Andre d'Avila

Feasibility and Safety of Dabigatran Versus Warfarin for Periprocedural Anticoagulation in Patients Undergoing Radiofrequency Ablation for Atrial Fibrillation Results From a Multicenter Prospective Registry

OBJECTIVES The purpose of this study was to evaluate the feasibility and safety of periprocedural dabigatran during atrial fibrillation (AF) ablation. BACKGROUND AF ablation requires optimal periprocedural anticoagulation for minimizing bleeding and thromboembolic complications. The safety and efficacy of dabigatran as a periprocedural anticoagulant for AF ablation are unknown. METHODS We performed a multicenter, observational study from a prospective registry including all consecutive patients undergoing AF ablation in 8 high-volume centers in the United States. All patients receiving dabigatran therapy who underwent AF ablation on periprocedural dabigatran, with the dose held on the morning of the procedure, were matched by age, sex, and type of AF with an equal number of patients undergoing AF ablation with uninterrupted warfarin therapy over the same period. RESULTS A total of 290 patients, including 145 taking periprocedural dabigatran and an equal number of matched patients taking uninterrupted periprocedural warfarin, were included in the study. The mean age was 60 years with 79% being male and 57% having paroxysmal AF. Both groups had a similar CHADS(2) score, left atrial size, and left ventricular ejection fraction. Three thromboembolic complications (2.1%) occurred in the dabigatran group compared with none in the warfarin group (p = 0.25). The dabigatran group had a significantly higher major bleeding rate (6% vs. 1%; p = 0.019), total bleeding rate (14% vs. 6%; p = 0.031), and composite of bleeding and thromboembolic complications (16% vs. 6%; p = 0.009) compared with the warfarin group. Dabigatran use was confirmed as an independent predictor of bleeding or thromboembolic complications (odds ratio: 2.76, 95% confidence interval: 1.22 to 6.25; p = 0.01) on multivariate regression analysis. CONCLUSIONS In patients undergoing AF ablation, periprocedural dabigatran use significantly increases the risk of bleeding or thromboembolic complications compared with uninterrupted warfarin therapy.

2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation

During the past three decades, catheter and surgical ablation of atrial fibrillation (AF) have evolved from investigational procedures to their current role as effective treatment options for patients with AF. Surgical ablation of AF, using either standard, minimally invasive, or hybrid techniques, is available in most major hospitals throughout the world. Catheter ablation of AF is even more widely available, and is now the most commonly performed catheter ablation procedure. In 2007, an initial Consensus Statement on Catheter and Surgical AF Ablation was developed as a joint effort of the Heart Rhythm Society (HRS), the European Heart Rhythm Association (EHRA), and the European Cardiac Arrhythmia Society (ECAS).1 The 2007 document was also developed in collaboration with the Society of Thoracic Surgeons (STS) and the American College of Cardiology (ACC). This Consensus Statement on Catheter and Surgical AF Ablation was rewritten in 2012 to reflect the many advances in AF ablation that had occurred in the interim.2 The rate of advancement in the tools, techniques, and outcomes of AF ablation continue to increase as enormous research efforts are focused on the mechanisms, outcomes, and treatment of AF. For this reason, the HRS initiated an effort to rewrite and update this Consensus Statement. Reflecting both the worldwide importance of AF, as well as the worldwide performance of AF ablation, this document is the result of a joint partnership between the HRS, EHRA, ECAS, the Asia Pacific Heart Rhythm Society (APHRS), and the Latin American Society of Cardiac Stimulation and Electrophysiology (Sociedad Latinoamericana de Estimulacion Cardiaca y Electrofisiologia [SOLAECE]). The purpose of this 2017 Consensus Statement is to provide a state-of-the-art review of the field of catheter and surgical ablation of AF and to report the findings of a writing group, convened by these five international societies. The writing group is charged with defining the indications, techniques, and outcomes of AF ablation procedures. Included within this document are recommendations pertinent to the design of clinical trials in the field of AF ablation and the reporting of outcomes, including definitions relevant to this topic. The writing group is composed of 60 experts representing 11 organizations: HRS, EHRA, ECAS, APHRS, SOLAECE, STS, ACC, American Heart Association (AHA), Canadian Heart Rhythm Society (CHRS), Japanese Heart Rhythm Society (JHRS), and Brazilian Society of Cardiac Arrhythmias (Sociedade Brasileira de Arritmias Cardiacas [SOBRAC]). All the members of the writing group, as well as peer reviewers of the document, have provided disclosure statements for all relationships that might be perceived as real or potential conflicts of interest. All author and peer reviewer disclosure information is provided in Appendix A and Appendix B. In writing a consensus document, it is recognized that consensus does not mean that there was complete agreement among all the writing group members. Surveys of the entire writing group were used to identify areas of consensus concerning performance of AF ablation procedures and to develop recommendations concerning the indications for catheter and surgical AF ablation. These recommendations were systematically balloted by the 60 writing group members and were approved by a minimum of 80% of these members. The recommendations were also subject to a 1-month public comment period. Each partnering and collaborating organization then officially reviewed, commented on, edited, and endorsed the final document and recommendations. The grading system for indication of class of evidence level was adapted based on that used by the ACC and the AHA.3,4 It is important to state, however, that this document is not a guideline. The indications for catheter and surgical ablation of AF, as well as recommendations for procedure performance, are presented with a Class and Level of Evidence (LOE) to be consistent with what the reader is familiar with seeing in guideline statements. A Class I recommendation means that the benefits of the AF ablation procedure markedly exceed the risks, and that AF ablation should be performed; a Class IIa recommendation means that the benefits of an AF ablation procedure exceed the risks, and that it is reasonable to perform AF ablation; a Class IIb recommendation means that the benefit of AF ablation is greater or equal to the risks, and that AF ablation may be considered; and a Class III recommendation means that AF ablation is of no proven benefit and is not recommended. The writing group reviewed and ranked evidence supporting current recommendations with the weight of evidence ranked as Level A if the data were derived from high-quality evidence from more than one randomized clinical trial, meta-analyses of high-quality randomized clinical trials, or one or more randomized clinical trials corroborated by high-quality registry studies. The writing group ranked available evidence as Level B-R when there was moderate-quality evidence from one or more randomized clinical trials, or meta-analyses of moderate-quality randomized clinical trials. Level B-NR was used to denote moderate-quality evidence from one or more well-designed, well-executed nonrandomized studies, observational studies, or registry studies. This designation was also used to denote moderate-quality evidence from meta-analyses of such studies. Evidence was ranked as Level C-LD when the primary source of the recommendation was randomized or nonrandomized observational or registry studies with limitations of design or execution, meta-analyses of such studies, or physiological or mechanistic studies of human subjects. Level C-EO was defined as expert opinion based on the clinical experience of the writing group. Despite a large number of authors, the participation of several societies and professional organizations, and the attempts of the group to reflect the current knowledge in the field adequately, this document is not intended as a guideline. Rather, the group would like to refer to the current guidelines on AF management for the purpose of guiding overall AF management strategies.5,6 This consensus document is specifically focused on catheter and surgical ablation of AF, and summarizes the opinion of the writing group members based on an extensive literature review as well as their own experience. It is directed to all health care professionals who are involved in the care of patients with AF, particularly those who are caring for patients who are undergoing, or are being considered for, catheter or surgical ablation procedures for AF, and those involved in research in the field of AF ablation. This statement is not intended to recommend or promote catheter or surgical ablation of AF. Rather, the ultimate judgment regarding care of a particular patient must be made by the health care provider and the patient in light of all the circumstances presented by that patient. The main objective of this document is to improve patient care by providing a foundation of knowledge for those involved with catheter ablation of AF. A second major objective is to provide recommendations for designing clinical trials and reporting outcomes of clinical trials of AF ablation. It is recognized that this field continues to evolve rapidly. As this document was being prepared, further clinical trials of catheter and surgical ablation of AF were under way.

Esophageal Injury and Temperature Monitoring During Atrial Fibrillation Ablation

Background— It is common practice to empirically limit the radiofrequency (RF) power when ablating the posterior left atrium during atrial fibrillation ablation to avoid thermal injury to the esophagus. The objective of this study was to determine whether RF energy delivery limited by luminal esophageal temperature (LET) monitoring is associated with a reduction in esophageal injury compared with a strategy of RF power limitation alone. Methods and Results— Eighty-one consecutive patients who underwent atrial fibrillation ablation followed by esophageal endoscopy were included in this observational study. All patients underwent extraostial electric pulmonary vein isolation by using an electroanatomic mapping system and irrigated RF ablation. All RF applications on the posterior left atrium were limited to 35 W. A commercially available, single-thermocouple esophageal probe was used to monitor LET in a subset of patients (n=67). In these cases, applications were promptly interrupted when LET was ≥38.5°C; further applications were performed at reduced power to obtain a LET <38.5°C. Esophageal endoscopy was performed 1 to 3 days after the procedure. Ablation-related esophageal ulcerations were identified in 9 of 81 (11%) patients. All patients were asymptomatic. Of these 81 patients, LET monitoring during ablation occurred in 67 (83%) of patients. Esophageal injury was observed more frequently (36% versus 6%, P<0.006) in the group without LET monitoring. Conclusions— These data suggest that LET monitoring may be associated with a reduction in esophageal injury compared with power limitation alone.

Esophageal Injury and Temperature Monitoring During Atrial Fibrillation AblationCLINICAL PERSPECTIVE

Background— It is common practice to empirically limit the radiofrequency (RF) power when ablating the posterior left atrium during atrial fibrillation ablation to avoid thermal injury to the esophagus. The objective of this study was to determine whether RF energy delivery limited by luminal esophageal temperature (LET) monitoring is associated with a reduction in esophageal injury compared with a strategy of RF power limitation alone. Methods and Results— Eighty-one consecutive patients who underwent atrial fibrillation ablation followed by esophageal endoscopy were included in this observational study. All patients underwent extraostial electric pulmonary vein isolation by using an electroanatomic mapping system and irrigated RF ablation. All RF applications on the posterior left atrium were limited to 35 W. A commercially available, single-thermocouple esophageal probe was used to monitor LET in a subset of patients (n=67). In these cases, applications were promptly interrupted when LET was ≥38.5°C; further applications were performed at reduced power to obtain a LET <38.5°C. Esophageal endoscopy was performed 1 to 3 days after the procedure. Ablation-related esophageal ulcerations were identified in 9 of 81 (11%) patients. All patients were asymptomatic. Of these 81 patients, LET monitoring during ablation occurred in 67 (83%) of patients. Esophageal injury was observed more frequently (36% versus 6%, P <0.006) in the group without LET monitoring. Conclusions— These data suggest that LET monitoring may be associated with a reduction in esophageal injury compared with power limitation alone. Received March 20, 2008; accepted May 30, 2008.

The esophageal effects of cryoenergy during cryoablation for atrial fibrillation.

BACKGROUND Cryoenergy is being increasingly used for atrial fibrillation (AF) ablation, but the thermal effect of cryoenergy on the esophagus remains undefined. OBJECTIVE This study examines the esophageal effects of cryoenergy used during AF ablation. METHODS Catheter ablation was performed using a cryoballoon catheter in 67 AF patients (Cryoballoon group), and a spot cryocatheter to complete irrigated radiofrequency lesion sets at segments in close proximity to the esophagus in 7 AF patients (Cryo-Focal group). A temperature probe monitored the luminal esophageal temperature (LET) in all patients; LET changes did not guide therapy. Post-procedural endoscopy was performed on 35 of 67 (52%) Cryoballoon and all Cryo-Focal patients. RESULTS Significant LET decreases (>1 degrees C) occurred in 62 of 67 (93%) Cryoballoon patients. LET continued to decrease after termination of cryoablation before recovering to normal. Temperature decreases were more pronounced during ablation at the inferior (3.1 degrees C) than superior pulmonary veins (1.5 degrees C); the lowest observed temperature was 0 degrees C. Post-procedural endoscopy showed esophageal ulcerations in 6 of 35 (17%) patients. There were no atrial-esophageal fistulas, and all ulcers had healed on follow-up endoscopy. Patients with and without ulceration differed with respect to mean LET nadir, cumulative LET decrease, and number of LETs <30 degrees C. In the Cryo-Focal group, 6 +/- 2 spot cryolesions per patient resulted in 1.3 +/- 1 LET decreases per patient, and an absolute nadir of 32.5 degrees C. CONCLUSION Cryoballoon ablation can cause significant LET decreases, resulting in reversible esophageal ulcerations in 17% of patients. No ulcerations occurred with adjunctive spot cryoablation at regions near the esophagus during radiofrequency ablation procedures.

Catheter ablation of atrial fibrillation without the use of fluoroscopy

BACKGROUND In performing catheter ablation of paroxysmal atrial fibrillation (PAF), the advent of electroanatomical mapping (EAM) has significantly reduced fluoroscopy time. Recent advances in the ability of EAM systems to simultaneously visualize multiple catheters have allowed some operators to perform certain procedures, such as catheter ablation of supraventricular tachycardias, with zero fluoroscopy use. OBJECTIVE The purpose of this study was to evaluate the feasibility and safety of pulmonary vein (PV) isolation with zero fluoroscopy use, using a combination of three-dimensional EAM and intracardiac echocardiography (ICE). METHODS Using the NavX EAM system, the right atrial (RA) and coronary sinus (CS) geometries were created without fluoroscopy. Fluoroless transseptal puncture was performed under ICE guidance. Using a deflectable sheath and a multipolar catheter, the left atrial (LA) and PV anatomies were rendered and, in select cases, integrated with a three-dimensional computed tomography (CT) image. Irrigated radiofrequency ablation was performed to encircle each pair of ipsilateral PVs. RESULTS This series included 20 consecutive PAF patients. RA/CS mapping required 5.5 ± 2.6 minutes. In all patients, single (n = 18) or dual (n = 2) transseptal access was successfully achieved. The LA-PV anatomy was rendered using either a circular (14 patients) or penta-array (six patients) catheter in 22 ± 10 minutes; CT image integration was used in 11 patients. Using 49 ± 18 ablation lesions/patient, electrical isolation was achieved in 38/39 ipsilateral PV isolating lesion sets (97%). The procedure time was 244 ± 75 minutes. There were no complications. CONCLUSION Completely fluoroless catheter ablation of paroxysmal AF is safely feasible using a combination of ICE and EAM.

Activation and Entrainment Mapping of Hemodynamically Unstable Ventricular Tachycardia Using a Percutaneous Left Ventricular Assist Device

OBJECTIVES Our goal was to investigate the effects of percutaneous left ventricular assist device (pLVAD) support during catheter ablation of unstable ventricular tachycardia (VT). BACKGROUND Mechanical cardiac support during ablation of unstable VT is being increasingly used, but there is little available information on the potential hemodynamic benefits. METHODS Twenty-three consecutive procedures in 22 patients (ischemic, n = 11) with structural heart disease and hemodynamically unstable VT were performed with either pLVAD support (n = 10) or no pLVAD support (intra-aortic balloon pump counterpulsation, n = 6; no support, n = 7). Procedural monitoring included vital signs, left atrial pressure, arterial blood pressure, cerebral perfusion/oximetry, VT characteristics, and ablation outcomes. RESULTS The pLVAD group was maintained in VT significantly longer than the non-pLVAD group (66.7 min vs. 27.5 min; p = 0.03) and required fewer early terminations of sustained VT for hemodynamic instability (1.0 vs. 4.0; p = 0.001). More patients in the pLVAD group had at least 1 VT termination during ablation than non-pLVAD patients (9 of 10 [90%] vs. 5 of 13 [38%]; p = 0.03). There were no differences between groups in duration of cerebral deoxygenation, hypotension or perioperative changes in left atrial pressure, brain natriuretic peptide levels, lactic acid, or renal function. CONCLUSIONS In patients with scar-related VT undergoing catheter ablation, pLVAD support was able to safely maintain end-organ perfusion despite extended periods of hemodynamically unstable VT. Randomized studies are necessary to determine whether this enhanced ability to perform entrainment and activation mapping will translate into a higher rate of clinical success.

Visual balloon-guided point-by-point ablation: reliable, reproducible, and persistent pulmonary vein isolation.

Background—While conceptually straightforward, placing point-to-point contiguous radiofrequency lesions to achieve pulmonary vein isolation (PVI) is technically challenging in patients with paroxysmal atrial fibrillation. Furthermore, chronic efficacy is limited by late PV reconnections. A novel compliant balloon ablation catheter able to deliver visually guided short arcs/spots of laser energy was tested in initial preclinical and clinical cases to determine if visual guidance could predict reliable and persistent PVI. Methods and Results—This study consisted of (1) an experimental porcine phase with both acute (n=15 pigs) and 4-week chronic (n=10) data and (2) a single-center clinical feasibility phase (n=27 patients with paroxysmal atrial fibrillation), again with acute and 3-month chronic data. Under endoscopic guidance, point-by-point perivenous ablation was performed in a contiguous and overlapping manner. Each porcine PV was longitudinally sectioned for detailed histological analysis. At 3 months after ablation, patients underwent a prespecified remapping procedure regardless of symptomotology. In the acute and chronic animals, 29 of 30 (97%) PVs were electrically isolated after placing the initial circumferential lesion set. For the 4-week chronic animals, 80% of PVs remained isolated; lesions were histologically circumferential in 120 of 120 (100%) PV sections and transmural in 116 of 120 (96.7%) PV sections (average transmurality=99.0±5.5%). In patients, 100% of the PVs were isolated after 1.3 attempts per PV—84% of them (85 of 101) isolated after the initial visually guided lesion set. At 3 months, 61 of 68 (90%) PVs continued to be electrically isolated. Conclusions—Using a visually guided, compliant balloon ablation catheter with point-by-point ablative capability, PV isolation can be achieved in a reliable, reproducible, and persistent manner.

Long-term outcomes of combined epicardial and endocardial ablation of monomorphic ventricular tachycardia related to hypertrophic cardiomyopathy.

Background— Monomorphic ventricular tachycardia (MMVT) is rare in patients with hypertrophic cardiomyopathy (HCM). There are limited data on the utility of catheter ablation for the treatment of MMVT in this population. This study details a series of case reports from multiple centers where combined epicardial-endocardial ablation was performed in a highly selected group of patients with HCM-related MMVT. Methods and Results— The cohort consisted of 10 patients with HCM-related MMVT. Pericardial access was achieved using the percutaneous subxyphoid approach. Epicardial and endocardial ventricular 3D bipolar voltage maps were generated. Ablation sites were identified using a combination of entrainment, activation, late/fractionated potential, and pace mapping. Electrophysiological-identified epicardial scar was present in 8 (80%) patients, endocardial scar in 6 (60%), and no scar in 1 (10%). In the 5 patients with inducible, stable MMVT, 3 cases were successfully terminated with ablation from the epicardium and 1 from the endocardium. The case that failed catheter ablation required surgical cryoablation to abolish the incessant VT. In the remaining 5 patients, 4 underwent epicardial and endocardial ablation of sites with good pace maps and late/fractionated potentials. No ablation was performed in the remaining patient because of noninducibility and lack of identifiable scar. After 37±17 months (limits, 2 to 62 months; median, 37 months), the freedom from recurrent implantable cardioverter-defibrillator shocks was 78% (7/9 patients) in those who underwent ablation. Conclusions— In highly selected patients with HCM, combined epicardial and endocardial mapping and ablation is a feasible and reasonably efficacious option for MMVT if refractory to aggressive trials of antiarrhythmic drugs and antitachycardia pacing.

Bipolar irrigated radiofrequency ablation: A therapeutic option for refractory intramural atrial and ventricular tachycardia circuits

BACKGROUND Irrigated radiofrequency (RF) ablation can be insufficient to eliminate intramurally located septal atrial flutter (AFL) and ventricular tachycardia (VT) circuits. Bipolar ablation between 2 ablation catheters may be considered for such circuits. OBJECTIVE To evaluate the utility of bipolar irrigated ablation to terminate arrhythmias resistant to unipolar ablation. METHODS In vitro: Bipolar and sequential unipolar RF ablation lesions were placed on porcine ventricular tissue in a saline bath to assess for lesion transmurality. Clinical: 3 patients with atypical septal flutter (AFL), 4 patients with septal VT, and 2 with left ventricle free-wall VT, all of whom failed sequential unipolar RF ablation, underwent bipolar RF ablation using irrigated catheters placed on either surface of the interatria/interventricular septum and left ventricle free-wall, respectively. RESULTS In vitro: Bipolar RF was found to be more likely to achieve transmural lesions (82% vs 33%; P = .001) and could do so in tissues with thicknesses of up to 25 mm. Clinical: All 5 AFLs (3 patients) were successfully terminated with bipolar RF. In follow-up, AFL recurred in 2 of the 3 patients and atrial fibrillation and AFL recurred in 1 of the 3. All 3 thereafter underwent repeat procedures with successful maintenance of sinus rhythm in 2 of the 3 patients (6-month follow-up). In the VT subgroup, 5 of 6 septal VTs and 2 of 3 free-wall VTs were terminated successfully during ablation. In follow-up (12 months), 2 of the 4 patients in the septal bipolar group and 1 of the 2 patients in the free-wall group remained free of VT. CONCLUSIONS Bipolar RF can be used to terminate arrhythmias in select patients with tachyarrhythmias.