Several meta-analyses concluded that cardioselective -blockers do not produce clinically sig- nificant adverse respiratory effects in patients with chronic obstructive pulmonary disease, suggesting that -blockers should not be withheld from these patients.196,197 5.3.3. Calcium Channel Blockers In general, CCBs have not been found to be useful in the set- ting of acute STEMI. Clinical trials of the rapid-release form of nifedipine showed an increase in mortality in patients treated with this agent after MI,198 and there is currently no role for short-acting nifedipine in clinical practice. The non- dihydropyridine agents diltiazem and verapamil have also been disappointing in the early-MI setting and are not recom- mended for routine use in patients with STEMI.190,195 Although several randomized, clinical trials suggested somewhat greater efficacy for CCBs in non ST-segment some of these studies were performed 30 years ago and predate the era of routine -blocker use. Moreover, benefit in these trials was limited to nonfatal recur- rent ischemic events, and among patients with LV dysfunc- tion, a detrimental effect on mortality was seen.118,201 Thus, there is no indication for routine use of CCBs in patients with UA or NSTEMI. The AHA/ACC guidelines for the manage- ment of UA and NSTEMI suggest that, in patients with con- tinuing or frequently recurring ischemia when -blockers are contraindicated, a nondihydropyridine CCB (verapamil or dil- tiazem) may be used as an alternative in the absence of severe LV dysfunction or other contraindications.195 It is prudent to avoid the use of verapamil or diltiazem in patients who have LV dysfunction, and they should not be used together with -blockers in that situation. Evidence for the utility of dihydropyridine CCBs in ACS is limited. These agents effectively lower BP and may relieve ischemic symptoms. 