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Chagas disease is caused by infection from the protozoan parasite Trypanosoma cruzi. Although it is endemic to Latin America, global migration has led to an increased incidence of Chagas in Europe, Asia, Australia, and North America. Following acute infection, up to 30% of patients will develop chronic Chagas disease, with most patients developing Chagasic cardiomyopathy. Chronic Chagas cardiomyopathy is highly arrhythmogenic, with estimated annual rates of appropriate implantable cardioverter-defibrillator therapies and electrical storm of 25% and 9.1%, respectively. Managing arrhythmias in patients with Chagasic cardiomyopathy is a major challenge for the clinical electrophysiologist, requiring intimate knowledge of cardiac anatomy, advanced training, and expertise. Endocardial-epicardial mapping and ablation strategy is needed to treat arrhythmias in this patient population, owing to the suboptimal long-term success rate of endocardial mapping and ablation alone. We also describe innovative approaches to improve acute and long-term clinical outcomes in patients with refractory ventricular arrhythmias following catheter ablation, such as bilateral cervicothoracic sympathectomy and bilateral renal denervation, among others.

Resumo Fundamento A ablação da taquicardia atrial (TA) com local de ativação mais precoce próxima ao feixe de His é um desafio, devido ao risco de bloqueio de AV completo por sua proximidade ao sistema de His-Purkinje (SHP). Uma alternativa para minimizar esse risco é posicionar o cateter na cúspide não coronária (CNC), que é anatomicamente contígua à região para-Hissiana. Objetivos O objetivo deste estudo foi fazer uma revisão de literatura e avaliar as características eletrofisiológicas, a segurança e o índice de sucesso de aplicação de radiofrequência (RF) por cateter na CNC para o tratamento de TA para-Hissiana em uma série de casos. Métodos Avaliamos retrospectivamente dez pacientes (Idade: 36±10 anos) que foram encaminhados para ablação de taquicardia paroxística supraventricular (TPSV) e haviam sido diagnosticados com TA focal para-Hissiana confirmada por manobras eletrofisiológicas clássicas. Para a análise estatística, um P valor d

Background Epicardial mapping and ablation are frequently necessary to eliminate ventricular tachycardia (VT) in patients with Chagas disease. Nonetheless, there are no randomized controlled trials demonstrating the role of this strategy. Objective We conducted this randomized controlled trial to evaluate the efficacy and safety of combined epicardial ablation in patients with Chagas disease. Methods We randomized patients with Chagas disease and VT in a 1:1 fashion to either the endocardial (endo) mapping and ablation group or the combined endocardial/epicardial (endo/epi) mapping and ablation group. The efficacy end points were measured by VT inducibility and all-ventricular arrhythmia recurrence. Safety was assessed by the rate of periprocedural complications. Results Thirty patients were enrolled, and most were male. The median age was 67 (Q1: 58; Q3: 70) years in the endo group and 58 (Q1: 43; Q3: 66) years in the endo/epi group. The left ventricular ejection fraction was 33.0% ± 9.5% and 35.2% ± 11.5%, respectively P = .13. Acute success (non-reinducibility of clinical VT) was obtained in 13 patients (86%) in the endo/epi group and in 6 patients (40%) in the endo-only group (P = .021). There were 12 patients with VT recurrence (80%) in the endo-only group and 6 patients (40%) in the endo/epi group (P = .02) (by intention-to-treat analysis). Epicardial ablation was ultimately performed in 9 patients (60%) in the endo-only group because of an absence of endocardial scar or maintenance of VT inducibility. There was no difference in complications between the groups. Conclusion Combining endo/epi VT catheter ablation in patients with Chagas disease significantly increases short- and long-term freedom from all-ventricular arrhythmias. Epicardial access did not increase periprocedural complication rates.

OBJECTIVE To compare the prevalence of esophageal and periesophageal thermal injury in patients undergoing radiofrequency (RF) atrial fibrillation (AF) ablation using 8 mm tip catheters during three different esophageal protection strategies. METHODS Forty-five consecutive patients with paroxysmal or persistent AF underwent first ablation procedure, besides esophagogastroduodenoscopy (EGD) combined with radial endosonography (EUS) performed before and after the pulmonary vein (PV) isolation. Before the procedure, patients were randomly assigned to one of three esophageal lesion protection strategies: group I-without any protective or monitoring dispositive and limiting RF applications to 30 W for 20 seconds, in left atrium posterior wall (LAPW); group II-power and time of RF delivery, up to 50 W for 20 seconds at LAPW, limited by esophageal temperature monitoring; group III-applications of RF in LAPW with fixed power application of 50 W for 20 seconds during continuous esophageal cooling. RESULTS Baseline characteristics of patients were similar in all groups. The four PVs were isolated in 14 (93.3%), 13 (86.7%), and 15 (100%) patients, respectively in groups I, II, and III. The mean RF power was significantly higher (P

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The atrioventricular (AV) reentrant tachycardia (AVRT) is the most common cause of supraventricular tachycardia (SVT) in the young pediatric population. Some newborns might present with congestive heart failure and require interventional treatment. Catheter ablation in small infants (

BACKGROUND Direct comparisons of combined (C-ABL) and non-combined (NC-ABL) endo-epicardial ventricular tachycardia (VT) ablation outcomes are scarce. We aimed to investigate the long-term clinical efficacy and safety of these 2 strategies in ischemic heart disease (IHD) and nonischemic cardiomyopathy (NICM) patients. METHODS Multicentric observational registry including 316 consecutive patients who underwent catheter ablation for drug-resistant VT between January 2008 and July 2019. Primary and secondary efficacy endpoints were defined as VT-free survival and all-cause death after ablation. Safety outcomes were defined by 30-days mortality and procedure-related complications. RESULTS Most of the patients were male (85%), with IHD (67%) and mean age of 63±13 years. During a mean follow-up of 3±2 years, 117 (37%) patients had VT recurrence and 73 (23%) died. Multivariate survival analysis identified electrical storm (ES) at presentation, IHD, left ventricular ejection fraction (LVEF), New York Heart Association (NYHA) class III/IV, and C-ABL as independent predictors of VT recurrence. In 135 patients undergoing repeated procedures, only C-ABL and ES were independent predictors of relapse. The independent predictors of mortality were C-ABL, ES, LVEF, age and NYHA class III/IV. C-ABL survival benefit was only seen in patients with a previous ablation (P for interaction=0.04). Mortality at 30-days was similar between NC-ABL and C-ABL (4% vs. 2%, respectively, P=0.777), as was complication rate (10.3% vs. 15.1% respectively, P=0.336). CONCLUSION A combined endo-epicardial approach was associated with greater VT-free survival and lower all-cause death in IHD and NICM patients undergoing repeated VT catheter ablations. Both strategies seem equally safe.

Background Chagas disease (ChD) is a major cause of non-ischemic cardiomyopathy (NICM) in Latin America and is becoming more frequent in other parts of the world, especially due to immigration movements. Ventricular Tachycardia (VT) is more common in this type of NICM than others, and finding an effective treatment strategy still is a challenge. Catheter ablation is an option, but there is poor data regarding its efficacy and safety. Purpose Evaluate the outcomes after VT catheter ablation in ChD patients. Methods Data were collected by VT studies reports and patient record analysis, including comorbidities and clinical status at baseline and on follow-up. We analyzed all-cause mortality, one-year VT recurrence rate and procedure related major complications. Results Between January 2013 and December 2018, 157 catheter ablation procedures in 121 ChD patients were performed in our institution. The mean follow-up time was 22.6±22.1 (mean ± SD) months. Overall post procedure mortality was 33.1%, and mean survival time was 51.2 months (95% CI: 44.8–58. NYHA functional class (p=0.022), ejection fraction (p=0.020) and immediate ablation result (p 0.002) were predictors of all-cause mortality in the follow-up. Clinical VT inducibility after ablation was a predictor of VT recurrence at one year (p=0.04). An epicardial approach was performed in 125 (79%) procedures, and accidental right ventricle (RV) puncture occurred in 23 (18.4%), in which open-chest surgery for bleeding hemostasis was necessary in 4 procedures (3.2%). Conclusion Mortality and recurrence rates in ChD patients after VT ablation were high, and correlated with heart failure severity. Epicardial approach is often necessary in this subset of patients. There was a correlation between immediate ablation results and recurrence. Kaplan-Meier of cumulative survival Funding Acknowledgement Type of funding source: None

Regular radiofrequency (RF) catheter ablation is not encouraged during pregnancy, owing to radiation exposure and the uncertainties about the maternal and fetal health, being postponed to the postpartum period. However, the intervention may be indispensable in pregnant women with severe drug-resistant tachyarrhythmia. In such cases, catheter ablation without fluoroscopy is recommended. The aim of this case report is to describe a successful atrial tachycardia catheter ablation on the non-coronary cusp, during pregnancy, and without fluoroscopy.

Aims To develop quality indicators (QIs) that may be used to evaluate the quality of care and outcomes for adults with atrial fibrillation (AF). Methods and results We followed the ESC methodology for QI development. This methodology involved (i) the identification of the domains of AF care for the diagnosis and management of AF (by a group of experts including members of the ESC Clinical Practice Guidelines Task Force for AF); (ii) the construction of candidate QIs (including a systematic review of the literature); and (iii) the selection of the final set of QIs (using a modified Delphi method). Six domains of care for the diagnosis and management of AF were identified: (i) Patient assessment (baseline and follow-up), (ii) Anticoagulation therapy, (iii) Rate control strategy, (iv) Rhythm control strategy, (v) Risk factor management, and (vi) Outcomes measures, including patient-reported outcome measures (PROMs). In total, 17 main and 17 secondary QIs, which covered all six domains of care for the diagnosis and management of AF, were selected. The outcome domain included measures on the consequences and treatment of AF, as well as PROMs. Conclusion This document defines six domains of AF care (patient assessment, anticoagulation, rate control, rhythm control, risk factor management, and outcomes), and provides 17 main and 17 secondary QIs for the diagnosis and management of AF. It is anticipated that implementation of these QIs will improve the quality of AF care.

Introduction: Catheter ablation of the parahisian accessory pathways (PHAP) has been established as the definitive therapy for this type of arrhythmia. However, the PHAP proximity to the normal atrioventricular conduction system makes the procedure technically challenging. Here, we have reported a case series of 20 patients with PHAP who underwent aortic access ablation to evaluate the safety and efficacy of this approach in the PHAP ablation. Methods and results: The ablation through the aortic cusps was the successful approach in 13 of 20 (65%) of the cases. In 11 patients, the aortic approach was the initial strategy for ablation, and the accessory pathway was eliminated in seven (63.6%) of them. The aortic approach followed a failed right-sided attempt in nine patients. In six (66.7%) patients, the ablation was successful with the aortic approach. The only independent predictor for the successful ablation with each approach was the earliest ventricular activation before delta wave (predelta time) and a right-sided earliest ventricular activation of more than 23 ms had high sensitivity and specificity for right-sided success. Systematically using the two strategies (right and left approaches), the ablation of the PHAP was successful in 18 (90%) patients. Conclusion: The aortic approach seems to be a safe and effective strategy for the ablation of PHAP. It can be used when the right-sided approach fails or even considered as an initial strategy when the predelta time is less than 23 ms in the right septal region. When combining the right- and left-sided approaches, the success rate is high. We believe that the retrograde aortic approach remains a key tool for this challenging ablation.

A 49-years-old female with Chagas cardiomyopathy and multiple ICD therapies was referred for catheter ablation. Epicardial and endocardial scar mapping was performed using a multieletrode catheter showing very delayed potentials on the inferior-basal portion of the scar. Then substrate modification resulted in VT non-inducibility.

Catheter ablation has become a cornerstone of therapy in the management of patients with atrial fibrillation (AF). Thermal energy generated in the left atrium (LA) during ablation has the potential to damage adjacent structures. The most feared and rare complication in these ablations is atrial-esophageal fistula (AEF) result from the thermal injury to the esophagus due to the proximity to the LA, with potential catastrophic outcome. This review focuses on the diagnosis and management of AEF after catheter ablation for AF, including preventive measures to avoid esophageal lesions. Symptoms of AEF are often vague and nonspecific, sometimes asymptomatic until they present with fistula or perforation, making the diagnosis somewhat challenging. The esophagogastroduodenoscopy is the gold standard for early detection of esophageal lesions related to AF ablation. Chest CT with oral and intravenous contrast is preferred when there is suspicion of perforation. The use of an esophageal temperature probe during ablation to monitoring esophageal temperature, associated with mechanical displacement of the esophagus, may be feasible to prevent thermal esophageal lesions and enabling adequate energy delivery to the posterior wall of the LA. Prophylactic use of proton pump inhibitors after AF ablation is accepted to be effective and justified as preventive treatment. AEF is an unpredictable complication. Be aware of these complications in the follow-up of patients after AF ablation can lead to the early recognition to start treatment, including surgical repair, as soon as possible to prevent the fatal outcome.

Purpose of review To review the most relevant published data on epicardial ablation of cardiac arrhythmias in the last few years. Recent findings Several studies performing epicardial and endocardial ablation have demonstrated that epicardial ablation may improve the results of ventricular tachycardia (VT) ablation in almost all cardiomyopathies. New imaging techniques have been recently applied, refining the identification of patients who actually benefit from epicardial ablation and increasing its safety. Summary Epicardial VT ablation is an important tool for electrophysiologists to deal with the challenge of scar-related ventricular arrhythmias.

Introducao A fibrilacao atrial (FA) e a arritmia cardiaca sustentada mais comum na pratica clinica. Sua prevalencia aumenta com a idade e frequentemente esta associada a doencas estruturais cardiacas, levando a danos hemodinâmicos e complicacoes tromboembolicas com grandes implicacoes economicas e na morbimortalidade da populacao., As tecnicas de ablacao de FA, quando realizadas por operadores experientes, tem se mostrado seguras e com resultados bastante satisfatorios, porem em alguns pacientes e necessaria a abordagem de focos extra-venosos, como apendice atrial esquerdo, [...]

Aims Atrial-oesophageal fistula is a serious complication related to ablation of atrial fibrillation. As its occurrence is rare, there is a great lack of information about their mechanisms, incidence, presentations, and treatment. The objective of this manuscript is to present a series of cases of atrial-oesophageal fistula in Brazil, focusing on incidence, clinical presentation, and follow-up. Methods and results This is a retrospective multicentre registry of atrial-oesophageal fistula cases that occurred in eight Brazilian centres from 2003 to 2015. Ten cases (0.113%) of atrial-oesophageal fistula were reported in 8863 ablation procedures in the period. Most of the subjects were male (70%) with age 59.6 ± 9.3 years. Eight centres were reference units in atrial fibrillation ablation with an experience over than 200 procedures at the time of fistula occurrence. Oesophageal temperature monitoring was performed in eight cases using coated sensors in six. The first atrial-oesophageal fistula clinical manifestation was typically fever (in six patients), with a median onset time of 16.5 (12–43) days after ablation. There was a delay of 7.8 ± 3.3 days between the first manifestation and the diagnosis in five patients. The treatment was surgical in six cases, clinical in three and stenting in one. Seven patients died (70%) and two developed permanent neurological sequelae. Conclusion Atrial-oesophageal fistula remains a serious complication following AF ablation despite the incorporation of protective measures and increased technical experience of the groups. The high morbidity and mortality despite the treatment indicates the need to develop adequate preventive strategies.

FUNDAMENTO: Ablação por radiofrequência (ARF) em crianças consiste em uma prática cada vez mais frequente. OBJETIVO: Avaliar, em nossa instituição, os resultados da ARF em crianças com idade abaixo de 15 anos. MÉTODOS: Foram analisadas 125 crianças submetidas à ARF entre maio de 1991 a maio de 2010. RESULTADOS: Sessenta e sete (53,6%) crianças eram do sexo masculino, com idade entre 44 dias e 15 anos (média de 8,6 ± 3,3 anos) e peso mediano de 31 kg. Cardiopatia esteve presente em 21 (16,8%) pacientes. A ARF de vias acessórias (VA) foi o procedimento mais comum (62 crianças - 49,6%). A ARF de taquicardias por reentrada nodal (TRN) foi a segunda arritmia mais frequente, em 27 (21,6%), seguida de taquicardias atriais (TA), em 16 (12,8%) e de taquicardias ventriculares (TV) em 8 (6,4%) crianças. Os critérios de sucesso foram alcançados em 86,9%, 96,1%, 80% e 62,5% dos pacientes submetidos à ARF de VA, TRN, TA e TV, respectivamente. Os bloqueios atrioventriculares transitórios (BAVT) ocorreram durante a ARF em 4 (3,2%) e BRD em 7 (5,6%) crianças. Vinte e cinco crianças foram submetidos à nova ARF por insucesso inicial ou recorrência. Durante o seguimento médio de 5,5 ± 3,4 anos, 107 (88,4%) persistiram sem recorrência. Não houve diferença estatística em relação aos resultados e à idade em que o paciente se submeteu ao procedimento. Nenhuma criança apresentou BAVT persistente ou necessitou de marca-passo definitivo. CONCLUSÃO: A ablação por cateter é uma alternativa terapêutica segura e eficiente em crianças com taquicardias recorrentes refratárias ao tratamento clínico.

Aims To verify whether spectral components of atrial electrograms (AE) during sinus rhythm (SR) correlate with cardiac ganglionated plexus (GP) sites. Methods and results Thirteen patients undergoing atrial fibrillation (AF) ablation were prospectively enrolled. Prior to radio frequency application, endocardial AE were recorded with a sequential point-by-point approach. Electrical stimuli were delivered at 20 Hz, amplitude 100 V, and pulse width of 4 ms. A vagal response was defined as a high-frequency stimulation (HFS) evoked atrioventricular block or a prolongation of RR interval. Spectral analysis was performed on single AE during SR, sampling rate of 1000 Hz, Hanning window. Overall, 1488 SR electrograms were analysed from 186 different left atrium sites, 129 of them corresponding to negative vagal response sites, and 57 to positive response sites. The electrogram duration and the number of deflections were similar in positive and negative response sites. Spectral power density of sites with vagal response was lower between 26 and 83 Hz and higher between 107 and 200 Hz compared with negative response sites. The area between 120 and 170 Hz normalized to the total spectrum area was tested as a diagnostic parameter. Receiver operating characteristic curve analysis demonstrated that an area120–170/areatotal value >0.14 identified vagal sites with 70.9% sensitivity and 72.1% specificity. Conclusion Spectral analysis of AE during SR in sites that correspond to the anatomical location of the GP is feasible and may be a simpler method of mapping the cardiac autonomic nervous system, compared with the HFS technique.

This editorial refers to ‘Comparison between single- and multi-sensor oesophageal temperature probes during atrial fibrillation ablation: thermodynamic characteristics’ by C.M. Tschabrunn et al ., doi: 10.1093/europace/euu356. Atrioesophageal fistula as a complication of radiofrequency (RF) catheter ablation of atrial fibrillation (AF) was first described in 2004, shortly after strategies for pulmonary vein isolation moved from ostial to circumferential antral ablation.1,2 Atrioesophageal fistula was initially interpreted as a transitory technical problem that could be prevented by recognizing the oesophagus position and titrating RF energy during ablation in the proximity to the oesophagus. After more than 10 years of development, AF ablation has become the most common catheter ablation procedure performed worldwide. However, atrioesophageal fistula has remained a serious and unpredictable complication occurring in 0.03–0.2% of the ablation procedures even in experienced centres,3 without a convincing demonstration that a specific strategy might prevent it. The crucial problem is that atrioesophageal fistula is often unexpected, and when it occurs, the risk of death or severe neurologic sequelae is around 80%. Moreover, the incidence of atrioesophageal fistula may increase in the next years because technical improvements have been implemented in order to obtain ‘better RF lesions’ to prevent pulmonary vein reconnections and the increasing number of new operators. Thermal injury is the postulated mechanism for oesophageal injury during RF ablation due to the close anatomical relationship between the left atrium and the oesophagus. Radiofrequency energy delivery may extend beyond the atrial myocardium and may reach the oesophagus leading to distinctive grades of ischaemic necrosis of the mucosal layers with different consequences.4 In the past years, many interventions have being proposed …

Background— The aim of this study was to evaluate whether selective radiofrequency (RF) catheter ablation of the atrial sites in which high-frequency stimulation induces vagal reflexes prevents paroxysmal atrial fibrillation (AF). Methods and Results— Ten patients with episodes suggestive of vagal-induced paroxysmal AF and no heart disease were selected for percutaneous epicardial and endocardial mapping of the atria to search for sites in which high-frequency transcatheter stimulation (20 Hz,) induced vagal reflexes. A vagal response defined as AV block of >2 seconds was elicited in 7 of 10 patients (70%) with an average of 5±2.4 (range, 2 to 9) sites per patient, and RF pulses (21.0±12.0 per patient) were applied at those sites to eliminate all evoked vagal reflexes. The 3 patients in whom evoked vagal reflexes were not obtained underwent circumferential pulmonary vein ablation with an average of 58.0±13.9 RF pulses per patient ( P =0.022). Autonomic evaluation was performed before and 48 hours and 3 months after the procedure and was consistent with vagal withdrawal in all patients. Two of the 7 patients who underwent denervation remained asymptomatic without the use of antiarrhythmic medication at a mean follow-up of 8.3±2.8 months (range, 5 to 15 months); 4 had frequent recurrences and were referred for circumferential pulmonary vein ablation; and 1 had few AF episodes without antiarrhythmic medication. The 3 patients without evoked vagal reflexes who underwent circumferential pulmonary vein ablation remained asymptomatic without antiarrhythmic medication. One patient had acute delayed gastric emptying after atrial vagal denervation. Conclusions— RF catheter ablation of selected atrial sites in which high-frequency stimulation induced vagal reflexes may prevent AF recurrences in selected patients with apparently vagal-induced paroxysmal AF.

Background— Epicardial mapping and ablation of accessory pathways through a subxiphoid approach can be an alternative when endocardial or epicardial transvenous mapping has failed. Methods and Results— We reviewed acute and long-term follow-up of 21 patients (14 males) referred for percutaneous epicardial accessory pathway ablation. There was a median of 2 previous failed procedures. All patients were highly symptomatic, 8 had atrial fibrillation (3 with cardiac arrest) and 13 had frequent symptomatic episodes of atrioventricular reentrant tachycardia. Six patients (28.5%) had a successful epicardial ablation. Five patients (23.8%) underwent a successful repeated endocardial mapping, and ablation after epicardial mapping yielded no early activation site. Epicardial mapping was helpful in guiding endocardial ablation in 2 patients (9.5%), showing that the earliest activation was simultaneous at the epicardium and endocardium. Four patients (19%) underwent successful open-chest surgery after failing epicardial/endocardial ablation. Two patients (9.5%) remained controlled under antiarrhythmic drugs after unsuccessful endocardial/epicardial ablation. Two patients had a coronary sinus diverticulum and one a right atrium to right ventricle diverticulum. Three patients acquired postablation coronary sinus stenosis. There was no major complication related to pericardial access. Conclusions— Percutaneous epicardial approach is an alternative when conventional endocardial or transvenous epicardial ablation fails in the elimination of the accessory pathway. A new attempt by endocardial approach was successful in a significant number of patients. Open-chest surgery may be required in symptomatic cases refractory to endocardial–epicardial approach.

In the last decade, radio-frequency catheter ablation of atrial and ventricular tachycardia has become progressively common, driven predominantly by increasing success and low complication rates. At the same time, there was no significant development in antiarrhythmic drug effectiveness that still present limited efficacy and frequent side effects. As patients with congenital heart disease that have undergone surgical repair or palliation have been getting older, a wide variety of rhythm disturbances have been detected. Although electrophysiological procedures often are problematic due to the complex anatomy of such patients, a high level of success can be achieved with careful attention to surgical history and modern imaging technology. Thus, nowadays, interventional electrophysiological techniques play a major role in their management.

Radiofrequency (RF) catheter ablation is the treatment of choice in patients with accessory pathways (APs) and Wolff-Parkinson-White syndrome. Endocardial catheter ablation has limitations, including the inability to map and ablate intramural or subepicardial APs. Some of these difficulties can be overcome using an epicardial approach performed through the epicardial venous system or by percutaneous catheterisation of the pericardial space. When a suspected left inferior or infero-paraseptal AP is refractory to ablation or no early activation is found at the endocardium, a transvenous approach via the coronary sinus is warranted because such epicardial pathways can be in close proximity to the coronary venous system. Associated congenital abnormalities, such as right atrial appendage, right ventricle diverticulum, coronary sinus diverticulum and absence of coronary sinus ostium, may also hamper a successful outcome. Percutaneous epicardial subxiphoid approach should be considered when endocardial or transvenous mapping and ablation fails. Epicardial mapping may be successful. It can guide and enhance the effectiveness of endocardial ablation. The finding of no epicardial early activation leads to a more persistent new endocardial attempt. When both endocardial and epicardial ablation are unsuccessful, open-chest surgery is the only option to eliminate the AP. info:eu-repo/semantics/publishedVersion

Hypertension is the cause of thousands of deaths annually1, and half of the patients treated present controlled blood pressure (BP)2. Resistant hypertension (RH)is defined when the BP remains above the recommended targets with the use of three antihypertensive drugs with synergistic actions at maximum doses recommended and tolerated, preferably one being a diuretic, or when in use of four or more anti-hypertensive drugs, even with controlled BP3. It is estimated that 12%-15% of persons with hypertension are considered resistant, with high risk of cardiovascular morbidity and mortality4. The pathogenesis of hypertension is multifactorial, but the sympathetic activity plays an important role, especially in patients with resistant hypertension2. Efferent renal sympathetic activity stimulates renin release, increases sodium reabsorption and reduces renal blood flow and may be a mechanism for the development and maintenance of hypertension2. Genetic, behavioral and environmental factors influence increased sympathetic activity in persons with hypertension5. New therapies aiming to reduce sympathetic activity have been developed. Renal Sympathetic Denervation (RSD) by radiofrequency catheter ablation of renal arteries has been shown to control BP in resistant hypertension6,7 and in associated clinical conditions such as sleep destructive apnea8 and insulin resistance9. The main RSD clinical studies used a specific catheter not yet available in Brazil, but the radiofrequency ablation of arrhythmias is a procedure that has been performed by electrophysiologists through appropriate catheters for years in our country. Experimental studies of RSD with catheters used for ablation of arrhythmias indicated the possibility of using these to replace those used in international studies, considering the unavailability of those in our reality. Based on this, for the procedure to be reported, the model used for ablation in children (4 mm tip and 5F), which was proven to be more appropriate, was chosen. The objective of the report is to show the result of the first RSD in our community, with the aid of technology used in cardiac arrhythmias.

Radiofrequency ablation (RFA) in children is an increasingly common practice.To evaluate, in our institution, the results of RFA in children younger than 15 years.A total of 125 children submitted to RFA between May 1991 and May 2010 were analyzed.Sixty-seven (53.6%) children were males, aged between 44 days and 15 years (mean 8.6 ± 3.3 years) with median weight of 31 kg. Heart disease was present in 21 (16.8%) patients. The RFA of accessory pathways (AP) was the most common procedure (62 children - 49.6%). The RFA of nodal reentrant tachycardia (NRT) was the second most common arrhythmia in 27 (21.6%), followed by atrial tachycardia (AT) in 16 (12.8%) and ventricular tachycardias (VT) in 8 (6.4%) children. The success criteria were achieved in 86.9%, 96.1%, 80% and 62.5% of patients undergoing RFA of AP, NRT, AT and VT, respectively. Transient AVB occurred during RFA in 4 (3.2%) and LBBB in 7 (5.6%) children. Twenty-five children underwent a new RFA due to initial failure or recurrence. During the mean follow up of 5.5 ± 3.4 years, 107 (88.4%) remained without recurrence. There was no statistical difference regarding the results and the age at which the patient underwent the procedure. No child had persistent AVB or required a permanent pacemaker.Catheter ablation is a safe and effective alternative therapy in children with recurrent tachycardias refractory to medical treatment.

Background— Puncture of the atrial appendage may provide access to the pericardial space. The aim of this study was to evaluate the feasibility of epicardial mapping and ablation through an endocardial transatrial access in a swine model. Methods and Results— An 8-F Mullins sheath was used to perforate the right (n=16) or left (n=1) atrial appendage in 17 pigs (median weight, 27.5 kg; first and third quartiles [Q1, Q3], 25.2, 30.0 kg). A 7-F ablation catheter was introduced into the pericardial space to perform epicardial mapping and deliver radiofrequency pulses on the atria. The pericardial space was entered in all 17 animals. In 15 (88%) animals, there was no hemodynamic instability (mean blood pressure monitoring, initial median, 80 mm Hg; Q1, Q3, 70, 86 mm Hg; final median, 88 mm Hg; Q1, Q3, 80, 96 mm Hg; P =0.426). In these 15, a mild hemorrhagic pericardial effusion was identified and aspirated (median, 20 mL; Q1, Q3, 15, 30 mL) during the procedure, and postmortem gross analysis revealed that the atrial perforation was closed in these animals. In 2 (12%) of the 17 animals, there was major pericardial bleeding with hemodynamic collapse. On gross examination, it was found that pericardial space was accessed through right ventricular perforation in 1 animal and the tricuspid annulus in the other. After the initial study, we used an occlusion device in 3 other animals to attempt to seal the puncture (2 at the right atrial appendage and 1 at the right ventricle). These 3 animals had no significant pericardial bleeding. Conclusions— Transatrial endovascular right atrial appendage puncture may provide a potential alternative route for pericardial access. Further studies are needed to evaluate its safety with longer and more-complex procedures before being applied in clinical settings.

FUNDAMENTO: A ocorrência de fibrilação atrial (FA) após a ablação com sucesso do flutter atrial istmo cavo-tricuspídeo (FLA-ICT) dependente consiste em um evento de importância clínica. Os fatores preditores dessa ocorrência ainda são controversos. OBJETIVO: Determinar a incidência de FA e os fatores preditores para a sua ocorrência nos pacientes submetidos a ablação do flutter atrial istmo cavo-tricuspídeo (FLA-ICT) dependente. MÉTODOS: Cinquenta e dois pacientes portadores de FLA-ICT foram submetidos à ablação no período de janeiro de 2003 a março de 2004, no InCor do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. RESULTADOS: Durante o seguimento médio de 26,2 (± 9,2) meses, 16 (30,8%) pacientes apresentaram FA. A análise univariada revelou duas variáveis clínicas como preditoras de ocorrência de FA após a ablação do FLA-ICT maior ou igual a três anos (RR: 3,00; P = 0,020). Na análise multivariada, esses fatores foram variáveis independentes associadas à ocorrência de FA após ablação do FLA-ICT. CONCLUSÃO: A FA é frequentemente observada durante o seguimento dos pacientes após ablação de FLA-ICT dependente. O FLA-ICT persistente e a história de arritmia maior que três anos são fatores preditores para a ocorrência de FA durante o seguimento clínico. BACKGROUND: The occurrence of atrial fibrillation (AF) after successful ablation of cavotricuspid isthmus-dependent atrial flutter (CTI-AFL) is an important medical event, but predictors of this event are still controversial. OBJECTIVE: To determine the incidence of AF and its predictors in patients undergoing ablation of cavotricuspid isthmus-dependent atrial flutter (CTI-AFL). METHODS: Fifty two patients with CTI-AFL underwent ablation from January 2003 to March 2004, in Instituto do Coração (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. RESULTS: During the mean follow-up period of 26.2 ± 9.2 months, 16 (30.8%) patients presented AF. The univariate analysis revealed two clinical variables as predictive of the occurrence of AF after ablation of CTI-AFL for three years or longer (RR: 3.00; p = 0.020). In the multivariate analysis, these factors were independent variables associated with the occurrence of AF after ablation of CTI-AFL. CONCLUSION: AF is frequently observed during the follow-up of patients undergoing ablation of CTI-AFL. Persistent CTI-AFL and history of arrhythmia for more than three years are predictors of the occurrence of AF during the clinical follow-up. FUNDAMENTO: La ocurrencia de fibrilación atrial (FA) tras la ablación con éxito del flutter atrial istmo cavotricuspídeo (FLA-ICT) dependiente consiste en un evento de importancia clínica. Los factores predictores de esta ocurrencia todavía son controvertidos. OBJETIVO: Determinar la incidencia de FA y los factores predictores para su ocurrencia en los pacientes sometidos a la ablación del flutter atrial istmo cavotricuspídeo (FLA-ICT) dependiente. MÉTODOS: Cincuenta y dos pacientes portadores de FLA-ICT se sometieron a la ablación en el período de enero de 2003 a marzo de 2004, en el InCor del Hospital de Clínicas de la Facultad de Medicina de la Universidad de São Paulo. RESULTADOS: Durante el seguimiento promedio de 26,2 (± 9,2) meses, 16 (30,8%) pacientes presentaron FA. El análisis univariado reveló dos variables clínicos como predictoras de ocurrencia de FA después de la ablación del FLA-ICT mayor o igual a tres años (RR: 3,00; P = 0,020). En el análisis multivariado, estos factores fueron variables independientes asociadas a la ocurrencia de FA tras ablación del FLA-ICT. CONCLUSIÓN: La FA se observa frecuentemente durante el seguimiento de los pacientes tras la ablación de FLA-ICT dependiente. El FLA-ICT persistente y la historia de arritmia mayor que tres años son factores predictores para la ocurrencia de FA durante el seguimiento clínico.

A 15-year-old female patient presented with frequent episodes of vasovagal syncope refractory to non-pharmacological and pharmacological measures. Two tilt-table tests performed before and after conventional therapy were positive and reproduced the patient's clinical symptoms. Selective vagal denervation, guided by HFS, was performed. Six radiofrequency pulses were applied on the left and right sides of the interatrial septum, abolishing vagal responses at these locations. Basal sinus node and Wenckebach cycle lengths changed significantly following ablation. A tilt test performed after denervation was negative and revealed autonomic tone modification. The patient reported significant improvement in quality of life and remained asymptomatic for 9 months after denervation. After this period, three episodes of NMS occurred during a 4-month interval and a tilt test performed 11 months after the procedure demonstrated vagal activity recovery.

The occurrence of atrial fibrillation (AF) after successful ablation of cavotricuspid isthmus-dependent atrial flutter (CTI-AFL) is an important medical event, but predictors of this event are still controversial.To determine the incidence of AF and its predictors in patients undergoing ablation of cavotricuspid isthmus-dependent atrial flutter (CTI-AFL).Fifty two patients with CTI-AFL underwent ablation from January 2003 to March 2004, in Instituto do Coração (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo.During the mean follow-up period of 26.2 +/- 9.2 months, 16 (30.8%) patients presented AF. The univariate analysis revealed two clinical variables as predictive of the occurrence of AF after ablation of CTI-AFL for three years or longer (RR: 3.00; p = 0.020). In the multivariate analysis, these factors were independent variables associated with the occurrence of AF after ablation of CTI-AFL.AF is frequently observed during the follow-up of patients undergoing ablation of CTI-AFL. Persistent CTI-AFL and history of arrhythmia for more than three years are predictors of the occurrence of AF during the clinical follow-up.

Radiofrequency ablation of the pulmonary veins has been used to treat patients with paroxysmal atrial fibrillation (AF), and atrial damage after ablation is an issue of concern. To evaluate left atrial function shortly and midterm after ablation, 33 consecutive patients with paroxysmal AF were studied at baseline, 24 hours, and > or =6 months after ablation. Patients in sinus rhythm with normal ventricular function were included in the study. Echocardiographic measurements of left atrial volumes (Simpson's rule) and transmitral and tissue Doppler myocardial (A') velocities at the septal and lateral mitral annulus were undertaken at each time. Left atrial emptying fraction (EF; maximal - minimal left atrial volume/maximal left atrial volume) was used to express left atrial function. After 8 +/- 2 months, 30 of 33 patients returned (23 men, age 53 +/- 13 years), and all except 2 were in sinus rhythm. Shortly after ablation, left atrial minimal volumes increased (from 30 +/- 15 to 35 +/- 15 ml; p = 0.02), with maximal volumes unchanged, resulting in decreased left atrial EF (from 47 +/- 8 to 40 +/- 7 ml; p