The answer, as it is for most questions in medicine, is “it depends.” The perioperative beta blocker controversy is a good example of the simplistic fallacy of categorizing treatments into those that “work” and those that “don't work.” As the pendulum continues to swing around this controversy we're beginning to see a pattern. Large fixed doses of beta blockers given to beta blocker naïve patients perioperatively are likely to carry risks that exceed benefits. On the other hand low starting doses gradually titrated to heart rate and blood pressure seem to produce better results. This was illustrated in the recently published DECREASE-IV looking at low dose bisoprolol in intermediate risk patients, which nudged the pendulum back toward beta blocker use.
An ACCF/AHA focused guideline update was released late last year. The recommendations differ very little from the previous focused update. The only class I recommendation is for continuation of beta blockers perioperatively in patients previously taking them for a class I guideline indication. Class IIa recommendations include certain high risk patients, mainly those undergoing vascular surgery, with emphasis on titration to pulse and blood pressure.
A recent article in Today's Hospitalist discusses the ins and outs.