Catheter-based Atrial Fibrillation Ablation Research Articles

Relation of Morbid Obesity and Female Gender to Risk of Procedural Complications in Patients Undergoing Atrial Fibrillation Ablation

Obese patients with atrial fibrillation (AF) are frequently treated with AF ablation. We sought to examine whether a body mass index (BMI) threshold exists beyond which the odds of experiencing a complication from AF ablation increases. All patients enrolled in the Vanderbilt AF Registry who underwent catheter-based AF ablation from May 1999 to February 2012 were included. Major complications were recorded. Morbid obesity was defined as a BMI >40 kg/m(2) and examined in multivariable analysis. A total of 35 complications (6.8%) occurred in 512 ablations. Morbidly obese patients experienced a greater rate of complications (6 of 42, 14.3%) than the nonmorbidly obese (29 of 470, 6.2%; p = 0.046). Using a discrete BMI cutoff, the odds of complications increased 3.1-fold in those with morbid obesity (odds ratio [OR] 3.1, 95% confidence interval [CI] 1.1 to 8.4, p = 0.03) and 2.1-fold for female gender (OR 2.1, 95% CI 1.04 to 4.38, p = 0.04). With BMI as a continuous variable, the odds of complications increased by 5% per 1 unit increase in BMI (OR 1.05, 95% CI 1.0 to 1.11, p = 0.05), and the increase for female gender was 2.2-fold (OR 2.2, 95% CI 1.1 to 4.6, p = 0.03). In conclusion, morbid obesity represents a BMI threshold above which the odds of complications with AF ablation increase significantly. The increase in complications appears to be driven primarily by events in women, suggesting that morbidly obese women are a special population when considering AF ablation.

Intracardiac Echocardiography during Catheter-Based Ablation of Atrial Fibrillation

Accurate delineation of the variable left atrial anatomy is of utmost importance during anatomically based ablation procedures for atrial fibrillation targeting the pulmonary veins and possibly other structures of the atria. Intracardiac echocardiography allows real-time visualisation of the left atrium and adjacent structures and thus facilitates precise guidance of catheter-based ablation of atrial fibrillation. In patients with abnormal anatomy of the atria and/or the interatrial septum, intracardiac ultrasound might be especially valuable to guide transseptal access. Software algorithms like CARTOSound (Biosense Webster, Diamond Bar, USA) offer the opportunity to reconstruct multiple two-dimensional ultrasound fans generated by intracardiac echocardiography to a three-dimensional object which can be merged to a computed tomography or magnetic resonance imaging reconstruction of the left atrium. Intracardiac ultrasound reduces dwell time of catheters in the left atrium, fluoroscopy, and procedural time and is invaluable concerning early identification of potential adverse events. The application of intracardiac echocardiography has the great capability to improve success rates of catheter-based ablation procedures.

Interatrial Electrical Dissociation After Catheter-Based Ablation for Atrial Fibrillation and Flutter

A 58-year-old man with hypertension and diabetes with recurrent persistent symptomatic atrial fibrillation resistant to sotalol-facilitated cardioversions was referred for ablation. Catheter-based radiofrequency ablation for persistent atrial fibrillation was performed, which consisted of isolation of all 4 pulmonic veins; linear ablations along the left atrial roof; an ablation line from the lateral mitral annulus to the left inferior vein; and ablation of areas with complex fractionated atrial electrograms along the posterior mitral annulus, anterior septum, and base of left atrial appendage. After these ablation lesions, the atrial fibrillation converted to a focal right atrial tachycardia, which was terminated by ablation in the inferior crista terminalis. The patient remained in sinus rhythm after the procedure for 2 weeks but returned with an incessant atrial tachycardia requiring repeat electrophysiological study. Electroanatomic mapping revealed earliest atrial activation in the proximal coronary sinus. Entrainment from the cavotricuspid isthmus returned long postpacing intervals. Postpacing interval identical to tachycardia cycle length was obtained with entrainment from the ostium of the coronary sinus. A linear ablation from the ostium of the coronary sinus to the inferior vena cava terminated tachycardia and rendered the patient noninducible for atrial arrhythmias. Atrial tachycardia recurred after 3 weeks. The patient's antiarrhythmic medication was switched from sotalol to …

Exposing Gaps in Linear Radiofrequency Lesions

The termination of atrial fibrillation (AF) by radiofrequency ablation in the left atrium is undeniable evidence that the pathophysiology underlying AF can be ameliorated. The cornerstone of this therapy, pulmonary vein isolation, can be achieved acutely in virtually 100% patients.1,2 Recurrent AF is the bane of this procedure, however, and is most commonly attributed to recovery of pulmonary vein conduction through the ablation lines.2 Return of conduction across ablation lines to the mitral isthmus and the left atrial roof contribute to postablation arrhythmias as well. Intensive investigation of sophisticated ablation systems have failed to yield consistently durable ablation lines. Efforts to map and eliminate conductive gaps at the time of ablation have not resolved this problem. Gaps in linear ablation lines for AF ablation are a reality of current clinical practice. As a result, the single procedure success rate for AF ablation is constrained. It appears that a major advance in ablation and/or mapping technologies is needed to improve the state of catheter ablation for AF. Article see p 279 Despite the clinical problems they produce, gaps within ablation lines represent fascinating examples of myocardial electrophysiology. A brief review is relevant to placing new studies in perspective. The animal model of the myocardial gap was introduced almost 100 years ago by Garrey3 to study fibrillatory conduction patterns over an isthmus of myocardial tissue. With the advent of linear surgical and catheter-based ablation for AF, the model has been used extensively to reveal the complex conduction behavior associated with discontinuous linear lesions.4–10 Direct experimentation has benefited from computer modeling to provide deeper insights into gap conduction.11,12 A description of gap conduction invokes all 3 determinants of myocardial impulse propagation: (1) passive tissue electric properties, (2) excitable membrane properties, and (3) …

Ablation of Atrial Fibrillation: Comparison of Catheter-Based Techniques and the Cox-Maze III Operation

Catheter-based ablation is often recommended for treatment of atrial fibrillation (AF), but there are no data that directly compare late results to those of the Cox-Maze procedure. Although catheter ablation avoids operation, lack of reliable transmurality may reduce effectiveness. We compared clinical outcomes of the cut-and-sew Cox-Maze procedure with catheter ablation. Between January 1993 and October 2007, 97 patients aged 25 to 80 years underwent an isolated cut-and-sew Cox-Maze procedure. Patients were matched 1:2 according to age, sex, and AF type, with 194 patients undergoing catheter-based ablation for lone AF. At last follow-up, 82% of patients who underwent the Cox-Maze procedure were free of AF and had stopped taking antiarrhythmic medications compared with 55% of patients who underwent ablation (p<0.001). When analyzed as a time-related event, freedom from recurrent AF was 87% 5 years after the Cox-Maze procedure compared with 28% after catheter ablation (p<0.001). Late warfarin anticoagulation was required in 12% of patients who underwent the Cox-Maze procedure compared with 55% of patients who underwent ablation (p<0.001), and use of antiarrhythmic medications during follow-up was significantly higher in patients who underwent ablation (68% versus 15%, p<0.001). Forty-one patients (24%) required repeated ablation procedure and 9 required a second repeated ablation. Compared with catheter-based ablation, the Cox-Maze procedure results in greater freedom from AF and less medical treatment with antiarrhythmic drugs and warfarin anticoagulation during follow-up.

Meta-Analysis of Obstructive Sleep Apnea as Predictor of Atrial Fibrillation Recurrence After Catheter Ablation

The association between obstructive sleep apnea (OSA) and atrial fibrillation (AF) is strong and is now well established. However, studies on the role of OSA on AF recurrence after catheter ablation have yielded conflicting results. The aim of the present study was to investigate the role of OSA on AF recurrence after catheter-based pulmonary vein isolation. We performed a data search on the PubMed, Web of Science, and the Cochrane databases for studies published by August 2010. In addition, we manually searched the conference proceedings of the European Society of Cardiology, American College of Cardiology, and American Heart Association for related abstracts. After the initial search returned 402 reports, we identified 6 studies with a total of 3,995 patients that met our inclusion criteria. Overall, patients with OSA have a 25% greater risk of AF recurrence after catheter ablation than those without OSA (risk ratio 1.25, 95% confidence interval 1.08 to 1.45, p = 0.003). Subgroup analysis showed that OSA diagnosed using polysomnography is a strong predictor of AF recurrence (risk ratio 1.40, 95% confidence interval 1.16 to 1.68, p = 0.0004) but not when OSA was diagnosed using the Berlin questionnaire (risk ratio 1.07, 95% confidence interval 0.91 to 1.27, p = 0.39). In conclusion, patients with OSA have significantly greater AF recurrence rates after pulmonary vein isolation. In addition to other factors, a diagnosis of OSA merits special consideration when evaluating patients for catheter-based AF ablation.

Time-resolved mr venography pre catheter-based ablation for atrial fibrillation

Objective The purpose of this study was to evaluate Time-resolved MR venography (TR-MRV) of the pulmonary venous circulation using the time-resolved angiography with interleaved stochastic trajectories (TWIST) method of time-resolved MRA (TR-MRA) and compare it with the more commonly used conventional Contrast enhanced magnetic resonance angiography (CE-MRA) approach in atrial fibrillation patients referred for pre-ablation pulmonary vein mapping. Background Catheter-based ablation of the pulmonary veins prevents recurrence of atrial fibrillation in 70-80% of patients during the first year of follow-up 1,2 . CE-MRA depicts the left atrium and pulmonary veins with high spatial resolution, enabling accurate measurement of pulmonary vein ostia to be made with depiction of their relationship to other structures. 1,3 Conventional CE-MRA however requires timing of contrast enhancement and produces images with overlap of venous and arterial structures, potentially obscuring pulmonary vein ostia. TR-MRA is an alternative to conventional CE-MRA and has been used successfully in other vascular territories. 4 Such an approach may be particularly advantageous in the pulmonary circulation with its rapid arteriovenous transit time, allowing acquisition of pure pulmonary venous phase images with a simpler imaging protocol. Material and methods 26 patients (15 males; age 60.0 ± 12.7y) referred for preablation pulmonary vein mapping underwent both conventional CE-MRA and TR-MRV with TWIST. Imaging was performed on a 1.5 Tesla (MAGNETOM Avanto, Siemens Healthcare) MRI scanner. Source partition and MIP images were evaluated. Quantitative Analysis: Pulmonary vein ostium orthogonal dimensions were measured using double oblique multiplanar reformatting. Qualitative Analysis: For qualitative analysis, both source partition images and MIP images were assessed by two observers. Pulmonary vein conspicuity was scored on a scale of 1-4 (1=poor, 2=fair, 3=good, 4=excellent). The number of pulmonary veins (3 veins= common ostium, 4 veins = normal, 5 veins=accessory vein) was recorded.

Atrial Fibrillation Ablation

Due to the toxicities and limited efficacy of medical therapy, nonpharmacologic strategies for the management of atrial fibrillation in patients with heart failure are often employed. This chapter describes the techniques, clinical indications, and the devices utilized to perform catheter-based ablation of atrial fibrillation, including pulmonary vein isolation and left atrial substrate ablation.

A shock in time saves ablation?

This editorial refers to ‘Atrial defibrillation threshold as a novel predictor of clinical outcome of catheter ablation for persistent atrial fibrillation’ by Y. Komatsu et al ., on page 213. Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice and is associated with substantial mortality and morbidity due to stroke and heart failure. In the last 10 years, catheter-based AF ablation aiming at isolation of arrhythmogenic pulmonary venous triggers and atrial substrate of AF has evolved as an important treatment option for patients with paroxysmal AF because of its high efficacy and reasonable safety. In fact, AF recurrence-free survival during 12-month follow-up after a single ablation procedure has been reported to be as high as 85%.1 In a recent meta-analysis of 63 studies by Calkins et al ., major complications of AF ablation, including pulmonary vein stenosis, cardiac tamponade, pericardial effusion, peri-procedural stroke, and periprocedural transient ischaemic attack, occurred …

Prevention of Thromboembolic Stroke in Patients Undergoing Catheter‐Based Ablation for Atrial Fibrillation: Has It Been Optimized?

Journal of Cardiovascular ElectrophysiologyVolume 20, Issue 12 p. 1364-1365 Prevention of Thromboembolic Stroke in Patients Undergoing Catheter-Based Ablation for Atrial Fibrillation: Has It Been Optimized? YONG-MEI CHA M.D., YONG-MEI CHA M.D. Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, USASearch for more papers by this authorBRIAN D. POWELL M.D., BRIAN D. POWELL M.D. Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, USASearch for more papers by this authorSTEPHEN C. HAMMILL M.D., STEPHEN C. HAMMILL M.D. Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, USASearch for more papers by this author YONG-MEI CHA M.D., YONG-MEI CHA M.D. Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, USASearch for more papers by this authorBRIAN D. POWELL M.D., BRIAN D. POWELL M.D. Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, USASearch for more papers by this authorSTEPHEN C. HAMMILL M.D., STEPHEN C. HAMMILL M.D. Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, USASearch for more papers by this author First published: 23 November 2009 https://doi.org/10.1111/j.1540-8167.2009.01559.xCitations: 1 Address for correspondence: Yong-Mei Cha, M.D., Mary-Brigh Room 4523, St. Mary's Hospital, Rochester, MN 55905, USA. Fax: 507-255-2550; E-mail: [email protected] J Cardiovasc Electrophysiol, Vol. 20, pp. 1364–1365, December 2009. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article.Citing Literature Volume20, Issue12December 2009Pages 1364-1365 RelatedInformation

Preablation Assessment for the Left Atrium: Comparison of ECG-gated Cardiac CT with Echocardiography

Evaluate the role of two-dimensional echocardiography and electrocardiographically (ECG)-gated contrast-enhanced multislice computed tomographic (MSCT) cardiac imaging to assess cardiac anatomy, specifically pulmonary venous anatomy and left atrial thrombus, in a selected group of patients before catheter-based atrial fibrillation ablation. Left atrial anatomy and associated findings in 34 consecutive patients scheduled for electrophysiologic testing who underwent both echocardiography and ECG-gated 16-slice MSCT cardiac imaging were retrospectively compared. Results from two-dimensional transthoracic echocardiography (TTE), cardiac MSCT, electrophysiologic study (EPS), and transesophageal echocardiography (TEE) (when performed) were taken from the official medical record without prior knowledge of this study when interpretation was rendered for clinical use. Electronic record review included: presence of left atrial thrombus (defined as constant filling defect on at least two echocardiographic views or filling defect on computed tomography) and location, pulmonary venous anatomy, and other cardiac, mediastinal, or pulmonary abnormalities. Left atrial thrombus was identified by cardiac MSCT alone in five patients (15%). Pulmonary venous variants were identified with cardiac MSCT in two patients (6%). Both MSCT and echocardiography were normal in 17 subjects (79%). Echocardiography was better at identifying associated valvular abnormalities that were seen in 10 patients (29%). Cardiac MSCT angiography alone identified other cardiac and noncardiac abnormalities, including suspicious pulmonary malignancy, mediastinal adenopathy, and coronary stenosis in 15 patients (44%). Echocardiography and cardiac MSCT angiography often provide complimentary findings during the preprocedural evaluation for patients with atrial fibrillation requiring ablation. Cardiac MSCT may provide significant additional information about the left atrium, mediastinum, coronary circulation, and visualized lung fields. Based on this study, we would advise that patients considered for radiofrequency ablation for uncontrolled right atrial fibrillation have both echocardiography and ECG-gated contrast-enhanced cardiac MSCT performed as part of the preprocedure evaluation.

Life‐Threatening Left Atrial Wall Hematoma Secondary to a Pulmonary Vein Laceration: An Unusual Complication of Catheter Ablation for Atrial Fibrillation

Several complications may occur during catheter ablation for atrial fibrillation (AF). We report an unusual case of left atrial wall hematoma without pericardial effusion secondary to a right inferior pulmonary vein (PV) laceration. The use of real-time transesophageal echocardiography (TEE) during the procedure can be useful for early detection of this potentially lethal complication. A 49-year-old woman was referred for AF ablation. Her past medical history included severe systemic lupus with chronic renal failure treated with immunosuppressive and steroid drugs. A TEE-guided hybrid approach for AF ablation was performed with circular PV lesions and antrum and ostial electrical isolation. While performing the mitral isthmus line, the TEE showed a growing hematoma at the posterior left atrial wall. Rapidly, left atrium (LA) collapse associated with hemodynamic compromise occurred without any pericardial effusion. The patient was brought to the operating room. No pericardial effusion was seen at the time of surgery. The cardiac exploration showed a right inferior PV laceration. The visual inspection of the LA revealed thin and friable tissue. The patient survived. After 25 months of follow-up, she is still free from symptomatic AF. Left atrial wall hematoma without pericardial effusion is a rare and life-threatening complication after catheter-based AF ablation. TEE is a valuable monitoring tool to accurately diagnose several acute complications and prompt rapid intervention.

Real-time Imaging in Left Atrial Mapping and Ablation

The catheter-based ablation of atrial fibrillation has been transformed greatly by the introduction of new technologies and techniques. This article describes the major advancements in real-time navigation systems, including both 3D mapping systems and 2D echocardiography. The relative strengths and weakness of these systems and their accuracy on clinical outcome is also discussed. Finally, we explore current and emerging MRI technologies that will allow the assessment of disease progression and enable procedural planning.

Computed Tomography‐Fluoroscopy Image Integration‐Guided Catheter Ablation of Atrial Fibrillation

This study examines the feasibility of atrial fibrillation (AF) ablation using registered three-dimensional computed tomography (CT) images of the left atrium with fluoroscopy. A total of 50 consecutive patients with symptomatic AF refractory to medical therapy (32 paroxysmal, 18 persistent, age 55 +/- 10 years) were randomized to undergo a catheter-based AF ablation procedure with or without the CT-fluoroscopy guidance system. All patients underwent preprocedural contrast-enhanced CT imaging and segmentation of the left atrium. For the CT-fluoroscopy group, circumferential lesions encompassing the pulmonary vein (PV) antrum and linear lesions along the roof of the left atrium between the superior PVs and the mitral isthmus were created on the CT image, which was registered with real-time fluoroscopy. The registered images were then used to navigate the ablation catheters to the sites of planned ablation. After the ablation sites were completed, any remaining PV potentials were isolated with electrophysiological guidance. In the control patients, the same technique was performed without using the CT-fluoro guidance system. CT scans were accurately registered to fluoroscopic images with minimal manual correction. Operators could navigate catheters on the registered images to preplanned, extraostial sites for ablation. CT-fluoroscopy guidance decreased procedure duration and fluoro times (P < 0.05). At a mean follow-up of 9 +/- 2 months, 21 patients (84%) in the CT-fluoro guidance group and 16 patients (64%) in the control group have had no recurrence of AF. CT-fluoroscopic-guided left atrial ablation is feasible and allows appropriate catheter manipulation in the left atrium.

Relationship of the esophagus and aorta to the left atrium and pulmonary veins: Implications for catheter ablation of atrial fibrillation

A potential complication during ablation of atrial fibrillation (AF) is damage to adjacent structures such as the esophagus and aorta. Fatal atrio-esophageal fistulas have developed after surgery- or catheter-based AF ablation procedures. The purpose of this study was to analyze multidetector computed tomography (MDCT) angiographic images to determine the anatomic relationship of the aorta and esophagus to the left atrium (LA). Sixty-five subjects underwent CT imaging using a 16-slice MDCT scanner: 24 with paroxysmal AF, 21 with chronic AF, and 20 "control" subjects without a history of AF. Measurements assessed included LA diameters, width of the esophagus and aorta in contact with the posterior LA wall, and distance from the esophagus to the four pulmonary veins (PVs), spine, and LA endocardium. Mean LA diameters were significantly larger in patients with AF vs the control group (P = .003 for anteroposterior diameter; P = .009 for transverse diameter). The anterior aspect of the esophagus was directly apposed to the LA in all cases (contact width 18.9 +/- 4.4 mm). The position of the esophagus varied in the posterior mediastinum but on average was closer to the ostia of the left PVs (P = .0001). The descending aorta was in contact with the LA and/or left PVs in 50 of 65 subjects. The esophagus was closer to the spine in the chronic AF vs control group (P = .007), likely due to increased LA dimension. In addition to its ability to assess PV anatomy, preprocedural MDCT imaging can investigate the variable relationship of adjacent structures, such as the esophagus and aorta to the LA and PVs.

PII: S0003-4975(99)01222-9

The treatment options available for chronic atrial fibrillation continue to evolve in parallel with our understanding of the underlying pathophysiologic and electrophysiologic mechanisms of this complex arrhythmia. Evidence continues to accumulate that the arrhythmia atrial fibrillation is a constellation of electrophysiologic abnormalities, with a spectrum of complexity based on the multiciplicity of reentrant circuits, the relationship of circuit(s) to normal anatomic structures, and the relationship of circuit(s) to pathophysiological conditions (eg, valvular heart disease). Recent advances in the catheter-based ablation of atrial fibrillation with a predominant site of origin in one or more pulmonary veins substantiate the concept of a focal origin of fibrillation, for example. It is important to recognize that this focal concept differs from the “multiple reentrant circuits, independent of anatomic structures” concept that developed based on the extensive work on atrial fibrillation at Washington Universityunder Boineau and Cox. It now appears that both concepts are correct, as representative components of a spectrum of arrhythmias known as atrial fibrillation.