Hemodynamic response to exercise in patients with sickle cell anemia.

In order to evaluate potential electrocardiographic (ECG) correlates of ST-segment depression during exercise in patients with sickle cell anemia (SS), 43 subjects, aged 5-23 years, underwent submaximal exercise testing. Eight (19%) had ST-segment depression on the exercise ECG during submaximal exercise. These eight patients had significantly lower hemoglobin levels than the 35 subjects without evidence of ST-segment depression. These eight subjects also had significantly higher peak blood pressures and peak heart rates than the 35 subjects without ST-segment depression. The product of peak heart rate and peak systolic blood pressure, the maximal double product, is a correlate of myocardial oxygen consumption and was significantly higher in the patients with ST-segment depression than in the patients without ST-segment depression. These results indicate that patients with SS and evidence of exercise-induced ST-segment depression may have decreased myocardial oxygen supply due to low hemoglobin levels and increased myocardial oxygen demand (elevated double products) when compared to subjects with SS who do not have exercise-induced ST-segment depression.