Computerized tomographic quantification of chronic obstructive pulmonary disease as the principal determinant of frontal P vector.
Verticalization of the P-wave axis is characteristic of chronic obstructive pulmonary disease (COPD). We studied the correlation of P-wave axis and computerized tomographically quantified emphysema in patients with COPD/emphysema. Individual correlation of P-wave axis with different structural types of emphysema was also studied. High-resolution computerized tomographic scans of 23 patients >45 years old with known COPD were reviewed to assess the type and extent of emphysema using computerized tomographic densitometric parameters. Electrocardiograms were then independently reviewed and the P-wave axis was calculated in customary fashion. Degree of the P vector (DOPV) and radiographic percent emphysematous area (RPEA) were compared for statistical correlation. The P vector and RPEA were also directly compared to the forced expiratory volume at 1 second. RPEA and the P vector had a significant positive correlation in all patients (r = +0.77, p <0.0001) but correlation was very strong in patients with predominant lower lobe emphysema (r = +0.89, p <0.001). Forced expiratory volume at 1 second and the P vector had almost a linear inverse correlation in predominantly lower lobe emphysema (r = -0.92, p <0.001). DOPV positively correlated with radiographically quantified emphysema. DOPV and RPEA were strong predictors of qualitative lung function in patients with predominantly lower lobe emphysema. In conclusion, a combination of high DOPV and predominantly lower lobe emphysema indicates severe obstructive lung dysfunction in patients with COPD.
Department of Internal Medicine, Saint Vincent Hospital, University of Massachusetts Medical School, Worcester, USA. lovids@hotmail.com
Lovely
L
Chhabra
Pooja
P
Sareen
Amit
A
Gandagule
David
D
Spodick
D000465:Algorithms; D004562:Electrocardiography; D006801:Humans; D008875:Middle Aged; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011656:Pulmonary Emphysema / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed