I took a couple of deep breaths, then held it and managed to slow my heart down a little.

She heard his footsteps fade, panic racing and then slowing her heart.

She took a deep breath to slow her heart, and handed him the carved whistle she'd made for Germain.

She took a breath before she asked, attempting to slow her heart.

She took deep breaths to slow her pounding heart.

Max sat still and tried to slow his heart.

He crouched in the darkness, listening and trying to slow his pounding heart.

He was still for a moment, breathing deeply, calming himself, slowing his heart.

But it was necessary to put you on an opiate to slow your heart down.

Deep in a meditative state, the man was able to slow both his heart and respiratory rates.