OBJECTIVE: To assess the value of a cardiac technicians' report on electrocardiographs (ECGs) in reducing serious errors of interpretation by senior house officers. METHODS: A parallel study of interpretation of ECGs by senior house officers from 238 cases seen in an accident and emergency (A&E) department in a teaching hospital. 129 ECGs were reported by a cardiac technician at the time of recording and before the senior house officer wrote a report, and 109 were reported only by the senior house officers. Misinterpretations by doctors and technicians were graded by a consultant cardiologist on a four point scale and compared in the two groups. Serious errors (grade 4) were defined as those which potentially affected immediate management. RESULTS: The number of grade 4 errors of interpretation of ECGs by A&E senior house officers was reduced by 59% when there was a prior technical report (mean (SD), 18(17)% v 6 (7%); Fisher's exact test P < 0.05). CONCLUSIONS: When cardiac technicians provide a report on an ECG at the time of its recording, serious errors of interpretation by senior house officers are reduced.