Calcium antagonists in the post-myocardial infarction setting

At present, the use of calcium antagonists for the secondary prevention of cardiac events following an acute myocardial infarction (MI) is not recommended. This advice is based on several large mortality studies using short-acting calcium antagonists in the absence of coronary reperfusion therapy. Even in these studies, discrepancies between the different pharmacological classes of calcium antagonists were recognised. When separated from the dihydropyridine calcium antagonists, the rate-lowering calcium antagonists, verapamil and diltiazem, do appear to provide some benefit in reduction of recurrent MI. Three large trials using verapamil post-MI demonstrated a significant reduction in reinfarction with a favourable trend towards reducing death as well. Similarly, the effects of diltiazem post-MI have been evaluated in 3 large trials. In 2 earlier trials, diltiazem lessened cardiac events in patients with nonQ-wave infarctions and those without pulmonary congestion upon presentation. Overall, there was a significant benefit in lessening reinfarction with no effect on mortality. The recently completed Incomplete Infarction Trial of European Research Collaborators Evaluating Prognosis Post-Infarction (INTERCEPT) trial found that sustained-release diltiazem given after thrombolytic therapy for acute MI lessened cardiac events by 23% (a nonsignificant difference) without worsening congestive symptoms. Overall, there is adequate data to support the use of heart-rate-lowering calcium antagonists for secondary prevention post-MI provided the patient is intolerant of beta-blocker therapy. These trials are reviewed in detail, and suggestions for clinical practice are provided in this article.