Assessment of cardiac autonomic modulation during graded head-up tilt by symbolic analysis of heart rate variability
Alberto Porta, Eleonora Tobaldini, Stefano Guzzetti, Raffaello Furlan, Nicola Montano, Tomaso Gnecchi-Ruscone
American Journal of Physiology-Heart and Circulatory Physiology · 2007
10.1152/ajpheart.00006.2007