Little is known about the value of electrocardiography in primary care.
Aims: To assess whether electrocardiography (ECG) is a useful instrument, in addition to history taking and physical examination, in that it changes the general practitioner's management of patients with suspected cardiovascular symptoms or disease.
Methods and results: We performed a prospective study in a group practice of eight general practitioners in The Netherlands. During 2 years all ECGs that were recorded in these practices were studied. Two questionnaires were filled out by the general practitioners, one before and one after the ECG recording, to determine indication for electrocardiography, the general practitioner's anticipated management before and after ECG results, and the subjective usefulness according to the applying doctor. All ECGs were reviewed by an experienced general practitioner working in the group practice and later on by a cardiologist. In addition, all clinical information, including the 6 months follow-up period, was scrutinised by both the cardiologist and general practitioner to establish the patients' prognosis. A total of 301 ECGs was included in the analysis. Main indications for electrocardiography were chest pain (57%), and collapse or palpitation (30%). In 92 (30.6%; 95% CI 25.4-35.8) patients a change in management by the general practitioner occurred following the ECG results. Most prevalent changes were non-referral to a cardiologist, while referral was anticipated before the ECG results (34%), referral while the patient would not have been referred without ECG results (20%), and change in cardiovascular therapy (40%). In one of these cases only, this change could be considered unfavourable, since a subendocardial infarction, not detectable on the ECG, was missed. In patients with chest pain, a normal ECG (likelihood ratio (LR) 0.06) and an abnormal ECG (LR 13.3) were very useful to distinguish between patients likely or unlikely to experience cardiac events in the near future. The mean subjective usefulness, on a scale of 0-100, of the ECG evaluation according to the applying general practitioner was 77. 5 (S.D. 14.4). There was good agreement in ECG interpretation between the experienced general practitioner, the cardiologist and a second general practitioner.
Conclusion: Electrocardiography in addition to history taking and physical examination, may be an important tool in primary care. It can reduce considerably the number of unnecessary referrals.