Alternating Left Anterior Hemiblock

Report:

Sinus tachycardia 102/min

Alternating LAD, probably LAHB

Acute or recent anterior infarction

Comment:

The presenting symptoms of both angina and infarction are often atypical in women5. This patient had post-infarction angina at the time of this recording.

The LAD complexes are broader than usual for LAHB at approximately 0.12” and the only other differential diagnostic item, incomplete LBBB, cannot be excluded. Of course, the former is a form of the latter. Neither has any prognostic significance per se, but the LAHB would worsen the patient’s outlook if combined with RBBB in the setting of acute anterior infarction.

A day earlier, all her complexes had LAHB morphology (Fig 8a below). In this trace the small initial q in lead 1 is more easily seen; it provides a point in favour of LAHB and against – but not absolutely – incomplete LBBB. On admission (Fig 8b) the intraventricular conduction was normal.

She did well following primary angioplasty.

Fig 8a. LAHB throughout.

Fig 8b. Normal conduction on admission. The anterior infarction looks acute or very recent.

Fig 9. 29 year old lady in chronic renal failure, inclined to allorhythmia.