Tarjeta de adquisición de datos para el sistema integrado de estetoscopio digital y ECGAR del proyecto SEDAR / Data acquisition card for integrated system of digital stethoscope and ECGAR of SEDAR Project

El artículo presenta el desarrollo de una tarjeta de adquisición de datos (TAD) para uso biomédico. Este diseño forma parte de un sistema que permite realizar un análisis comparativo entre los sonidos cardiopulmonares (SC) y el electrocardiograma de alta definición (ECGAR). La TAD reportada digitaliza simultáneamente tres señales adquiridas. Los dos primeros canales digitalizan las señales correspondientes a las derivaciones dI y dIII del ECGAR. El tercer canal digitaliza la señal captada del SC. El instrumento consta de dos partes, una etapa de hardware para adquirir la señal y un software para la manipulación de datos en la computadora. El hardware está compuesto por un microcontrolador de alto rendimiento, una interfaz de comunicación con la computadora vía USB y los circuitos de seguridad eléctrica inherentes a un equipo médico. El software permite la adquisición de las señales transmitidas desde el hardware, su visualización gráfica y el almacenamiento de la información en una base de datos. Las pruebas de funcionamiento demostraron errores inferiores al 0,1 % en las mediciones de amplitud y no se registró perdida de información en la comunicación con la computadora

The paper reports the development of a data acquisition card (TAD) for biomedical use. This design is part of a system that allows a comparative analysis between cardiopulmonary sounds (SC) and the high-definition electrocardiogram (ECGAR). The reported TAD simultaneously digitizes three acquired signals. The channels 1 and 2 digitize the ECGAR signals corresponding to leads dI and dIII. The channel 3 digitizes to SC captured signal. The instrument consists of two parts, a hardware for acquire the signal and a software for data manipulation in the computer. The hardware consists of a high performance microcontroller, a USB communication interface with the computer and the electrical safety circuits inherent to medical equipment. The software allows the signals acquisition transmitted from the hardware, its graphic visualization and the information storage in a database. The performance tests showed errors less than 0.1 % in amplitude measurements and no loss of information in the communication with the computer

Time-domain signal-averaged electrocardiogram in healthy German Shepherd and Boxer dogs / Eletrocardiograma de alta resolução (ECGAR) no domínio do tempo em cães sadios das raças Pastor Alemão e Boxer

Signal-averaged electrocardiogram (SAECG) identifies ventricular late potentials (LP), low-amplitude electrical signals that are markers of slow cardiac conduction in fibrous myocardium, consisting in a predictive factor for sudden death in dogs at risk of sustained ventricular tachycardia. The aim of this study was to establish reference values of SAECG for German Shepherd and Boxer dogs. SAECG was performed in 19 German Shepherd and 28 Boxer client-owned dogs, and parameters analyzed were QRSd (duration of filtered QRS), LAS<40μV (duration of low-amplitude signals in terminal portion of filtered QRS) and RMS40 (root square of mean voltage over the last 40 milliseconds of filtered QRS), with two different filters (25-250 Hz and 40-250 Hz). Statistical analyses was achieved by T Student test (p<0.05) to identify differences between the two groups and between the values obtained with the two filters. No statistical difference was found in SAECG variables between the two breeds with the two different filters (p>0.05). Achieving normal values of SAECG in German Shepherd and Boxer dogs is important to further research late potentials in animals of these breeds with hereditary ventricular tachycardia or arrhythmogenic cardiomyopathy and identification of individuals at high risk of cardiac-related sudden death...

O eletrocardiograma de alta resolução (ECGAR) identifica os potenciais tardios (PT), sinais elétricos de baixa amplitude considerados marcadores de condução cardíaca lenta de áreas fibrosadas do miocárdio, cuja presença consiste em fator preditivo de morte súbita em cães com taquicardia ventricular sustentada. O objetivo deste estudo foi o estabelecimento de valores de referência para o ECGAR de cães Boxer (n=28) e Pastor Alemão (n=19). Os seguintes parâmetros do ECGAR foram analisados: dQRS (duração do QRS filtrado), LAS<40μV (duração dos sinais de baixa amplitude no final do QRS filtrado) e RMS40 (raiz quadrada da voltagem média do final do QRS filtrado), com dois tipos diferentes de filtro (25-250 Hz e 40-250 Hz). Análise estatística foi realizada por meio do teste T de Student (p<0,05) para identificar diferenças entre os dois grupos e entre os valores obtidos com os dois filtros. Não foram encontradas diferenças significativas entre as variáveis de ECGAR nas duas raças estudadas com os dois diferentes filtros (p>0,05). A obtenção dos valores de normalidade de ECGAR em cães dessas raças auxiliará na realização de futuras pesquisas de potenciais tardios em animais com taquicardia ventricular hereditária ou cardiomiopatia arritmogênica, bem como na identificação dos indivíduos com alto risco de morte súbita de origem cardíaca...

High-resolution electrocardiography in dogs under doxorubicin-induced cardiomyopathy / Eletrocardiografia de alta resolução em cães com cardiomiopatia induzida pela doxorrubicina

The occurrence of late potentials in dogs under doxorubicin-induced cardiomyopathy and their relationship with the development of ventricular arrhythmias or sudden death were studied. Seven adult mongrel dogs of both sexes were used. Cardiomyopathy was induced by slow intravenous infusion of doxorubicin (30mg/m²) at 21-day intervals, until a total cumulative dose of 240mg/m² was reached. Animals were monitored by echocardiography. After the induction of cardiomyopathy, high-resolution electrocardiography was recorded. Late potentials were observed in two animals that suddenly died a few days later.

Determinaram-se a ocorrência de potencial tardio em cães com cardiomiopatia induzida pela doxorrubicina e sua relação com o desenvolvimento de arritmias ventriculares ou morte súbita. Sete cães adultos, sem raça definida, de ambos os sexos foram utilizados. A cardiomiopatia foi induzida por infusão venosa lenta de doxorrubicina (30mg/m²) em intervalos de 21 dias, até uma dose total cumulativa de 240mg/m². Os animais foram monitorados ecocardiograficamente. Após a confirmação da cardiomiopatia, foi feito o registro da eletrocardiografia de alta resolução. Potenciais tardios foram observados em dois animais que morreram subitamente poucos dias após.

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