Effects of submaximal exercise and hyperventilation on ECG components in healthy, young adult men with recording leads typically used for evaluation of ischemic heart disease

Abstract

The present study was undertaken to determine if leads CM₅, CC₅, and V₅ are equally sensitive in detecting ST segment depression with exercise or hyperventilation in apparently normal males. Seven physically active men (29.4 + 2.9 yrs, 180.9 + 2.5 cm, 77.9 + 3.4 kg, x±SEM), free of risk factors for heart disease, were initially found to have J point (J₀) depression with mild exercise in lead V₅. Simultaneous ECG recordings from CM₅, CC₅ and V₅ during seated rest (REST), immediately post-moderate exercise (IPE), and after 30 s of hyperventilation (HVT). ECG signals were manually evaluated for ST segment depression at the J point and 60 ms and 80 ms past the J point (J₆₀, J₈₀). None of the three leads differed in their ability to detect ST segment changes. With exercise, J₀ was significantly (P<.05) reduced compared to REST; neither J₆₀ nor J₈₀ differed from REST. HVT reduced J₀ significantly but not J₆₀ or J₈₀ Exercise provoked greater reductions than HVT. These data suggest that, in apparently healthy adult males, these three ECG leads are equally able to detect J point changes with exercise and hyperventilation, but exercise results in a relatively greater downward ST segment shift than does hyperventilation.