Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Motley Fool Rule Breakers recommendation Volcano (Nasdaq: VOLC) surged as much as 10% in intraday trading, after exceeding analyst estimates for first-quarter financial results.

So what: Interestingly, the move up came despite lower full-year guidance. Management cited $5 million worth of revenue impact from the twin tsunamis that struck Japan in March in lowering Volcano's 2011 targets from a range of $347 million to $352 million in revenue and $0.22 to $0.24 in per-share earnings to $342 million to $347 million in revenue and $0.19 to $0.21 in per-share profit. The revised estimates remained within reach of the midpoint of Wall Street's own projections.

Now what: Not so for Q1 results, however. Demand for Volcano's cardiac-imaging technology surged as revenue improved by 22% to $80.9 million. Markedly higher gross margin -- up 560 basis points year over year -- transformed last year's $0.08-per-share loss into a $0.02-per-share profit. Analysts had been expecting $78.4 million and a $0.03-per-share loss. Even though Volcano trades for a significant premium to peers Boston Scientific (NYSE: BSX) and St. Jude Medical (NYSE: STJ), judging by these results, it's worth every penny.

Interested in more info on Volcano? Add it to your watchlist.

Fool contributor Tim Beyers is a member of the Motley Fool Rule Breakers stock-picking team. Volcano is a Rule Breakers recommendation. You can try any of our Foolish newsletter services free for 30 days.

Tim didn't own shares in any of the companies mentioned in this article at the time of publication. Check out his portfolio holdings and Foolish writings, or connect with him on Twitter as @milehighfool. You can also get his insights delivered directly to your RSS reader. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool is also on Twitter as @TheMotleyFool. Its disclosure policy is at least 10% better than other disclosure policies.