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Electrocardiographic screening for emphysema: the frontal plane P axis
1Division of Cardiology, Saint Vincent Hospital, Worcester, MA 01604, USA.
Background:
Because the most characteristic and sensitive electrocardiographic (ECG) correlate of pulmonary emphysema in adults is verticalization of the frontal plane P-wave vector (P axis), we investigated its strength as a lone criterion to screen for obstructive pulmonary disease (OPD) in an adult hospital population.
Methods:
In all, 954 consecutive unselected ECGs were required to yield 100 with P axis > or = +70 degrees (unequivocally negative P in a VL during sinus rhythm) and pulmonary function tests. and 100 with P axis < or = +50 degrees (unequivocally positive P-aVL).
Results:
Obstructive pulmonary disease by both pulmonary function test and clinical criteria was present in 89 of 100 patients with vertical P axes and 4 of 100 patients without OPD.
Conclusion:
The high sensitivity (89% for this series) and high specificity (96%) makes vertical P axis a useful screening criterion. Its at-a-glance simplicity makes it "user-friendly."
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