[1] Virginia Commonwealth Univ, Dept Phys Therapy, Richmond, VA 23298 USA
[2] Univ Milan, San Paolo Hosp, Div Cardiol, Milan, Italy
[3] VA Palo Alto Hlth Care Syst, Div Cardiol, Palo Alto, CA USA
[4] Virginia Commonwealth Univ, Dept Internal Med, Richmond, VA 23298 USA