In order to evaluate the effects of propafenone (an antiarrhythmic class 1 c agent) acutely administered intravenously on left ventricular function, 10 patients with acute myocardial infarction (AMI), affected by arrhythmias (greater than or equal to Lown class III), belonging to Killip class I and II, and with normal serum electrolyte levels, were studied 2-4 days after an acute episode. No patients had previously been treated with antiarrhythmic drugs, or, if treated, the agent was withdrawn since at least 4 half-lives. In no case were inotropic substances or other pharmacological treatments, capable affecting L.V. function administered. Intravenous nitroderivative (Venitrin) infusion was continued when indicated. Each patient was administered a propafenone bolus (1 mg pro Kg in 4 minutes). Two dimensional and Doppler echocardiography were performed under basal conditions i.e. before propafenone infusion, during the infusion and after 1, 2, 3 and 4 hours, deriving following parameters: L.V. end diastolic and end systolic dimensions and volumes, ejection fraction (area-length method), II motion abnormalities, and transmitral flow velocity profile (E/A ratio). Statistical data were obtained using two way analysis of variance.
Results: In no case was the treatment interrupted, on the basis of our protocol criteria (reactions of hypersensitivity, proarrhythmic effects, acute hemodynamic deterioration that requires immediate positive inotropic and chronotropic agents administration, worsening of previous arrhythmic class). Heart rate and systemic arterial blood pressure did not change significatively during or after infusion.(ABSTRACT TRUNCATED AT 250 WORDS)