Axis Illusion in Emphysema

Report:

Sinus tachycardia 110/min

Right atrial abnormality

P axis +85o

Left axis deviation

QRS –90o

Late (or no) transition

Comment:

An immediate clue that the LAD is not due to an LAHB (its commonest cause, overall) is that S2 > S3, opposite of what happens in the hemiblock. It is thought that the LAD here is due to cardiac position in a hyperinflated chest rather than a true change of the cardiac vector28 – hence the “illusion”.

The trace as a whole is virtually diagnostic of emphysema: classical P pulmonale, P axis almost +90o, narrow QRS (0.07”), marked clockwise rotation (late transition) and the LAD configuration itself.

Incidentally, P wave axis over +70o is the earliest ECG sign of emphysema29.

The patient returned to Casualty a month later (Fig 20a) in marked respiratory distress (she was a “pink puffer” rather than “blue bloater”). Her P pulmonale – I find it quite difficult to relinquish the term – was even more prominent. Some of it may be due to tachycardia itself.

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