Nilda Espinola-Zavaleta1,2. 1. Nuclear Cardiology Department, National Institute of Cardiology Ignacio Chavez, Juan Badiano Nº 1, Colonia Seccion XVI, Tlalpan, 14030, Mexico City, Mexico. niesza2001@hotmail.com. 2. Department of Echocardiography, ABC Medical Center, I.A.P, Mexico City, Mexico. niesza2001@hotmail.com.