ECG and quality control in general practice (English abstract).
Just about every general practice surgery has an ECG machine. Procedural mistakes produce flawed recordings, and can cause diagnostic errors. A search in PubMed revealed that most of the studies done pertain to hospital medicine. The most common mistakes were:
Incorrect placement of the precordial leads, mainly a vertical displacement of V1, V2 and that V4-V6 are placed to low and too far to the left.
Electrode placement interchanges, by mainly switching left and right electrodes and the wrong leads of the precordial electrodes.
A simple survey was done of 12 general practices with 27 doctors and 30 ancillary staff workers. The ancillary staff workers were asked to do an ECG on me, and fill in a short questionnaire regarding electrode placement. This revealed that the same procedural mistakes are common in general practice, and that a lot of the ancillary staff do not know the correct electrode placement. The ECG results were compared to 20 ECGs taken of me at the National Hospital (Rikshospitalet) over a period of 3 weeks. Only 4 of the 30 ECGs had all values within 2 standard deviations of the measurements done at Rikshospitalet.
The doctors were asked to evaluate six ECGs. Three were normal and three demonstrated the most common procedural mistakes. Only five of the 27 doctors suggested that the abnormal ECGs were cause by procedural mistakes.
This survey indicates that ECG procedural errors are common in general practice, that they influence ECG measurements and that doctors need to be more aware of the problem.