Brugada syndrome unmasked by left ventricle posteromedial papillary muscle ventricular tachycardia: Coincidence or consequence.

A 46-year-old man presented with left ventricle posteromedial papillary muscle ventricular tachycardia, presyncope, and a type-1 Brugada pattern on the post-electrical cardioversion electrocardiogram. There was a probability of a Brugada syndrome with the expression of its disease in the left ventricle; or a left monomorphic ventricular tachycardia as a part of Brugada phenocopy; or a Brugada syndrome with left monomorphic ventricular tachycardia as an epiphenomenon. Cardiac magnetic resonance, electrophysiological study, and ajmaline test were the key diagnostic tools employed.

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.

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.

Catheter ablation of typical right atrial flutter in a 20-day-old neonate with tachycardiomyopathy.

Background: Fetal echocardiography can diagnose neonatal atrial flutter, which can cause heart failure in newborns. Little is known about catheter ablation in this population. Methods: Case report that aimed to review a successful ablation in a 20-day-old patient with refractory atrial flutter. Results: This is the first report of a successful neonatal atrial flutter ablation without any early recurrence after the procedure. Conclusions: Atrial flutter ablation performed on newborns is a reliable and long-lasting treatment option.

Prognosis of programmed ventricular stimulation in adult patients with syncope of unexplained origin: A historical cohort.

Background: Programmed ventricular stimulation (PVS) during electrophysiological study (EPS), is a globally accepted tool for risk stratification of sudden cardiac death (SCD) in some specific clinical situations. The aim of this study was to evaluate the prognosis of ventricular arrhythmia induction in a cohort of patients with syncope of undetermined origin (SUO). Methods: This is a historical cohort study in a population of patients with SUO referred for EPS between the years 2008-2021. In this interval, 575 patients underwent the procedure. Results: Patients with induced ventricular arrhythmias had a higher occurrence of structural heart disease (36.7% vs. 76.5%), ischemic heart disease (28.2 vs. 57.1%), heart failure (15.5% vs. 34.4%), and lower left ventricular ejection fraction (59.16% vs. 47.51%), when compared to the outcome with a negative study. PVS triggered ventricular arrhythmias in 98 patients, 62 monomorphic and 36 polymorphic. During a median follow-up of 37.6 months, 100 deaths occurred. Only the induction of sustained ventricular arrhythmias showed a significant association with the primary outcome (all-cause mortality) with a p value <.001. After the performance of EPS, 142 patients underwent cardioverter-defibrillator (ICD) implantation. At study follow-up, 30 patients had therapies by the device. Only the induction of sustained monomorphic ventricular arrhythmia showed statistically significant association with appropriate therapies by the device (p = .012). Conclusion: In patients with SUO, the induction of sustained monomorphic ventricular arrhythmia after programmed ventricular pacing is related to a worse prognosis, with a higher incidence of mortality and appropriate therapies by the ICD.

Atrial Fibrillation Ablation: Impact of Intracardiac Echocardiography in Reducing Procedure Time and Hospitalization. / Ablação da Fibrilação Atrial: Impacto da Ecocardiografia Intracardíaca na Redução do Tempo de Procedimento e Internação.

BACKGROUND: Intracardiac echocardiography (ICE) allows visualization of cardiac structures and recognition of complications during atrial fibrillation ablation (AFA). Compared to transesophageal echocardiography (TEE), ICE is less sensitive to detecting thrombus in the atrial appendage but requires minimal sedation and fewer operators, making it attractive in a resource-constrained setting. OBJECTIVE: To compare 13 cases of AFA using ICE (AFA-ICE group) with 36 cases of AFA using TEE (AFA-TEE group). METHODS: This is a single-center prospective cohort study. The main outcome was procedure time. Secondary outcomes: fluoroscopy time, radiation dose (mGy/cm2), major complications, and length of hospital stay in hours. The clinical profile was compared using the CHA2DS2-VASc score. A p-value <0.05 was considered a statistically significant difference between groups. RESULTS: The median CHA2DS2-VASc score was 1 (0-3) in the AFA-ICE group and 1 (0-4) in the AFA-TEE group. The total procedure time was 129 ± 27 min in the AFA-ICE group and 189 ± 41 min in the AFA-TEE group (p<0.001); the AFA-ICE group received a lower dose of radiation (mGy/cm2, 51296 ± 24790 vs. 75874 ± 24293; p=0.002), despite the similar fluoroscopy time (27.48 ± 9. 79 vs. 26.4 ± 9.32; p=0.671). The median length of hospital stay did not differ; 48 (36-72) hours (AFA-ICE) and 48 (48-66) hours (AFA-TEE) (p=0.27). CONCLUSIONS: In this cohort, AFA-ICE was related to shorter procedure times and less exposure to radiation without increasing the risk of complications or the length of hospital stay.

FUNDAMENTO: O ecocardiograma intracardíaco (EIC) permite visualizar estruturas cardíacas e reconhecer complicações durante a ablação da fibrilação atrial (AFA). Comparado ao ecocardiograma transesofágico (ETE), o EIC é menos sensível para detecção de trombo no apêndice atrial, porém requer mínima sedação e menos operadores, tornando-o atrativo num cenário de recursos restritos. OBJETIVO: Comparar 13 casos de AFA utilizando EIC (grupo AFA-EIC) com 36 casos de AFA utilizando ETE (grupo AFA-ETE). MÉTODO: Trata-se de corte prospectiva realizada em um único centro. O desfecho principal foi o tempo de procedimento. Desfechos secundários tempo de fluoroscopia, dose de radiação (mGy/cm2), complicações maiores e tempo de internação hospitalar em horas. O perfil clínico foi comparado pelo escore CHA2DS2-VASc. Um valor de p <0,05 foi considerado uma diferença estatisticamente significativa entre os grupos. RESULTADOS: A mediana do escore de CHA2DS2-VASc score foi 1 (0-3) no grupo AFA-EIC e 1 (0-4) no grupo AFA-ETE. O tempo total de procedimento foi de 129 ± 27 min grupo AFA-EIC e 189 ± 41 no AFA-ETE (p<0,001); o grupo AFA-EIC recebeu uma dose menor de radiação (mGy/cm2, 51296 ± 24790 vs. 75874 ± 24293; p=0,002), no entanto, o tempo de fluoroscopia em minutos mostrou-se semelhante (27,48 ± 9,79 vs. 26,4 ± 9,32; p=0,671). As medianas do tempo de hospitalização não se mostraram diferentes, 48 (36-72) horas (AFA-EIC) e 48 (48-66) horas (AFA-ETE) (p=0,27). CONCLUSÃO: Nesta coorte, AFA-EIC foi relacionado a menores tempos de procedimento e menor exposição à radiação, sem aumentar o risco de complicações ou o tempo de internação hospitalar.

Electrophysiological study as a predictor of mortality in unexplained syncope.

Background: Electrophysiological study can help in the diagnosis of arrhythmic syncope. According to the electrophysiological study finding, the prognosis of patients with syncope is still a matter of study. Objective: The aim of this study was to assess the survival of patients undergoing electrophysiological study according to their findings and to identify clinical and electrophysiological independent predictors of all-cause mortality. Methods: A retrospective cohort study included patients with syncope who underwent electrophysiological study from 2009 to 2018. A Cox logistic regression analysis was performed to identify independent prognostic factors for all-cause mortality. Results: We included 383 patients in our study. During a mean follow-up of 59 months, 84 (21.9%) patients died. The split His group had the worst survival compared with the control group, followed by sustained ventricular tachycardia and HV interval ≥ 70 ms, respectively (p = .001; p < .001; p = .03). The supraventricular tachycardia group showed no differences compared with the control group (p = .87). In the multivariate analysis, independent predictors of all-cause mortality were Age (OR 1.06; 1.03-1.07; p < .001); congestive heart failure (OR 1.82; 1.05-3.15; p = .033); split His (OR 3.7; 1.27-10.80; p = .016); and sustained ventricular tachycardia (OR 1.84; 1.02-3.32; p = .04). Conclusion: Split His, sustained ventricular tachycardia, and HV interval ≥ 70 ms groups had worse survivals when compared to the control group. Age, congestive heart failure, split His, and sustained ventricular tachycardia were independent predictors for all-cause mortality.

Comparison of surgical cut and sew versus radiofrequency pulmonary veins isolation for chronic permanent atrial fibrillation: a randomized study.

BACKGROUND: Surgical pulmonary veins isolation (PVI) is done to restore sinus rhythm (SR) in patients with chronic permanent atrial fibrillation (CPAF) and mitral valve disease. Here we compare the efficacy of electrical block lines performed with radiofrequency (RF) compared with conventional surgery. METHODS: Randomized trial of 22 patients with CPAF and indication for mitral valve surgery. Ten patients underwent conventional surgery (SURG) and 12 RF. To prove the efficacy of the blockage lines, epicardial pacemaker wires were placed in the isolated pulmonary veins region (IPVR) and right atria (RA). RESULTS: There were no differences in the baseline data among the groups. All patients remained in SR during the immediate postoperative period. Block lines were tested in patients who remained in SR during the following days (eight in SURG and nine in RF). The median value of thresholds to conduct the stimulus of IPVR for the RA was 18 mA in SURG and 3 mA in RF (P < 0.022). Eight SURG patients and seven RF patients (P < 0.38) remained in SR at hospital discharge. Eleven RF patients and one SURG required amiodarone to maintain SR (P < 0.001). The incidence of recurrent atrial fibrillation (AF) in the follow-up was 10.7/100 patients/year in the SURG group versus 73.1/100 patients/year in the RF group (P = 0.009). CONCLUSIONS: PVI by SURG formed more effective block lines than RF. SR at hospital discharge was similar among the groups, but more amiodarone was used in RF. During follow-up, incidence of recurrent AF was higher in the RF group.

Ablação da Fibrilação Atrial: Impacto da Ecocardiografia Intracardíaca na Redução do Tempo de Procedimento e Internação / Atrial Fibrillation Ablation: Impact of Intracardiac Echocardiography in Reducing Procedure Time and Hospitalization

Resumo Fundamento O ecocardiograma intracardíaco (EIC) permite visualizar estruturas cardíacas e reconhecer complicações durante a ablação da fibrilação atrial (AFA). Comparado ao ecocardiograma transesofágico (ETE), o EIC é menos sensível para detecção de trombo no apêndice atrial, porém requer mínima sedação e menos operadores, tornando-o atrativo num cenário de recursos restritos. Objetivo Comparar 13 casos de AFA utilizando EIC (grupo AFA-EIC) com 36 casos de AFA utilizando ETE (grupo AFA-ETE). Método Trata-se de corte prospectiva realizada em um único centro. O desfecho principal foi o tempo de procedimento. Desfechos secundários tempo de fluoroscopia, dose de radiação (mGy/cm2), complicações maiores e tempo de internação hospitalar em horas. O perfil clínico foi comparado pelo escore CHA2DS2-VASc. Um valor de p <0,05 foi considerado uma diferença estatisticamente significativa entre os grupos. Resultados A mediana do escore de CHA2DS2-VASc score foi 1 (0-3) no grupo AFA-EIC e 1 (0-4) no grupo AFA-ETE. O tempo total de procedimento foi de 129 ± 27 min grupo AFA-EIC e 189 ± 41 no AFA-ETE (p<0,001); o grupo AFA-EIC recebeu uma dose menor de radiação (mGy/cm2, 51296 ± 24790 vs. 75874 ± 24293; p=0,002), no entanto, o tempo de fluoroscopia em minutos mostrou-se semelhante (27,48 ± 9,79 vs. 26,4 ± 9,32; p=0,671). As medianas do tempo de hospitalização não se mostraram diferentes, 48 (36-72) horas (AFA-EIC) e 48 (48-66) horas (AFA-ETE) (p=0,27). Conclusão Nesta coorte, AFA-EIC foi relacionado a menores tempos de procedimento e menor exposição à radiação, sem aumentar o risco de complicações ou o tempo de internação hospitalar.

Abstract Background Intracardiac echocardiography (ICE) allows visualization of cardiac structures and recognition of complications during atrial fibrillation ablation (AFA). Compared to transesophageal echocardiography (TEE), ICE is less sensitive to detecting thrombus in the atrial appendage but requires minimal sedation and fewer operators, making it attractive in a resource-constrained setting. Objective To compare 13 cases of AFA using ICE (AFA-ICE group) with 36 cases of AFA using TEE (AFA-TEE group). Methods This is a single-center prospective cohort study. The main outcome was procedure time. Secondary outcomes: fluoroscopy time, radiation dose (mGy/cm2), major complications, and length of hospital stay in hours. The clinical profile was compared using the CHA2DS2-VASc score. A p-value <0.05 was considered a statistically significant difference between groups. Results The median CHA2DS2-VASc score was 1 (0-3) in the AFA-ICE group and 1 (0-4) in the AFA-TEE group. The total procedure time was 129 ± 27 min in the AFA-ICE group and 189 ± 41 min in the AFA-TEE group (p<0.001); the AFA-ICE group received a lower dose of radiation (mGy/cm2, 51296 ± 24790 vs. 75874 ± 24293; p=0.002), despite the similar fluoroscopy time (27.48 ± 9. 79 vs. 26.4 ± 9.32; p=0.671). The median length of hospital stay did not differ; 48 (36-72) hours (AFA-ICE) and 48 (48-66) hours (AFA-TEE) (p=0.27). Conclusions In this cohort, AFA-ICE was related to shorter procedure times and less exposure to radiation without increasing the risk of complications or the length of hospital stay.

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.

Clinical Characteristics of Patients with Tetralogy of Fallot who Underwent an Invasive Procedure for Arrhythmias

Introduction: Tetralogy of Fallot (TOF) is a cyanotic congenital heart disease that has an incidence of sudden cardiac death of 0.2% per year, being arrhythmias the main cause of its occurrence. Objective: To compare characteristics of TOF patients referred for electrophysiological study (EPS) against those that were not (No-EPS). Method: Retrospective cohort with 215 patients (57.2% men; age = 29 ± 4) with corrected TOF (median of three years, ranging from 0.33 to 51) that underwent EPS between 2009-2020. The primary outcome was composed of death, implantable cardiac defibrillator (ICD) requirement and hospitalization. Results: Pre-syncope (EPS = 4.7%, No-EPS = 0%; p = 0.004), syncope (EPS = 7.1%, No-EPS = 1.7%; p = 0.056) and palpitations (EPS = 31%, No-EPS = 5.8%; p < 0.001) were symptoms that justified electrophysiological investigation. ICD was implanted in 24% of EPS and 0.6% of No-EPS (p=0.001). Twenty-six percent of the EPS group presented non-sustained ventricular tachycardia, while 0% in No-EPS (p = 0.012). The EPS group had more atrial fibrillation or atrial Flutter (35.7% vs. 6.9%; p < 0.001). The EPS patients had a wider QRS duration than the no-EPS group (171.12 ± 29.52 ms vs. 147 ± 29.77 ms; p < 0.001). Also, 26.2% of EPS performed ablation to correct macroreentrant atrial tachycardias. The incidence of primary outcome (death + ICD requirement + hospitalization) was higher in patients in the EPS group compared to the No-EPS group (p = 0.001). However, the total of seven deaths occurred during the clinical follow-up, but without differences between the groups (EPS = 4.7% vs. No-EPS = 2.8%; p = 0.480). Conclusion: EPS group had a profile of greater risk, more complex heart disease, and a greater occurrence of the primary outcome when compared to the No-EPS group.

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.

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)

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.

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.

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.

Supraventricular tachycardia and syncope during pregnancy: A case for catheter ablation without fluoroscopy.

Arrhythmias during pregnancy pose a dilemma for the treating physician. Most antiarrhythmic drugs are classified as category C in the FDA labeling system during pregnancy. We describe the case of a pregnant woman who presented syncope due to drug-refractory supraventricular tachycardia who underwent catheter ablation without the use of fluoroscopy.