ABSTRACT
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
Subject(s)
Humans , Male , Female , Child , Adolescent , Heart Block/congenital , Heart Rate/physiology , Heart Block/physiopathologyABSTRACT
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