Guilherme Fenelon

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.

Prognostic significance of transient complete atrioventricular block during radiofrequency ablation of atrioventricular node reentrant tachycardia

One hundred eighty-six consecutive patients underwent radiofrequency ablation and were divided into 2 groups: group 1 included 19 patients (13 women, mean age 50 +/- 15 years) with transient atrioventricular (AV) block during the procedure. The duration of AV block ranged from 4 seconds to 30 minutes (mean 2.8 +/- 7.0 minutes); and group 2 included 167 patients (142 women, mean age 40 +/- 17 years) without transient AV block. Follow-up was 8.6 +/- 8.3 months in group 1 and 10.1 +/- 9.4 months in group 2. No significant differences were observed between the 2 groups concerning the ablation approach (fast or slow pathway), the number of radiofrequency applications, and recurrences of tachycardia. Four patients from group 1 who underwent fast pathway ablation developed late complete AV block, whereas no patient in group 2 had such a complication (p = 0.0001). Late complete AV block occurred 20 hours, 6 days, 1 month, and 25 days after ablation, respectively, and was not related to the duration of transient AV block. Another patient from group 1 developed an asymptomatic 2:1 AV block during exercise, 3 months after slow pathway ablation. Transient AV block, a common finding occurring as often during fast as during slow pathway ablation, did not preclude recurrences of tachycardia but was associated with late complete AV block.

Left Ventricle Radio-frequency Ablation in the Rat: A New Model of Heart Failure due to Myocardial Infarction Homogeneous in Size and Low in Mortality

BACKGROUND The purpose of the current study was to create a model of myocardial infarction (MI) that is homogeneous in size with a low immediate (24 hours) mortality. METHODS AND RESULTS Male and female rats (n = 256) underwent left ventricle (LV) ablation (Ab) by a radiofrequency current (1000 kHz; 12 watts for 12 seconds) to promote a MI. A transmural MI occurred in all rats. Post-Ab complex arrhythmias were frequent (atrioventricular block, ventricular tachycardia, and fibrillation), which rapidly and spontaneously reverted to sinus rhythm. Among 66 male rats, immediate mortality occurred in 7.5%. Small MI size dispersion was characterized by smaller variability following Ab (x +/- SD: 45 +/- 8%) when compared with coronary occlusion (Oc; 40 +/- 19%). The histopathologic evaluations identified lesions similar to those which occurred following Oc, with scarring complete at 4 weeks. The hemodynamic and Doppler echocardiograms showed comparable increases in LV dimension, end-diastolic pressure, and pulmonary water content 1 and 4 weeks post-MI. Papillary muscle mechanics 6 weeks post-MI had matched inotropic and lusitropic dysfunction. CONCLUSIONS LV Ab gave rise to a MI within a narrow size limit and with a low immediate mortality. LV Ab resulted in histopathologic evolution, ventricular dilation, and dysfunction, impairment in myocardial mechanics, and congestive outcome that reproduced a MI from Oc.

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

Hugh Calkins & Gerhard Hindricks & Riccardo Cappato & Young-Hoon Kim & Eduardo B. Saad & Luis Aguinaga & Joseph G. Akar & Vinay Badhwar & Josep Brugada & John Camm & Peng-Sheng Chen & Shih-Ann Chen & Mina K. Chung & Jens Cosedis Nielsen & Anne B. Curtis & D. Wyn Davies & John D. Day & André d’Avila & N.M.S. (Natasja) de Groot & Luigi Di Biase & Mattias Duytschaever & James R. Edgerton & Kenneth A. Ellenbogen & Patrick T. Ellinor & Sabine Ernst & Guilherme Fenelon & Edward P. Gerstenfeld & David E. Haines & Michel Haissaguerre & Robert H. Helm & Elaine Hylek & Warren M. Jackman & Jose Jalife & Jonathan M. Kalman & Josef Kautzner &Hans Kottkamp &Karl Heinz Kuck &Koichiro Kumagai &Richard Lee & Thorsten Lewalter & Bruce D. Lindsay & Laurent Macle & Moussa Mansour & Francis E. Marchlinski & Gregory F. Michaud & Hiroshi Nakagawa & Andrea Natale & Stanley Nattel & Ken Okumura & Douglas Packer & Evgeny Pokushalov & Matthew R. Reynolds & Prashanthan Sanders & Mauricio Scanavacca & Richard Schilling &Claudio Tondo &Hsuan-Ming Tsao &Atul Verma &David J.Wilber & Teiichi Yamane

Combined Therapy with Steroids and Antioxidants Prevents Ultrastructural Damage Surrounding Chronic Radiofrequency Lesions

We evaluated the effects of combined therapy with anti‐inflammatory and antioxidant drugs on the healing of radiofrequency (RF) lesions (70°C, 60 s) produced in the right atrium and each ventricle of 21 adult dogs. Three groups were studied: acute (n= 7, sacrificed 1 hour after RF); control (n = 7, sacrificed 54 ± 29 days after RF); and dogs (n = 7, sacrificed 32 ± 5 days after RF) receiving combined therapy with allopurinol (400 mg po 24 and 2 hours before RF); verapamil (200 μg/kg IV 15 min before and after RF); hydrocortisone (10 mg/kg IV after RF) and prednisone (20 mg po for 29 days). Atrial (n = 37) and ventricular (n = 70) lesion dimensions were determined and 21 right ventricular apex lesions (1 per dog) were selected for light and electron microscopy analysis. Histological and ultrastructural (US) characteristics in three zones extending from the visible lesion border, A (0–3 mm); B (3–6 mm); and C (6–9 mm), were assessed. In chronic groups, atrial and ventricular lesion dimensions were similar, but delayed scar formation was noted in treated animals. Acutely and at follow‐up, significant US abnormalities occurred in zones A and B and chronic lesions exhibited type I collagen proliferation. In Zone A, the extent of US injury and collagen proliferation was significantly less in treated dogs. Further, Zone B was normal in 5/7 (71%) treated dogs and in 0/7 (0%) controls. Zone C was essentially normal in all groups. Combined therapy with steroids, verapamil, and allopurinol is effective in limiting US damage surrounding chronic RF lesions. (PACE 2004; 27:65–72)

Epicardial radiofrequency ablation of ventricular myocardium: Factors affecting lesion formation and damage to adjacent structures

We evaluated the factors affecting epicardial radiofrequency (RF) lesion formation in normal ventricular myocardium. In 16 dogs, a minithoracotomy was made and a sheath was placed in the pericardial space. Standard ablation lesions (4-mm tip catheter; 70 ∘ C/60 seconds) were created in each ventricle under fluoroscopy guidance (n = 7) or hand-held with direct visualization of the catheter to assure optimal electrode-tissue contact (n = 6). In the latter, thermally-shielded (TS) electrodes (50% tip surface along its 4 mm length) were used in 3/6 dogs. Catheter tip (4 mm) irrigation (13 mL/minutes; 40 ∘ C/60 seconds) was employed with conventional techniques in 3 additional dogs. Results: With optimal electrode-tissue contact (11 lesions), power (3.4 ± 2.3 W vs. 16 ± 13 W; p < 0.001) and pacing thresholds (0.2 ± 0.0 mA vs. 3.6 ± 5.7 mA; p = 0.004) were lower than standard RF (25 lesions). However, lesion dimensions were similar and transmural lesions did not occur (depth 2.8 ± 1.1 mm vs. 3.0 ± 1.5 mm). Catheter irrigation allowed high power outputs (43 ± 6.1 W; p < 0.001) generating transmural lesions, 5/9 (55%), depth 6.4 ± 2.1 mm. At constant power (2 W), catheter-tip temperature (52 ± 5.2∘ C vs. 57 ± 6.6∘ C; p = NS) and lesion (10 in each group) dimensions were similar for conventional and TS electrodes, but damage to parietal pericardium and lungs occurred with conventional electrodes only (70% vs. 0% p = 0.02). Conclusion: Standard epicardial RF ablation does not produce deep lesions and exhibits a significant energy loss probably due to poor electrode-tissue contact. Catheter irrigation allows delivery of high power outputs to the epicardium consistently creating deeper lesions than standard ablation. TS electrodes may reduce damage to neighboring structures during epicardial RF ablation.

Atrial fibrillation ablation in Brazil: results of the registry of the Brazilian Society of Cardiac Arrhythmias

BACKGROUND Aiming to define the profile of curative atrial fibrillation (AF) ablation in Brazil, the Brazilian Cardiac Arrhythmia Society [Sociedade Brasileira de Arritmias Cardíacas] (SOBRAC) created the Brazilian Registry of AF Ablation [Registro Brasileiro de Ablação da FA]. OBJECTIVE To describe the results of this registry. METHODS A questionnaire was sent to SOBRAC members asking about data on patients submitted to AF ablation between September 2005 and November, 2006. RESULTS A total of 29 groups from 13 states completed the forms. Of these, 22 (76%) had performed AF ablations. Between 1998 and 2001, 7 groups (32%) initiated AF ablations and between 2002 and 2006, 15 groups began to perform them (68%). From 1998 to 2006, 2,374 patients were submitted to ablation, 755 (32%) of them during the registry period. Most (70%) were males and 89% presented with paroxysmal or persistent AF. Ancillary imaging methods (intracardiac echocardiography and electroanatomic mapping) were used by 9 groups (41%). During an average five-month follow-up period, total success was 82% and success without use of antiarrhythmic agents was 57%. Nevertheless, 35% of the patients required two or more procedures. There were 111 complications (14.7%) and 2 deaths (0.26%). CONCLUSION Curative AF ablation has been increasing significantly in our country, with success rates comparable to international indexes, but often more than one procedure is necessary. Despite promising results, AF ablation still results in significant morbidity. Supplementary imaging methods have been used more and more in an effort to increase efficacy and safety of the procedure. These findings should be considered by public and private funding agencies.

Electrocardiographic Identification of Mid-Septal Accessory Pathways in Close Proximity to the Atrioventricular Conduction System

In order to identify ECG characteristics of overt midseptal accessory pathways (APs) predictive of close proximity to the AV conduction system we analyzed data from patients who underwent successful RF catheter ablation of a mid‐septal AP, Mean patient age was 31 ± 16 years, and 13 were male. The 40° right anterior oblique view was used to divide the mid‐septal area into 3 zones: 1 (anteriorportion); 2 (intermediate); and 3 (posterior portion). The 12‐lead ECG was analyzed with regard to delta wave polarity and R/S transition in the precordial leads. The findings from patients ablated at zone 3 were compared to those at zones 1 and 2. All patients had a positive delta wave in the leads I, II, aVL, and negative delta wave in the leads III and aVR. The R/S transition occurred in lead V2 in 80% of patients. The delta wave in lead aVF was the only ECG characteristic that correlated with the AP ablation zone. Six of 8 patients ablated at zone 3 had a negative delta wave in lead aVF while 6 out of 7 patients ablated at zone 1 or 2 had a positive or isoelectric delta wave in lead aVF (P = 0.03). A positive or isoelectric delta wave in lead aVF identifies mid‐septal AP in close proximity to the AV conduction system.

Initial Clinical Experience with a New Small Sized Third‐Generation Implantable Cardioverter Defibrillator: Results of a Multicenter Study

This study reports the acute clinical experience with the new CPI VENTAK MINI: a small sized (68 cc), implantable cardioverter defibrillator (ICD) with 33 J stored energy. Implantation of the device was attempted in 113 patients (90 men, mean age 57 ± 16 years, 64 with coronary artery disease, mean left ventricular ejection fraction 41%) with ventricular tachycardia or ventricular fibrillation (VF). All 113 patients (100%) were ultimately implanted, 12% of them for ICD replacement. Transvenous lead implantation was accomplished in all 104 patients (100%) receiving new leads, 95% of them with a single lead configuration. The safety criteria for implantation (2 consecutive VF conversions at 15 J or 3 at 20 J. in both cases without failures to convert) were demonstrated in all but 7 patients (6%). In 6 of these, safety criteria were not fully assessed while in the last patient defibriliation efficacy was not determined. Of the 104 patients with new leads, 90% underwent pectoral implantation. Of the 9 patients (9%) abdominally implanted, only 4 (4%) (3 children) were judged small sized for pectoral implant. At predischarge testing, reliable VF detection and conversion were noted in 96 of 97 patients tested. There was no perioperative mortality. At a 3.6 ± 1.3 months follow‐up, 34% of the patients had a spontaneous arrhythmic event, and 24% of the patients received shocks. Clinically inappropriate therapies occurred in 8% of the episodes in which any kind of therapy was delivered. This study demonstrates the short‐term clinical efficacy and safety of the new device, and that pectoral implantation can be performed in the large majority of patients.

Impact of prophylactic corticosteroids on systemic inflammation after extensive atrial ablation in pigs

AIMS Prophylactic corticosteroids have been reported to attenuate the increase in C-reactive protein (CRP) and the incidence of atrial fibrillation (AF) both after heart surgery and AF ablation. We tested the impact of a single prophylactic corticosteroid dose on ultrasensitive CRP 24 h and 14 days after extensive linear atrial ablation (8 mm or 3.5 irrigated tip) guided by electroanatomical mapping (NavX) in pigs with normal hearts. METHODS AND RESULTS Pigs (n = 19; 35 kg) were divided into three groups: corticoid (n = 7), atrial ablation with administration of 500 mg methylprednisolone intravenous at anaesthetic induction; control (n = 7), atrial ablation only; and sham (n = 5), surgical procedure without ablation. Troponin and CRP were measured before, 24 h and 14 days after the procedure. After sacrifice, lesions were analysed macroscopically and histologically. Linear lesions were created in the right (n = 23) and left (n = 21) atrium of 14 animals, with no difference between groups. In all groups there was elevation of troponin and CRP 24 h after ablation, with a return to baseline values after 14 days. However, CRP levels of the control, corticoid, and sham groups were similar at all three time points analysed (baseline P = 0.52, 24 h P = 0.21, 14 days P = 0.66). Histological analysis did not show any difference between corticoid and control groups. CONCLUSION In this model, extensive biatrial RF ablation, per se, does not promote systemic inflammation. The use of a prophylactic single corticoid dose before ablation did not prevent systemic inflammation or alter the healing of the lesions.