Cardiomiopatia arritimogênica do ventrículo direito. Valor preditivo da dispersäo do intervalo QT para avaliaçäo de risco arritmogênico e de morte súbita / Arrhythmogenic cardiomyopathy of the right ventricle. Predictive value of QT interval dispersion to assess arrhythmogenic risk and sudden death

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.

Bradarritmias na sala de emergência / Bradyarrhythmias in the emergency room

Tem sido reconhecido, há muito tempo, que o ritmo cardíaco extremamente lento é capaz de produzir sintomas severos. As bradiarritmias sintomáticas implicam em distúrbios da função sinusal, da condução AV, ou de ambos. As causas dessas anormalidades podem ser classificadas, de uma maneira ampla em: 1) distúrbios intrínsecos, 2) distúrbios extrínsecos, ou 3) distúrbios funcionais reflexos mediados neuralmente. A disfunção do nódulo sinusal (ou doença do nódulo sinusal) compreende um espectro de arritmia do nódulo sinusal e/ou atriais, que resultam em períodos intermitentes ou persistentes de batimentos cardíacos inapropriados, lentos ou rápidos. Distúrbios da condução AV abrangem desde alentecimento da condução AV, à falta intermitente da transmissão do impulso, até completa falha da condução. Na maioria dos casos, a estimulação cardíaca artificial substituiu a terapia farmacológica no tratamento de pacientes com bradiarritmia sintomática. A disfunção dos MP, em pacientes dependentes do mesmo, representa também uma importante causa de períodos intermitentes de ritmo cardíaco lento sintomático

Taquicardia sinusal inapropriada: análise espectral dos ciclos R-R normais / Inapropriate sinus tachycardia: spectral analysis of normal R-R cycles

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.

Efeitos do sotalol sobre o eletrocardiograma de alta resoluçäo avaliados por ensaio duplo-cego cruzado randomizado / Effects of sotalol over signal-averaged electrocardiogram: a randomized double-blind crossover trial

A presente investigaçäo teve por objetivo avaliar os efeitos do Sotalol sobre o eletrocadiograma de alta resoluçäo (ECGAR), em uma populaçäo com arritmia ventricular idiopática. Foi estudado um grupo de 12 pacientes submetidos a um ensaio clínico do tipo duplo-cego cruzado e randomizado, para avaliaçäo da eficácia da droga. Foram obtidos ECGAR em condiçöes de controle (C), uso de placebo (P) e de droga (D). confrontando os resultados entre as três situaçöes e a eficácia medicamentosa. No vetor-magnitude foram analisados os seguintes parâmetros: voltagem média dos 40ms terminais do complexo QRS filtrado (VM - normal > 20 µV), duraçäo dos sinais de baixa amplitude < 40 µV no final da ativaçäo (SBA - normal < 38ms) e duraçäo total do complexo QRS filtrado (DQRS - normal < 114.0ms). Em funçäo da resposta terapêutica, os pacientes foram divididos em responsivos (G1) e näo-responsivos (G2). Näo foram observadas diferenças estatisticamente significativas entre C e P. No grupo I, composto por 5 pacientes (42 'por cento' de eficácia), näo foram observadas diferenças significativas nas 3 variáveis avaliadas entre as condiçöes de P e D. No grupo II, composto por 7 pacientes, ocorreram modificaçöes nos SBA, cujos valores no P estavam em 24.80 ñ 7.60ms e passando com D para 29.10 ñ 14.76ms (p<0,01). Em 5 dos 7 pacientes deste grupo (71 'por cento'), prolongam-se no pós-droga os SBA, numa média de 11.20 ñ 4.80ms, com significância estatística em relaçäo ao placebo (p<0,04). Frente aos resultados observados com os SBA, foram obtidos sensibilidade de 71'por cento', especificidade de 86 'por cento', valor preditivo positivo de 83 'por cento' e negativo de 75 'por cento' para definir a populaçäo responsiva à droga. Concluiu-se que na populaçäo estudada, o Sotalol, quando efetivo, nço produziu modificaçöes significativas nos parâmetros do ECGAR. Um incremento médio dos SBA de 11.2 ñ 4.8ms, por influência da droga, associou-se a uma ausência de resposta terapêutica.

Efficácia das drogas antiarrítmicas. Proposta para uma nova forma de avaliação baseada nos efeitos farmacológicos horários / Antiarrhythmic drug effectiveness. Proposal for a new approach based on pharmacological hourly effects

PURPOSE--To use a new approach in order to assess the antiarrhythmic drugs, based in the hourly autonomic effects and antiarrhythmic efficacy of sotalol. METHODS--Sixteen patients were evaluated in a randomized double-blind placebo-controlled study. Patients were classified in group 1 (anti-arrhythmic efficacy) and group 2 (no antiarrhythmic efficacy). The following parameters were analyzed: 1) clinical variables as age, gender, cardiac disease and ventricular ectopies density; 2) drug effects on pNN50 in 24-hour and on mean hourly cardiac cycle length; 3) percentage of hourly ventricular ectopies distribution and its correlation with pNN50 and with mean hourly cardiac cycle length in all patients; 4) drug effects on mean hourly cardiac cycle length in groups 1 and 2; 5) correlation between hourly pNN50 and ventricular ectopies density after sotalol administration in groups 1 and 2; 6) hourly drug efficacy in groups 1 and 2 and correlation with pNN50. RESULTS--Efficacy of the drug was present in 8 (50) patients. Sotalol significantly increased 24-hour pNN50 (placebo 5.01 +/- 2.02; after drug, 11.70 +/- 5.59-p < 0.001), also increasing mean hourly cardiac cycle length during the day and night, in all patients (placebo 758.25 +/- 75.68 ms; after drug 967.71 +/- 80.17 ms-p < 0.000). It was noted that patients under placebo had different autonomic tonus; group 1 showed higher sympathetic activity as compared to group 2. Hourly drug efficacy was seen in 23 of 24-hour recordings in group 1 while it was not seen at any time in group 2. CONCLUSION--Sotalol significantly increased parasympathetic cardiac activity. The anti-arrhythmic response was related to the autonomic tonus seen before and after drug administration.

O eletrocardiograma de alta resolução da onda P em pacientes com história de fibrilação atrial paroxística / The P-Wave Signal-Averaged Electrocardiogram in Patients with Episodes of Paroxysmal Atrial Fibrillation

PURPOSE--To study by using the signal-averaged P wave, the atrial activation of patients with documented episodes of paroxysmal atrial fibrillation (PAF). METHODS--This study enrolled a total of 20 patients with documented episodes of paroxysmal atrial fibrillation (males 14; mean age 58.4 +/- 10.6 years). The signal-averaged P wave was recorded with a Corazonix Predictor II system. The total P wave duration was determined from the combined filtered x,y,z vector-magnitude and used for analysis. The results were compared with a normal group of 10 patients, matched in age. RESULTS--In the control group, the total P wave duration ranged from 120.0 to 135.0 (mean = 128.3 +/- 5.8) ms. In the group of PAF, the total P wave duration ranged from 118.0 to 168.5 (mean = 151.5 +/- 13.7) ms (p < 0.000). Sixteen (80) of this patients showed a P wave duration > 140.0 ms. With a cut < 140.0 ms for the normal atrial activation, the sensitivity was 76, specificity was 100, positive and negative predictive value were 100 and 60 respectively for the method detected patients with PAF. CONCLUSION--Patients with PAF showed a prolonged signal-averaged P wave duration and should be differentiated by this method from the normal population.

Eficácia do sotalol nas arritmias ventriculares idiopáticas com origem em trato de saída de ventrículo direito / Efficacy of Sotalol in Patients With Idiophatic Right Ventricular Arrhythmias

PURPOSE--To evaluate the effects of sotalol in patients (pts) with idiophatic ventricular arrhythmias (VT) from right ventricular outflow tract. METHODS--Eighteen pts with VT were enrolled (five with monomorphic repetitive ventricular tachycardia - MRVT). Pts were submitted to a double-blind crossover randomized study (placebo vs. 320 mg/po/d/sotalol; four weeks each), after a wash-out control period. Holter recording were recorded in control and placebo and drug periods. Eligible pts have > 50/h isolated ventricular premature beats (VPB) in control, with or without paired VPB or nonsustained VT (NSVT- > 3 beats, > 100bpm). Drug efficacy criteria was: > 75//reduction in isolated VPB and > 90//of paired VPB or NSVT. The effects of the drug on uncorrected QT interval was evaluated and also on circadian rhythm of VT through the hourly pNN50/VPB ratios. Values are given as mean +/- SD. Three recordings were compared by using paired Student's ®t® test. Statistical significance was assumed for p < 0.05. RESULTS--Differences between control and placebo were NS. Drug was effective in 61//of pts, reducing the 3 types of ET (VPB: placebo = 23.508 +/- 34.537; drug: 975 +/- 1357; paired placebo = 443 +/- 587; drug = 9 +/- 20). The drug was evaluated in 4 pts with MRVT, reducing all ectopic events, with efficacy of 60//over VPB and paired and 80//over NSVT (VPB: placebo = 52.639 +/- 42.207; drug: 1631 +/- 2062; paired: placebo = 796 +/- 754; drug: 20 +/- 30; NSVT: placebo = 4287 +/- 6343; drug: 9 +/- 11). Mean QT interval was 0.40 +/- 0.01s in control and 0.50 +/- 0.04s in the drug period, with no correlation between duration and efficacy. Sotalol modified the circardian rhythm of VPB in the non-responders group, mainly during the morning. CONCLUSION--Sotalol was effective in control of VT, mainly the MRVT. Its effect on VPB circadian rhythm may independently contribute to the overall efficacy profile and myocardial protective effect of this drug

O eletrocardiograma de alta resoluçäo durante taquicardia ventricular / The Signal-Averaged Electrocardiogram During Ventricular Tachycardia

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

Estudo do comportamento autonômico dos ritmos de escape no bloqueio atrioventricular congênito / Study of the Autonomic Behavior of the Escape Rhythms in Complete Congenital Heart Block

PURPOSE--To study the autonomic behavior of the escape rhythm in congenital complete heart block (CCHB), using heart rate variability (HRV). METHODS--A group of 10 asymptomatic patients with CCHB and narrow QRS was studied, 7 females; mean age = 14 +/- 9 years. The following time domain indexes were analyzed from a 24 hour Holter monitoring. The mean of all RR intervals (NN); the standard deviation of the mean (CLV5); the mean of all standard deviations (SDNN); the percent of successive differences longer than 50 ms (pNN50); the shortest cycle (CC) and the longest cycle (CL). The results were compared with a control group, using the Wilcox test for statistical analysis. RESULTS--The results were: NN = 1016 +/- 276 ms in CHB and 725 +/- 121 ms in control (p < 0.01); CLV5 = 184 +/- 97 ms in CHB and 125 +/- 38 ms in control (p = NS); SDNN = 102 +/- 32 ms in CHB and 88 +/- 29 ms in control (p = NS); rMSSD = 113 +/- 69 ms in CHB and 78 +/- 28 ms in control (p = NS); pNN50 = 43 +/- 26 per cent in CHB and 33 +/- 12 per cent in control (p = NS); CC = 582 +/- 129 ms in CHB and 333 +/- 49 ms in control (p = 0.05). CONCLUSION--No statistical difference was noted by comparing HRV indexes in CHB with control subjects, showing that the autonomic behavior of the escape rhythm in CCHB is similar to the sinus node in asymptomatic patients. The differences in NN, CC and CL are probably related to intrinsic properties of each command

Taquicardia ventricular monomórfica repetitiva / Repetitive Monomorphic Ventricular Tachycardia

PURPOSE--To evaluate retrospectively clinical features of repetitive monomorphic ventricular tachycardia (RMVT). METHODS--Files of 11 patients with RMVT were analyzed (9 females, mean-age 37 +/- 17 years). All patients were submitted to clinical evaluation, ECG, Holter monitoring stress test, high-resolution ECG and echocardiogram; they were treated with antiarrhythmic drugs. RESULTS--Patients were in NYHA class I or II, 9 asymptomatics and 2 with palpitations. The ECG was normal in all of them. Cardiac memory was observed in 3. A left bundle branch block with inferior axis deviation in the frontal plane was present during RMVT in all patients (right ventricular outflow tract focus). Holter monitoring revealed mean of 12031 +/- 8345 isolated PVC/24h; 2892 +/- 234 ventricular couplets/24h and 1367 +/- 890 VTs/24h (mainly nonsustained). In 6 patients RMVT was suppressed during maximal exercise treadmill. High-resolution ECG was negative in all group. Five patients had a normal echocardiogram while 5 showed mitral valve prolapse. One patient developed tachycardiomyopathy. The arrhythmia was controlled with 320mg of oral sotalol in 3 of 4 that used this drug and with 120mg oral propranolol in one of 6 that used this drug. Drug resistance was present in the others. The mean follow-up period was 38 +/- 16 months. CONCLUSION--The results demonstrate that RMVT is a benign form of VT with no detectable anatomic substract by the currently used methods. It is probably induced by nonreentrant mechanism and frequently drug resistance is observed. Among the antiarrhythmic drugs commonly used, sotalol showed to be the most effective

Objetivo - Avaliar, retrospectivamente, os dados clínicos mais relevantes da taquiarritmia ventricular monomórfica repetitiva (TVMR). Métodos - Foram analisados os registros de 11 pacientes, 9 femininos, idade média de 37±17 anos, portadores de TVMR, todos submetidos à avaliação clínica seqüencial, ECG, Holter, prova de esforço em esteira, ECG de alta resolução (ECGAR) e ecocardiograma, sendo tratados com drogas antiarrítmicas. Resultados - Os pacientes encontravam-se em classe funcional I/II da NYHA, sendo 9 assintomáticos e 2 com queixas de palpitações. O ECG, em ritmo sinusal, foi normal nos 11 pacientes, havendo em 3 o fenômeno de memória cardíaca. O ECG durante a taquicardia mostrou QRS com BRE e eixo inferior no plano frontal (foco em via de saída de VD) em todo o grupo. O Holter mostrou no total dos pacientes, média de 12031±8345 extra-sístoles nas 24h; pareadas de 2892±234 e surtos de TV de 1367±890, a maioria não-sustentados. A prova de esforço aboliu a taquiarritmia no esforço máximo em 6 pacientes. O ECGAR foi negativo em todo o grupo. Cinco pacientes apresentavam ecocardiogramas normais, havendo em 5, sinais de prolapso da válvula mitral. Um paciente evoluiu com sinais de taquicardiomiopatia. A arritmia foi controlada em 3 pacientes com 320mg de sotalol VO (4 fizeram uso desta droga) e em 1 com 120mg de propranolol VO (usado em 6 pacientes), havendo nos restantes resistência medicamentosa. O tempo de seguimento médio foi de 38±16 meses. Conclusão - Os resultados indicaram ser a TVMR arritmia de evolução benigna, sem um substrato anatômico detectável pelos meios diagnósticos de rotina, desencadeada muito provavelmente por mecanismo eletrofisiológico não reentrante e com freqüente resistência medicamentosa. Dos antiarrítmicos utilizados de rotina, este estudo sugere ser o sotalol o mais efetivo

Taquicardias supraventriculares incessantes: estudo retrospectivo de treze pacientes / Incessant Supraventricular Tachycardias. Retrospective Study of Thirteen Patients

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

Electrocardiografia de alta resoluçäo na doença ventricular direita arritmogênica / High-Resolution Electrocardiography in the Arrhythmogenic Right Ventricular Disease

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

Variabilidade de R-R no infarto agudo anterior após a terapêutica trombolítica / Heart Rate Variability in Patients with Acute Anterior Myocardial Infarction and Thrombolytic Therapy

Objetivo - Avaliar os efeitos da trombólise sobre a integridade do sistema nervoso autônomo , em pacientes com infarto agudo do miocárdio de parade anterior, através da determinação da variabilidade de R-R. Métodos - Em 31 pacientes com infarto agudo de parade anterior, submetidos a terapêutica trombolítica (25 masculinos; idade 59 ± 14 anos), determinou-se por gravações de Holter de 24 h, as variabilidades de R-R. Utilizou-se um sistema de medidas algorítmicas, acoplado a um micro 286, determinando-se as flutuações de R-R durante ritmo sinusal e por períodos sucessivos de 5 min. Os resultados foram expressos como a média global de todos os períodos determinados, o desvio padrão da média de todos os períodos computados e a média dos desvios padrões dos intervalos processados. Valores inferiores a 50 ms dos desvios padrões das médias e das médias dos desvios padrões foram considerados anormais. Utilizou-se como critério de reperfusão a associação de um pico enzimático precoce de CKMB (£ 12 h), com a redução em 50% ou mais no grau de supra desnível de segmento ST dentro da lª hora após o início da terapêutica trombolítica e o aparacimento de ritmo idioventricular acelerado dentro do mesmo período. Separaram-se os pacientes em reperfundidos (grupo 1; n: 16) e não reperfundidos (grupo 2; n: 15). Resultados - Média de R-R: grupo 1 = 716±84 ms (variações de 540 a 820 ms); grupo 2: 595±115 ms (variações de 390 a 870 ms - p < 0,01). Desvio padrão de R-R: grupo 1 = 67±19 ms (variações de 34 a 92 ms); grupo 2: 50±14 ms (variações de 23 a 67 ms - p < 0,01). Variações de R-R inferiores a 50 ms: grupo 1 = 2 pacientes; grupo 2 = 5 pacientes. Média dos desvios padrões de R-R: grupo 1 = 44±14 ms (variacões de 26 a 65 ms); grupo 2: 39±17 ms (variações de 19 a 69 ms - p: ns). Conclusão - Pacientes com infarto agudo anterior beneficiados por trombólise química, apresentam maior variabilidade de R-R; esses resultados sugerem uma resposta mais adequada do sistema nervoso autônomo frente a patência vascular, havendo possíveis efeitos sobre o prognóstic

Purpose - To analyse the effects of thrombolysis on the integrity of the autonomic nervous system, in patient with acute myocardial infarction (AMI) of the anterior wall, using the determination of the heart rate variability. Methods - We prospectively evaluated the R-R variability of the 31 consecutive pattents with anterior AMI submitted to coronary thrombolysis 625 males; mean age 59±14 years) from Holter tapes. An algorythm in a 286 computer program was used for heart rate variability (HRV). With this system, R-R variations during synus rhythm and for a five consecutive minutes periods was determined. The results were expressed as the mean of the total determined periods; the standard deviation of the mean of all determined periods and the mean of the standard deviation. The reperfusion criteria was the early enzymatic rise of the CKMB activity levels (£ 12 h) combined with a 50% or more reduction in the ST segment elevation within the first hour after thrombolytic therapy and the presence of an accelerated idioventricular rhythm at the same time. The repefused group (group 1 = 16 patients) andnon-reperfused group (group 2 = 15 patients) were comparad in terms of R-R variability. Results - Mean R-R: group 1 = 716 ± 84 ms (540 - 820 ms); group 2 = 595 ± 115 ms (390 - 870 ms) - p < 0.02. SD of the R-R: group 1 = 67±19 ms (34 - 92 ms); group 2 = 50 ±14 ms (23 - 77 ms) - p < 0.01. HRV 50 ms: group 1 = 2 patients; group 2 = 5 patients. Means SD of the R-R: group 1 = 44 ± 14 ms (26 - 65 ms); group 2 = 39 ± 1 7 ms (19 -69 ms) - p:ns. Conclusion - Patients with anterior AMI and thrombolytic therapy demonstrate greater HRV; this finding suggested better integrity of the autonomic nervous system, with possible effects on prognosis

Memória cardíaca em pacientes com marcapasso artificial definitivo / Cardiac memory in patients with permanent cardiac pacemakers

Objetivo Analisar concordância ou diocordância entre a polaridade dos QRS artificialmente induzidos e das ondas T durante ritmo espontâneo (memória cardíaca), em pacientes com marcapasso (MP) artificial permamente. Métodos Trinta e cinco pacientes, obtendo-se seus ritmos espontâneos por inibição exter na ou reprogramação do gerador. Correlacionou-se a polaridade dos complexos QRS arti ficiais e das ondas T espontâneas, em busca de concordância ou discordância entre ativação e recuperação. Analisaram-se as melhores projeções do fenômeno concordante (memória cardíaca) e sua possível dependência de variáveis específicas, como o ritmo espontâneo e as características dos complexos QRS, tipo e modo de estimulação artificial e cronicidade do implante. Resultados Houve concordância entre QRS artificial e T espontânea em 5 ou mais derivações do PF em 77% e no pH em 50% dos casos. Nos pacientes com comando supraventricular, a concordância foi observada em 82% dos casos e em 50% nos com idioventricular. O fenômeno foi mais bem evidenciado quando o padrão de condução intraventricular era normal. Não houve correlação entre tipo, modo de estimulação e cronicidade do implante e o fenômeno da memória cardíaca. Esta foi mais bem evidenciada nas derivações aVF, D2, D3, V3 e V4. Conclusão O fenômeno da memória cardíaca é freqüente em paciente com MP artificial definitivo. A existência de um padrão normal de ativação ventricular, durante ritmo espontâneo, é o fator mais significativo para o seu aparecimento

Purpose To correlate the direction of QRS complex of paced beats and postpacing T wave, in patients with artificial pacemaker. Methods Thirty five patients with spontaneous rhythm obtained by chest wall stimulation or by programmability of the automatic interval. It was correlated in all patients, the direction forces of QRS complexes of paced beats and postpacing T waves in all 12 ECG leads. It was considered as a cardiac memory phenomenon when QRS complexes of paced beats and postpacing T waves had the same polarity. The phenomenon was correlated with the 12 ECG leads and with specific variables like spontaneous rhythm, QRS complex duration, type and modality of artificial stimulation and chronicity of the implant. Results The artificial QRS complexes and spontaneous T waves had the same direction in 5 or more leads of the frontal plane in 77% of the patients and in 50% of the patients in the horizontal plane. In patients with supraventricular command, this correlation was found in 82% of the patients and in 50% of the patients with idioventricular rhythm. Regardless of the type of spontaneous command, the phenomenon was better observed with normal intraventricular conduction. It was not found correlation between type, modality of stimulation and chronicity of the implant and cardiac memory. It was better observed in aVF, D2, D3 and V3, V4. Conclusion The phenomenon of cardiac memory in patients with artificial pacemaker is very frequent. The most important factor to develop the phenomenon seem to be a normal pattern of ventricular activation

Torsades de Points: análise de 105 episódios / Torsades de Pointes: analysis of 105 episodes

Purpose - To analyze episodes of Torsades de Pointes (TP), in search of its electrocardiographic characteristics. Patients and Methods - We analyzed 105 episodes of TP, in 4 patients using quinidine and diuretics, recorded by 24-hour Holter monitoring The following parameters were studied; ventricular repolarization out of TP, rhythm disturbances before TP; EKG characteristics of the onset, the bouts and the end of the TP. Results - Ventricular repolarization, out of the TP, was abdormal, with the presence of U-waves at the end of the T-waves, resulting in prolongation of the QT (QU) interval. The U-wave voltage was noted to be cycle-lenght dependent. Ventricular bigeminy preceded TP in 100 episodes (95%) and the mean interval between both parameters was 18 ±16 min. The onset of the TP episodes showed the "short/long/ short cycle rale", hereby called "pre-pause cycle", "preparing cycle" and "trigger cycle" respectively. The rotatory QRS-T morphology around the baseline, was seen in 75% of episodes, at the beginning or throughtout the bout. Monomorphic ventricular tachycardia pattern was seen in the other 25% of episodes. Termination of bouts was sudden in all cases, and persistent ventricular bigeminy led to another bout in 90 episodes (85% ). Conclusion - In TP patients, there is enlargement of QT intervals mostly due to U-waves appearence. The U-waves seen in these cases, probably have an important role in the genesis of TP and are probably related to ventricular after potentials (triggered activity). Ventricular bigeminy is a premonitory sign of TP in patients using class 1A antiarrhythmic drugs Persistent ventricular bigeminy post-TP episoaes is a strong indicator of another bout of TP. The onset of TP is more important than its morphology for the correct diagnosis of this arrhythmia