LA) diameter (β = 0.044 per 5-mm increase in LA diameter, 95% CI 0.034-0.055, P <.0001), and persistent AF (β = 0.174, 95% CI 0.147-0.201, P <.0001). CVEs and cardiac and all-cause mortality occurred in 71 (2.3%), 33 (1.1%), and 111 (3.6%), respectively. SR after RFA was associated with a significantly lower risk of cardiac mortality (hazard ratio [HR] 0.41, 95% CI 0.20-0.84, P = .015). There was not a significant reduction in all-cause mortality (HR 0.86, 95% CI 0.58-1.29, P = .48) or CVEs (HR 0.79, 95% CI 0.48-1.29, P = .34) in patients who remained in SR after RFA., Conclusion: Maintenance of SR after RFA is associated with a reduction in cardiovascular mortality in patients with AF., (Copyright © 2014 Heart Rhythm Society. All rights reserved.)

Background: The prevalence and clinical consequences of coronary arterial injury in a large series of patients undergoing radiofrequency ablation (RFA) of atrial fibrillation (AF) are unknown., Objective: The purpose of this study was to describe the frequency and clinical consequences of coronary arterial injury in a large series of patients undergoing catheter ablation of AF and postablation atrial tachycardia., Methods: The medical records of 5,709 consecutive patients undergoing RFA of AF were reviewed. Heart specimens were also dissected to analyze the course of the coronary arteries., Results: Arterial injury occurred in 8 patients (0.14%). Three patients developed ventricular fibrillation (VF) due to occlusion of the distal or proximal circumflex (Cx) artery related to RFA in the distal coronary sinus (CS) or base of the LA appendage, respectively. Two VF patients underwent stenting. Five patients developed acute sinus node (SN) dysfunction. In 4/5 patients, the culprit site was subjacent to the SN artery (per computed tomography) coursing over the anterior LA (n = 3) or the septal RA (n = 1). Two patients required a permanent pacemaker. In the heart specimens, the SN artery, after its origin from the proximal Cx artery, coursed along the anterior LA. Also, the proximal Cx artery was found in the atrioventricular groove underneath the base of the LA appendage., Conclusion: Clinically apparent injury to the coronary arteries during LA ablation for AF is rare. However, it may be associated with potentially life-threatening ventricular arrhythmias and acute SN dysfunction requiring permanent pacing. The culprit sites seem to be in the distal coronary sinus and the anterior LA, and correlate well with the course of the coronary arteries in pathologic specimens. Vigilance and low-power settings are important in minimizing the risk of arterial injury., (© 2013 Heart Rhythm Society. All rights reserved.)

Background: Ventricular arrhythmias have been described to originate from intramural locations. Intramural scar can be assessed by delayed-enhanced MRI, but MRIs cannot be performed on every patient. The objective of this study was to assess the value of voltage mapping to detect MRI-defined intramural scar and to correlate the scar with ventricular arrhythmias., Methods and Results: In 15 consecutive patients (3 women; age 55±16 years; ejection fraction, 49±13%) with structural heart disease, intramural scar was detected by delayed-enhanced MRI. All patients underwent endocardial unipolar and bipolar voltage mapping guided by the registered intramural scar. Scar volume by MRI was 11.7±8 cm3 with a scar thickness of 4.6±0.7 mm and a preserved endocardial/epicardial rim of 3.3±1.6 and 4.8±2.6 mm, respectively. Endocardial bipolar voltage was 1.6±1.73 mV at the scar, 2.12±2.15 mV in a 1 cm perimeter around the scar, and 2.83±3.39 mV in remote myocardium without scar. The corresponding unipolar voltage was 4.94±3.25, 6.59±3.81, and 8.32±3.39 mV, respectively (P<0.0001). Using receiver-operator characteristic curves, a unipolar cut-off value of 6.78 mV (area under the curve, 0.78) and a bipolar cut-off value of 1.55 mV (area under the curve, 0.69) best separated endocardial measurements overlying scar as compared with areas not overlying a scar. At least 1 intramural ventricular arrhythmia was eliminated in all but 2 patients in this series., Conclusions: Intramural scar can be detected by unipolar and bipolar voltage, unipolar voltage being more useful. Mapping and ablation of intramural arrhythmias originating from an intramural focus can be accomplished.

Background: The right ventricular outflow tract (RVOT) is the most common site of origin of ventricular arrhythmias (VAs) in patients with idiopathic VAs. A left bundle branch block, inferior axis morphology arrhythmia is the hallmark of RVOT arrhythmias. VAs from other sites of origin can mimic RVOT VAs, and ablation in the RVOT typically fails for these VAs., Objective: To analyze reasons for failed ablations of RVOT-like VAs., Methods: Among a consecutive series of 197 patients with an RVOT-like electrocardiographic (ECG) morphology who were referred for ablation, 38 patients (13 men; age 46 ± 14 years; left ventricular ejection fraction 47% ± 14%) in whom a prior procedure failed within the RVOT underwent a second ablation procedure. ECG characteristics of the VA were compared to a consecutive series of 50 patients with RVOT VAs., Results: The origin of the VA was identified in 95% of the patients. In 28 of 38 (74%) patients, the arrhythmia origin was not in the RVOT. The VA originated from intramural sites (n = 8, 21%), the pulmonary arteries (n = 7, 18%), the aortic cusps (n = 6, 16%), and the epicardium (n = 5, 13%). The origin was within the RVOT in 10 (26%) patients. In 2 (5%) patients, the origin could not be identified despite biventricular, aortic, and epicardial mapping. The VA was eliminated in 34 of 38 (89%) patients with repeat procedures. The ECG features of patients with failed RVOT-like arrhythmias were different from the characteristics of RVOT arrhythmias., Conclusions: In patients in whom ablation of a VA with an RVOT-like appearance fails, mapping of the pulmonary artery, the aortic cusps, the epicardium, the left ventricular outflow tract, and the aortic cusps will help identify the correct site of origin. The 12-lead ECG is helpful in differentiating these VAs from RVOT VAs., (Copyright © 2013 Heart Rhythm Society. All rights reserved.)

Background: Most infarct-related ventricular tachycardias (VTs) have an exit site that can be targeted by endocardial ablation. However, some VT reentry circuits have an exit site that is intramural or epicardial. Even these circuits may have an endocardial component that can be endocardially ablated., Objective: To assess the prevalence of postinfarction VTs with a nonendocardial exit site that can be successfully eliminated by endocardial ablation., Methods: Twenty-eight consecutive patients with postinfarction VT (27 men, age 69 ± 8 years, ejection fraction 0.25% ± 0.15%) were referred for VT ablation. A total of 213 VTs were inducible (cycle length 378 ± 100 ms). Pace mapping was performed throughout the scar, and critical sites were identified for 137 VTs (64.5%). Critical sites identified by entrainment mapping and/or pace mapping were divided into exit and nonexit sites depending on the stimulus-QRS/VT cycle length ratio (S-QRS/VT CL ≤ 0.3 vs>0.3)., Results: Endocardial exit sites (S-QRS/VTCL ≤ 0.3) were identified for 100 of 137 VTs. Only critical nonexit sites were identified for 37 of 137 (27%) VTs. Nonexit sites were confined to a smaller area within the endocardium (1.81 ± 1.7 cm(2)) and were located within dense scar (0.28 ± 0.24 mV) further away from the border zone (2.05 ± 2.79 cm) than did the VT exit sites. Exit sites had a larger area of matching pace maps (3.86 ± 1.9 cm(2); P<.01) and were at a closer distance to the border zone (0.93 ± 1.06 cm; P<.01). A total of 133 of 137 VTs were ablated. The success rate was similar for VTs in which exit sites were targeted (n = 90 of 100) and VTs in which only nonexit sites were targeted (n = 36 of 37) (P = .83)., Conclusions: In about one-third of postinfarction VTs for which critical sites were identified, the exit site was not endocardial. Critical nonexit sites that are effective for ablation are often within dense scar at a distance from the border zone and can be missed if only the border zone is targeted., (Copyright © 2013 Heart Rhythm Society. All rights reserved.)

Background: It is not clear whether dabigatran is as safe and effective as uninterrupted anticoagulation with warfarin during radiofrequency catheter ablation (RFA) of atrial fibrillation (AF)., Objective: To compare the safety and efficacy of dabigatran by using a novel administration protocol and uninterrupted anticoagulation with warfarin for periprocedural anticoagulation in patients undergoing RFA of AF., Methods: In this case-control analysis, 763 consecutive patients (mean age 61±10 years) underwent RFA of AF using dabigatran (N = 191) or uninterrupted warfarin (N = 572) for periprocedural anticoagulation. In all patients, anticoagulation was started≥4 weeks before RFA. Dabigatran was held after the morning dose on the day before the procedure and resumed 4 hours after vascular hemostasis was achieved., Results: A transesophageal echocardiogram performed in all patients receiving dabigatran did not demonstrate an intracardiac thrombus. There were no thromboembolic complications in either group. The prevalence of major (4 of 191, 2.1%) and minor (5 of 191, 2.6%) bleeding complications in the dabigatran group were similar to those in the warfarin group (12 of 572, 2.1%; P = 1.0 and 19 of 572, 3.3%; P = .8, respectively). Pericardial tamponade occurred in 2 of 191 (1%) patients in the dabigatran group and in 7 of 572 (1.2%) patients in the warfarin group (P = 1.0). All patients who had a pericardial tamponade, including 2 in the dabigatran group, had uneventful recovery after perdicardiocentesis. On multivariate analysis, international normalized ratio (odds ratio [OR] 4.0; 95% confidence interval [CI] 1.1-15.0; P = .04), clopidogrel use (OR 4.2; 95% CI 1.5-12.3; P = .01), and CHA2DS2-VASc score (OR 1.4; 95% CI 1.1-1.8; P = .01) were the independent risk factors of bleeding complications only in the warfarin group., Conclusions: When held for approximately 24 hours before the procedure and resumed 4 hours after vascular hemostasis, dabigatran appears to be as safe and effective as uninterrupted warfarin for periprocedural anticoagulation in patients undergoing RFA of AF., (Copyright © 2013 Heart Rhythm Society. All rights reserved.)

Background: While macroreentrant atrial tachycardias (ATs) have been reasonably well described, little is known about small reentrant circuits., Objective: To compare characteristics of large and small reentrant circuits after ablation of persistent atrial fibrillation., Methods: Seventy-seven patients (age 61±10 years; left atrium 46±6 mm; ejection fraction 0.52±0.13) underwent a procedure for postablation AT. The p-wave duration, circuit size, electrogram characteristics, and conduction velocity were determined., Results: AT was due to macroreentry in 62 (80%) patients, a small reentrant circuit in 13 (17%), and a focal mechanism in 2 (3%). The p-wave duration during small reentrant ATs was shorter than that during macroreentry (174±12 ms vs 226±22 ms; P<.0001). The duration of fractionated electrograms at the critical site was longer in small vs large circuits (167±43 ms vs 98±38 ms, respectively; P<.0001) and accounted for a greater percentage of the tachycardia cycle length (59%±18% vs 38%±14%, respectively; P<.0001). The mean diameters of macroreentrant and small reentrant circuits were 44±7 and 26±11 mm, respectively (P<.0001). The mean conduction velocity along the small circuits was lower (0.5±0.2 m/s vs 1.2±0.3 m/s; P<.0001). Catheter ablation eliminated the AT in all 77 patients., Conclusions: AT due to a small reentrant circuit after ablation of atrial fibrillation may be distinguished from macroreentry by a shorter p-wave duration and the presence of long-duration electrograms at the critical site owing to extremely slow conduction. These features may aid the clinician in the mapping of postablation ATs., (Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Patients with frequent premature ventricular complexes (PVCs) and PVC-induced cardiomyopathy usually have recovery of left ventricular (LV) dysfunction postablation. The time course of recovery of LV function has not been described., Objective: To describe the time course and predictors of recovery from LV dysfunction after effective ablation of PVCs in patients with PVC-induced cardiomyopathy., Methods: In a consecutive series of 264 patients with frequent idiopathic PVCs referred for PVC ablation, LV dysfunction was present in 87 patients (mean ejection fraction 40%±10%). The PVC burden was reduced to<20% of the initial PVC burden in 75 patients. In these patients, echocardiography was repeated 3-4 months postablation. If LV function did not normalize after 3-4 months, a repeat echocardiogram was performed every 3 months until there was normalization or stabilization of LV function., Results: The ejection fraction normalized at a mean of 5±6 months postablation. The majority of patients (51 of 75, 68%) with PVC-induced LV dysfunction had a recovery of LV function within 4 months. In 24 (32%) patients, recovery of LV function took more than 4 months (mean 12±9 months; range 5-45 months). An epicardial origin of PVCs was more often present (13 of 24, 54%) in patients with delayed recovery of LV function than in patients with early recovery of LV function (2 of 51, 4%; P<.0001). The PVC-QRS width was significantly longer in patients with delayed recovery than in patients with recovery within 4 months (170±21 ms vs 159±16 ms; P = .02). In multivariate analysis, only an epicardial PVC origin was predictive of delayed recovery of LV function in patients with PVC-induced cardiomyopathy., Conclusions: PVC-induced cardiomyopathy resolves within 4 months of successful ablation in most patients. In about one-third of the patients, recovery is delayed and can take up to 45 months. An epicardial origin predicts delayed recovery of LV function., (Copyright © 2013 Heart Rhythm Society. All rights reserved.)

A 42-year-old woman with a history of cardiomyopathy and multiple ablation procedures for atrial tachycardia developed intra-atrial conduction block that mimicked atrioventricular (AV) nodal block during radiofrequency ablation at the cavotricuspid isthmus. She was treated with atrial pacing (from the coronary sinus), which overcame intra-atrial conduction block and resulted in AV nodal conduction., (© 2012 Wiley Periodicals, Inc.)

Background: Advancing age is a strong risk factor for the development of atrial fibrillation (AF). However, its impact on the left atrial (LA) substrate in patients is not well defined., Methods: Forty-seven patients underwent catheter ablation of persistent AF. Bipolar electrograms from the LA were recorded for voltage analysis. The AF cycle length was determined by averaging the cycle lengths of ten fibrillatory ("f") waves on lead V(1). The mean amplitude of the same ten "f" waves was also determined. The ablation strategy consisted of pulmonary vein isolation, electrogram guided, and linear ablation., Results: There was an inverse relationship between the mean bipolar LA voltage and age (R = -0.58; P < 0.0001). There was a direct relationship between AF cycle length and age (R = 0.74; P < 0.0001). There was an inverse relationship between amplitude of the "f" waves and age (R = -0.62; P < 0.0001). Areas of scar were found in 15 of the 47 patients (32%). AF cycle length was longer in patients with vs. those without scar (183 ± 20 vs. 151 ± 15 ms; P < 0.0001). Advancing age was the only predictor of LA scar (OR, 1.32; 95% CI, 1.11-1.58; P < 0.01). Forty patients (85%) remain arrhythmia-free without antiarrhythmic medications after a mean follow-up of 18 ± 10 months. Neither age nor LA scar was associated with outcome., Conclusions: In patients undergoing ablation of persistent AF, advancing age makes for a complex LA substrate that is characterized by areas of low voltage/scar, and yet is associated with a lower AF frequency. LA scar did not seem to impact outcome in this small study.

Purpose: This study aims to determine the impact of preprocedural imaging using computerized tomography (CT) or magnetic resonance imaging (MRI) with 3-D reconstruction on procedural efficiency, efficacy, complications and clinical outcome in patients who undergo radiofrequency catheter ablation (RFA) to eliminate atrial fibrillation (AF)., Methods: In this registry, a CT (n = 161) or MRI (n = 37) was obtained prior to RFA in 198 of 333 consecutive patients (age 61 ± 10 years) with paroxysmal (172) or persistent (161) AF. Antral pulmonary vein isolation was performed in all patients using an open-irrigation-tip catheter with a 3-D electroanatomical navigation system. Procedural and clinical outcomes were compared among patients who underwent RFA with and without preprocedural imaging., Results: The mean duration of the procedure (246 ± 47 vs. 242 ± 40 min, P = 0.55), fluoroscopy (47 ± 13 vs. 50 ± 10 min, P = 0.16), and total RF application (83 ± 27 vs. 78 ± 23 min, P = 0.17) were similar among patients who did and did not have preprocedural imaging. The likelihood of a complication also was similar (5/198 [3%] vs. 4/135 [3%], P = 1.0). A repeat ablation was performed in 95/198 (48%) and 61/135 (45%) of the patients who did and did not have imaging study, respectively (P = 0.62). At 22 ± 9 months, after a mean of 2 ± 1 procedures, 140/198 (71%) and 101/135 (75%) of the patients who did and did not have preprocedural imaging were in sinus rhythm (P = 0.4)., Conclusions: Preprocedural awareness of pulmonary venous and left atrial anatomy does not appear to have an effect on procedural efficiency or clinical outcomes in patients who undergo catheter ablation for AF.

Background: Intramural septal idiopathic ventricular arrhythmias have not been described systematically., Methods and Results: In a consecutive group of 93 patients with idiopathic ventricular arrhythmias referred for ablation, the site of origin of ventricular arrhythmias was assessed by activation mapping and pace-mapping. In 7 of 93 patients (8%), an intramural focus in the interventricular septum was identified. All ventricular arrhythmias arising intramurally had a left bundle-branch block morphology with inferior axis. The intramural focus was effectively ablated from both sides of the septum in 4 patients and from within the septum in 1 patient. The ablation procedure of an intramural focus near the His bundle failed in 2 of 7 patients. ECG and mapping characteristics of the patients with intramural septal ventricular arrhythmias differentiated intramural arrhythmias from other sites of origin., Conclusions: Idiopathic septal ventricular arrhythmias can originate from intramural foci. Activation mapping from within a perforator branch within the interventricular septum is helpful in identifying the site of origin of intramural septal arrhythmias. Ablation within the septum or from both sites of the septum may be required to eliminate the targeted arrhythmia.

Post-infarction arrhythmias are most often confined to scar tissue. Scar can be detected by delayed-enhanced cardiac magnetic resonance. The purpose of this study was to assess the feasibility of pre-procedural scar identification and intraprocedural real-time image registration with an electroanatomical map in 23 patients with previous infarction and ventricular arrhythmias (VAs). Registration accuracy and cardiac magnetic resonance/electroanatomical map correlations were assessed, and critical areas for VA were correlated with the presence of scar. With a positional registration error of 3.8 ± 0.8 mm, 86% of low-voltage points of the electroanatomical map projected onto the registered scar. The delayed-enhanced cardiac magnetic resonance-defined scar correlated with the area of low voltage (R = 0.82, p < 0.001). All sites critical to VAs projected on the registered scar. Selective identification and extraction of delayed-enhanced cardiac magnetic resonance defined scar followed by registration into a real-time mapping system are feasible and help to identify and display the arrhythmogenic substrate in post-infarction patients with VAs., (Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Frequent idiopathic premature ventricular complexes (PVCs) can result in a reversible form of cardiomyopathy. In this study, the determinants of PVC-induced left ventricular (LV) dysfunction were assessed., Methods: The subjects of this study were 241 consecutive patients (115 men [48%], mean age 48 ± 14 years) referred for ablation of frequent PVCs. One hundred eighty patients (75%) experienced palpitations and 61 (25%) did not. The PVC burden was determined by 24-hour Holter monitoring, and echocardiograms were performed to assess LV function. An LV ejection fraction of <50% was considered abnormal., Results: LV ejection fraction (mean 0.36 ± 0.09) was present in 76 of 241 patients (32%). There was a higher prevalence of males among the patients with PVC cardiomyopathy compared to patients with normal LV function (51/76 [67%] vs 64/165 [39%]; P <.0001). The mean PVC burden was significantly higher in patients with PVC cardiomyopathy than in patients with normal LV function (28% ± 12% vs 15% ± 13%; P <.0001). Among symptomatic patients, those with cardiomyopathy had a significantly longer duration of palpitations (135 ± 118 months) compared with patients with normal LV function (35 ± 52 months; P <.0001). The proportion of asymptomatic patients was significantly higher in the presence of cardiomyopathy (36/76, 47%) than in normal LV function (25/165, 15%; P <.0001). Symptom duration of 30 to 60 months, symptom duration >60 months, the absence of symptoms, and the PVC burden in asymptomatic patients were independent predictors of impaired LV function (adjusted odds ratio [95% confidence interval]: 4.0 [1.1-14.4], 20.1 [6.3-64.1], 13.1 [4.1-37.8], and 2.1 [1.2-3.6], respectively)., Conclusions: The duration of palpitations and the absence of symptoms are independently associated with PVC-induced cardiomyopathy., (Copyright © 2012 Heart Rhythm Society. All rights reserved.)

Introduction: Factors associated with cerebrovascular events (CVEs) after radiofrequency catheter ablation (RFA) of atrial fibrillation (AF) have not been well defined in elderly patients (≥65 years). The purpose of this study was to determine the prevalence and predictors of CVEs after RFA in patients with AF ≥65 years old, in comparison to patients <65 years, and with or without AF., Methods and Results: This study included 508 consecutive patients ≥65 years old (mean age: 70 ± 4 years), who underwent RFA for paroxysmal (297) or persistent (211) AF. A stratified group of 508 patients < 65 years old who underwent RFA for AF served as a control group. All patients were anticoagulated with warfarin for ≥3 months after RFA. A perioperative CVE (≤4 weeks after RFA) occurred in 0.8% and 1% of patients ≥65 and <65 years old, respectively (P = 1). Among the patients ≥65 years old who remained in sinus rhythm after RFA, warfarin was discontinued in 60% and 56% of the patients with a CHADS(2) score of 0 and ≥1, respectively. Paroxysmal AF, no history of CVE, and successful RFA were independent predictors of discontinuing warfarin. During a mean follow-up of 3 ± 2 years, a late CVE (>4 weeks after the RFA) occurred in 15 of 508 (3%) of patients ≥65 years old (1% per year) and in 5 of 508 (1%) patients <65 years old (0.3% per year, P = 0.03). Among patients ≥65 years old, age >75 years old (OR = 4.9, ±95% CI: 3.3-148.5, P = 0.001) was the only independent predictor of a CVE. Among patients <65 years old, body mass index was the only independent predictor of a late CVE (OR = 1.2, ±95% CI: 1.03-1.33, P = 0.02)., Conclusions: The risk of a periprocedural CVE after RFA of AF is similar among patients ≥65 and <65 years old. Late CVEs after RFA are more prevalent in older than younger patients with AF, and age >75 years old is the only independent predictor of late CVEs regardless of the rhythm, anticoagulation status, or the CHADS(2) score (Congestive heart failure, Hypertension, Age ≥ 75 years, Diabetes mellitus and prior Stroke or transient ischemic attack)., (© 2011 Wiley Periodicals, Inc.)

Objective: The objective was to determine the effect of radiofrequency catheter ablation (RFA) on progression of paroxysmal atrial fibrillation (AF)., Background: Progression to persistent AF may occur in up to 50% of patients with paroxysmal AF receiving pharmacological therapy. Hypertension, age, prior transient ischemic event, chronic obstructive pulmonary disease, and heart failure (HATCH score) have been identified as independent risk factors for progression of AF., Methods: RFA was performed in 504 patients (mean age: 58 ± 10 years) to eliminate paroxysmal AF. A repeat RFA procedure was performed in 193 patients (38%). Clinical variables predictive of outcome and their relation to progression of AF after RFA were assessed using multivariate analysis., Results: At a mean follow-up of 27 ± 12 months after RFA, 434/504 patients (86%) were in sinus rhythm; 49/504 patients (9.5%) continued to have paroxysmal AF; and 14 (3%) were in atrial flutter. Among the 504 patients, 7 (1.5%) progressed to persistent AF. In patients with recurrent AF after RFA, paroxysmal AF progressed to persistent AF in 7/56 (13%, P < 0.001). The progression rate of AF was 0.6% per year after RFA (P < 0.001 compared to 9% per year reported in pharmacologically treated patients). Age >75 years, duration of AF >10 years and diabetes were independent predictors of progression to persistent AF. The HATCH score was not significantly different between patients with paroxysmal AF who did and did not progress to persistent AF (0.7 ± 0.8 vs 1.0 ± 0.5, P = 0.3)., Conclusions: Compared to a historical control group of pharmacologically treated patients with paroxysmal AF, RFA appears to reduce the rate of progression of paroxysmal AF to persistent AF. Age, duration of AF, and diabetes are independent risk factors for progression to persistent AF after RFA., (© 2011 Wiley Periodicals, Inc.)

Objectives: The purpose of this study was to assess the prevalence of the re-entry circuit within the interventricular septum in post-infarction patients referred for ventricular tachycardia (VT) ablation., Background: Post-infarction ventricular tachycardia can involve the endocardial myocardium, the intramural myocardium, the epicardium, or the His Purkinje system., Methods: Among 74 consecutive patients with recurrent post-infarction VT, 33 patients (45%) were identified in whom the critical part of the VT involved the interventricular septum. A total of 206 VTs were induced in these 33 patients. In 46 of the 206 VTs, a critical component was identified in the interventricular septum. The critical isthmus of the re-entry circuit was identified by entrainment mapping, activation mapping, or pace-mapping., Results: In 32 of 46 VTs (70%), the critical component of the re-entry circuit was confined to the endocardium. In 9 of 46 VTs (20%), the critical component involved the Purkinje system, and in 5 of 46 VTs (11%), an intramural area was critical. Entrainment and/or pace-mapping helped to identify critical areas of endocardial VTs as well as VTs involving the Purkinje fibers, but neither of these mapping techniques localized intramural VTs. Electrocardiographic characteristics were specific for each of the septal locations. All VTs mapped to the interventricular septum were acutely successfully ablated. VTs recurred in 9 of 33 patients with septal VTs during a mean follow-up period of 40 ± 20 months., Conclusions: Post-infarction VT involving the interventricular septum can involve the endocardial muscle, Purkinje fibers, or intramural muscle fibers. Electrocardiographic characteristics differ depending on the type of tissue involved., (Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Prior studies have suggested that left atrial (LA) volume and frequency of atrial fibrillation (AF) are associated with suboptimal outcomes in patients undergoing catheter ablation of AF. However, the interaction of these factors and their relative impact on outcome are not clear., Methods: Seventy-nine consecutive patients underwent catheter ablation of persistent AF. LA volume was determined by echocardiography. Electrograms from the LA appendage (LAA), coronary sinus (CS), and lead V(1) were obtained before ablation, and the dominant frequency (DF) was determined by fast Fourier transformation. The ablation strategy consisted of pulmonary vein isolation, electrogram-guided, and linear ablation., Results: The mean LA volume indexed, LA voltage, and DF in the LAA were 48 ± 16 mL/m(2), 0.58 ± 0.20 mV, and 6.3 ± 0.8 Hz, respectively. There was a significant inverse correlation between LA volume and DF in the CS (P < 0.0001, R = -0.51). The mean LA amplitude also correlated with DF in the LAA (P = 0.0008, R = 0.37). In 38 patients (48%), AF terminated during catheter ablation. Sixty-six of the 79 patients (84%) are arrhythmia-free without antiarrhythmic drugs at a mean follow-up of 14 ± 7 months after the last procedure. Advancing age was associated with recurrence (odds ratio (OR), 1.2; 95% confidence interval (CI), 1.02 to 1.42; P = 0.02), and duration of radiofrequency energy delivery was associated with a favorable outcome (OR, 0.93; 95% CI, 0.86 to 0.99; P = 0.04)., Conclusion: Atrial enlargement is associated with a lower AF frequency. Age and RF duration seem to be better predictors of outcome than LA volume or AF frequency.

Background: Idiopathic epicardial ventricular arrhythmias can be targeted from the coronary venous system or the pericardial space, the endocardium, or the aortic sinus cusps., Objective: The purpose of this study was to analyze systematically the contribution of ablation at sites other than the epicardium to eliminate an arrhythmia originating in the epicardium., Methods: In a consecutive patient series of 33 patients (14 women, age 51 ± 14 years, ejection fraction 51% ± 9%) with epicardial ventricular arrhythmias, mapping and ablation was performed via the cardiac venous system/pericardial space, the aortic sinus cusp, and the left ventricular endocardium. An arrhythmia was defined as epicardial if the earliest onset of activation and a matching pace-map (≥10/12 leads) were identified in the epicardium., Results: In 12/33 patients (36%), either an endocardial approach alone (n = 3) or a combined endocardial/epicardial (n = 6), cusp/endocardial (n = 1), or cusp/epicardial (n = 2) approach was required to eliminate the ventricular arrhythmias. In 10 of 33 patients (30%), epicardial ablation alone was effective in eliminating epicardial ventricular arrhythmias. Ablation was ineffective due to failure to reach the site of origin with the ablation catheter in 5 of 33 patients (15%), the site of origin was too close to an epicardial artery or the phrenic nerve in 3 patients (6%), and power delivery was insufficient in 3 patients (9%)., Conclusion: About one-third of epicardial arrhythmias require ablation from sites other than the epicardium to eliminate the arrhythmia focus., (Copyright © 2011 Heart Rhythm Society. All rights reserved.)

Background: Although prior studies have described the anatomy of the mitral isthmus in patients undergoing left atrial (LA) ablation of atrial fibrillation (AF), none has examined the impact of isthmus anatomy on the likelihood of achieving conduction block., Objective: The purpose of this study was to identify morphologic characteristics of the mitral isthmus that may influence the acute efficacy of linear ablation at the mitral isthmus., Methods: Fifty-five patients (age 61 ± 10 years, 41 [75%] men, LA 46 ± 6 mm, ejection fraction 0.55 ± 0.11, AF duration 4 ± 3 years) underwent linear ablation at the mitral isthmus during an ablation procedure for persistent AF. Computed tomographic scan was performed before the procedure. The morphology of the mitral isthmus and its anatomic relationship to the adjacent vasculature were analyzed., Results: Complete block along the mitral isthmus was achieved in 35 (64%) of 55 patients, 23 (66%) of whom required radiofrequency ablation in the coronary sinus (CS). Patients with incomplete block were more likely to have a pouch at the isthmus (40% vs 9%; P = .01), a greater isthmus depth (8.1 ± 4.2 mm vs 5.7 ± 3.4 mm; P = .04), and a higher prevalence of an interposed circumflex artery between the CS and the mitral isthmus (60% vs 20%; P = .003) compared to patients with isthmus block. An interposed circumflex artery was the only independent predictor of incomplete conduction block at the mitral isthmus (odds ratio 4.9, 95% confidence interval 1.3-18.2; P = .02)., Conclusion: Preprocedural computed tomographic imaging identifies patients in whom linear ablation at the mitral isthmus is unlikely to be successful. Interposition of the circumflex artery between the mitral isthmus and the CS is associated with a lower probability of achieving complete mitral isthmus block., (Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Large-tip (10 mm) catheters (LTCs) and open-irrigation-tip catheters (OITCs), both capable of creating large lesions, are more effective than conventional catheters for cavotricuspid isthmus (CTI) ablation. However, it is not clear whether complete CTI block can be achieved more efficiently using an LTC or an OITC. The purpose of this study was to compare the efficiency of radiofrequency catheter ablation (RFA) of the CTI using LTC versus OITC to eliminate atrial flutter (AFL)., Methods and Results: Sixty consecutive patients (age = 62 ± 10 years) with typical AFL were randomized to undergo RFA of CTI using an LTC (10 mm) or an OITC. If complete CTI block was not achieved by ≤30 minutes of RFA, patients were allowed to cross over to ablation with the other catheter. A 3-dimensional electroanatomical mapping system was used for catheter navigation only with the OITC. The mean duration of RFA to achieve CTI block in 50% of the patients was 6.8 ± 2.2 minutes with an LTC and 11.7 ± 2.7 minutes with an OITC (P = 0.001). After 30 minutes of RFA, CTI block was achieved in 26/30 (87%) and 25/30 patients (83%) using an LTC and an OITC, respectively (P = 1.0). After crossover, CTI block was achieved in 4/5 (80%) and in 4/4 patients (100%) with an LTC and OITC, respectively (P = 1.0). LTC was associated with a lower volume of intravenous fluid administration (388 ± 365 mL versus 865 ± 451 mL, P = 0.0001) and a trend for shorter procedure duration (95 ± 31 minutes versus 114 ± 50 minutes, P = 0.09) than the OITC. At 6 ± 3 months, 30/30 patients (100%) in the LTC and 27/30 patients (90%) in the OITC groups remained free from AFL, respectively (P = 0.24). Except for one inconsequential steam-pop during RFA with the OITC, there were no complications., Conclusions: Complete CTI block is achieved more rapidly using an LTC than an OITC, and with a similar clinical efficacy. , (© 2011 Wiley Periodicals, Inc.)

Background: Cardiac tamponade (CT) is a possible complication of radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF). Although the incidence of CT is not higher when RFCA is performed with a therapeutic international normalized ratio (INR), outcomes of CT are unclear., Objective: We compared outcomes among patients with and without a therapeutic INR who developed CT as a complication of RFCA of AF., Methods: The subjects of this retrospective study were 40 consecutive patients who developed CT during RFCA of AF at 3 centers. We divided the patients into 2 groups: RFCA performed with INR < 2 (group 1) and INR ≥ 2 (group 2). There were 23 patients in group 1 and 17 patients in group 2., Results: Baseline clinical and procedure characteristics were not different between the 2 groups. Heparin was reversed by protamine in 83% and 94% of patients (P = .37), and warfarin was reversed by fresh frozen plasma or factor VIIa in 17% and 35% of patients (P = .27) in groups 1 and 2, respectively. All patients were successfully treated by percutaneous drainage, and none required surgical intervention. There were no significant differences in the amount of initial pericardial drainage (523 ± 349 ml vs. 409 ± 157 ml, P = .22) or the duration of drainage (P = .14) between the 2 groups. All patients survived to hospital discharge. Median length of hospital stay was 2 days longer in group 1 (P <.01)., Conclusion: Cardiac tamponade is not more severe or difficult to manage in the presence of therapeutic anticoagulation with warfarin in patients undergoing RFCA of AF., (Published by Elsevier Inc.)

Introduction: Up to 6% of patients experience complications after radiofrequency catheter ablation (RFA) of atrial fibrillation (AF). The purpose of this study is to determine the prevalence and predictors of periprocedural complications after RFA for AF., Methods and Results: The subjects were 1,295 consecutive patients (age = 60 ± 10 years) who underwent RFA (n = 1,642) for paroxysmal (53%) or persistent AF (47%) from January 2007 to January 2010. A complication occurred in 57 patients (3.5%); a vascular access complication in 31 (1.9%); pericardial tamponade in 20 (1.2%); a thromboembolic event in 4 (0.2%); deep venous thrombosis in 1 (<0.01%); and pulmonary vein stenosis in 1 patient (<0.01%). There were no procedure-related deaths. On multivariate analysis, female gender (OR = 2.27; ±95% CI: 1.31-2.57, P < 0.01) and procedures performed in July or August (OR = 2.10; ±95% CI: 1.16-3.80, P = 0.01) were independent predictors of any complication. For vascular complications, treatment with clopidogrel (OR = 4.40; ±95% CI: 1.43-13.53, P = 0.01), female gender (OR = 3.65; ±95% CI: 1.72-7.75, P < 0.01) and performing RFA in July or August (OR = 2.71; ±95% CI: 1.25-5.87, P = 0.01) were independent predictors. The only predictor of cardiac tamponade was prior RFA (OR = 3.32; ±95% CI: 0.95-11.61; P < 0.05)., Conclusion: Prevalence of perioperative complications for RFA of AF is 3.5% and vascular access complications constitute the majority. The need for clopidogrel therapy should be carefully considered prior to RFA. At teaching institutions close supervision should be exercised during vascular access early in the year. Improvements in ablation technology and elimination of the need for repeat procedures may decrease the risk of pericardial tamponade., (© 2011 Wiley Periodicals, Inc.)