The impact of syncope during clinical presentation of sustained ventricular tachycardia on total and cardiac mortality in patients with chronic Chagasic heart disease

OBJECTIVE: To assess the impact of syncope during sustained ventricular tachycardia on total and cardiac mortality in patients with chronic chagasic heart disease. METHODS: We assessed 78 patients with sustained ventricular tachycardia and chronic Chagas' heart disease. The mean age was 53±10 years, 45 were males, and the mean ejection fraction was 49.6±13%. The patients were divided into 2 groups according to the presence (GI=45) or absence (GII=33) of syncope during sustained ventricular tachycardia. RESULTS: After a mean follow-up of 49 months, total mortality was 35% (28 deaths), 22 deaths having a cardiac cause (78.6%). No difference was observed in total (33.3% x 39.4%) and cardiac (26.7% x 30.3%) mortality, or in nonfatal sustained ventricular tachycardia between GI and GII patients (57.6% x 54.4%, respectively). However, the presence of syncope during recurrences was significantly greater in those patients who had had the symptom from the beginning (65.4% x 18.1%, p<0.01). CONCLUSION: Syncope during the presentation of sustained ventricular tachycardia is not associated with an increase in total or cardiac mortality in patients with chronic Chagas' heart disease. However, syncope during the recurrence ventricular tachycardia is greater in patients experiencing syncope in the first episode, of sustained ventricular tachycardia.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Setor de Eletrofisiologia ClínicaUNIFESP, EPM, Setor de Eletrofisiologia ClínicaSciEL

Efeitos dos corticoesteroides nas lesões por radiofrequência na coxa de ratos em diferentes faixas etárias

BACKGROUND: The corticosteroids limit the late growth of the lesions by radiofrequency (RF) on the rats' infants' thighs, but the effects on the pubescent and adult rats are unknown. OBJECTIVE: Evaluate the effects of the corticosteroids in the healing of the lesions by RF on the rats' thighs muscles in different age groups. METHODS: Ablation was performed on the thigh muscle of 30 rats (1 lesion per animal): infants (30 days old, weight 73 g, n = 10), pubescents (60 days old, weight 230 g, n = 10) and 10 adults (90 days old, 310 g, n = 10), subdivided in control and treated groups, that received Hydrocortisone (10 mg/kg IM post-RF) and Betametasone (3.5 mg/kg IM, twice a week, for 29 days). The rats were sacrificed 60 days after the ablation for hystopathological and planimetric analysis with specified software (ImageJ®). RESULTS: In the infant, pubescent and adult groups, the weight gain in the follow up did not differ between the control and the treated ones. In the control group, the lesions of the infants and pubescents were superior (p = 0.01) to the adults'. The treatment reduced the size of the lesion in the infants (5.58+0.61 mm² vs 4.02+0.23 mm²; p < 0.01) and pubescents (5.20+0.47 mm² vs 4.16+0.48 mm²; p < 0.01), but not in the adults (4.44+0.50 mm² vs 4.79+0.53 mm², p = NS). Infant and pubescent treated groups presented lower collagen deposition and less fibrotic bands invading the healthy tissue from the central fibrosis area, and forming lesions with remarkably more reduced dimensions than their controls. There were no differences in the adult groups. CONCLUSION: The corticosteroids seem to reduce the late growth of lesion, in addition to attenuate the fibrotic proliferation in the infant and pubescent rats.FUNDAMENTO: Os corticosteroides limitam o crescimento tardio das lesões por radiofrequência (RF) no músculo da coxa de ratos filhotes, mas seus efeitos em ratos púberes e adultos são desconhecidos. OBJETIVO: Avaliar os efeitos dos corticoesteroides na cicatrização das lesões por RF no músculo da coxa de ratos em diferentes faixas etárias. MÉTODOS: Realizou-se ablação no músculo da coxa de 30 ratos (1 lesão por animal): infantis (30 dias de idade, peso 73 g, n = 10), púberes (60 dias de idade, peso 230 g, n = 10) e 10 adultos (90 dias de idade, 310 g, n = 10), subdivididos em controles e tratados, que receberam Hidrocortisona (10 mg/kg IM pós-RF) e Betametasona (3,5 mg/kg IM, duas vezes por semana, por 29 dias). Os ratos foram sacrificados 60 dias após a ablação para análise histopatológica e planimétrica com software específico (ImageJ®). RESULTADOS: Nos infantis, púberes e adultos o ganho de peso no seguimento não diferiu entre controles e tratados. Nos controles, as lesões dos infantis e púberes eram maiores (p = 0,01) que as dos adultos. O tratamento reduziu o tamanho da lesão nos infantis (5,58+0,61 mm² vs 4,02+0,23 mm²; p < 0,01) e nos púberes (5,20+0,47 mm² vs 4,16+0,48 mm²; p < 0,01), mas não nos adultos (4,44+0,50 mm² vs 4,79+0,53 mm², p = NS). Tratados Infantil e Púbere apresentaram menor deposição de colágeno e menos traves fibróticas invadindo o tecido saudável a partir da área de fibrose central, e compondo lesão de dimensões notadamente mais reduzidas que seus controles. Não houve diferenças nos grupos adultos. CONCLUSÃO: Os corticoesteroides parecem reduzir o crescimento tardio da lesão, além de atenuar a proliferação fibrótica nos ratos infantis e púberes.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUNIFESP, EPMSciEL

Impact of prophylactic corticosteroids on systemic inflammation after extensive atrial ablation in pigs

Aims Prophylactic corticosteroids have been reported to attenuate the increase in C-reactive protein (CRP) and the incidence of atrial fibrillation (AF) both after heart surgery and AF ablation. We tested the impact of a single prophylactic corticosteroid dose on ultrasensitive CRP 24 h and 14 days after extensive linear atrial ablation (8 mm or 3.5 irrigated tip) guided by electroanatomical mapping (NavX) in pigs with normal hearts.Methods and results Pigs (n = 19; 35 kg) were divided into three groups: corticoid (n = 7), atrial ablation with administration of 500 mg methylprednisolone intravenous at anaesthetic induction; control (n = 7), atrial ablation only; and sham (n = 5), surgical procedure without ablation. Troponin and CRP were measured before, 24 h and 14 days after the procedure. After sacrifice, lesions were analysed macroscopically and histologically. Linear lesions were created in the right (n = 23) and left (n = 21) atrium of 14 animals, with no difference between groups. in all groups there was elevation of troponin and CRP 24 h after ablation, with a return to baseline values after 14 days. However, CRP levels of the control, corticoid, and sham groups were similar at all three time points analysed (baseline P = 0.52, 24 h P = 0.21, 14 days P = 0.66). Histological analysis did not show any difference between corticoid and control groups.Conclusion in this model, extensive biatrial RF ablation, per se, does not promote systemic inflammation. the use of a prophylactic single corticoid dose before ablation did not prevent systemic inflammation or alter the healing of the lesions.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo, Paulista Sch Med, Discipline Cardiol, BR-04039032 São Paulo, BrazilFed Univ São Paulo São Paulo, Paulista Sch Med, Dept Pathol, BR-04039030 São Paulo, BrazilUniversidade Federal de São Paulo, Paulista Sch Med, Discipline Cardiol, BR-04039032 São Paulo, BrazilFed Univ São Paulo São Paulo, Paulista Sch Med, Dept Pathol, BR-04039030 São Paulo, BrazilWeb of Scienc

Impact of corticosteroids on late growth of radiofrequency lesions in infant pigs: histopathological and electroanatomical findings

Aims Corticosteroids attenuate late growth of radiofrequency (RF) lesions in the thigh muscle of infant rats. We sought to assess the impact of these drugs on the late growth of RF lesions in immature swine myocardium and to determine the electroanatomical mapping (EAM) characteristics of these lesions.Methods and results Radiofrequency (60 degrees C; 60 s) lesions were created in the right atrium (n = 2) and ventricle (n = 2) of 14 piglets (age 65 days; weight 5 kg) and 3 adults. Piglets were divided into: controls (n 7) and treated (n 7), receiving hydrocortisone (10 mg/kg iv after RF) and prednisone (1 mg/kg/day) for 29 days. After 8 months, animals were sacrificed for histological analysis. in four piglets, endocardial and epicardial voltage EAM were performed.In infant groups, the dimensions of atrial (11 +/- 5 vs. 13 +/- 7 mm) and ventricular (12 +/- 3 vs. 11 +/- 3 mm) lesions were similar. in adults, atrial (6 +/- 1 mm) and ventricular (6 +/- 1 mm) lesions were smaller. in controls, ventricular lesions depicted dense fibrosis and multiple strands of fibrous tissue extending from the lesion into normal muscle. Treated piglets revealed scars exhibiting less dense fibrosis with predominance of fibroadipose tissue and less collagen proliferation. Large atrial and ventricular low-voltage areas corresponding to the macroscopic lesions were identified in all animals.Conclusion Radiofrequency lesions in infant pigs reveal late growth and invasion of normal muscle by intense collagen proliferation. Corticosteroids do not prevent late enlargement of the lesions but modulate the fibrotic proliferation. the expressive growth of the lesion may generate low-voltage areas detectable by EAM.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Universidade Federal de São Paulo, Discipline Cardiol, Paulista Sch Med, BR-04039030 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pathol, Paulista Sch Med, BR-04039030 São Paulo, BrazilUniversidade Federal de São Paulo, Discipline Cardiol, Paulista Sch Med, BR-04039030 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pathol, Paulista Sch Med, BR-04039030 São Paulo, BrazilWeb of Scienc

Characterization of the in vivo cardiac electrophysiologic effects of high-dose cocaine in closed-chest, anesthetized dogs with normal hearts

OBJECTIVE: To characterize the cardiac electrophysiologic effects of cocaine. METHODS: In 8 dogs (9-13 kg), electrophysiologic parameters and programmed stimulation were undertaken using transvenous catheters at baseline, and after cocaine intravenous infusion (12 mg/kg bolus followed by 0.22 mg/kg/min for 25 minutes). RESULTS: Cocaine plasma levels (n=5) rose to 6.73± 0.56 mg/mL. Cocaine did not affect sinus cycle length and arterial pressure. Cocaine prolonged P wave duration (54±6 vs 73±4 ms, P<0.001), PR interval (115±17 vs 164±15 ms, P<0.001), QRS duration (62±10 vs 88±14 ms, P<0.001), and QTc interval (344±28 vs 403±62 ms, P=0.03) but not JT interval (193±35 vs 226±53 ms, NS). Cocaine prolonged PA (9±6 vs 23±8 ms, P<0.001), AH (73±16 vs 92±15 ms; P=0.03), and HV (35±5 vs 45±3ms; P<0.001) intervals and Wenckebach point (247±26 vs 280±28 ms, P=0.04). An increase occurred in atrial (138±8 vs 184± 20 ms; P<0.001) and ventricular (160±15 vs 187±25 ms; P=0.03) refractoriness at a cycle length of 300 ms. Atrial arrhythmias were not induced in any dog. Ventricular fibrillation (VF) was induced in 2/8 dogs at baseline and 4/8 dogs after cocaine. CONCLUSION: High doses of cocaine exert significant class I effects and seem to enhance inducibility of VF but not of atrial arrhythmias.Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina (EPM)UNIFESP, EPMSciEL

Atrial fibrillation ablation in Brazil: results of the registry of the Brazilian Society of Cardiac Arrhythmias

BACKGROUND: Aiming to define the profile of curative atrial fibrillation (AF) ablation in Brazil, the Brazilian Cardiac Arrhythmia Society [Sociedade Brasileira de Arritmias Cardíacas] (SOBRAC) created the Brazilian Registry of AF Ablation [Registro Brasileiro de Ablação da FA]. OBJECTIVE: To describe the results of this registry. METHODS: A questionnaire was sent to SOBRAC members asking about data on patients submitted to AF ablation between September 2005 and November, 2006. RESULTS: A total of 29 groups from 13 states completed the forms. Of these, 22 (76%) had performed AF ablations. Between 1998 and 2001, 7 groups (32%) initiated AF ablations and between 2002 and 2006, 15 groups began to perform them (68%). From 1998 to 2006, 2,374 patients were submitted to ablation, 755 (32%) of them during the registry period. Most (70%) were males and 89% presented with paroxysmal or persistent AF. Ancillary imaging methods (intracardiac echocardiography and electroanatomic mapping) were used by 9 groups (41%). During an average five-month follow-up period, total success was 82% and success without use of antiarrhythmic agents was 57%. Nevertheless, 35% of the patients required two or more procedures. There were 111 complications (14.7%) and 2 deaths (0.26%). CONCLUSION: Curative AF ablation has been increasing significantly in our country, with success rates comparable to international indexes, but often more than one procedure is necessary. Despite promising results, AF ablation still results in significant morbidity. Supplementary imaging methods have been used more and more in an effort to increase efficacy and safety of the procedure. These findings should be considered by public and private funding agencies.FUNDAMENTO: Buscando delinear o perfil da ablação curativa de fibrilação atrial (FA) no Brasil, a Sociedade Brasileira de Arritmias Cardíacas (SOBRAC) idealizou o Registro Brasileiro de Ablação da FA. OBJETIVO: Descrever os resultados desse registro. MÉTODOS: Foi enviado um formulário aos sócios da SOBRAC, inquirindo sobre os dados de pacientes submetidos a ablação de FA entre setembro de 2005 e novembro de 2006. RESULTADOS: No total, 29 grupos, de 13 Estados, responderam ao formulário. Desses, 22 (76%) realizaram ablações de FA. Entre 1998 e 2001, 7 grupos (32%) iniciaram ablações de FA e entre 2002 e 2006, 15 grupos (68%). De 1998 a 2006, 2.374 pacientes foram submetidos a ablação, sendo 755 (32%) no período do registro. A maioria (70%) era do sexo masculino e 89% apresentavam FA paroxística ou persistente. Métodos auxiliares de imagem (ecocardiografia intracardíaca e mapeamento eletroanatômico) foram utilizados por 9 grupos (41%). Durante seguimento médio de cinco meses, o sucesso total foi de 82% e o sucesso sem uso de antiarrítmicos foi de 57%. Contudo, 35% dos pacientes necessitaram de dois ou mais procedimentos. Houve 111 complicações (14,7%) e 2 óbitos (0,26%). CONCLUSÃO: A ablação curativa de FA vem crescendo significativamente em nosso País, com taxas de sucesso comparáveis às internacionais, mas comumente há necessidade de mais de um procedimento. Apesar dos resultados promissores, a ablação de FA ainda acarreta morbidade significativa. Métodos auxiliares de imagem têm sido cada vez mais utilizados, visando a aumentar a eficácia e a segurança do procedimento. Esses achados devem ser considerados pelos órgãos pagadores públicos e privados.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUNIFESP, EPMSciEL

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 (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.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.FAPESPUniversidade Federal de São Paulo (UNIFESP) Disciplina de CardiologiaHospital Israelita Albert Einstein Centro de ArritmiaUniversidade Federal de São Paulo (UNIFESP) Disciplina de PatologiaUNIFESP, Disciplina de CardiologiaUNIFESP, Disciplina de PatologiaSciEL