This study was undertaken to evaluate the effects of intravenous Propafenone (2 mg/kg over 5') on Left Ventricular (LV) function and coronary blood flow. Twelve patients with coronary artery disease and post-ischemic LV disfunction were examined during routine cardiac catheterization. Serial measurements of central hemodynamics, LV high-fidelity pressure and coronary blood flow were recorded at rest and every 10' after Propafenone administration. Heart rate was unchanged, suggesting that Propafenone did not affect sympathetic tone. Cardiac index slightly decreased (from 3.3 +/- 0.9 L/min/m2 to 3.1 +/- 0.6 L/min/m2 at 10', p = ns), LV end-diastolic pressure rose significantly (from 17.7 +/- 2.1 mmHg to 22.7 +/- 4.2 mmHg at 20', p less than 0.01) and dP/dt max fell from 1897 +/- 291 mmHg/sec to 1577 +/- 312 mmHg/sec (p less than 0.02). Systemic vascular resistances had only minimal changes. Concomitantly, coronary vascular resistances decreased (from 0.77 +/- 0.17 mmHg/ml/min to 0.61 +/- 0.12 mmHg/ml/min, p less than 0.02) and coronary blood flow increased (from 138 +/- 29 ml/min to 172 +/- 21 ml/min, p less than 0.01). No significant difference was noted in myocardial oxygen consumption. No symptoms related to LV failure were observed during the study. In conclusion hemodynamic effects of Propafenone are characterized by moderate LV depression and by coronary artery dilatation, probably due to a calcium blocker-like activity.