This 66-year-old man is in the Emergency Department with acute exacerbation of severe chronic obstructive lung disease and emphysema:

• Sinus rhythm, 95/min.
• Biatrial enlargement
• Markedly superior axis deviation (negative inferior leads with isoelectric lead I makes it difficult to determine if the superior axis is either “right” or “left”)

Comments: The ECG of patients with chronic obstructive lung disease may show prominent negative P waves in V1 in the absence of left atrial enlargement, alone or in association with tall P waves in the inferior leads. Chou who reported this finding suggested that this was “probably due to the relatively high position of the (V1) electrode in relation of the heart” (because of the low diaphragm).

Patients with severe pulmonary emphysema may have right or left axis deviation. There have been a number of explanations for the left axis deviation, one being that the emphysematous lung gives “an illusion” of axis deviation by affecting the conduction of the electrical activity of the heart to the chest wall. As Chou noted, in true left axis deviation S wave in lead 3 is greater than S wave in lead 2, while the reverse is often seen in emphysema with apparent left axis deviation (as in this case). Our patient is normotensive and has no history of coronary artery disease.   His echocardiogram shows normal left ventricle and left atrium and signs of right ventricular overload and tricuspid insufficiency.  (Te-Chuan Chou: Electrocardiography in Clinical Practice, 2nd edition, 1986 – pages 302-303)