Assessment of the technical quality of electrocardiograms

The technical quality of 600 electrocardiograms (ECG's) was assessed for missing leads and clipping, and graded from 1 to 5 for each of noise, lead drift and beat-to-beat drift. Three subgroups of 200 ECGs each were studied: group A, those obtained by emergency department staff (non-technicians); group B, records obtained by ECG technicians; and group C, telephone-transmitted records obtained by technicians performing all the laboratory work at a smaller, outlying hospital. Records with missing leads, clipping, grade 4 or 5 noise, grade 5 lead drift or grade 5 beat-to-beat drift were classified as unsatisfactory or rejected. With these stringent criteria the rejection rate was 71.0% for group A records, 58.5% for group B and 44.5% for group C. The proportions of records with peak quality (no missing leads or clipping, and grade 1 noise, lead drift or beat-to-beat drift) were 4.5% for group A, 5.5% for group B and 23.0% for group C. Suggested revisions in the grading of technical quality of ECGs are presented.