LAS VEGAS — More than 400 medical calls were reported during the first night of the Electric Daisy Carnival music festival, held in the Nevada desert during Las Vegas’ first major heat wave.

Las Vegas police says six people were taken to a local hospital overnight.

Officials won’t say how many of those 443 medical calls were related to the heat, as reported drug use or pre-existing health conditions could also be a factor.

Festival organizers estimate that there were 136,000 attendees partying from sundown Friday to sunrise Saturday at the Las Vegas Motor Speedway.

An excessive heat warning issued by the National Weather Service is in effect for the next seven days, as temperatures are expected to hit as high as 117 degrees.