Changes in Tachycardia Cycle Length with Varying Degrees of Right Bundle Branch Block: What Is the Mechanism?

The present case contributes to understanding the mechanism and differential diagnosis of a wide QRS complex tachycardia with varying degrees of right bundle branch block morphology.

Atrial fibrillation promotion in a rat model of heart failure induced by left ventricle radiofrequency ablation.

BACKGROUND: Atrial fibrillation (AF) frequently coexists with congestive heart failure (CHF). The increased susceptibility to AF in CHF has been attributed to a variety of structural and electrophysiological changes in the atria, particularly dilation and interstitial fibrosis. We evaluated atrial remodeling and AF vulnerability in a rat model of CHF induced by left ventricle (LV) radiofrequency (RF) ablation. METHODS: Wistar rats were divided into 3 groups: RF-induced CHF (Ab, n = 36), CHF animals treated with spironolactone (AbSpi, n = 20) and sham controls (Sham, n = 29). After 12 weeks, animals underwent echocardiographic and electrophysiological evaluation and were sacrificed for histological (atrial fibrosis) and Western blotting (TGF-ß1, collagen I/III, connexin 43 and CaV1.2) analysis. RESULTS: Mild LV dysfunction and marked atrial enlargement were noted in both ablated groups. AF inducibility (episodes ≥2 s) increased in the Ab group compared to sham animals (31/36, 86%; vs. 15/29, 52%; p = 0.005), but did not differ from the AbSpi group (16/20, 80%; p = NS). Sustained AF (>30 s) was also more frequent in the Ab group compared to shams (56% vs. 28%; p = 0.04). Spironolactone reduced atrial fibrosis (p < 0.01) as well as TGF-ß1 (p < 0.01) and collagen I/III (p < 0.01) expression but did not affect connexin 43 and CaV1.2 expression. CONCLUSIONS: Rats with RF-induced CHF exhibit pronounced atrial structural remodeling and enhanced AF vulnerability. This model may be useful for studying AF substrate in CHF.

Arritmias na sala de emergência e UTI. Taquicardias de QRS estreito: fundamentos para a abordagem / Arrythmias in the emergency room and ICU Narrow QRS rachycardias: bases for clinical approach

As taquicardias de QRS estreito apresentam origem supraventricular. O histórico clínico, exame físico e eletrocardiograma na sala de emergência constituem-se nas principais ferramentas para o tratamento do quadro. As taquicardias que apresentam instabilidade hemodinâmica devem ser, imediatamente, revertidas através de cardioversão elétrica sincronizada. Aquelas que se apresentam como estáveis hemodinamicamente podem, se regulares, ser tratadas através de manobras vagais ou através do uso de fármacos endovenosos. Se irregulares, podem caracterizar fibrilação e flutter atrial, sendo, então, avaliados a duração do episódio e o risco de tromboembolismo para determinar não apenas a necessidade de anticoagulação, mas também a estratégia para tratamento do quadro, seja através do controle da frequência cardíaca ou do controle do ritmo, este último podendo ser alcançado através do uso de fármacos (propafenona oral ou amiodarona endovenosa) ou da cardioversão elétrica sincronizada. Dessa forma, o papel do clínico na sala de emergência é fundamental para garantir a condução adequada dos episódios de taquicardia supraventricular, especialmente, na prevenção ou pronta intervenção em caso de deterioração hemodinâmica relacionada ao quadro

Narrow QRS tachycardias are supraventricular in origin. The clinical history, physical exam, and electrocardiogram in the emergency room are the main tools used to manage this condition. Tachycardias that present haemodynamic instability must be promptly reverted through synchronized electrical cardioversion. Those that present haemodynamic stability may be treated with vagal maneuvers or intravenous drugs. If irregular, they may take the form of atrial fibrillation or atrial flutter, and in this case, the duration of the episode and the thromboembolic risk are evaluated to determine not only the need for anticoagulation, but also the treatment strategy, whether through heart rate or rhythm control. The latter may be achieved through the use of drugs (oral propafenone or intravenous amiodarone) or synchronized electrical cardioversion. The role of the clinician in the emergency room is therefore fundamental in ensuring adequate conduct of episodes of supraventricular tachycardia, especially in prevention or prompt intervention in case of haemodynamic deterioration related to the condition

Effect of atenolol pre-treatment in heart damage in a model of intestinal ischemia-reperfusion.

PURPOSE: To investigate the effects of atenolol in inflammatory mediator and oxidative stress in a myocardial injury by intestinal ischemia/reperfusion in rat model. METHODS: Adult Wistar male rats were randomly (n=8), anesthetized and divided in: Sham: submitted to operation only; group SS+IR: intravenous saline infusion following superior mesenteric artery occlusion during 60 minutes (ischemia) and open for 120 minutes (reperfusion); group AT+IR: intravenous atenolol infusion (2 mg/kg) following superior mesenteric artery occlusion during 60 minutes (ischemia) and open for 120 minutes (reperfusion); and group AT+I+AT+R: intravenous atenolol infusion following superior mesenteric artery occlusion during 60 minutes (ischemia) and in the time 45 minutes other atenolol doses were administrated and the artery was open for 120 minutes (reperfusion), all animals were submitted to muscular relaxation for mechanical ventilation. In the end of experiment the animals were euthanized and the hearts tissue were morphology analyzed by histology and malondialdehyde by ELISA, and the plasma were analyzed for tumor necrosis factor-alpha by ELISA. RESULTS: The group SS+IR demonstrated the higher malondialdehyde levels when compared with the atenolol treated-groups (p=0.001) in the heart tissue. The tumor necrosis factor-alpha level in plasma decrease in the treated groups when compared with SS+IR group (p=0.001). Histology analyses demonstrate pyknosis, edema, cellular vacuolization, presence of inflammatory infiltrate and band contraction in the heart tissue of the rats. CONCLUSION: Atenolol significantly reduce the degree of cardiac damage after intestinal ischemia-reperfusion.

Effect of atenolol pre-treatment in heart damage in a model of intestinal ischemia-reperfusion

Abstract Purpose: To investigate the effects of atenolol in inflammatory mediator and oxidative stress in a myocardial injury by intestinal ischemia/reperfusion in rat model. Methods: Adult Wistar male rats were randomly (n=8), anesthetized and divided in: Sham: submitted to operation only; group SS+IR: intravenous saline infusion following superior mesenteric artery occlusion during 60 minutes (ischemia) and open for 120 minutes (reperfusion); group AT+IR: intravenous atenolol infusion (2 mg/kg) following superior mesenteric artery occlusion during 60 minutes (ischemia) and open for 120 minutes (reperfusion); and group AT+I+AT+R: intravenous atenolol infusion following superior mesenteric artery occlusion during 60 minutes (ischemia) and in the time 45 minutes other atenolol doses were administrated and the artery was open for 120 minutes (reperfusion), all animals were submitted to muscular relaxation for mechanical ventilation. In the end of experiment the animals were euthanized and the hearts tissue were morphology analyzed by histology and malondialdehyde by ELISA, and the plasma were analyzed for tumor necrosis factor-alpha by ELISA. Results: The group SS+IR demonstrated the higher malondialdehyde levels when compared with the atenolol treated-groups (p=0.001) in the heart tissue. The tumor necrosis factor-alpha level in plasma decrease in the treated groups when compared with SS+IR group (p=0.001). Histology analyses demonstrate pyknosis, edema, cellular vacuolization, presence of inflammatory infiltrate and band contraction in the heart tissue of the rats. Conclusion: Atenolol significantly reduce the degree of cardiac damage after intestinal ischemia-reperfusion.

Effect of atenolol pre-treatment in heart damage in a model of intestinal ischemia-reperfusion

Purpose: To investigate the effects of atenolol in inflammatory mediator and oxidative stress in a myocardial injury by intestinal ischemia/reperfusion in rat model. Methods: Adult Wistar male rats were randomly (n=8), anesthetized and divided in: Sham: submitted to operation only; group SS+IR: intravenous saline infusion following superior mesenteric artery occlusion during 60 minutes (ischemia) and open for 120 minutes (reperfusion); group AT+IR: intravenous atenolol infusion (2 mg/kg) following superior mesenteric artery occlusion during 60 minutes (ischemia) and open for 120 minutes (reperfusion); and group AT+I+AT+R: intravenous atenolol infusion following superior mesenteric artery occlusion during 60 minutes (ischemia) and in the time 45 minutes other atenolol doses were administrated and the artery was open for 120 minutes (reperfusion), all animals were submitted to muscular relaxation for mechanical ventilation. In the end of experiment the animals were euthanized and the hearts tissue were morphology analyzed by histology and malondialdehyde by ELISA, and the plasma were analyzed for tumor necrosis factor-alpha by ELISA. Results: The group SS+IR demonstrated the higher malondialdehyde levels when compared with the atenolol treated-groups (p=0.001) in the heart tissue. The tumor necrosis factor-alpha level in plasma decrease in the treated groups when compared with SS+IR group (p=0.001). Histology analyses demonstrate pyknosis, edema, cellular vacuolization, presence of inflammatory infiltrate and band contraction in the heart tissue of the rats. Conclusion: Atenolol significantly reduce the degree of cardiac damage after intestinal ischemia-reperfusion.(AU)

Ablación por catéter de fibrilación auricular en Latinoamérica: resultados del primer registro de la Sociedad Latinoamericana de Estimulación Cardíaca y Electrofisiología (SOLAECE) / Catheter ablation of atrial fibrillation in Latin America: results of the first registry of the Latin American Society of Pacing and Electrophysiology Cardiac (SOLAECE)

Objetivo: conocer los resultados de la ablación por catéter de fibrilación auricular (FA) en Latinoamérica. Material y método: se analizaron los resultados (éxito agudo, complicaciones totales y complicaciones mayores) de los procedimientos de ablación de FA paroxística (FA-P), FA-NO paroxística (FA-NP) y FA total (FA-P + FA-NP) incluidos en el Primer Registro Latinoamericano de Ablación por Catéter dirigido y coordinado por la Sociedad Latinoamericana de Estimulación Cardíaca y Electrofisiología (SOLAECE), y su relación con las características de los centros. Las variables categóricas se expresaron como proporciones y se compararon utilizando la prueba de chi cuadrado. Se consideró diferencia estadísticamentemente significativa un valor de P < 0,05. Resultados: la FA fue el cuarto sustrato más frecuentemente abordado con 1.649 procedimientos (11%). De ellos, 1.161 fueron de FA-P (70,4%) y 488 de FA-NP (29,6%). El número de ablaciones de FA al año fue de 30 o menos en 46 centros (81%); 50 o más en siete centros (12%), y 100 o más en cinco centros (9%). El promedio por centro fue de 26. El éxito agudo de la ablación de FA total fue de 90%. No se observaron diferencias entre FA-P y FA-NP (88,9% versus 90,8%, P=NS). La tasa de complicaciones totales fue de 8,31%, y tampoco se observaron diferencias entre los dos sustratos (FA-P 8,4% versus FA-NP 8,2%, P=NS). Las complicaciones mayores fueron de 4,12%. El resultado de la ablación (éxito agudo y complicaciones) se relacionó principalmente con el volumen de procedimientos de los centros. Conclusiones: los resultados de la ablación de FA en Latinoamérica son similares a los reportados en el resto del mundo. La experiencia del centro se relacionó directamente con los resultados, en particular con las complicaciones. Aquellos centros con tasas elevadas de complicaciones mayores deberían reanalizar sus programas de ablación de FA a fin de mejorar la seguridad de este tratamiento.

Summary Objective: to evaluate the results of catheter ablation of atrial fibrillation (AF) in Latin America. Material and methods: the results (acute success, total complications and major complications) of ablation procedures of paroxysmal-AF (AF-P), Non-paroxysmal (AF-NP), and total FA (AF-P + AF-NP) included in the First Latin American Catheter Ablation Registry coordinated by SOLAECE were analyzed and the relationship of these results with the characteristics of the centers were established. Categorical variables were expressed as proportions and compared using the chi² test. A P value of <0,05 was considered statistically significant. Results: AF was the fourth most frequently substrate treated with 1,649 procedures (11%). Of these, 1,161 were AF-P (70.4%) and 488 AF-NP (29.6%). The number of AF ablations per year was 30 or less in 46 centers (81%), 50 or more in 7 (12%) and 100 or more in five (9%). The per center procedures average was 26. The acute ablation success of total AF was 90%. No difference between acute ablation success of AF-P and AF-NP (88.9% vs 90.8%, P=NS) was observed. The total complications rate was 8.31%, and no difference between the two substrates was observed (AF-P 8.4% vs AF-NP 8.2%, P =NS). Major complications rate was 4.12%. The result of ablation (acute success and complications) was related mainly to the number of procedures performed by the center. Conclusions: the results of AF ablation in Latin America do not differ greatly from those observed in other places around the world. Features related to the characteristics of the centers, especially its experience, were directly related to the results, particularly complications. Those centers with high rates of major complications should re-examine its AF ablation programs to improve the safety of this treatment.

Ablación por catéter de fibrilación auricular en Latinoamérica: resultados del primer registro de la Sociedad Latinoamericana de Estimulación Cardíaca y Electrofisiología (SOLAECE)

Objetivo: conocer los resultados de la ablación por catéter de fibrilación auricular (FA) en Latinoamérica.Material y método: se analizaron los resultados (éxito agudo, complicaciones totales y complicaciones mayores) de los procedimientos de ablación de FA paroxística (FA-P), FA-NO paroxística (FA-NP) y FA total (FA-P + FA-NP) incluidos en el Primer Registro Latinoamericano de Ablación por Catéter dirigido y coordinado por la Sociedad Latinoamericana de Estimulación Cardíaca y Electrofisiología (SOLAECE), y su relación con las características de los centros. Las variables categóricas se expresaron como proporciones y se compararon utilizando la prueba de chi cuadrado. Se consideró diferencia estadísticamentemente significativa un valor de P < 0,05.Resultados: la FA fue el cuarto sustrato más frecuentemente abordado con 1.649 procedimientos (11%). De ellos, 1.161 fueron de FA-P (70,4%) y 488 de FA-NP (29,6%). El número de ablaciones de FA al año fue de 30 o menos en 46 centros (81%); 50 o más en siete centros (12%), y 100 o más en cinco centros (9%). El promedio por centro fue de 26. El éxito agudo de la ablación de FA total fue de 90%. No se observaron diferencias entre FA-P y FA-NP (88,9% versus 90,8%, P=NS). La tasa de complicaciones totales fue de 8,31%, y tampoco se observaron diferencias entre los dos sustratos (FA-P 8,4% versus FA-NP 8,2%, P=NS). Las complicaciones mayores fueron de 4,12%. El resultado de la ablación (éxito agudo y complicaciones) se relacionó principalmente con el volumen de procedimientos de los centros.Conclusiones: los resultados de la ablación de FA en Latinoamérica son similares a los reportados en el resto del mundo. La experiencia del centro se relacionó directamente con los resultados, en particular con las complicaciones. Aquellos centros con tasas elevadas de complicaciones mayores deberían reanalizar sus programas de ablación de FA a fin de mejorar la seguridad de este tratamiento.

The first Latin American Catheter Ablation Registry.

AIMS: To assess the results of transcatheter ablation of cardiac arrhythmias in Latin America and establish the first Latin American transcatheter ablation registry. METHODS AND RESULTS: All ablation procedures performed between 1 January and 31 December 2012 were analysed retrospectively. Data were obtained on the characteristics and resources of participating centres (public or private institution, number of beds, cardiac surgery availability, type of room for the procedures, days per week assigned to electrophysiology procedures, type of fluoroscopy equipment, availability and type of electroanatomical mapping system, intracardiac echo, cryoablation, and number of electrophysiologists) and the results of 17 different ablation substrates: atrio-ventricular node reentrant tachycardia, typical atrial flutter, atypical atrial flutter, left free wall accessory pathway, right free wall accessory pathway, septal accessory pathway, right-sided focal atrial tachycardia, left-sided focal atrial tachycardia, paroxysmal atrial fibrillation, non-paroxysmal atrial fibrillation, atrio-ventricular node, premature ventricular complex, idiopathic ventricular tachycardia, post-myocardial infarction ventricular tachycardia, ventricular tachycardia in chronic chagasic cardiomyopathy, ventricular tachycardia in congenital heart disease, and ventricular tachycardias in other structural heart diseases. Data of 15 099 procedures were received from 120 centres in 13 participating countries (Argentina, Bolivia, Brazil, Chile, Colombia, Cuba, El Salvador, Guatemala, Mexico, Peru, Dominican Republic, Uruguay, and Venezuela). Accessory pathway was the group of arrhythmias most frequently ablated (31%), followed by atrio-ventricular node reentrant tachycardia (29%), typical atrial flutter (14%), and atrial fibrillation (11%). Overall success was 92% with the rate of global complications at 4% and mortality 0.05%. CONCLUSION: Catheter ablation in Latin America can be considered effective and safe.

The use of external event monitoring (web-loop) in the elucidation of symptoms associated with arrhythmias in a general population.

OBJECTIVE: To correlate arrhythmic symptoms with the presence of significant arrhythmias through the external event monitoring (web-loop). METHODS: Between January and December 2011, the web-loop was connected to 112 patients (46% of them were women, mean age 52±21 years old). Specific arrhythmic symptoms were defined as palpitations, pre-syncope and syncope observed during the monitoring. Supraventricular tachycardia, atrial flutter or fibrillation, ventricular tachycardia, pauses greater than 2 seconds or advanced atrioventricular block were classified as significant arrhythmia. The association between symptoms and significant arrhythmias were analyzed. RESULTS: The web-loop recorded arrhythmic symptoms in 74 (66%) patients. Of these, in only 14 (19%) patients the association between symptoms and significant cardiac arrhythmia was detected. Moreover, significant arrhythmia was found in 11 (9.8%) asymptomatic patients. There was no association between presence of major symptoms and significant cardiac arrhythmia (OR=0.57, CI95%: 0.21-1.57; p=0.23). CONCLUSION: We found no association between major symptoms and significant cardiac arrhythmia in patients submitted to event recorder monitoring. Event loop recorder was useful to elucidate cases of palpitations and syncope in symptomatic patients.

The use of external event monitoring (web-loop) in the elucidation of symptoms associated with arrhythmias in a general population / Utilização do monitor de eventos externo (web-loop) na identificação de sintomas associados a arritmias cardíacas em uma população geral

Objective To correlate arrhythmic symptoms with the presence of significant arrhythmias through the external event monitoring (web-loop). Methods Between January and December 2011, the web-loop was connected to 112 patients (46% of them were women, mean age 52±21 years old). Specific arrhythmic symptoms were defined as palpitations, pre-syncope and syncope observed during the monitoring. Supraventricular tachycardia, atrial flutter or fibrillation, ventricular tachycardia, pauses greater than 2 seconds or advanced atrioventricular block were classified as significant arrhythmia. The association between symptoms and significant arrhythmias were analyzed. Results The web-loop recorded arrhythmic symptoms in 74 (66%) patients. Of these, in only 14 (19%) patients the association between symptoms and significant cardiac arrhythmia was detected. Moreover, significant arrhythmia was found in 11 (9.8%) asymptomatic patients. There was no association between presence of major symptoms and significant cardiac arrhythmia (OR=0.57, CI95%: 0.21-1.57; p=0.23). Conclusion We found no association between major symptoms and significant cardiac arrhythmia in patients submitted to event recorder monitoring. Event loop recorder was useful to elucidate cases of palpitations and syncope in symptomatic patients. .

Objetivo Correlacionar sintomas arrítmicos com a presença de arritmias significativas por meio do monitor de eventos externo (web-loop). Métodos Entre janeiro e dezembro de 2011, o web-loop foi instalado em 112 pacientes (46% mulheres, 52±21 anos). Sintomas específicos foram definidos como palpitação, pré-síncope e síncope, presentes durante a monitorização. Arritmia significativa foi definida como taquicardia paroxística supraventricular, flutter e fibrilação atrial, taquicardia ventricular, pausas superiores a 2 segundos ou bloqueio atrioventricular avançado. A associação entre presença de sintomas e arritmias significativas foi avaliada. Resultados O monitor de eventos registrou sintomas específicos em 74 (66%) pacientes, entretanto a associação entre sintomas específicos e arritmia significativa foi observada em apenas 14 (19%) deles. Em 11 pacientes (9,8%), foi detectada arritmia significativa na ausência de sintomas. Não houve associação entre a presença de sintomas e a detecção de arritmia significativa (OR=0,57, IC95%: 0,21-1,57; p=0,23). Conclusão Em pacientes monitorizados pelo web-loop, não houve associação entre a presença de sintomas específicos e a detecção de arritmias significativas. O monitor de eventos pode ter importância na elucidação de sintomas de palpitações e síncope dos pacientes. .

Análise crítica dos estudos com os novos anticoagulantes / Critical anlysis of studes on the novel anticoagulantes

Os eventos tromboembólicos são complicações significativas da fibrilação atrial (FA) e podem ser prevenidos com a anticoagulação oral plena. A varfarina reduz em 64% o risco de tromboembolismo, no entanto, a dificuldade no seu manejo clínico motivou a busca por novos anticoagulantes orais (NOACs). Os NOACs inibem especificamente um único fator na cascata da coagulação, têm meia vida curta, efeito previsível e estável, dispensam monitorização e interagem pouco com alimentos e medicamentos.Os estudos RE-LY, ROCKET-AF, ARISTOTLE e ENGAGE AFTIMI48 compararam a varfarina com a dabigratana, rivaroxabana,apixabana e edoxabana, respectivamente, e evidenciaram que os NOACS são equivalentes (dabigatrana 110 mg, rivaroxabana,edoxabana) ou superiores (dabigatrana 150 mg, apixabana) à varfarina na prevenção de tromboembolismo sistêmico ou AVC em pacientes com FA não valvar. Ademais, apresentam índices de hemorragias intracranianas substancialmente menores do quea varfarina. Já a apixabana foi superior à aspirina na prevençãode AVC, com os mesmos índices de sangramento. Os NOACs não devem ser usados em gestantes, crianças, e em pacientes com estenose mitral significativa, próteses valvares ou função renal muito deprimida. Porém, podem ser usados nos cenários de cardioversão e ablação da FA. Ainda não há estudos comparativos entre os diversos NOACs, nem consenso de quando recomendara troca da varfarina em pacientes com RNI estável. Cerca de 50%dos pacientes com FA e indicação de anticoagulação não recebem terapia anticoagulante. Portanto, com advento dos NOACs, a expectativa é reduzir essa parcela, diminuindo a incidência de fenômenos tromboembólicos na FA.

Thromboembolic events are important complications of atrialfibrillation (AF) and can be prevented by oral anticoagulation.Warfarin reduces by 64% the risk of thromboembolism,however, the difficulties in its clinical management promptedthe search for novel oral anticoagulants (NOACs). The NOACsspecifically inhibit a single factor in the coagulation cascade,have a short half-life, predictable and stable effect, do not requiremonitoring and have minor interactions with food and drugs.The RE-LY, ROCKET-AF, ARISTOTLE and ENGAGE AFTIMI48 trials compared warfarin to dabigatran, rivaroxaban,apixaban and edoxaban, respectively, and showed that NOACSare equivalent (110 mg dabigatran, rivaroxaban, edoxaban) orsuperior (dabigatran 150 mg, apixaban) to warfarin in preventingstroke or systemic embolism in patients with nonvalvular AF.Furthermore, they are associated with substantially lower levelsof intracranial bleeding than warfarin. Apixaban was superiorto aspirin in preventing strokes, with the same rate of bleeding.The NOACs should not be used in pregnant women, children,and patients with significant mitral stenosis, prosthetic valvesor impaired renal function. However, these novel drugs can beused in the scenarios of cardioversion and AF ablation. Thereare no studies comparing individual NOACs or consensus aboutswitching patients on warfarin with stable INR. Approximately50% of patients with AF and recommendation for anticoagulationdo not receive anticoagulant therapy. Therefore, with the adventof NOACs, the expectation is to improve this figure, ultimatelydecreasing the incidence of thromboembolic events in AF.

As linhas virtuais criadas com o sistema de mapeamento eletroanatômico ensite são de fato contínuas? / Are the virtual lines created with the ensite electroanatomical mapping system really continuous?

FUNDAMENTO: O sistema de mapeamento eletro anatômico Ensite Navx é muito usado na ablação por radiofrequência (RF) da fibrilação atrial, ajudando na confecção de lesões lineares. Contudo, a correspondência da linha virtual criada pelo Ensite com a lesão patológica ainda não foi avaliada. OBJETIVO: Avaliar a continuidade da linha virtual criada pelo Ensite em modelo suíno. MÉTODOS: Realizamos ablação linear por RF (cateter de 8 mm e irrigado) em ambos os átrios de 14 suínos (35 kg) guiada pelo EnSite. Os animais foram sacrificados 14 dias pós-ablação para análise macroscópica e histológica. RESULTADOS: Foram confeccionadas 23 lesões lineares em átrio direito e 21 em átrio esquerdo dos 14 animais. A potência, temperatura e impedância médias das aplicações foram de 56 W, 54 ºC e 231 Ω para o cateter de 8mm, e de 39 W, 37 ºC e 194 Ω para o cateter irrigado. Todas (100%) as linhas foram identificadas nas faces epicárdica e endocárdica, denotando transmuralidade. À macroscopia, as lesões eram extensas e pálidas, com 3,61 cm de comprimento e 0,71 cm de profundidade e contínuas. A transmuralidade das lesões foi confirmada pela microscopia. Houve correspondência na localização das linhas do mapa virtual com as da peça anatômica em 21 das 23 (91,3%) das linhas do átrio direito e 19/21 (90,4%) do átrio esquerdo. CONCLUSÃO: Nesse modelo, as linhas criadas no mapa virtual pelo sistema EnSiteNavX se correlacionam a lesões lineares transmurais contínuas na peça anatômica, sugerindo que esse método é adequado para a ablação linear da fibrilação atrial.

BACKGROUND: EnSiteNavx electroanatomic mapping system is widely used in radiofrequency (RF) atrial fibrillation ablation, helping the creation of linear lesions. However, the correspondence of the virtual line created by EnSite with the pathological lesion has not yet been evaluated. OBJECTIVE: to assess the continuousness of Ensite-guided virtual lines in a swine model. METHODS: we performed RF ablation linear lesions (8mm and irrigated catheters tips) in both atria of 14 pigs (35Kg) guided by the EnSite. The animals were sacrificed 14 days post-ablation for macroscopic and histological analysis. RESULTS: a total of 23 lines in the right atrium and 21 lines in the left atrium were created in 14 animals. The medium power, impedance and temperature applications were 56 W, 54 ºC and 231 Ω for the 8mm tip, and 39W, 37ºC, 194 Ω for the irrigated tip catheter, respectively. All (100%) lines were identified on the epicardial and endocardial surfaces, denoting transmurality. At macroscopic examination, lesions were extensive and pale, continuous, with 3.61 cm long and 0.71 cm deep. The transmurality of the lesions was confirmed by microscopy. There was a correlation in the location of the lines at the virtual map and the anatomical lesions in 21 of 23 (91.3%) of the right atrium and 19/21 (90.4%) of the left atrium. CONCLUSION: In this model, the lines created in the virtual map by EnSiteNavX system correspond to continuous transmural linear lesions in anatomical specimen, suggesting that this method is suitable for linear ablation of atrial fibrillation.

Are the virtual lines created with the EnSite electroanatomical mapping system really continuous?

BACKGROUND: EnSiteNavx electroanatomic mapping system is widely used in radiofrequency (RF) atrial fibrillation ablation, helping the creation of linear lesions. However, the correspondence of the virtual line created by EnSite with the pathological lesion has not yet been evaluated. OBJECTIVE: to assess the continuousness of Ensite-guided virtual lines in a swine model. METHODS: we performed RF ablation linear lesions (8mm and irrigated catheters tips) in both atria of 14 pigs (35 Kg) guided by the EnSite. The animals were sacrificed 14 days post-ablation for macroscopic and histological analysis. RESULTS: a total of 23 lines in the right atrium and 21 lines in the left atrium were created in 14 animals. The medium power, impedance and temperature applications were 56 W, 54 ºC and 231 Ω for the 8mm tip, and 39 W, 37 ºC, 194 Ω for the irrigated tip catheter, respectively. All (100%) lines were identified on the epicardial and endocardial surfaces, denoting transmurality. At macroscopic examination, lesions were extensive and pale, continuous, with 3.61 cm long and 0.71 cm deep. The transmurality of the lesions was confirmed by microscopy. There was a correlation in the location of the lines at the virtual map and the anatomical lesions in 21 of 23 (91.3%) of the right atrium and 19/21 (90.4%) of the left atrium. CONCLUSION: In this model, the lines created in the virtual map by EnSiteNavX system correspond to continuous transmural linear lesions in anatomical specimen, suggesting that this method is suitable for linear ablation of atrial fibrillation.

A cardiologia intervencionista nas arritmias supraventriculares / Interventional cardiology in supraventricular arrhythmias

As taquicardias supraventriculares são comuns na prática clínica e, apesar de raramente levarem a morte, são motivos de visitas frequentes a pronto-socorros, piora da qualidade de vida e elevados custos ao sistema de saúde. O tratamento medicamentoso, apesar de amplamente empregado, tem demonstrado eficácia limitada e seu uso a longo prazo encontra-se associado ao desenvolvimento de efeitos colaterais. O conhecimento dos mecanismos destas arritmias favoreceram o desenvolvimento de técnicas e tecnologias intervencionistas seguras e altamente eficazes no controle e na cura destas doenças. Vários estudos têm demonstrado o custo-efetividade, bem como a superior eficácia da ablação nas taquicardias paroxísticas supraventriculares e no flutter atrial quando comparada ao tratamento medicamentoso. Apesar de ainda não ser possível a cura da fibrilação atrial por meio da ablação, esta ferramenta tem se mostrado superior ao tratamento farmacológico no controle dos sintomas e nos casos paroxísticos, evidências apontam que a ablação é capaz de retardas a progressão da doença. A despeito deste conhecimento, algumas evidências apontam que, no Brasil, este recurso vem sendo subaproveitado. Este trabalho tem como objetivo revisar as indicações de ablação das arritmias supraventriculares, bem como fornecer noções técnicas destas ferramentas terapêuticas.

Supraventricular tachycardias are common in clinical practice and rarely lead to sudden death but are a frequent reason for visits to emergency rooms, poor quality of life and high costs to the health system. Drug treatment shown limited efficacy and its long-term use is associated with side effects. Knowledge of the mechanisms related to these arrhythmias favored the development of safe and highly effective interventional technologies in the control and cure of these diseases. Several studies have demosntrated the cost-effectiveness as well as the superior efficacy of catheter ablation in the treatment of paroxysmal supraventricular tachycardia and trial flutter when compared to medical therapy. Although results of catheter ablation of atrial fibrilation are modest, they are modest, they are superior to pharmalogical for symptoms control. This paper reviews the indications for ablation of supraventricular arrhythmias as well as provides technical notions regarding these therapeutic tools still under utilized in Brazil.