Incidence of adverse events during treatment with verapamil for suspected acute myocardial infarction

Abstract The potential clinical role of non-dihydropyridine calcium antagonists, such as verapamil and diltiazem, in the management of patients during and subsequent to acute myocardial infarction (AMI) is an area of considerable and changing controversy. 1 Recent investigations suggest that both verapamil 1,2 and diltiazem 1,2,4 exert beneficial effects after AMI, largely, if not entirely mediated by reduction in the incidence of reinfarction. However, there is considerable concern about the use of these negatively inotropic calcium antagonists in patients with significantly impaired left ventricular systolic function. 1,2,4 Although diltiazem may be beneficial in the periinfarct period 3 and verapamil may exert beneficial effects on both ischemia 5 and infarct size 6 in this setting, the results of the only large randomized study conducted to date concerning the early use of verapamil — Danish Verapamil Infarction Trial-I (DAVIT-I) 1 — discouraged initiation of verapamil therapy in the first week, representing the period of maximal risk for reinfarction. Specifically, in DAVIT-I the incidence of death due to cardiogenic shock or pulmonary edema, or both, complicating infarction was 5.3%, somewhat higher than in the placebo-treated patients (3.2%). These results of DAVIT-I may have been influenced by the use of large intravenous doses of the drug and by the absence of thrombolytic therapy, which would be expected to both reduce the potential risk of the development of cardiogenic shock and increase the risk of reinfarction. Therefore, there is a need to reevaluate this area of therapeutics. We prospectively examined the incidence of potential drug-associated adverse events in consecutive patients treated with intravenous or oral verapamil, or both, in the early management of suspected AMI. We also sought to determine potential clinical parameters predisposing to the occurrence of such adverse outcomes. End points included death, significant bradyarrhythmia requiring treatment due to hemodynamic compromise and symptomatic left ventricular failure. Frequency of these outcomes was expressed as a percentage with 95% confidence intervals (CI). Correlates between 12 prospectively chosen clinical variables and individual end points were determined using multiple logistic regression.