ECG in sickle cell trait at rest and during exercise and hypoxia.

The electrocardiograms of 28 volunteers with sickle cell trait were compared to those of 28 control subjects. Tracings were recorded at rest, at peak exercise, at simulated sea level, and at a simulated altitude of 4,000 m. No differences between the subjects with sickle cell trait and control subjects were observed for the majority of electrocardiographic measurements. Several measurements had statistically significant differences that persisted after correcting for body surface area and physical fitness. The magnitude of the differences does not appear to have physiologic or clinical significance. The observation that the differences were greatest for resting and sea level recordings indicates that sickling is probably not responsible. Further investigation will be needed to substantiate these differences and determine whether these electrical observations have any physiologic implication.