Abstract
Objectives. Exercise electrocardiogram (ExECG) in low risk populations frequently generates false positive ST depression. We aimed to characterize factors that are associated with exercise-induced ST depression in asymptomatic men without coronary artery disease. Design. Cycle ergometer exercise tests from 509 male firefighters without imaging proof of significant coronary artery disease were analysed. Analysed test data included heart rate at rest before exercise, and workload, blood pressure, heart rate, ST depression and ST segment slope at peak exercise. ST depression of >0.1 mV was considered significant (STdep). With a mean follow-up of 6.1 ± 1.7 years, medical records were reviewed for cardiovascular diagnoses, hyperlipidemia and diabetes. Logistic regression analysis was used for risk assessment. Results. In total, 22% had STdep in ≥1 lead. Subjects with STdep were older than those with normal ExECG (p < .001). Downsloping STdep was more common in extremity leads (9%) than in precordial leads (2%). STdep was categorized according to location (precordial/extremity) and slope direction into eight categories. Larger age-adjusted heart rate increase predicted STdep in seven categories (p < .05). Age-adjusted peak heart rate correlated with STdep in five categories, predominantly where the ST slope was positive. Peak blood pressure and exercise capacity were both associated with STdep in few categories. We found no association between STdep and hypertension, hyperlipidemia or diabetes (all p > .05). Conclusions. In asymptomatic men with a physically demanding occupation and no coronary artery disease, both age and heart rate response were associated with ST depression, whereas common cardiovascular risk factors, blood pressure response and exercise capacity were not.
Highlights
Exercise testing has the dual purpose of assessing physical capacity and evaluating cardiovascular health
We have previously found the prevalence of exercise-induced ST depression - one of the cornerstones in exercise ECG (ExECG) interpretation for identification of coronary artery disease (CAD) - to be around 20% in a firefighter cohort [2]
8% had gone through cardiac imaging studies during the inclusion period or follow-up, with negative result for exercise-induced ischemia or with none or
Summary
Exercise testing has the dual purpose of assessing physical capacity and evaluating cardiovascular health. In the periodic evaluation of Swedish firefighters, exercise ECG (ExECG) to maximal exhaustion is mandatory, with the aim to detect subclinical signs of cardiovascular disease [1]. The aerobic capacity of firefighters is higher than in the general population. They are disqualified from duty if their medical health deteriorates. We have previously found the prevalence of exercise-induced ST depression - one of the cornerstones in ExECG interpretation for identification of coronary artery disease (CAD) - to be around 20% in a firefighter cohort [2]. The IHD event rate was only 2% during follow-up, which illustrates the interpretational challenge in differentiating true from false positive ST changes in this firefighter cohort as well as in any asymptomatic population with low pre-test probability [3]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
