The extended use of interventional surgery of revascularisation has modified the prognosis and the evolution of ischaemic heart diseases. However, both coronary artery bypass graft and percutaneous transluminal coronary angioplasty failed to make the symptomatic or subclinical ischaemic manifestations of chronic coronary insufficiency disappear. The interest of using betablockers as a first-line therapy was widely demonstrated. However, their combination with another efficient molecule is often necessary. The aim of this trial has been to appreciate the efficiency of the association of a betablocker with either trimetazidine or with isosorbide monoitrate. Hundred and eighty five patients retaining a positive effort test despite 100 mg of atenolol, received in addition, either 60 mg of trimetazidine (93 cases) of 60 mg of isosorbide mononitrate (92 cases) for a two-month period and are then re-evaluated at the end of this period. The ischaemic threshold is delayed in a significant way in both groups (p < 0.0001; trimetazidine +7%, isosorbide mononitrate +10.7%). Twenty-three percent of the exercise tests under trimetzidine and 19% under isosorbide mononitrate become negative after two months of the therapeutic combination. The clinical improvement is even clearer with the disappearance of the angina crisis during the week before the second exercise test in 63% of the cases under trimetazidine and 54% of the cases under isosorbide mononitrate, among the patients who had kept it under atenolol at the inclusion. In conclusion, the combination of a second efficient molecule, trimetazidine or isosorbide mononitrate, brings a functional and objective improvement to patients with insufficient chronic coronary disease not totally controlled using a betablocker, even with high dosage. One should notice two important advantages in favour of the trimetazidine: one is practical due to a better tolerance (lack of cephalalgia), the other is conceptual (use of the complementary metabolic approach of cellular oxygenation rather than the haemodynamic approach of nitrate compounds which are already in concurrency with all other anti-ischaemic molecules).