Analysis of Conduction Intervals in Normal Electrophysiological Studies: Establishment of Reference Values the Brazilian Population

Abstract Background In the investigation of cardiac rhythm disorders, a normal electrophysiological (EPS) study is associated with a favorable prognosis. One of the normality criteria is established by conduction intervals within expected range. Objective To establish reference values in EPS for the intracavitary conduction intervals (PA, AH and HV) in a Brazilian population. Methods A retrospective cohort study of the first 1,500 patients submitted to EPS ablation was performed at Instituto de Cardiologia do Rio Grande do Sul, Brazil. The EPS was considered normal if the test was performed for diagnostic purpose; absence of induced arrhythmias; and conduction intervals within the expected range. The REDCap software was used for data collection and management, and the SPSS Statistics 22.0 used for data analysis. Continuous variables were compared with Student's t-test for independent samples and categorical variables with the chi-square test (X 2 ). Values of p ≤ 0.05 were considered significant. Results A total of 124 (8.3%) with EPS considered normal were included; mean age was 52 ± 21 years, and 63 were male. The mean values in milliseconds of PA, AH and HV were 23 ± 9, 88 ± 25 and 44 ± 7, respectively. The PA, AH, and HV percentile ranges were 13 - 25, 81-107 and 40 - 52, respectively. When the patients were divided into three age groups (1 to 18 years, 19 to 64 years and 65 or more), we observed that the group of older patients had significantly higher values of PA, AH and HV compared with younger patients. Conclusion This study showed that intracavitary conduction intervals in a sample of the Brazilian population were similar to previously published studies. Elderly patients tend to have higher values of intracavitary conduction intervals in EPS. Future studies including broader age ranges could enable the acquisition of more reliable and reproducible reference values. (Int J Cardiovasc Sci. 2020; [online].ahead print, PP.0-0)

Internal Validation of a Risk Score for Prediction of Postoperative Atrial Fibrillation after Cardiac Surgery

Abstract Background: Postoperative atrial fibrillation (POAF) after cardiac surgery has great clinical and economic implications. Many attempts have been made to identify risk factors aiming at a better evaluation of prophylactic treatment strategies. Objective: To perform an internal validation of a risk score for POAF. Methods: A prospective cohort of 1,054 patients who underwent myocardial revascularization and/or valve surgery was included. The risk score model was developed in 448 patients, and its performance was tested in the remaining 606 patients. Variables with a significance level of 5% in the cohort were included and subjected to a multiple logistic regression model with backward selection. Performance statistics was performed using the c-statistic, the chi-square and the Hosmer-Lemeshow (HL) goodness-of-fit, Pearson's correlation coefficient. Results: Four variables were considered predictors of outcome: age (≥ 70 years), mitral valve disease, the non-use or discontinuation of beta-blockers and a positive water balance (> 1,500 mL). The ROC curve was 0.76 (95% confidence interval [CI]: 0.72-0.79). The risk model showed a good ability according to the performance statistics - HL test x(2) = 0.93; p = 0.983 and r = 0.99 (Pearson's coefficient). There was an increase in the frequency of POAF with the increase of the score: very low risk = 0.0%; low risk = 3.9%; intermediate risk = 10.9%; and high risk = 60.0%; p < 0.0001. Conclusion: The predictive variables of POAF allowed us to construct a simplified risk score. This scoring system showed good accuracy and can be used in routine clinical practice.

Recurrencia de fibrilación auricular posablación de venas pulmonares. Identificación de factores predictores / Atrial fibrillation recurrence post pulmonary vein ablation. Identification of predictive factors / Recorrência da fibrilação atrial pós-ablação das veias pulmonares. Identificação de fatores preditivos

Resumen: La ablación de la fibrilación auricular mediante el aislamiento de las venas pulmonares, es una estrategia ampliamente utilizada en la actualidad. La recurrencia posablación es un problema frecuente. Se han investigado varios predictores de recurrencia con el fin de optimizar la elección del paciente que más se beneficia del procedimiento. Actualmente la evidencia es controvertida, siendo necesarios más estudios al respecto.

Summary: The ablation of atrial fibrillation based on pulmonary veins isolation, is a widely used strategy nowadays. Post ablation recurrence is a frequent problem. Several recurrence predictors have been researched, with the purpose of choosing the patient that would benefit the most from this procedure. Current evidence is controversial and more research is needed.

Non-fluoroscopic catheter ablation: A randomized trial.

BACKGROUND: Catheter ablation provides curative treatment for tachyarrhythmias. Fluoroscopy, the method used for this, presents several risks. The electroanatomical mapping (MEA) presents a three-dimensional image without using X-rays, and may be adjunct to fluoroscopy. OBJECTIVES: We evaluated the possibility of performing catheter ablation with the exclusive use of electroanatomical mapping (MEA), dispensing with fluoroscopy. We compared the total time of procedure and success rates against the technique using fluoroscopy (RX) with emission of X-rays. METHODS: Randomized, unicentric, uni-blind study of patients referred for tachyarrhythmia ablation. RESULTS: Twelve patients were randomized to the XR group and 11 to the EAM group. The mean age was 48.5 (±12.6) vs 46.3 (±16.6) (P = ns). Success occurred in 11 patients (91.7%) in the RX group and 9 (81.8%) in the MEA group (P = 0.46). The procedure time in minutes was higher in the MEA group than in the RX group (79-47-125min vs 49-30-100min; P = 0.006). The mean fluoroscopy time was 11 ±â€¯9 min versus zero (RX vs MEA: P < 0.001). The mean radiofrequency applications were lower in the RX group against the MEA group (6 ±â€¯3.5 × 13.2 ±â€¯18.2 p < 0.019). There were no complications. CONCLUSION: MEA opened new therapeutic possibilities for patients with arrhythmias, reducing the risk of radiation. In this study, it was possible to demonstrate that it is feasible to perform ablation only with the use of MEA, with similar success with fluoroscopy, at the expense of a longer procedure time.

Coronary sinus cannulation predicts atrioventricular nodal reentry as mechanism of supraventricular tachycardia.

INTRODUCTION: Common clinical teaching, for invasive electrophysiology, is that if the first year fellow cannulates the coronary sinus (CS) in his first attempt, the arrhythmia is more likely to be atrioventricular nodal reentry tachycardia (AVNRT). This general perception has not yet been clinically tested. We evaluated this theory in prospective patients undergoing an electrophysiological study (EPS) for paroxysmal supraventricular tachycardia (PSVT). METHODS: Cohort study. CS ease of cannulation (CSCS) was graded as: 1) 1st year fellow cannulates in first attempt; 2) 1st year fellow needs more than one attempt or maneuver to cannulate the CS; 3) staff physician cannulates in first attempt after the fellow was unsuccessful; 4) staff physician requires more than one maneuver to cannulate the CS; 5) staff physician judges that the cannulation process was extremely difficult. RESULTS: Of the 1361 patients undergoing EPS in our institution, 165 were selected. Age was 49 ±â€¯15 years. AVNRT occurred in 77.6%, atrioventricular reentry tachycardia (AVRT) in 15.1% and atrial tachycardia (AT) in 7.3% of cases. The CSCS = 1 was more prevalent in AVNRT, 89% versus 68% AVRT and 58.3% of AT (P = 0.0005). Patients with CSCS = 1 have a higher chance of the PSVT being AVNRT (odds ratio: 4.41; 95CI: 1.84-10.56; P = 0.0009). CONCLUSION: The CSCS predicts the likelihood of the induced PSVT being AVNRT as compared to AVRT and AT. More studies are required to try to associate this finding to clinical patient characteristics to create a score for PSVT mechanism prediction.

Cohort of Patients Referred for Brugada Syndrome Investigation in an Electrophysiology Service - 19-Year Registry / Coorte de Pacientes Encaminhados para Investigação de Síndrome de Brugada em um Serviço Terciário de Eletrofisiologia - Registro de 19 Anos

Abstract Background: Brugada syndrome (SBr) is an arrhythmic condition characterized by ST-T segment abnormalities in the right precordial leads associated with a high risk of ventricular arrhythmias and sudden death. Local data regarding the clinical characteristics of patients with a typical electrocardiographic (ECG) pattern undergoing electrophysiological study are scarce. Objective: To evaluate patients with an ECG pattern suggestive of SBr referred for electrophysiological evaluation in a specialized center. Methods: Cohort study of patients referred for electrophysiological study because of an ECG pattern compatible with SBr between January 1998 and March 2017. Results: Of the 5506 procedures, 35 (0.64%) were for SBr investigation, 25 of which (71.42%) were performed in men. The mean age was 43.89 ± 13.1 years. The ECG patterns were as follows: type I, 22 (62.85%); type II, 12 (34.30%); and type III, 1 (2.85%). Twenty-three patients (65.7%) were asymptomatic, 6 (17.14%) had palpitations, 5 (14.3%) had syncope, and 3 (8.6%) had a family history of sudden death. Electrophysiological study induced ventricular tachyarrhythmias in 16 cases (45.7%), the mean ventricular refractory period being 228 ± 36 ms. Ajmaline / procainamide was used in 11 cases (31.4%), changing the ECG pattern to type I in 7 (63.6%). Sixteen cases (45.7%) received an implantable cardioverter defibrillator (ICD). In a mean 5-year follow-up, 1 of the 16 patients (6.25%) with ICD had appropriate therapy for ventricular fibrillation. There was no death. Other arrhythmias occurred in 4 (11.4%) cases. Conclusions: Most patients are men, and a type I ECG pattern is the main indication for electrophysiological study. Class IA drugs have a high ECG conversion rate. The ICD event rate was 6%. (Arq Bras Cardiol. 2018; [online].ahead print, PP.0-0)

Resumo Fundamento: Síndrome de Brugada (SBr) é uma condição arrítmica definida por anormalidades do segmento ST-T em derivações V1-V3 associada a risco elevado de arritmias ventriculares e morte súbita. Dados locais quanto às características clínicas dos pacientes com padrão eletrocardiográfico (ECG) típico avaliados por estudo eletrofisiológico (EEF) são escassos. Objetivo: Avaliar pacientes com padrão ECG sugestivo de SBr encaminhados para EEF em um centro especializado. Métodos: Estudo de coorte de casos encaminhados para EEF por padrão ECG compatível com SBr, entre janeiro de 1998 e março de 2017. Resultados: Dos 5506 procedimentos, 35 (0,64%) foram para investigação de SBr. Vinte e cinco (71,42%) eram homens. Idade média 43,89 ± 13,1 anos. Apresentação ECG foi tipo I em 22 casos (62,85%), tipo II em 12 (34,30%) e tipo III em 1 (2,85%). Vinte e três (65,7%) eram assintomáticos, 6 (17,14%) apresentavam palpitações, 5 (14,3%) síncope, 3 (8,6%) história familiar de morte súbita. Estudo eletrofisiológico induziu taquiarritmias ventriculares em 16 casos (45,7%), sendo o período refratário ventricular médio de 228 ± 36 ms. Utilizou-se ajmalina/procainamida em 11 casos (31,4%), sendo o padrão ECG transformado em tipo I em 7 (63,6%). Dezesseis casos (45,7%) receberam cardiodes fibrilador (CDI). Em seguimento médio de 5 anos, 1 dos 16 pacientes (6,25%) com CDI teve terapia apropriada para fibrilação ventricular. Nenhuma morte foi registrada. Outras arritmias ocorreram em 4 (11,4%) casos. Conclusões: Homens são maioria, sendo o padrão ECG tipo I a principal indicação de EEF. Droga classe IA possui alta taxa de conversão do padrão ECG. A taxa de eventos no CDI foi de 6%. (Arq Bras Cardiol. 2018; [online].ahead print, PP.0-0)

Cohort of Patients Referred for Brugada Syndrome Investigation in an Electrophysiology Service - 19-Year Registry.

BACKGROUND: Brugada syndrome (SBr) is an arrhythmic condition characterized by ST-T segment abnormalities in the right precordial leads associated with a high risk of ventricular arrhythmias and sudden death. Local data regarding the clinical characteristics of patients with a typical electrocardiographic (ECG) pattern undergoing electrophysiological study are scarce. OBJECTIVE: To evaluate patients with an ECG pattern suggestive of SBr referred for electrophysiological evaluation in a specialized center. METHODS: Cohort study of patients referred for electrophysiological study because of an ECG pattern compatible with SBr between January 1998 and March 2017. RESULTS: Of the 5506 procedures, 35 (0.64%) were for SBr investigation, 25 of which (71.42%) were performed in men. The mean age was 43.89 ± 13.1 years. The ECG patterns were as follows: type I, 22 (62.85%); type II, 12 (34.30%); and type III, 1 (2.85%). Twenty-three patients (65.7%) were asymptomatic, 6 (17.14%) had palpitations, 5 (14.3%) had syncope, and 3 (8.6%) had a family history of sudden death. Electrophysiological study induced ventricular tachyarrhythmias in 16 cases (45.7%), the mean ventricular refractory period being 228 ± 36 ms. Ajmaline / procainamide was used in 11 cases (31.4%), changing the ECG pattern to type I in 7 (63.6%). Sixteen cases (45.7%) received an implantable cardioverter defibrillator (ICD). In a mean 5-year follow-up, 1 of the 16 patients (6.25%) with ICD had appropriate therapy for ventricular fibrillation. There was no death. Other arrhythmias occurred in 4 (11.4%) cases. CONCLUSIONS: Most patients are men, and a type I ECG pattern is the main indication for electrophysiological study. Class IA drugs have a high ECG conversion rate. The ICD event rate was 6%. (Arq Bras Cardiol. 2018; [online].ahead print, PP.0-0).

Uninterrupted Use of Oral Anticoagulants for the Ablation of Atrial Flutter: A Single Center Cohort of 154 Patients.

BACKGROUND: The uninterrupted use of oral anticoagulation (OAC) with vitamin K antagonists (VKAs) for electrophysiology procedures has been more and more recommended. The clinical practice in our service recommends the continuous use of these drugs for atrial flutter ablation. There is little evidence as to the uninterrupted use of non-vitamin K antagonist oral anticoagulants (NOACs) in this scenario. OBJECTIVE: To compare the rates of complications related with the uninterrupted use of different types of oral anticoagulants in patients referred to atrial flutter (AFL) ablation. METHODS: Historical, single-center cohort of ablation procedures by AFL conducted from November 2012 to April 2016. The primary outcome was the occurrence of hemorrhagic or embolic complication during the procedure. The secondary outcome was the occurrence of stroke or transient ischemic attack (TIA) in follow-up. The statistical significance level was 5%. RESULTS: There were 288 ablations per AFL; 154 were carried out with the uninterrupted use of OAC (57.8% with VKA and 42.2% with NOAC). Mean age was 57 ± 13 years. The rate of hemorrhagic complication during the procedure was 3% in each group (p = NS). The rate of stroke/TIA was, respectively, of 56/1,000 people-year in the VKA group against zero/1,000 people-year in the NOAC group (p = 0.02). CONCLUSION: In our population there were no hemorrhagic complications regarding the procedure of OAC use uninterruptedly, including NOACs. There was higher occurrence of stroke/TIA in the follow-up of the group of patients undergoing VKAs; however, this difference may not only be a result of the type of OAC used.

Uninterrupted Use of Oral Anticoagulants for the Ablation of Atrial Flutter: A Single Center Cohort of 154 Patients / Uso Ininterrupto de Anticoagulantes Orais na Ablação de Flutter Atrial Istmo-Cavotricuspídeo Dependente: Coorte Unicêntrica de 154 Pacientes

Abstract Background: The uninterrupted use of oral anticoagulation (OAC) with vitamin K antagonists (VKAs) for electrophysiology procedures has been more and more recommended. The clinical practice in our service recommends the continuous use of these drugs for atrial flutter ablation. There is little evidence as to the uninterrupted use of non-vitamin K antagonist oral anticoagulants (NOACs) in this scenario. Objective: To compare the rates of complications related with the uninterrupted use of different types of oral anticoagulants in patients referred to atrial flutter (AFL) ablation. Methods: Historical, single-center cohort of ablation procedures by AFL conducted from November 2012 to April 2016. The primary outcome was the occurrence of hemorrhagic or embolic complication during the procedure. The secondary outcome was the occurrence of stroke or transient ischemic attack (TIA) in follow-up. The statistical significance level was 5%. Results: There were 288 ablations per AFL; 154 were carried out with the uninterrupted use of OAC (57.8% with VKA and 42.2% with NOAC). Mean age was 57 ± 13 years. The rate of hemorrhagic complication during the procedure was 3% in each group (p = NS). The rate of stroke/TIA was, respectively, of 56/1,000 people-year in the VKA group against zero/1,000 people-year in the NOAC group (p = 0.02). Conclusion: In our population there were no hemorrhagic complications regarding the procedure of OAC use uninterruptedly, including NOACs. There was higher occurrence of stroke/TIA in the follow-up of the group of patients undergoing VKAs; however, this difference may not only be a result of the type of OAC used.

Resumo Fundamento: O uso ininterrupto de anticoagulação oral (ACO) com antagonistas da vitamina K (AVKs) para procedimentos de eletrofisiologia está sendo cada vez mais recomendado. A prática clínica em nosso serviço é de uso continuado dessas drogas para ablação de flutter atrial. Existem poucas evidências quanto ao uso ininterrupto dos anticoagulantes orais não antagonistas da vitamina K (NOACs) nesse cenário. Objetivos: Comparar as taxas de complicações relacionadas ao uso ininterrupto de diferentes tipos de anticoagulantes orais em pacientes referidos para ablação por flutter atrial (FLA). Métodos: Coorte histórica e unicêntrica dos procedimentos de ablação por FLA realizados no período de novembro de 2012 a abril de 2016. O desfecho primário foi o de ocorrência de complicação hemorrágica ou embólica durante o procedimento. O desfecho secundário foi o de ocorrência de acidente vascular cerebral (AVC) ou acidente isquêmico transitório (AIT) no acompanhamento. O nível de significância estatística adotado foi de 5%. Resultados: Foram incluídas 288 ablações por FLA; 154 foram feitas com uso ininterrupto de ACO (57,8% com AVK e 42,2% com NOAC). A idade média foi de 57 ± 13 anos. A taxa de complicação hemorrágica durante o procedimento foi de 3% em cada grupo (p = NS). A taxa de AVC/AIT foi, respectivamente, de 56/1.000-pessoas-ano no grupo AVK contra zero/1.000-pessoas-ano no grupo NOAC (p = 0,02). Conclusão: Em nossa população não ocorreram complicações hemorrágicas relacionadas ao procedimento com uso de ACO de forma ininterrupta, incluindo NOACs. Houve maior ocorrência de AVC/AIT no seguimento no grupo de pacientes em uso de AVK, contudo essa diferença pode não ser decorrente apenas do tipo de ACO em uso.

CHA2 DS2 VASc Score as a Predictor of Cardiovascular Events in Ambulatory Patients without Atrial Fibrillation.

BACKGROUND: New evidence suggests that the CHA(2)DS(2)VASc (congestive heart failure, hypertension [HTN], age, diabetes, stroke, vascular disease, and female gender) score may be a reliable tool to predict the risk of thromboembolic events in patients without documented atrial fibrillation (AF). METHODS: We performed a prospective cohort study of outpatients without AF or flutter, who were not using oral anticoagulation. Clinical characteristics were assessed and patients were stratified according to the CHA(2)DS(2)VASc score. We evaluated the incidence of major adverse cardiac outcomes and its relation to the CHA(2)DS(2)VASc score during the follow-up. RESULTS: Four hundred sixty-eight patients without AF were enrolled with a mean follow-up of 12 ± 6 months. Age was 64.9 ± 11.3 years. The prevalence of HTN was 88.4%, diabetes 37.6%, heart failure 26.3%, and vascular disease 61.7%. Overall, CHA(2)DS(2)VASc score was 3.4 ± 1.4. There were 15 major adverse cardiac outcomes during 12.2 months of follow-up (overall incidence of 3.2 per 100 person-years). We found significant differences in relation to gender, age, previous stroke, and follow-up length in patients with and without adverse outcomes. The CHA(2)DS(2)VASc score was higher in those with adverse outcomes (4.2 ± 1.7 vs 3.4 ± 1.4; P = 0.035). Patients with a CHA(2)DS(2)VASc ≥6 had a relative risk for adverse outcomes of 4.2 (95% confidence interval: 1.27-13.90). CONCLUSIONS: In our population, CHA(2)DS(2)VASc score predicts major adverse cardiac outcomes, including stroke and death, in a cohort of patients without AF.

Clinical Differences between Subtypes of Atrial Fibrillation and Flutter: Cross-Sectional Registry of 407 Patients / Diferenças Clínicas entre Subtipos de Fibrilação Atrial e Flutter: Registro Transversal de 407 Pacientes

Atrial fibrillation and atrial flutter account for one third of hospitalizations due to arrhythmias, determining great social and economic impacts. In Brazil, data on hospital care of these patients is scarce.

Clinical Differences between Subtypes of Atrial Fibrillation and Flutter: Cross-Sectional Registry of 407 Patients.

INTRODUCTION: Atrial fibrillation and atrial flutter account for one third of hospitalizations due to arrhythmias, determining great social and economic impacts. In Brazil, data on hospital care of these patients is scarce. OBJECTIVE: To investigate the arrhythmia subtype of atrial fibrillation and flutter patients in the emergency setting and compare the clinical profile, thromboembolic risk and anticoagulants use. METHODS: Cross-sectional retrospective study, with data collection from medical records of every patient treated for atrial fibrillation and flutter in the emergency department of Instituto de Cardiologia do Rio Grande do Sul during the first trimester of 2012. RESULTS: We included 407 patients (356 had atrial fibrillation and 51 had flutter). Patients with paroxysmal atrial fibrillation were in average 5 years younger than those with persistent atrial fibrillation. Compared to paroxysmal atrial fibrillation patients, those with persistent atrial fibrillation and flutter had larger atrial diameter (48.6 ± 7.2 vs. 47.2 ± 6.2 vs. 42.3 ± 6.4; p < 0.01) and lower left ventricular ejection fraction (66.8 ± 11 vs. 53.9 ± 17 vs. 57.4 ± 16; p < 0.01). The prevalence of stroke and heart failure was higher in persistent atrial fibrillation and flutter patients. Those with paroxysmal atrial fibrillation and flutter had higher prevalence of CHADS2 score of zero when compared to those with persistent atrial fibrillation (27.8% vs. 18% vs. 4.9%; p < 0.01). The prevalence of anticoagulation in patients with CHA2DS2-Vasc ≤ 2 was 40%. CONCLUSIONS: The population in our registry was similar in its comorbidities and demographic profile to those of North American and European registries. Despite the high thromboembolic risk, the use of anticoagulants was low, revealing difficulties for incorporating guideline recommendations. Public health strategies should be adopted in order to improve these rates.

Electrophysiological Studies and Radiofrequency Ablations in Children and Adolescents with Arrhythmia / Estudos Eletrofisiológicos e Ablações com Radiofrequência em Crianças e Adolescentes com Arritmia

Background: Radiofrequency ablation is the standard non-pharmacological treatment for arrhythmias in pediatric patients. However, arrhythmias and their associated causes have particular features in this population. Objective: To analyze the epidemiological characteristics and findings of electrophysiological diagnostic studies and radiofrequency ablations in pediatric patients referred to the Electrophysiology Unit at Instituto de Cardiologia do Rio Grande do Sul, in order to characterize the particularities of this population. Methods: Cross-sectional study with 330 electrophysiological procedures performed in patients aged less than 20 years between June 1997 and August 2013. Results: In total, 330 procedures (9.6% of the overall procedures) were performed in patients aged less than 20 years (14.33 ± 3.25 years, age range 3 months to 19 years), 201 of which were males (60.9%). A total of 108 (32.7%) electrophysiological diagnostic studies were performed and of these, 48.1% showed abnormal findings. Overall, 219 radiofrequency ablations were performed (66.3%) with a success rate of 84.8%. The presence of an accessory pathway was the most prevalent finding, occurring in 158 cases (72.1%), followed by atrioventricular nodal reentrant tachycardia (16.8%), typical atrial flutter (3.1%) and extrasystoles originating from the right ventricular outflow tract (2.7%). Three patients developed complications during ablation (1.4%). Among congenital heart diseases, which occurred in 51 (15.4%) patients, atrial sept defect was the most frequent (27.4%), followed by ventricular sept defect (25.4%) and Ebstein's anomaly (17.6%). Conclusion: Electrophysiological study and radiofrequency ablation are effective tools for diagnosis and treatment of arrhythmias in the pediatric population. .

Fundamento: A ablação com radiofrequência é o tratamento não farmacológico de eleição para arritmias na população pediátrica. Porém, as arritmias e suas causas apresentam características particulares nesta população. Objetivos: Analisar as características epidemiológicas e os achados de estudo eletrofisiológico diagnóstico e ablação com radiofrequência na população pediátrica encaminhada à Eletrofisiologia do Instituto de Cardiologia do Rio Grande do Sul, a fim de caracterizar as suas particularidades. Resultados: Foram realizados 330 procedimentos (9,6% do total de procedimentos) em pacientes com idade inferior a 20 anos (14,33 ± 3,25 anos, variação entre 3 meses e 19 anos), dos quais 201 eram do sexo masculino (60,9%). Foram realizados 108 (32,7%) exames eletrofisiológicos diagnósticos e destes, 48,1% apresentaram anormalidades em seus achados. Ao todo, 219 ablações com radiofrequência foram realizadas (66,3%), obtendo-se sucesso em 84,8%. A presença de feixe acessório foi o achado mais prevalente, responsável por 158 casos (72,1%), seguida de taquicardia por reentrada nodal atrioventricular (16,8%), flutter atrial típico (3,1%) e extrassístole de via de saída de ventrículo direito (2,7%). Três pacientes apresentaram complicações durante a ablação (1,4%). Cardiopatia congênita esteve presente em 51 (15,4%) casos, sendo a comunicação interatrial a mais encontrada (27,4%), seguida de comunicação interventricular (25,4%) e anomalia de Ebstein (17,6%). Conclusão: Estudo eletrofisiológico e ablação com radiofrequência constituem ferramentas eficazes no diagnóstico e tratamento das arritmias na população pediátrica. .

Electrophysiological studies and radiofrequency ablations in children and adolescents with arrhythmia.

BACKGROUND: Radiofrequency ablation is the standard non-pharmacological treatment for arrhythmias in pediatric patients. However, arrhythmias and their associated causes have particular features in this population. OBJECTIVE: To analyze the epidemiological characteristics and findings of electrophysiological diagnostic studies and radiofrequency ablations in pediatric patients referred to the Electrophysiology Unit at Instituto de Cardiologia do Rio Grande do Sul, in order to characterize the particularities of this population. METHODS: Cross-sectional study with 330 electrophysiological procedures performed in patients aged less than 20 years between June 1997 and August 2013. RESULTS: In total, 330 procedures (9.6% of the overall procedures) were performed in patients aged less than 20 years (14.33 ± 3.25 years, age range 3 months to 19 years), 201 of which were males (60.9%). A total of 108 (32.7%) electrophysiological diagnostic studies were performed and of these, 48.1% showed abnormal findings. Overall, 219 radiofrequency ablations were performed (66.3%) with a success rate of 84.8%. The presence of an accessory pathway was the most prevalent finding, occurring in 158 cases (72.1%), followed by atrioventricular nodal reentrant tachycardia (16.8%), typical atrial flutter (3.1%) and extrasystoles originating from the right ventricular outflow tract (2.7%). Three patients developed complications during ablation (1.4%). Among congenital heart diseases, which occurred in 51 (15.4%) patients, atrial sept defect was the most frequent (27.4%), followed by ventricular sept defect (25.4%) and Ebstein's anomaly (17.6%). CONCLUSION: Electrophysiological study and radiofrequency ablation are effective tools for diagnosis and treatment of arrhythmias in the pediatric population.

Major bleeding risk assessment in atrial fibrillation patients taking vitamin K antagonists

The use of risk scores for the assessment of major bleeding and stroke in patients with atrial fibrillation (AF) helps evaluate the risks and benefits of oral anticoagulation therapy. The aim of this study was to describe the percentage of patients receiving anticoagulants for non-valvular AF with a high risk of major bleeding based on the HAS-BLED score, as well as identify potential modifiable risk factors of bleeding and compare the risk of major bleeding with the risk of stroke. Methods: Retrospective cohort study involving patients of the anticoagulation outpatient clinic of the Division of Internal Medicine at Hospital de Clínicas de Porto Alegre. Major bleeding risk was estimated based on the HAS-BLED score and stroke risk was determined using the CHADS2 and CHA2 DS2 -VASc scores. Results: Sixty-three patients were investigated (mean age 74.3±10.9 years). The median HAS-BLED score was 2 points, 19 (30.2%) patients had a score ≥ 3 (high risk). The most prevalent modifiable risk factors were labile TP/INR (36.5%) and concomitant use of drugs (30.2%). The absolute risk of major bleeding based on the HAS-BLED score was higher than the risk of stroke in three (4.8%) and four (6.3%) patients in comparison with the CHADS2 and CHA2 DS2 -VASc score, respectively. Conclusions: We concluded that the percentage of patients with high risk of major bleeding is similar to the rate found in the national literature (30.2%). In addition, the most prevalent modifiable risk factors in our cohort were labile TP/INR and concomitant drug use...

Relationship between silent atrial fibrillation and the maximum heart rate in the 24-hour Holter: cross-sectional study / Relação entre fibrilação atrial silenciosa e frequência cardíaca máxima no Holter de 24 horas: estudo transversal

CONTEXT AND OBJECTIVE: Occurrences of asymptomatic atrial fibrillation (AF) are common. It is important to identify AF because it increases morbidity and mortality. 24-hour Holter has been used to detect paroxysmal AF (PAF). The objective of this study was to investigate the relationship between occurrence of PAF in 24-hour Holter and the symptoms of the population studied. DESIGN AND SETTING: Cross-sectional study conducted at a cardiology hospital. METHODS: 11,321 consecutive 24-hour Holter tests performed at a referral service were analyzed. Patients with pacemakers or with AF throughout the recording were excluded. RESULTS: There were 75 tests (0.67%) with PAF. The mean age was 67 ± 13 years and 45% were female. The heart rate (HR) over the 24 hours was a minimum of 45 ± 8 bpm, mean of 74 ± 17 bpm and maximum of 151 ± 32 bpm. Among the tests showing PAF, only 26% had symptoms. The only factor tested that showed a correlation with symptomatic AF was maximum HR (165 ± 34 versus 147 ± 30 bpm) (P = 0.03). Use of beta blockers had a protective effect against occurrence of PAF symptoms (odds ratio: 0.24, P = 0.031). CONCLUSIONS: PAF is a rare event in 24-hour Holter. The maximum HR during the 24 hours was the only factor correlated with symptomatic AF, and use of beta blockers had a protective effect against AF symptom occurrence. .

CONTEXTO E OBJETIVO: A ocorrência de fibrilação atrial (FA) assintomática é comum. A identificação da FA é importante e está associada com maior morbimortalidade. O Holter de 24 horas vem sendo utilizado para a detecção de FA paroxística (FAP). O objetivo desse estudo é investigar a relação entre a ocorrência de FAP no Holter de 24 horas e os sintomas na população estudada. TIPO DE ESTUDO E LOCAL: Estudo transversal realizado em um hospital de cardiologia. MÉTODOS: Análise de 11.321 exames consecutivos de Holter de 24 horas realizados em serviço de referência. Foram excluídos pacientes com marcapasso e aqueles com FA durante toda a gravação. RESULTADOS: Foram identificados 75 (0,67%) exames apresentando FAP. A idade média foi de 67 ± 13 anos e 45% eram do sexo feminino. A frequência cardíaca (FC) encontrada nas 24 horas foi mínima de 45 ± 8 bpm, média de 74 ± 17 bpm e máxima de 151 ± 32 bpm. Entre os exames apresentando FAP, apenas 26% apresentaram sintomas. O único fator testado que evidenciou correlação com FA sintomática foi a FC máxima (165 ± 34 versus 147 ± 30 bpm) (P = 0,03). O uso de betabloqueadores teve efeito protetor para ocorrência de sintomas na FA (odds ratio: 0.24, P = 0.031). CONCLUSÕES: A FAP é um evento raro em Holter de 24 horas. A FC máxima nas 24 horas foi o único fator relacionado com FA sintomática e o uso de betabloqueadores teve efeito protetor para ocorrência de sintomas na FA. .

Relationship between silent atrial fibrillation and the maximum heart rate in the 24-hour Holter: cross-sectional study.

CONTEXT AND OBJECTIVE: Occurrences of asymptomatic atrial fibrillation (AF) are common. It is important to identify AF because it increases morbidity and mortality. 24-hour Holter has been used to detect paroxysmal AF (PAF). The objective of this study was to investigate the relationship between occurrence of PAF in 24-hour Holter and the symptoms of the population studied. DESIGN AND SETTING: Cross-sectional study conducted at a cardiology hospital. METHODS: 11,321 consecutive 24-hour Holter tests performed at a referral service were analyzed. Patients with pacemakers or with AF throughout the recording were excluded. RESULTS: There were 75 tests (0.67%) with PAF. The mean age was 67 ± 13 years and 45% were female. The heart rate (HR) over the 24 hours was a minimum of 45 ± 8 bpm, mean of 74 ± 17 bpm and maximum of 151 ± 32 bpm. Among the tests showing PAF, only 26% had symptoms. The only factor tested that showed a correlation with symptomatic AF was maximum HR (165 ± 34 versus 147 ± 30 bpm) (P = 0.03). Use of beta blockers had a protective effect against occurrence of PAF symptoms (odds ratio: 0.24, P = 0.031). CONCLUSIONS: PAF is a rare event in 24-hour Holter. The maximum HR during the 24 hours was the only factor correlated with symptomatic AF, and use of beta blockers had a protective effect against AF symptom occurrence.

Management of anticoagulation with vitamin K antagonists in a tertiary hospital outpatient clinic

INTRODUCTION: Atrial fibrillation (AF) is one of the main risk factors for stroke. Vitamin K antagonists (VKA) reduce this risk, and the effectiveness of this treatment is directly related to time in therapeutic range (TTR). This study aimed to report the TTR in patients with non-valvular AF at an anticoagulation outpatient clinic; and to describe the profile of this population of patients in terms of risk of stroke, as well as the occurrence of adverse events during the follow-up. METHODS: Retrospective cohort study involving patients of the anticoagulation outpatient clinic of the Department of Internal Medicine at Hospital de Clínicas de Porto Alegre. We evaluated outpatient visits, hospital admissions, and emergency visits from January to December 2011. TTR was calculated using the Rosendaal method. RESULTS: Sixty-three patients were investigated. Their mean age was 74.3±10.9 years. The CHADS2 score was ≥ 4 in 44.5% of the patients; 63.5% of them had a CHA2 DS2 -VASc score ≥ 5. The TTR was 64.8%. During follow-up, the incidence of overall bleeding was 31.7%, with major and minor bleeding rates of 4.8% and 34.9%, respectively. There were no other complications related to AF or anticoagulation. CONCLUSION: The patients achieved a TTR of 64.8% during follow-up, which is deemed appropriate and in agreement with the literature. Patients had high risk for stroke, and the incidence of minor bleeding was higher than the rate found in the literature, whereas the incidence of major bleeding was similar to the one found in previous studies

Risco da radiação ionizante em mulheres férteis submetidas à ablação por radiofrequência / Risk of ionizing radiation in women of childbearing age undergoing radiofrequency ablation

FUNDAMENTO: A Comissão Internacional de Radiologia indica rastreamento com teste de gravidez a todas pacientes do gênero feminino em período fértil que serão submetidas a exame radiológico. Sabe-se que a radiação é teratogênica e que seu efeito é cumulativo. O potencial teratogênico inicia-se com doses próximas às das utilizadas durante esses procedimentos. Não se sabe a prevalência de teste de gravidez positivo em pacientes submetidos a estudo eletrofisiológico e/ou à ablação por cateter em nosso meio. OBJETIVO: Avaliar a prevalência de teste de gravidez positivo em pacientes do gênero feminino encaminhadas para estudo eletrofisiológico e/ou ablação por radiofrequência. MÉTODOS: Estudo transversal com análise de 2.966 pacientes submetidos a estudo eletrofisiológico e/ou ablação por cateter, de junho 1997 a fevereiro 2013, no Instituto de Cardiologia do Rio Grande do Sul. Foram realizados 1.490 exames em mulheres sendo que, destas, 769 encontravam-se em idade fértil. Todas as pacientes foram rastreadas com teste de gravidez no dia anterior ao procedimento. RESULTADOS: Detectou-se positividade do teste em três pacientes, impossibilitando a realização do exame. Observou-se prevalência de 3,9 casos por 1.000 mulheres em idade fértil. CONCLUSÃO: Devido ao baixo custo e à segurança, indica-se a realização de teste de rastreamento para gravidez a todas pacientes em idade fértil, uma vez que o grau de radiação ionizante necessária nesse procedimento é muito próximo ao limiar de teratogenicidade, principalmente no primeiro trimestre, quando os sinais de gestação não são exuberantes.

BACKGROUND: The International Commission of Radiology recommends a pregnancy screening test to all female patients of childbearing age who will undergo a radiological study. Radiation is known to be teratogenic and its effect is cumulative. The teratogenic potential starts at doses close to those used during these procedures. The prevalence of positive pregnancy tests in patients undergoing electrophysiological studies and/or catheter ablation in our midst is unknown. OBJECTIVE: To evaluate the prevalence of positive pregnancy tests in female patients referred for electrophysiological study and/or radiofrequency ablation. METHODS: Cross-sectional study analyzing 2966 patients undergoing electrophysiological study and/or catheter ablation, from June 1997 to February 2013, in the Institute of Cardiology of Rio Grande do Sul. A total of 1490 procedures were performed in women, of whom 769 were of childbearing age. All patients were screened with a pregnancy test on the day before the procedure. RESULTS: Three patients tested positive, and were therefore unable to undergo the procedure. The prevalence observed was 3.9 cases per 1000 women of childbearing age. CONCLUSION: Because of their safety and low cost, pregnancy screening tests are indicated for all women of childbearing age undergoing radiological studies, since the degree of ionizing radiation needed for these procedures is very close to the threshold for teratogenicity, especially in the first trimester, when the signs of pregnancy are not evident.