The Society of German Cardiologists in private practice (BNK) reports about its project on quality assurance in invasive cardiology (QuIK). Results of a computerized data collection and analysis of cardiac catheterizations and interventions in the years 1999-2002 are presented. These results are compared with other registries. The QuIK-project is done voluntarily by 70% of the society's cardiologists who perform invasive methods. A total of 225,562 diagnostic and 64,895 interventional procedures are documented over the 4 years. Patient characteristics and procedural data kept unchanged. Complication rates were low (< 2%), MACE < 0.5%. There was a rising number of patients referred with acute myocardial infarction. Less time was used to complete procedures from 1 year to another. Two out of three of the centers underwent a monitoring/auditing process in 2002. The desirable post-interventional follow-up after discharge in all cases appears to be impossible to fulfill under the given economical circumstances.