LBBB with RAD: Acute Inferior Infarction

Report:

Sinus rhythm 96-100/min

Third degree AV block

Junctional escape rhythm 45/min

Left bundle branch block

Right axis deviation +95o

Acute inferior infarction

Comment:

Three contributors to heart failure are present in this trace: Acute infarction, complete AV block and broad LBBB QRS complex.

LBBB does not always mask the primary ST/T changes of acute infarction: they would probably look very much the same if the conduction were normal. An unusual feature here is the RAD: it is a marker of congestive cardiomyopathy. This patient had severe heart failure, but not, exactly, a COCM. Some of the RAD might be due to the reciprocal ST depression in lead 1 “pulling” the terminal QRS down.

He went on to have CABGs but only incomplete revascularisation was possible. Over the next two years the frontal plane axis fluctuated between +70o and +105o, with LBBB throughout. His cardiac status deteriorated into a true COCM indistinguishable clinically from the primary variety. The axis settled around +100o (Fig 5a).

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