Most romance novels published today are faster paced than romance novels published thirty years ago. That said, there are still certain scenes that require faster pacing than others. Action sequences, for example, generally require faster pacing. So would a scene designed to build suspense.
When writing such a scene, focus on the mood, keep the description and introspection to a minimum, and as said before, strive to use short sentences. Notice the differences in the original and revised paragraphs below:
Original: Susan crept down the dark stairs to her Aunt Margaret's living room, trying to get a fix on the noise that had awakened her but she couldn't. Of course, she wasn't even sure what had awakened her, only that she'd heard something. It was dark but she could still make out a few details in the large, shadow-filled room, thanks to the moonlight pouring in through the partially open floorlength beige-colored drapes that covered the bank of tall windows against the east wall. She glanced from the overstuffed, Queen Anne — style, camel-colored easy chair in the corner to the two mocha-colored leather sofas and glass-and-chrome coffee table that sat in the center of the room. Then one of the shadows seemed to loom larger than the rest and started moving toward her. She gripped the baseball bat harder and raised it above her head, and demanded, “Who's there?”
Revised: Susan tightened her grip on the baseball bat and crept down the dark stairs to her Aunt Margaret's living room. She wasn't sure what had awakened her but something had. She looked around the room. It was shrouded in shadows, each more ominous than the last. Then one of the shadows started moving toward her.
She raised the bat above her head. “Who's there?”
Both examples describe the same event, but the second one is more effective at building suspense. Not only is it shorter, it uses a minimum of visual details about the living room. While those descriptions may paint a visual picture in the reader's mind of the room, they are unnecessary for the success of this scene.
Notice, also, that the reference to the baseball bat was moved to the first sentence. By leading with the image of Susan creeping down the stairs in the dark with a baseball bat in her hand, you immediately set the stage for suspense in the reader's mind.