Haemodynamic effects of intravenous cibenzoline in patients with coronary heart disease

The effect of a single dose of cibenzoline ((diphenyl 2,2 cyclopropyl) -2 imidazoline, Cipralan), a new compound with antiarrhythmic properties was studied in 14 patients undergoing routine heart catheterization for suspected coronary artery disease. The effect of the drug on dP/dt, V_max TP, Vce, negative dP/dt, heart rate (HR), left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), cardiac index (CI) and systemic vascular resistance (SVR) was measured before and after drug administration. A significant decrease in left ventricular isometric contraction parameters was manifested immediately after injection, with its maximal effect 2 to 5 min after injection. An increase in HR, a decrease in LVSP, a decrease in CI and an increase in SVR were observed; LVEDP was not significantly altered, nor was negative dP/dt. The effect of the drug on V_max TP and LVEDP was also examined during two atrial pacing stress tests (APST) done before and 10 to 20 min after drug administration. Although the negative inotropic action of the drug was apparent during the second APST, the effect was less pronounced at higher paced heart rates. No difference in the two tests was found between the maximal paced heart rate, nor was there a difference in the angina threshold. Finally the plasma level of the drug and the changes in certain parameters were compared. A positive correlation was found between the plasma level and dP/dt, V_max TP and cardiac index.