RESUMO
OBJECTIVE: To assess the changes in ventricular evoked responses (VER) produced by the decrease in left ventricular outflow tract gradient (LVOTG) in patients with hypertrophic obstructive cardiomyopathy (HOCM) treated with dual-chamber (DDD) pacing. METHODS: A pulse generator Physios CTM (Biotronik, Germany) was implanted in 9 patients with severe drug-refractory HOCM. After implantation, the following conditions were assessed: 1) Baseline evaluation: different AV delay (ranging from 150 ms to 50 ms) were sequentially programmed during 5 to 10 minutes, and the LVOTG (as determined by Doppler echocardiography) and VER recorded; 2) standard evaluation, when the best AV delay (resulting in the lowest LVOTG) programmed at the initial evaluation was maintained so that its effect on VER and LVOTG could be assessed during each chronic pacing evaluation. RESULTS: LVOTG decreased after DDD pacing, with a mean value of 59 +/- 24 mmHg after dual chamber pacemaker, which was significantly less than the gradient before pacing (98 + 22 mmHg). An AV delay > 100 ms produced a significantly lower decrease in VER depolarization duration (VERDD) when compared to an AV delay < or = 100 ms. Linear regression analyses showed a significant correlation between the LVOTG values and the magnitude of VER (r = 0.69; p < 0.05) in the 9 studied patients. CONCLUSION: The telemetry obtained intramyocardial electrogram is a sensitive means to assess left ventricular dynamics in patients with HOCM treated with DDD pacing.
Assuntos
Cardiomiopatia Hipertrófica/fisiopatologia , Marca-Passo Artificial , Adolescente , Adulto , Cardiomiopatia Hipertrófica/terapia , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-IdadeRESUMO
Uma série de registros do eletrograma intracavitário tem sido utilizada para monitorizaçäo nao invasiva da rejeiçao em pacientes transplantados usando um marcapasso de dupla câmara e eletrodos endocavitários revestidos com estrutura fractal. Os sinais têm sido avaliados usando o sistema CHARM (Computerized Heart Acute Rejection Monitoring - sistema computadorizado para monitorizaçäo da rejeiçäo cardíaca aguda). Os relatórios obtidos com este sistema contêm curvas com parâmetros sensíveis à rejeiçäo, que demonstram uma boa correlaçäo com a clínica e os resultados das biópsias convencionais. A monitorizaçäo a longo prazo, usando estas análises, mostrou ser uma feramenta valiosa no acompanhamento destes pacientes.
Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Eletrodiagnóstico/métodos , Transplante de Coração , Rejeição de Enxerto/diagnóstico , Redes de Comunicação de Computadores , Seguimentos , Marca-Passo Artificial , TelemedicinaRESUMO
A new method for non-invasive monitoring of acute rejection after heart transplantation is presented. The method is basead on the evaluation of telemetrically obtained epimyocardial electrograms using implanted pacemakers and electrodes with fractal surface structure. Parameters derived from the ventricular evoked response from stimulated heart beats are significantly related to acute cellular rejection of grade 2 and higher, as confirmed by endomyocardial biopsy. The results with regard to sensitity (93 por cento) and specificity (76 por cento) emphasize the potential of this new method for substantially reducing the number of endomyocardial biopsies, that are up to now required for a safe rejection surveillance in transplant patients.