Electrocardiographic Detection of Emphysema

Emphysema of any pathogenesis (nearly always chronic obstructive pulmonary disease) verticalizes the frontal P-wave axis >60° in adults, which, as a single criterion, has screened for obstructive pulmonary disease. In patients with emphysema, the QRS was of a significantly shorter duration than that in matched control patients. We investigated whether combining these 2 criteria would better detect or screen for emphysema. From consecutive unselected daily electrocardiograms with sinus rhythm, 50 were selected with a P-wave axis of >60°. An equal control group from the same electrocardiogram continuum with a P-wave axis of ≤60° was matched for age and gender. The QRS durations were those measured by the electrocardiographic computer and manually verified individually. The charts were then reviewed for the diagnosis of chronic obstructive pulmonary disease and/or pulmonary emphysema according to the pulmonary function test and chest radiographic findings, respectively. The patients and controls were well matched demographically. Those with a vertical P axis had a strikingly greater incidence of emphysema than did the controls (86% vs 4%, respectively). The sensitivity of a P axis >60° was 96% and the specificity was 87%. The mean QRS duration with emphysema was significantly shorter (78 ± 8 vs 89 ± 6 ms, p <0.01). The combination of QRS duration <75 ms in conjunction with a P axis of >60° achieved a specificity of 100%, although the sensitivity decreased to 33%. We have reported multiple other cutpoints for each and for the combination. In conclusion, a P axis >60° can be used alone with very high sensitivity and specificity to detect emphysema. The verticality of the P axis is usually immediately visible in the limb leads; therefore, this could be a rapid screening test for emphysema. The specificity was increased when combined with a shortened QRS duration, at the cost of the sensitivity.