Syncope, Vasovagal

• Centers for Disease Control and Prevention — Atlanta, Georgia, United States
• Duke University — Durham, North Carolina, United States

• Wake Forest University Baptist Health Center — Winston-Salem, North Carolina, United States

• Ohio University — Athens, Ohio, United States
• American Red Cross Blood Services - Central Ohio Region — Columbus, Ohio, United States

• University of Kansas Medical Center — Kansas City, Kansas, United States

• Daegu Catholic University Medical Center — Daegu, South Korea

• Hamilton Health Science-Heart Investigation Unit — Hamilton, Ontario, Canada

Not specified