The electrocardiogram (EKG) can sensitively reflect the presence of emphysema in patients with Chronic Obstructive Pulmonary (COPD). It is known that the presence of a vertical P wave axis can be used to detect emphysema. The QRS complexes in patients with emphysema seem to be of shorter duration than the QRS complexes of other patients. We observed the use of P wave vector and QRS duration in the detection of emphysema.
All EKGs done in the hospital on any particular day were randomly reviewed. Fifty consecutive EKGs with the P axis of 70° or more were selected (age 65.18 ± 12.27, 36% male) and matched with a control (normal P axis) for age and sex (age 64.40 ± 12.92, 34% male). The exclusion criteria were age less than 40 years, and presence of any intraventricular conduction delay (QRS duration of > 100 msec). The EKGs were reviewed by two independent observers. The diagnosis of emphysema was made by clinical presentation and findings on the chest X-ray.
Patients with a vertical P wave axis had a strikingly higher incidence of emphysema than the control group (86% vs. 4%, P < 0.01). The sensitivity of P wave axis of 70° or more for emphysema was 95.6%, and the specificity was 87.3%. The mean QRS duration in patients with emphysema was significantly shorter (77.93 ± 7.63 msec vs. 88.65 ± 6.30 msec, P < 0.01). When using QRS duration of <75 msec in conjunction with P wave axis of 70° or more, the specificity for emphysema was 100% but the sensitivity was down to 32.6%.
The QRS duration is significantly shorter in patients with emphysema. Vertical P axis and QRS duration can both sensitively and specifically reflect the presence of emphysema.
P wave axis of 70° or more can be used independently with high sensitivity and specificity for detection of emphysema. When used in conjunction with the narrow QRS duration, the specificity increases.
A.J. Thomas, None.