Relationship between recovery time of ST segment change and coronary lesions in the treadmill exercise test for pilots

Abstract

Objective To investigate the relationship between recovery time of ST segment changes and coronary lesions for treadmill exercise test (TET). Methods Two hundred and twenty-six civil aviation pilots with TET positive or suspected positive were selected as subjects. They were divided into immediate group, <3 min group and ≥3 min group according to the ST segment depression recovery time. The examination results of multi-slice spiral CT coronary angiography (MSCTA) and coronary angiography (CAG) of 3 groups were statistically analyzed. Results ①In all 226 cases, cases of immediate group, <3 min group and ≥3 min group were 24, 105, and 97 respectively. In TET, there were 32 cases of TET positive and 194 cases of suspected positive. Eighty-one positive and 145 negative cases of coronary angiography were detected. Eighteen cases were finally diagnosed as coronary heart disease and then disqualified. ②In 18 cases of coronary heart disease, 15 cases of ST segment changes appeared in exercising and recovery phase and 3 cases appeared in the recovery phase longer than 3 min. In 63 cases of coronary artery atherosclerotic with stenosis, the ST segment changes, 19 cases with ST segment change could recover to the baseline within 3 min and 44 cases could not. 79.55% (35/44) cases with ST segment changes appeared in exercising and recovery phase and the case appeared in the recovery phase longer than 3 min accounted for 20.45% (9/44). ③The positive incidence of MSCAT showed significant difference among 3 groups (χ2=63.034, P=0.000). The positive incidence of MSCTA in ≥3 min group was higher than that in immediate group and in <3 min group (χ2=39.754, 18.766, P<0.01). The positive incidence of CAG in ≥3 min group was higher than that in <3 min group (χ2=11.039, P=0.012). The predictive value of the positive in ≥3 min group was significantly higher than that in <3 min group (χ2=61.039, P<0.01). Conclusions For pilot's TET, if his ST segment change couldn't recover to baseline within 3 min or as the ST segment change happened beyond 3 min recovery and lasted for more than 2 min, it would indicate the possibility of coronary lesions. Paying more attention on recovery of ST segment change recovery in TET and performing normative TET would be significant for early detection of coronary lesions and ensuring flight safety. Key words: Exercise test; Coronary arteriosclerosis; Coronary stenosis; Eligibility determination; Pilots