OTTAWA, Ont. – Nickelback fans dominated Lebreton Flats Monday night.

A very excited crowd screamed and sang along with the Canadian rockers who headlined the main stage at RBC Royal Bank Bluesfest.  

Canadian boys, I Mother Earth, who recently reunited after an eight year hiatus, also hit the stage.

Meantime, there was a medical emergency during one of the concerts.  A man suffered what Ottawa Paramedics call “an evolving heart attack.”  The man, 59, was treated by paramedics who were already at the event, and then was sent to hospital where he underwent cardiac surgery.  The man is in stable condition.

We’ll see a switch from rock n’ roll to hip-hop Tuesday night.

Snoop Dog headlines the night on the main stage at 9:30 p.m.

Lauryn Hill will be making one of her few concert appearances scheduled for 2012.  She will perform on the Claridge Homes Stage at 8 p.m.