Emphysema: Northwest Axis

Report:

Sinus tachycardia 130/min

Right atrial abnormality

P axis +85o

Indeterminate abnormal axis +250o

S1S2S3 pattern

Poor R wave progression

RSR’ in V1-2

Comment:

The patient had advanced emphysema, with dilated right ventricle and clinical cor pulmonale, but echocardiographically normal left ventricle. The indeterminate axis probably has the same significance (RVH) as RAD; this is supported by large, right-axis P waves and RSR’ in V1. ST segment depression in the inferior leads tends to support RVH, but much of it is, in this case, due to atrial repolarisation (TA waves) due to both P pulmonale and the tachycardia.

The entire pattern is also consistent with emphysema without cor pulmonale.

The differential diagnosis of the patient’s frontal plane axis includes LAHB with loss of R wave height from, e.g., anterior infarction. Features against the diagnosis of LAHB are small q waves in the inferior leads and the synchronicity of R’ peaks in aVL and aVR; also S wave is usually smaller in Lead 3 than in Lead 2 in LAHB, as in the previous case.

Another patient with Northwest axis, a 37 year old man with α-1 antitrypsin deficiency, is illustrated in Fig 126a.

126a. 127. 58 year old man with irregular pulse. Why is the pulse irregular?

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