Valerie Alexander got up early on Friday morning at her Circuit Avenue home, briefly lounged outside in the sun then came inside and passed out on the floor.

She felt woozy standing in her kitchen and tried to get to the bedroom to tell her sleeping husband she was about to pass out, but couldn't wake him up in time.

That's when Alexander's 11-month-old yellow labrador Dory sprang into action and began urgently barking like she had never sounded before or since.

"There was no doubt about it she was sounding the alarm," said Rob Alexander, Valerie's husband.

Alexander has a heart condition called "atrial misfires" where for no discernible reason, her blood pressure plummets and her heart rate drops to dangerously low levels.

She said doctors have been unable to find a cause for her condition, which started in her 20s. It once it happened when she was driving three of her children on the highway, where she was able to pull over to safety. In another instance it happened five times in a row, and Alexander said she could practically see through her hands they were so pale.

"I thought I wasn't going to wake up," said Alexander, a 46-year-old hospice nurse.

Thankfully, on Friday she had Dory by her side.

After trying to wake up Rob, Dory flew through the house to wake up Valerie's 25-year-old son Aaron, asleep in his bedroom.

"From the barking noise she was making he thought there was a stranger breaking into the house. He came out ready to swing," said Alexander.

As Rob and Aaron became aware of the situation, Dory kept trying to nudge her owner up, jump on top of her and lick her face. She didn't get off Alexander until she thankfully came to moments later.

"The dog knew something was wrong," said Rob, who noted that Dory didn't have any kind of rescue training. "She's a very happy puppy, I didn't know she had that in her."

Alexander didn't have any fainting episodes in the nine months since she bought Dory as a two-month old puppy from Excalibur Labradors, a breeder in Acushnet.

She said when the family went to pick a puppy there were only two left, and Dory immediately connected with them. But Dory also cried the entire car ride to Wareham

"I almost said let's go back and take the dog back," said Alexander.

It's a good thing she didn't. The Alexanders said ever since, Dory has been nothing but a joy. They said she was house broken in two weeks, loves to play hide and seek in the woods, sit in kayaks on the water and is an all around great dog.

The Alexanders said they had never seen Dory as barking mad as she was on Friday, but they know she's ready if the situation ever happens again.

"Now every time I lay down to relax or watch TV she checks my breathing to see if I'm ok," said Alexander. "Doctors were considering getting me a pacemaker. She might be my homemade pacemaker."