The authors have recently demonstrated that 13% of indications for cardiac catheterisation performed "after hours" (week ends, holidays or from 6 pm to 7 am) are Class III of the AHA/ACC recommendations (i.e. indications not based on recognised medical evidence). In order to limit procedures performed for these unrecognised indications, a consensus of experts has defined a number of local recommendations. The aim of this paper was to study the impact of these recommendations on the indications of "out of hours" cardiac catheterisation. Two patient populations were identified and compared with respect to these recommendations. The first group comprised 157 consecutive patients treated between 1993 and 1994 (average age 58 +/- 13 years; 35% females) and the second one of 148 consecutive patients treated from 1998 to 1999 (average age 57 +/- 13 years; 25% females). The local recommendations were respected in 61% of cases and not applied in 39% of cases. This was a satisfactory result in view of the fact that the local recommendations are more restrictive than international guidelines as they cover emergency indications. In the second group of patients, there were no AHA/ACC Class III indications (30% Class I, 6% Class IIa and 3% Class IIb). There was a significant increase in the number of primary angioplasties for acute myocardial infarction (27 vs 2%; p < 0.001) and an expected reduction in salvage angioplasties (17 vs 7%; p < 0.01). There was no significant change in the indications in patients with unstable angina, the European and American guidelines having been published at the end of data collection. Therefore, the introduction of recommendations for out of hours cardiac catheterisation has limited the number performed for unrecognised indications in favour of evidence based procedures.