Manuel García

A través de una reconstrucción de la evolución de su pensamiento, en este artículo se estudia la utilización de infinitesimales por parte de Newton. Se distingue entre dos concepciones sucesivas de lo que denominó momento. A la primera de estas entidades la caracterizó como un infinitesimal, pero a la segunda (un indivisible generador de magnitudes finitas, que interviene en su método de las primeras y últimas razones) no la consideró corno tal. Se entiende así su manifestación de rechazo a los infinitesimales, formulada en una segunda etapa, y se ve que las dudas arrojadas por algunos investigadores sobre la veracidad de tal manifestación se deben a una determinada interpretación de esta última concepción de momento

Atrial fibrillation is the most common cardiac arrhythmia in clinical practice. It often starts with asymptomatic and short episodes, which are difficult to detect without the assistance of automatic monitoring tools. The vast majority of methods proposed for this purpose are based on quantifying the irregular ventricular response during the arrhythmia. However, although AF totally alters the atrial activity reflected on the electrocardiogram, replacing stable P-waves by chaotic and time-variant fibrillatory waves, this information has still not been explored for automated screening of AF. Hence, a pioneering AF detector based on quantifying the variability over time of the AA morphological pattern is here proposed. Results from two public reference databases have proven that the proposed method outperforms current state-of-the-art algorithms, reporting accuracy higher than 90%. A less false positive rate in the presence of other arrhythmias different from AF was also noticed. Finally, the combination of this algorithm with the classical analysis of RR series variability also yielded a promising trade-off between AF accuracy and detection delay. Indeed, this combination provided similar accuracy than RR-based methods, but with a significantly shorter delay of 10 beats.