Hemodynamic effects of intravenous flecainide in acute noncomplicated myocardial infarction

Hemodynamic and ECG effects of intravenous flecainide were assessed in 10 patients with acute myocardial infarction and no symptoms or signs of heart failure. The dose was 2 mg/kg injected over a 15-minute period. R-R interval did not change, but PR interval and QRS increased significantly, 28% (p less than 0.0005) and 20% (p less than 0.05), respectively. Duration of P wave also increased significantly, 15% (p less than 0.02). Pulmonary wedge pressure increased 29% (p less than 0.005) and cardiac index and left ventricular stroke work index decreased 9% (p less than 0.05) and 20% (p less than 0.05), respectively. No significant change in mean aortic pressure and systemic vascular resistance occurred. Thus, intravenous flecainide has a mild and transient negative inotropic effect in patients with noncomplicated acute myocardial infarction. It did not induce ventricular failure in this group of patients but should be administered cautiously to patients with overt heart failure or severe conduction defects.