Position paper concerning the competence, performance and environment required for the practice of ablation in children and in congenital heart disease.

The population of patients with congenital heart disease (CHD) is continuously increasing, and a significant proportion of these patients will experience arrhythmias because of the underlying congenital heart defect itself or as a consequence of interventional or surgical treatment. Arrhythmias are a leading cause of mortality, morbidity and impaired quality of life in adults with CHD. Arrhythmias may also occur in children with or without CHD. In light of the unique issues, challenges and considerations involved in managing arrhythmias in this growing, ageing and heterogeneous patient population and in children, it appears both timely and essential to critically appraise and synthesize optimal treatment strategies. The introduction of catheter ablation techniques has greatly improved the treatment of cardiac arrhythmias. However, catheter ablation in adults or children with CHD and in children without CHD is more technically demanding, potentially causing various complications, and thus requires a high level of expertise to maximize success rates and minimize complication rates. As French recommendations regarding required technical competence and equipment are lacking in this situation, the Working Group of Pacing and Electrophysiology of the French Society of Cardiology and the Affiliate Group of Paediatric and Adult Congenital Cardiology have decided to produce a common position paper compiled from expert opinions from cardiac electrophysiology and paediatric cardiology. The paper details the features of an interventional cardiac electrophysiology centre that are required for ablation procedures in adults with CHD and in children, the importance of being able to diagnose, monitor and manage complications associated with ablations in these patients and the supplemental hospital-based resources required, such as anaesthesia, surgical back-up, intensive care, haemodynamic assistance and imaging. Lastly, the need for quality evaluations and French registries of ablations in these populations is discussed. The purpose of this consensus statement is therefore to define optimal conditions for the delivery of invasive care regarding ablation of arrhythmias in adults with CHD and in children, and to provide expert and - when possible - evidence-based recommendations on best practice for catheter-based ablation procedures in these specific populations.

Management of acute cardiac tamponade by direct autologous blood transfusion in interventional electrophysiology.

AIMS: Acute cardiac tamponade (ACT) is the most common life-threatening complication of interventional electrophysiology. Urgent drainage by percutaneous pericardiocentesis and anticoagulation reversal are required. Immediate direct transfusion of the blood volume aspirated from the pericardial space to the patient has been rarely described. This study was designed to assess the efficacy and safety of immediate direct autologous blood transfusion (AutoBT). METHODS: A retrospective case series of direct AutoBT performed for ACT was collected. Urgent drainage by percutaneous pericardiocentesis and immediate direct AutoBT were performed to achieve hemodynamic stabilization without a cell-saver system. RESULTS: Twenty-two electrophysiology centers were contacted to participate in the case series. Fourteen centers reported not to use direct AutoBT. Three centers reported using direct AutoBT with the cell-saver system. Fourteen cases of immediate direct AutoBT without cell-saver system were included from the five remaining centers. Electrophysiological procedures were performed for ventricular tachycardia (n = 5), atrial fibrillation (n = 5), atrial tachycardia (n = 2), left accessory pathway (n = 1), and premature ventricular contraction (n = 1) with transseptal (n = 9), retroaortic (n = 4), and/or epicardial access (n = 4). Pericardial drainage was performed by percutaneous pericardiocentesis for 13 patients and via the transseptal sheath for one patient. Surgical hemostasis was required for seven patients. The mean volume of autologous blood directly transfused was 1207 ± 963 mL. Direct AutoBT permitted to resume the procedure in four patients. No major complication related to the use of AutoBT occurred. CONCLUSION: Direct AutoBT without a cell-saver system is a feasible, safe, and useful technique for salvage therapy in ACT in interventional electrophysiology.

Recommendations for the use of electrophysiological study: Update 2018.

The field of cardiac electrophysiology has greatly developed during the past decades. Consequently, the use of electrophysiological studies (EPSs) in clinical practice has also significantly augmented, with a progressively increasing number of certified electrophysiology centers and specialists. Since Zipes et al published the Guidelines for Clinical Intracardiac Electrophysiology and Catheter Ablation Procedures in 1995, no official document summarizing current EPS indications has been published. The current paper focuses on summarizing all relevant data of the role of EPS in patients with different types of cardiac pathologies and provides up-to-date recommendations on this topic. For this purpose, the PubMed database was screened for relevant articles in English up to December 2018 and ESC and ACC/AHA Clinical Practice Guidelines, and EHRA/HRS/APHRS position statements related to the current topic were analyzed. Current recommendations for the use of EPS in clinical practice are discussed and presented in 17 distinct cardiac pathologies. A short rationale, evidence, and indications are provided for each cardiac disease/group of diseases. In conclusion, because of its capability to establish a diagnosis in patients with a variety of cardiac pathologies, the EPS remains a useful tool in the evaluation of patients with cardiac arrhythmias and conduction disorders and is capable of establishing indications for cardiac device implantation and guide catheter ablation procedures.

Impact of bipolar electrodes contact on fractionation index measurement.

Signals such as Complex Fractionated Atrial Electrograms (CFAE) are tracked during ablation procedures to locate the arrhythmical substrate regions. Most of CFAE classification tools use fractionation indexes. However, recordings from intracardiac catheter depend on electrode contact quality. This paper investigates the impact of electrode contact area on fractionation indexes. It is assessed through three kinds of arrhythmical activations resulting from a numerical simulation of a small piece of the cardiac tissue. Bipolar electrograms are extracted corresponding to 25 different contact areas and fractionation indexes (Shannon entropy, non linear energy operator and maximum peak ratio) are computed. Results yield that the Shannon entropy offers a good potential discrimination between arrhythmic scenarios and is less sensitive to the electrode contact variation.

Clinical impact of the implantable loop recorder in patients with isolated syncope, bundle branch block and negative workup: a randomized multicentre prospective study.

BACKGROUND: Few studies have compared conventional testing with prolonged monitoring using an implantable loop recorder (ILR) following the first syncope episode in patients with bundle branch block (BBB) and negative workup. OBJECTIVES: To compare two syncope evaluation strategies-primary use of an ILR (Group 1) versus conventional testing (Group 2)-and to estimate the prevalence of significant arrhythmias in the ILR patient subset. METHODS: From January 2005 to December 2010, 78 patients admitted after one syncope episode were randomized to ILR (n=41) or conventional follow-up (n=37). Mean follow-up was 27 ± 12 months. RESULTS: Mean age was 76 ± 8 years and 30 patients were women (38.5%); 18 presented cardiomyopathy (23%) and 12 had a history of atrial fibrillation (15.4%). Mean left ventricular ejection fraction was 56.5 ± 11% and mean His-to-ventricle interval was 55 ± 6ms based on negative electrophysiological study (EPS). Electrocardiogram abnormalities involved: 34 left bundle branch blocks (BBBs); 11 right BBBs; and 33 bifascicular blocks. Overall, 21 patients (27%) developed significant arrhythmic events: ventricular tachycardia (n=1; 1.3%); sudden death (n=2; 2.6%); third-degree atrioventricular (AV) block (n=14; 18%); sick sinus syndrome (n=4; 5.1%). In 19 (24.4%) patients, relevant arrhythmias were detected, with a significant difference between the ILR group (n=15/41; 36.6%) and the conventional follow-up group (n=4/37; 10.8%) (P=0.02). Eighteen patients were implanted with pacemakers; one received an implantable defibrillator. No predictors of AV block were identified in the ILR group. CONCLUSIONS: In this randomized prospective study, the ILR strategy proved largely superior to conventional follow-up in detecting recurrent events, with a potential impact on therapeutic management. This observation highlights the usefulness of early monitoring in patients with BBB and negative EPS even after the first syncope episode but an empiric pacemaker strategy remains to be validated in this selected population.

Docosahexaenoic acid, but not eicosapentaenoic acid, supplementation reduces vulnerability to atrial fibrillation.

BACKGROUND: The potential health benefits of ω-3 polyunsaturated fatty acids (PUFAs) usually are studied using a combination of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). This combination reduces vulnerability to experimentally induced atrial fibrillation (AF). It is unknown whether EPA and DHA have differential effects when taken alone. Using a model of pacing-induced atrial hemodynamic overload, we investigated the individual effects of EPA and DHA on vulnerability to AF and atrial remodeling. METHODS AND RESULTS: Thirty-four dogs were randomized into 3 groups, all of which underwent simultaneous atrial and ventricular pacing at 220 beats per minute for 14 days. One group received purified DHA (≈1 g/d) orally for 21 days beginning 7 days before pacing began. Similarly, 1 group received ≈1 g/d purified EPA. In a third (control) group (No-PUFAs), 8 dogs received ≈1 g/d olive oil, and 12 were unsupplemented. Electrophysiological and echocardiographic measurements were taken at baseline and 21 days. Atrial tissue samples were collected at 21 days for histological and molecular analyses. Persistent AF inducibility was significantly reduced by DHA compared with No-PUFAs median [25-75 percentiles], 0% [0%-3%] for DHA versus 3.1% [2.2%-11%] for No-PUFAs; P=0.007) but not by EPA (3.4% [1.9%-8.9%]). DHA also reduced atrial fibrosis compared with No-PUFAs (11 ± 6% versus 20 ± 4%, respectively; P<0.05), whereas EPA did not (15 ± 5%; P>0.05). CONCLUSIONS: DHA is more effective than EPA in attenuating AF vulnerability and atrial remodeling in structural remodeling-induced AF.

Multifocal ectopic Purkinje-related premature contractions: a new SCN5A-related cardiac channelopathy.

OBJECTIVES: The aim of this study was to describe a new familial cardiac phenotype and to elucidate the electrophysiological mechanism responsible for the disease. BACKGROUND: Mutations in several genes encoding ion channels, especially SCN5A, have emerged as the basis for a variety of inherited cardiac arrhythmias. METHODS: Three unrelated families comprising 21 individuals affected by multifocal ectopic Purkinje-related premature contractions (MEPPC) characterized by narrow junctional and rare sinus beats competing with numerous premature ventricular contractions with right and/or left bundle branch block patterns were identified. RESULTS: Dilated cardiomyopathy was identified in 6 patients, atrial arrhythmias were detected in 9 patients, and sudden death was reported in 5 individuals. Invasive electrophysiological studies demonstrated that premature ventricular complexes originated from the Purkinje tissue. Hydroquinidine treatment dramatically decreased the number of premature ventricular complexes. It normalized the contractile function in 2 patients. All the affected subjects carried the c.665G>A transition in the SCN5A gene. Patch-clamp studies of resulting p.Arg222Gln (R222Q) Nav1.5 revealed a net gain of function of the sodium channel, leading, in silico, to incomplete repolarization in Purkinje cells responsible for premature ventricular action potentials. In vitro and in silico studies recapitulated the normalization of the ventricular action potentials in the presence of quinidine. CONCLUSIONS: A new SCN5A-related cardiac syndrome, MEPPC, was identified. The SCN5A mutation leads to a gain of function of the sodium channel responsible for hyperexcitability of the fascicular-Purkinje system. The MEPPC syndrome is responsive to hydroquinidine.

N-3 polyunsaturated fatty acid supplementation does not reduce vulnerability to atrial fibrillation in remodeling atria.

BACKGROUND: Prophylactic supplementation with omega-3 polyunsaturated fatty acids (PUFAs) reduce vulnerability to atrial fibrillation (AF). The effect of PUFAs given after cardiac injury has occurred is unknown. OBJECTIVE: To investigate using a model of pacing-induced cardiac injury, the time course of development of injury and whether it was altered by postinjury PUFAs. METHODS: Sixty-five dogs were randomized to undergo simultaneous atrial and ventricular pacing (SAVP, 220 beats/min) for 0, 2, 7, or 14 days. Twenty-two dogs received PUFAs (850 mg/d) either prophylactically or after some pacing had occurred (postinjury). Electrophysiologic and echocardiographic measurements were taken at baseline and sacrifice. Atrial tissue samples were collected at sacrifice for histologic and molecular analyses. RESULTS: With no PUFAs, the inducibility of AF increased with pacing duration (P < .001). Postinjury PUFAs (started after 7 days of pacing) did not reduce the inducibility of AF after 14 days of pacing (9.3% ± 8.8% no PUFAs vs 9.7% ± 9.9% postinjury PUFAs; P = .91). Atrial myocyte size and fibrosis increased with pacing duration (P < .05). Postinjury PUFAs did not significantly attenuate the cell size increase after 14 days of pacing (no PUFAs 38% ± 30% vs postinjury PUFAs 19% ± 28%; P = .11). Similarly, postinjury PUFAs did not attenuate the increase in fibrosis after 14 days of pacing (no PUFAs 66% ± 51% vs postinjury PUFAs 63% ± 76%; P = .90). CONCLUSION: PUFA supplementation begun after cardiac injury has already occurred does not reduce atrial structural remodeling or vulnerability to AF.

n-3 Polyunsaturated fatty acids alter expression of fibrotic and hypertrophic genes in a dog model of atrial cardiomyopathy.

BACKGROUND: We previously showed that omega-3 polyunsaturated fatty acids (PUFAs) reduce vulnerability to atrial fibrillation (AF). The mechanisms underlying this effect are unknown. OBJECTIVE: The purpose of this study was to use a genome-wide approach to identify gene expression profiles involved in a new model of AF vulnerability and to determine whether they were altered by PUFA therapy. METHODS: Thirty-six dogs were randomized evenly into three groups. Two groups were paced using simultaneous atrioventricular pacing (SAVP) at 220 bpm for 14 days to induce atrial enlargement, fibrosis, and susceptibility to AF. One group was supplemented with oral PUFAs (850 mg/day) for 21 days, commencing 7 days before the start of pacing (SAVP-PUFAs). The second group received no PUFAs (SAVP-No PUFAs). The remaining dogs were unpaced, unsupplemented controls (CTRL). Atrial tissue was sampled at the end of the protocol. Gene expression was analyzed in four dogs randomly selected from each group (n = 12) via microarray. Results were confirmed with quantitative real-time polymerase chain reaction (RT-PCR) and histology on all 36 dogs. RESULTS: Microarray or quantitative RT-PCR results showed that SAVP-No PUFAs dogs had significantly increased mRNA levels of protein kinase B (Akt), epidermal growth factor (EGF), JAM3, myosin heavy chain alpha (MHCalpha), and CD99 and significantly decreased levels of Smad6 compared with CTRL dogs. Quantitative RT-PCR showed that PUFA supplementation was associated with significant down-regulation of Akt, EGF, JAM3, MHCalpha, and CD99 levels compared with SAVP-No PUFAs dogs. CONCLUSION: The effect of PUFAs on these fibrosis, hypertrophy, and inflammation related genes suggests that, in this model, PUFA-mediated prevention of AF may be due to attenuation of adverse remodeling at the genetic level in response to mechanical stress.

Long chain n-3 polyunsaturated fatty acids reduce atrial vulnerability in a novel canine pacing model.

AIM: Our objective was to assess the effect of omega-3 polyunsaturated fatty acids (n-3 PUFAs) on atrial fibrillation (AF) vulnerability and atrial structure in a new model of atrial cardiomyopathy. METHODS AND RESULTS: Dogs were studied in three groups: seven control dogs (UNPACED) and 24 dogs undergoing simultaneous atrioventricular pacing (for 2 weeks) assigned to placebo treatment (SAVP-PLACEBO, n = 12 dogs) or oral n-3 PUFAs (1 g/day) treatment (SAVP-PUFA, n = 12 dogs). SAVP-PUFA dogs had less AF inducibility (percentage of burst attempts leading to AF episodes: 5.5 +/- 7.4 vs. 20.4 +/- 14.2, P < 0.001) and maintenance [median AF duration: 601 s (377-1216) vs. 1598 s (1195-2400), P < 0.05] than SAVP-PLACEBO dogs. SAVP-PUFA dogs had significantly less local slowing of conduction and conduction heterogeneity than SAVP-PLACEBO dogs. SAVP-PUFA dogs had a significantly smaller increase in atrial matrix metalloproteinase-9 activity and in collagen type I and III messenger RNA expression (in arbitrary units) than SAVP-PLACEBO dogs (0.62 +/- 0.51 vs. 10.80 +/- 5.61, respectively for collagen I, P < 0.05; 1.66 +/- 0.48 vs. 5.24 +/- 1.16, respectively, for collagen III, P < 0.05). CONCLUSION: n-3 PUFA supplementation can reduce AF vulnerability in a new canine pacing model of atrial cardiomyopathy. The mechanism may be related to attenuation of collagen turnover.

Simple and efficient identification of conduction gaps in post-ablation recurring atrial flutters.

AIMS: Cavo-tricuspid isthmus (CTI) radiofrequency (RF) ablation is a curative therapy for common atrial flutter (AFl), but is associated with a recurrence rate of 5-26%. Although complete bidirectional conduction block is usually achieved, the recurrence of AF is due to recovered conducting isthmus tissue through which activation wavefronts pass. We evaluated a simple and efficient electrophysiological strategy, which pinpoints the ablation target. METHODS AND RESULTS: Twenty-five patients (19 men), mean age 61 +/- 6, with recurrent AFl required a repeat ablation, 250 +/- 160 days after a successful RF CTI procedure. Transverse CTI conduction was monitored during AFl or coronary sinus (CS) pacing by a 24-pole mapping catheter positioned in the right atrium (RA), with the distal poles in the CS, proximal poles on the lateral RA, and intermediate poles on the CTI. A slow conduction area traversing the CTI (velocity, 37 +/- 22 vs. 98 +/- 26 cm/s on either side, P < 0.05) and a lower potential amplitude than at both sides (0.2 +/- 0.15 vs. 0.5 +/- 0.5 mV, P < 0.05), defined by a bayonet-shaped depolarization sequence, were considered to represent the incomplete line of block (InLOB). An ablation catheter was progressively dragged up to this InLOB, from the tricuspid annulus to the inferior vena cava, analysing the widely separated double potentials (DPs) until these coalesced. In nine patients (35%), the target conduction gap was a coalesced fractionated atrial potential within the InLOB (duration, 77 +/- 12 ms), and in 16 patients (65%), a narrow DP toward the healthy margins of this InLOB (duration, 28 +/- 15 ms). Adopting this strategy yields 100% successful re-ablation of recurring AFl leading to bidirectional block, with a mean 2.7 +/- 1.4 RF applications. CONCLUSION: Transverse CTI mapping precisely locates the InLOB and helps find conduction gaps along the CTI in re-ablation procedures for common AFl.

A new and simple method for distinguishing complete from incomplete block through the cavotricuspid isthmus.

BACKGROUND: A complete line of block (CLOB) in the cavotricuspid isthmus (CTI) is the endpoint of typical atrial flutter ablation. Before CTI block is obtained, a progressive CTI conduction delay due to an incomplete line of block (InLOB) can be difficult to distinguish from CLOB. The purpose of this study was to assess a new simple approach based on the changes in atrio-ventricular (AV) conduction delays during septal and lateral right atrial pacing, to distinguish a CLOB from an InLOB during typical atrial flutter (AFL) ablation. METHODS AND RESULTS: Forty patients who presented an InLOB before a CLOB, and a stable (AV) conduction delay at 600 ms cycle length pacing (when in sinus rhythm), during AFL ablation were included in this study. A 24-pole mapping catheter was positioned so that 2 adjacent dipoles bracketed the targeted CTI line of block (LOB), with proximal dipoles lateral to the LOB and distal dipoles in the coronary sinus. Two pacing sites were lateral (position L1 and L2) and one was septal (position S) to the LOB, with locations L1 and S closest to the LOB. During L1, L2 and S site pacing, the delay between the pacing artefact and the peak of the R wave in a surface ECG (lead II) was measured. We measured the following conduction delays (mean +/- SD in ms), during InLOB versus CLOB: (L1 to R) 320.5 +/- 68.0 versus 367.0 +/- 62.0, p = 0.001; (L2 to R) 333.0 +/- 59.0 versus 338.0 +/- 62.0, p = 0.663, (S to R) 259.4 +/- 51.5 versus 247.1 +/- 55.5, p = 0.987. We calculated the following data during an InLOB versus a CLOB: (L1R-L2R) -12.3 +/- 7 versus 20.2 +/- 12.7, p = 0.001; (L1R-SR) 51.1 +/- 21.5 versus 120.1 +/- 16.6, p < 0.05. The sensitivity, specificity, positive and negative predictive values for CLOB with (L1R-SR > 94 ms) and with (L1R-L2R > 0 ms) were respectively; 100%, 98%, 98% and 100%. CONCLUSIONS: This study establishes that lateral versus septal right atrial pacing sites combined with the measure of AV conduction delay on a surface ECG can be useful to distinguish a CLOB from an InLOB during AFL ablation.