The effect of intravenous nicardipine, a new calcium antagonist, on haemodynamics, left ventricular function and angina induced by atrial pacing has been investigated in patients with coronary artery disease. Patients were treated with beta-blockers and measurements were made at a fixed heart rate. Nicardipine produced a 24% fall in mean systemic blood pressure (P less than 0.02) and a 37% increase in cardiac index (P less than 0.02). Cardiac filling pressures, dp/dt max and left ventricular ejection fraction were unaltered. The time to pacing induced angina was prolonged (P less than 0.05) when the dose of nicardipine (0.75 mg X min-1) was selected not to cause an excessive fall in blood pressure. Nicardipine is a powerful arteriodilator without detectable negative inotropic effects and prolongs the time to pacing induced angina.