THE NEGATIVE INOTROPIC AND CHRONOTROPIC EFFECTS OF INTRAVENOUS R-56865 DURING PERCUTANEOUS TRANSLUMINAL CORONARY ANGIOPLASTY

The present study was designed to evaluate the potential anti-ischaemi c activity of R 56865 in patients with coronary artery disease, schedu led to undergo percutaneous transluminal coronary angioplasty (PTCA). At baseline a complete haemodynamic profile, including cardiac output and coronary sinus blood flow (CSBF) was obtained. In addition, left v entricular pressure and contractility parameters were measured. These parameters were also measured before and after additional balloon infl ations, preceded by placebo and R 56865 i.v. R 56865 was infused intra venously at three different dosages, namely: 20 mg (n = 8), 30 mg (n = 2), 40 mg (n = 2). No significant differences were observed between p lacebo and R 56865 (20 mg) concerning time to onset and duration of ST -segment changes and symptomatic angina pectoris, respectively. The ot her parameters did not show differences compared with the baseline val ues when R 56865 (20 and 30 mg) was infused. However, the two patients receiving a dose of 40 mg R 56865 developed a dramatic decrease in sy stolic and diastolic blood pressure, left ventricular (LV) systolic pr essure, peak positive dP/dt and the CSBF (ranging from 30-50%), while the LV end-diastolic pressure increased by 100%. The two patients who received this dose became pale and cyanotic and did not respond to ver bal commands. In summary, no anti-ischaemic effects of R 56865 were ob served under these conditions, whereas at the highest dose (40 mg) R 5 6865 induced hypotension and a reduction in cardiac contractile force.