Resting left ventricular systolic function was studied by cardiac catheterisation before and 6 months after effective transluminal coronary angioplasty (TCA) to evaluate the myocardial effects of this procedure. The global left ventricular systolic function was assessed by measuring ventricular volumes, the ejection fraction, the mean velocity of circumferential fibre shortening (m VCF) and mean normalised systolic ejection rate (MNSER). The regional function was studied by dividing the left ventricle into 8 regions using the Stanford radial model and measuring the percentage shortening and velocity of circumferential fibre shortening (VCF). These parameters were obtained from selective left ventriculography filmed at 100 frames/second in the RAD plane. Left ventricular function was analysed from the whole of systolic ejection and then sequentially during each third of systole (early-mid-and end systole). The 10 patients studied had an average age of 45 years. Coronary angiography was performed for unstable angina (6 cases), stable angina (3 cases) and post-infarction angina (1 case). Except for 1 patient with associated LAD and right coronary disease they all had single vessel disease. TCA was performed on the LAD artery in 8 cases, on a dominant left circumflex artery in 1 case and on a right coronary artery in 1 case. The efficacy was demonstrated by angiographic reduction of the degree of stenosis (85 to 25 p. 100 immediately after TCA, and 30 p. 100 at control angiography at 6 months), and by a reduction of more than 40 p. 100 in the average transstenotic pressure gradient.(ABSTRACT TRUNCATED AT 250 WORDS)