Abstract
Previous cross-sectional studies have shown age trends in electrocardiographic wave patterns, including leftward shift in frontal plane axis and decreases in R, S, and T wave amplitudes with age. The effects of smoking on electrocardiographic measurements have also been examined. Findings of several studies vary and include possible smokinginduced changes in T wave amplitude and frontal plane axis measurements. To examine both cross-sectionally and longitudinally the effects of cigarette smoking on electrocardiographic measurements, serial recordings obtained 5 yr apart were taken from 702 healthy male participants of the Normative Aging Study, who were 23–74 yr of age at their first examination. These men were classified as current smokers (at both baseline and follow-up examinations, N = 291), former smokers (men who stopped smoking prior to the baseline examination, N = 203), or never smokers (at any time, N = 208). At baseline, P-R interval duration was shorter in current smokers than in former or never smokers. Longitudinal results indicated that R, S, and T wave amplitudes decreased at greater rates in smokers than in nonsmokers. These findings suggest that changes in the electrocardiogram attributed to aging may be modified by smoking.