Association between silent ST segment depression in exercise electrocardiography and insulin resistance in obese...

This study was designed to clarify the association between ST segment depression in exercise electrocardiography (ECG) and insulin resistance in obese subjects.

A multistage graded submaximal exercise stress test on the bicycle ergometer was performed under CM5-lead ECG monitoring in 114 obese subjects (39 men and 75 women, mean age 50.9 +/- 12.2 years, mean body mass index 28.6 +/- 3.1 kg/m(2)).

In 27 patients showing ST segment depression at the final exercise intensities (abnormal ST), insulin resistance index by homeostasis model assessment (HOMA-IR) was higher and insulin sensitivity index was lower than in the remaining 87 patients with normal ST segment level (normal ST). The abnormal ST group showed significantly higher plasma glucose and serum insulin levels during the oral glucose tolerance test (OGTT) than the normal ST group. The abnormal ST group showed a significantly higher prevalence of hypertension, impaired glucose tolerance and metabolic syndrome than the normal ST group. Multiple logistic regression analysis showed that insulin resistance as evaluated by fasting insulin, sigma insulin during OGTT, HOMA-IR, insulin sensitivity index, the levels of uric acid, fasting glucose, systolic blood pressure and maximal oxygen uptake were independently associated with ST segment depression.

These results suggest that insulin resistance may involve pathological ST depression during exercise, as well as previously reported factors such as hyperglycemia, hyperuricemia, hypertension and lower aerobic capacity.