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OBJECTIVE: To determine in arrhythmogenic right ventricular cardiomyopathy the value of QT interval dispersion for identifying the induction of sustained ventricular tachycardia in the electrophysiological study or the risk of sudden cardiac death. METHODS: We assessed QT interval dispersion in the 12-lead electrocardiogram of 26 patients with arrhythmogenic right ventricular cardiomyopathy. We analyzed its association with sustained ventricular tachycardia and sudden cardiac death, and in 16 controls similar in age and sex. RESULTS: (mean +/- SD). QT interval dispersion: patients = 53.8+/-14.1ms; control group = 35.0+/-10.6ms, p=0.001. Patients with induction of ventricular tachycardia: 52.5+/-13.8ms; without induction of ventricular tachycardia: 57.5+/-12.8ms, p=0.420. In a mean follow-up period of 41+/-11 months, five sudden cardiac deaths occurred. QT interval dispersion in this group was 62.0+/-17.8, and in the others it was 51.9+/-12.8ms, p=0.852. Using a cutoff > or = 60ms to define an increase in the degree of the QT interval dispersion, we were able to identify patients at risk of sudden cardiac death with a sensitivity of 60 percent, a specificity of 57 percent, and positive and negative predictive values of 25 percent and 85 percent, respectively. CONCLUSION: Patients with arrhythmogenic right ventricular cardiomyopathy have a significant increase in the degree of QT interval dispersion when compared with the healthy population. However it, did not identify patients with induction of ventricular tachycardia in the electrophysiological study, showing a very low predictive value for defining the risk of sudden cardiac death in the population studied.

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Säo apresentados os resultados imediatos e tardios, observados com a modificaçäo do nódulo sinusial via cateter, usando-se energia de radiofreqüência, em portadora de taquicardia sinusal inapropriada. O procedimento normalizou os níveis de freqüência cardíaca nas 24h seguintes e após seis seis meses, mostrando-se, portanto,efetivo e seguro. Apesar da reduçäo da freqüência cardíaca a níveis normais, houve manutençäo dos sintomas apresentados pela paciente, sugerindo que näo säo decorridos, exclusivamente, do processo taquicárdico.

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OBJETIVOS: avaliar o perfil autonômico da taquicardia sinusal inapropriada (TSI) por análise espectral da variabilidade da frequência cardíaca (VFC). PACIENTES E MÉTODOS: foram estudados 05 pacientes (pts), três masculinos, idade média global de 25ñ 8 anos. todos foram submetidos a Holter-24 hs, determinando-se, nos registros, os ciclos cardíacos médios (CC - ms) e os seguintes componentes espectrais da VFC por método autoregressivo: energia total do espectro (ETE - ms2), componente de baixa frequência (CBF -ms2 - 0,04-0, 15 Hz), de alta frequência (CAF -ms2 - 0,15-0,40 Hz) e relaçöes entre CBF/CAF. Definiram-se os valores médios de todas as variáveis analisadas para as 24hs, para a vigília (V-10-18 hs) e sono (S-24-08hs). A dinâmica vigília/sono foi avaliada através de unidades normalizadas (un), representando o valor relativo do CBF e CAF em proporção a ETE menos o componente de muito baixa frequência. Os resultados foram comparados com os mesmos de um grupo controle (C) de 10 pts normais, idade sexo semelhantes e expressos pela média e 01 DP. RESULTADOS: CCM24hs - C: ... fórmulas ... CONCLUSÖES: os resultados observados indicam que a TSI cursa com depressão dos componentes espectrais da VFC consequentes a um aumento relativo da atividade simpática e baixa reatividade vagal. Os achados poderão ser responsáveis pela perpetuação do estado arrítmico observado, indicando haver nesta condição quador disautonômico bem definível.

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PURPOSE: To evaluate some features of ventricular arrhythmias in patients with mitral valve prolapse. METHODS: We studied 25 patients (female: 19; mean age: 37 +/- 13 years) with ventricular arrhythmias, mitral valve prolapse and normal ventricular function. All patients underwent a 24h Holter and high resolution ECG (HRECG). The Qtc intervals were measured in lead II (normal < 0.44 s). In order to define the possible origin of the ventricular focus, the morphology of the ectopic beats were analysed in leads I, II, aVF, V1 using the following criteria: 1) LBBB morphology with left axis deviation in the frontal plane (FP): origin at the inflow tract of the right ventricle (RV); 2) LBBB morphology with right axis deviation in the FP: origin at the outflow tract of the RV; 3) RBBB morphology with left axis deviation in the FP: origin at the posterior region of the left ventricle (LV). RBBB morphology with right axis deviation in the FP: origin at the anterior region of the LV. RESULTS: Twenty three (92) patients showed > 720 isolated ventricular ectopic beats/24 h. Paired ventricular response was detected in 18 (72) patients and non-sustained VT in 15 (60). HRECG was positive in six (24) patients and Qtc interval was prolonged in 13 (52). RV was the site of origin of the ventricular ectopic beats in 85 of the patients (outflow: 85; inflow: 15). Only five (20) patients had arrhythmias from the LV. CONCLUSION: There was a high incidence of ventricular arrhythmias with a low incidence of positive HRECG tests, suggesting that the mechanisms of the arrhythmias do not correlate with slow intramyocardial conduction. It was noted a strong association between mitral valve prolapse, arrhythmogenic right ventricular disease and Qtc prolongation. It is possible that in some of this patients the finding could represent a global myocardial disease.

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PURPOSE--To present initial experience on radiofrequency (RF) ablation of atrial flutter (AFL) guided by anatomic and electrophysiologic parameters. METHODS--Eight patients (six males), mean-age of 42 +/- 17.5 years with chronic type I AFL (mean cycle length of 251 +/- 14.3 msec, range 240 to 280 msec) were undergone to RF catheter ablation applied between inferior vena cava (IVC) and tricuspid annulus (TA). Two had persistent and two the paroxysmal form. Two had surgical corrected congenital heart disease (atrial septal defect in 2 and ventricular septal defect in 1). Four had systolic dysfunction and 2, an atrial tachycardia associated with the AFL. RESULTS--Areas of slow conduction represented by fractionated potentials were recorded between IVC and TA in all patients. RF ablation was successful in 8/8 patients (100). The mean number of RF applications was 9.2 +/- 6.2 (4-24). The successful ablation site was located in the isthmus between IVC and TA in seven patients and in the lateral wall in the patient with ASD. Successful sites had an early atrial activation preceding the atrial electrogram (range from -65 to -82 ms). In one patient the RF energy was successfully delivered between the atriotomy scar (AS) and IVC. After three months follow-up six remained free of recurrent AFL. One pt had type 1 AFL recurrence and one with ASD had a type II AFL. The Type II AFL was successfully ablated between AS and IVC. CONCLUSION--Fractionated potentials were commonly observed between IVC and T; AFL ablation can be guided by anatomic landmarks or electrophysiologic parameters; electrograms recorded at successful sites were early and never fractionated; the long-term evaluation must be analyzed prospectively.

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PURPOSE--To evaluate by the signal averaged-ECG (SAECG) the initial portion of the activation of the sustained ventricular tachycardia (SVT) and monomorphic repetitive ventricular tachycardia (MRVT), correlating the findings with those obtained during sinus rhythm (SR). METHODS--Ten patients was studied; five with SVT and five with MRVT. Patients with SVT presented a positive SAECG while patients with MRVT the test was negative, during SR. The findings of this two populations were compared with those obtained in a group of ten patients with advanced bundle branch block (ABBB--five RBBB and five LBBB). We analyzed in the vector-magnitude obtained during VT and ABBB, the root mean square of the initial 40 ms portion of the activation (RMS40) and the duration of the low amplitude signals < 40 microV from the beginning of the filtered QRS (LAS). To define the positiveness of the test in SR, we analyzed the final RMS40 (normal > 20 microV), the duration of the LAS < 40 microV at the end of the activation (normal < 38 ms) and the total QRS duration (QRSD-normal < 114 ms). RESULTS--(mean)-SVT in SR: RMS40 = 11.2 +/- 6.2 microV; LAS = 47.4 +/- 5.8 ms; QRSD = 131.2 +/- 8.7 ms. SVT during VT: RMS40 = 6.9 +/- 4.5 microV; LAS = 54.5 +/- 9.1 ms. RMVT in SR: RMS40 = 59.7 +/- 49.0 microV; LAS = 28.3 +/- 8.5 ms; QRSD = 93.1 +/- 13.0 ms. MRVT during VT: RMS = 25.2 +/- 8.8 microV; LAS = 28.9 +/- 11.1 ms. RBBB: RMS = 53.3 +/- 34.2 microV; LAS = 22.6 +/- 9.8 ms. LBBB: RMS = 54.7 +/- 37.3 microV; LAS = 11.4 +/- 4.6 ms. The comparison between the data from SVT and MRVT/ABBB showed p < 0.01. CONCLUSION--In the studied population, the SAECG was able to identify abnormal LAS initiating SVT, that were not present in MRVT and ABBB. This signals probably represents intra-myocardial slow conduction, as a portion of a re-entry circuit. There was an excellent correlation between the findings during SVT and MRVT with those obtained in SR

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PURPOSE--To analyze the characteristics of atrial (A) and ventricular (V) electrograms, AV and VA intervals relation to determine a precise radiofrequency ablation site. METHODS--A and V electrograms (EG) recorded at successful (group 1) and unsuccessful (group 2) sites in 22 patients submitted to RF catheter ablation were identified. Specific criteria as morphology, AV and VA intervals relation and the presence of an accessory pathway were analyzed. RESULTS--The shortest AV interval with a VEG that precedes the delta wave in the onset of the QRS recorded at the EKG leads was the best outcome predictor. The AV connection potential was only recorded in five out of 22 patients and did not interfere with the result when not present. The interval measured between the onset of the V electrogram and the onset (delta wave) of the QRS complex (V-d) varied from -4.9 to -11msec (m = 7.5 + 1.6) in G1 and from -6 to 15msec (m = 9.6 +/- 3) in G2 (p = 0.03). Unsuccessful sites had the VEG preceding the delta wave but the AV interval was not short. Success in the retrograde mapping of target site seems to be the presence of an atrial potential that occurs simultaneously with the nadir (S wave) of the QRS complex. CONCLUSION--Specific criteria such as morphology of the local VEG, a short AV or VA intervals and a VEG that precede the onset (delta wave) of the QRS identified a successful site for RF ablation. When present the accessory pathway potential indicates a high chance of a successful ablation; however when not present did not decrease the chance of success

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PURPOSE--To evaluate, retrospectively, the main clinical findings observed in patients with incessant supraventricular tachycardias. METHODS--Data from 13 patients were analyzed, 8 men and 5 women, mean age 24 +/- 19 years. All patients underwent to periodic clinical evaluation with serial ECG, Holter, echocardiography and in three patients an electrophysiological study. From these diagnostic methods it was possible to define the site of origin of the tachycardias, the autonomic influences upon them, the progressive hemodynamic compromise leading to tachycardiomyopathy and the drug response. RESULTS--In 9 patients the tachycardias had an atrial origin, in three an accessory pathway was involved and in one patient an atypical nodal reentry was identified. Clear autonomic influences upon the rate of the tachycardias were noted in the majority of patients, based on Holter recordings. Forty-six percent of the population developed progressive contractile deficit, contributing in one patient to his death. Drug failure was observed in 62 per cent of patients, even with the use of three antiarrhythmic drugs in a row. The large majority of the patients were still asymptomatic by the time of the retrospective data. CONCLUSION--The most relevant clinical aspects are the progressive development of tachycardiomyopathy, associated with refractoriness to drug therapy and indicate in this population the approach to be undertaken

Objetivo - Avaliar de forma retrospectiva, os achados clínicos principais observados em pacientes com taquicardias supraventriculares incessantes Métodos - Foram analisados os dados de 13 pacientes (8 masculinos) com idade média de 24±19 anos. Todos os pacientes foram submetidos a avaliação clínica periódica, com eletrocardiogramas, Holter e ecocardiogramas seriados. Três pacientes foram submetidos a estudo eletrofisiológico. A partir dos exames complementares definiram-se a origem das taquicardias, as influências autonomicas sobre as mesmas, as repercussões hemodinâmicas progressivas, levando a quadros de taquicardiomiopatias e a resposta medicamentosa. Resultados - Em 9 pacientes as taquicardias tinham origem nos átrios, em 3 pacientes ocorriam pela presença de vias anômalas e em um paciente era conseqüente a forma atípica de reentrada nodal. Em todos os pacientes pode-se detectar, a partir do Holter, nítidas influências autonômicas sobre a freqüencia das taquicardias. Ocorreu em 46% da população, déficit contrátil progressivo, colaborando em um paciente para a sua morte. Resistência medicamentosa foi observada em 62% dos pacientes, com o uso de até três antiarrítmicos. A grande maioria dos pacientes manteve-se assintomática até o período de levantamento dos dados do presente estudo. Conclusão - Os dados clínicos mais relevantes referem-se a presença de quadro progressivo de taquicardiomiopatia, associado a resistência medicamentosa para controle dos surtos e definem nessa população a conduta clínica a ser adotada

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PURPOSE--To determine the value of the high-resolution ECG for the differential diagnosis of arrhythmogenic right ventricular disease. METHODS--A group of 33 patients were studied, 16 males, mean age 34 +/- 16 years. All patients presented non-sustained or sustained or repetitive monomorphic ventricular tachycardias, with left bundle branch block morphology. The anatomic and functional evaluation of the right ventricle was made by a previous echocardiogram. No patient presented left ventricular or septal pathology. High-resolution ECG were obtained from a Corazonix-Predictor II program. In the filtered QRS was analyzed root mean square of the last 40ms QRS, the final lasting of the low amplitude signals < 40 microV and filtered QRS duration. Ten patients underwent to electrophysiological study with right ventricular mapping. RESULTS--The ventricular tachycardias was non-sustained in 18 patients, sustained in 8 and repetitive monomorphic in 7 patients. The echocardiogram was normal in 23 patients, and all these also presented normal high resolution ECG. Among the 10 patients with altered echocardiogram, 9 presented abnormal high-resolution ECG (sensibility 90 per cent ; specificity 100 per cent ; positive predictive value 100 per cent ; negative predictive value 96 per cent ; efficacy of the method to define the presence of manifested right ventricular pathology was 96 per cent ). Among the 10 patients with altered echocardiogram, 8 underwent to electrophysiological study. In all was detected an abnormal ventricular mapping and abnormal high-resolution ECG. CONCLUSION--The high-resolution ECG is an useful method to define a right ventricular manifested pathology in presence of arrhythmogenic disease of this cavity

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Objetivo - Avaliar os efeitos agudos da propafenona sobre os períodos refratários anterógrado e retrógrado de vias anômalas (VA). Métodos - Foram estudados 40 apcientes sintomáticos. Por técnica de extra-estímulos, determinaram-se os períodos refratários anterógrado e retrógrado das VA em condiçöes de controle e após 2,0mg/Kg de propafenona IV. Os resultados foram analisados em funçäo dos períodos refratários anterógrado e retrógrado das VA><270ms no controle. Resultados - Período refratário anterógrado médio da VA no controle de 275 ñ 76ms e no pós-droga de 462 ñ 190ms (p < 0,01). Período refratário retrógrado médio da VA no controle de 264 ñ 44ms, passando no pós-droga para 438 ñ 184ms (p < 0,01). Período refratário efetivo anterógrado do nódulo AV no controle de 236 ñ 40ms, passando no pós-droga para 276 ñ 47ms (p < 0,05). Período refratário efetivo atrial no controle de 210 ñ 23ms, passando para 215 ñ 24ms (p = ns). Período refratário efetivo ventricular no controle de 240 ñ 34ms, passando no pós-droga para 250 ñ 40ms (p:ns). Notou-se o aparecimento de bloqueio completo anterógrado e retrógrado da VA no pós-droga em, respectivamente, 15 e 12(42//, 35//) pacientes. Dos 15 pacientes com bloqueio anterógrado da VA no pós-droga, 11 apresentavam período refratário anterógrado da VA>270ms (p<0,02). Dos 12 pacientes com bloqueio completo retrógrado da VA no pós-droga, 4 apresentavam período refratário retrógrado da VA > 270ms e 8,<270ms (p=ns). Conclusäo - A propafenona produziu significativo aumento dos períodos refratários efetivos anterógrado e retrógrado das VA. Observou-se tendência a uma maior açäo frente a períodos refratários efetivos anterógrdos das VA>270ms. Este padräo de resposta näo foi observado em relaçäo aos períodos refratários efetivos retrógrdos da VA

Purpose - To evaluate the electrophysialogical effects of intravenous propafenone in the anterograde and retrograde effective refractory period of the accessory pathways (AP), in patients with WolffParkinson-White syndrome. Methods - Forty symptomatic patients were studied.. All patients were undergone to electrophysiologic study at baseline and after IV propafenone (2.0mg/kg). Drug effects were analysed according to the basal state of the anterograde and retrograde effective refractory periods of the AP><270ms. Results - The mean anterograde and retrograde effective refractory periods of the AP were 275±76ms and 264±44ms at the control and 462±190ms and 438±184ms after drug respectively (p<0.01 in both situations). The mean anterograde effective refractory period of the AV node was 236±40ms (control) and 276±57ms (post-drug )- p<0.05. The mean atrial and right ventricular effective refractory period in the control were 210±23ms and 240±34ms passing to 215±24ms and 250±40ms after drug respectively (p=ns). After drug, complete anterograde and retrograde block of the AP, ocurred in 15 (42°/) and 12 (35°/) patients respectively. Out of 15 patients with complete anterograde block of the AP, 11 had anterograde effective refractory period of the AP>270ms and 4,<270ms (p<0.02). Out of 12 patients with complete retrograde block of the AP after drag, 4 had retrograde effective refractory period >270ms and 8, <270ms (p:ns). Conclusion - Propafenone caused signifcant increase in the anterograde and retrograde effective refractory periods of the AP. There was a tendency of the drug to show better effectiveness in patients with anterograde effective refractory period of the AP>270ms. This results were not seen in relation to the retrograde effective refractory peried of the AP

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Objetivo - Analisar o início de surtos de taquicardias ventriculares polimórficas, com a finalidade de determinar a importância deste parâmetro no contexto clínico-eletrofisiológico. Métodos - Foram analisados um total de 124 inícios de episódios, em gravaçöes de Holter, em 6 pacientes. Quatro faziam uso de quinidina e diuréticos e 2 somente diuréticos. Determinaram-se os valores em ms, dos dois ciclos imediatamente precedentes ao início dos surtos e dos ciclos indutores (ciclos A, B e C). Analisaram-se as características da repolarizaçäo ventricular e os intervalos QT ou QTU desses ciclos, bem como os valores de QT fora dos episódios. Resultados - Em 105 ocasiöes (84%), os inícios de surtos foram pausas-dependentes; em 12 ocasiöes (10%) ocorreram sem pausas e a partir de uma fusäo ventricular e em 7 momentos (6%) sem pausas e a partir de um encurtamento súbito dos ciclos C (fenômeno R + T). Os surtos pausas-dependentes somente foram observados nos pacientes em uso de sulfato de quindina e diuréticos e os näo dependentes de pausas nos pacientes em uso somente de duréticos. Todos apresentavam intervalos QTU prolongados fora dos surtos, havendo uma relaçäo linear entre a amplitude das ondas U dos ciclos C e a duraçäo dos ciclos A e B. Conclusäo - Frente aos resultados, os seguintes aspectos foram acentuados, a partir da análise do início de surtos de taquicardias ventriculares polimórficas; pode-se diferenciar formas típicas de torsades de pointers (pausa-dependente) e atípicas. As primeiras ocorrem provavelmente em funçäo da presença de atividade de disparo (pós-potenciais precoces). As formas atípicas melhor se enquadrariam a presença de mecanismos reentrantes ou hiperautomáticos. Somente nas formas típicas, haveria benefício no uso de MP artificial provisório para tratamento, pela regularizaçäo dos ciclos cardíacos que este procedimento produz

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