2010 Volume 37 Issue 3 Pages 414-423
Objectives : Implementation of resting electrocardiogram (ECG) is obligated by law and widely conducted in occupational sites in Japan. However usefulness of resting ECG in assessing cardiovascular risk of working people is not clear, partly because the evaluation of abnormal ECG may vary among facilities. We conducted large scale survey of resting ECG implementation status in work site to identify factors influencing assessment of ECG abnormalities.
Methods : Self reporting questionnaire was sent to 379 screening institutions which have been under the accuracy control program conducted by the National Federation of Industrial Health Organization. The questionnaire included incidences of abnormal ECG and rate of requiring further evaluation.
Results : We received reply from 235 institutions (response rate 62%) and data of 218 institutions were analyzed. A total of 2,770,239 (men : 1,716,697 women : 1,053,542) ECG examinations were conducted during the survey period. In 66.5% institutions, computerized diagnosis system was always utilized. The survey showed that 14.7% of the total ECG examinations were assessed as abnormal, 8.1% resulted in repeated examination, and 2.5% resulted in further evaluation. There were ST • T abnormality (men 2.2%, women 2.4%), abnormal Q wave (men 0.5%, women 0.2%) and atrial fibrillation (men 0.6%, women 0.1%). When assessing clinical significance of ECG abnormalities to determine the need for further evaluation only 57.3% institutions referred to past medical histories, 50.5% referred to blood pressure values, 48.2% referred to subjective symptoms and 31.7% compared with previous ECG. The rate of abnormal findings resulting in further evaluation was significantly higher in institutions that did not refer to subjective symptoms, family history, past history, previous recording or cardiovascular risk factors, than institutions that referred to those factors. About a quarter of institutions were aware of final diagnosis.
Conclusion : Resting ECG is useful for medical screening examination in occupational sites since abnormal ECG results needing further evaluation or treatment have been detected. However the rate of abnormal ECG requiring further evaluation varies among institutions. The rate is influenced by whether the institution refer to factors such as subjective symptoms, previous recording and cardiovascular risk factors when assessing ECG abnormalities. Implementation of guidelines for assessment of clinical significance of ECG abnormalities in occupational sites may help enhancing consistent assessment among screening institutions.
