Análise da prevalência dos potenciais tardios ventriculares na fase tardia pós-infarto do miocárdio baseada na localização do infarto / Analysis of the prevalence of ventricular late potentials in the late phase of myocardial infarction based on the site of infarction

OBJECTIVE: The initial site of myocardial infarction (MI) may influence the prevalence of ventricular late potentials (VLP), high-frequency signals, due to the time course of ventricular activation. The prevalence of VLP in a period of more than 2 years after acute MI was assessed focusing on the initially injured wall . METHODS: The prevalence of VLP in a late phase after MI (median of 924 days) in anterior/antero-septal and inferior/infero-dorsal wall lesion was analyzed using signal-averaged electrocardiogram in time domain. The diagnostic performance of the filters employed for analysis on was tested at high-pass cut-off frequencies of 25 Hz, 40 Hz and 80 Hz. RESULTS: The duration of the ventricular activation and its terminal portion were larger in inferior than anterior infarction, at high-pass cut-off frequencies of 40 Hz and 80 Hz. In patients with ventricular tachycardia, these differences were more remarked. The prevalence of ventricular late potentials was three times greater in inferior than anterior infarction. CONCLUSION: Late after myocardial infarction, the prevalence and the duration of ventricular late potentials are greater in lesions of inferior/infero-dorsal than anterior/antero-septal wall confirming their temporal process, reflecting their high-frequency content

Avaliação clínica de cabos-eletrodos com estrutura fractal / Clinical evaluation of electrodes with fractal structure

Foi realizado o estudo da performance de 109 cabos-eletrodos (CEs) com superfície de estrutura fractal revestida com fina camada de irídio, sendo 84 de fixação passiva e 25 de fixação ativa. Na avaliação foram realizadas medições dos limiares de estimulação e sensibilidade com intervalo de tempo pós-implante médio de 13 Ý 8 meses. Os CEs investigados apresentaram excelentes valores de limiar de estimulação e sensibilidade a longo prazo. A estimulação e sensibilidade demonstraram ser efetivas e seguras