Supernormal Conduction in LBBB

Report:

Atrial fibrillation with ventricular response 93/min

Left bundle branch block, intermittent

Supernormal conduction

Probable LVH with ST/T changes (incomplete LBBB)

Comment:

The transition to narrow(er) QRS toward the end of the recording occurs with the shortest of all the recorded cycles. It is better than expected conduction – the supernormal conduction. In the rest of the ECG the faster rates are conducted with complete LBBB while longer cycles allow for partial QRS recovery.

Both complete and incomplete LBBB, once they occur, tend to persist regardless of the cycle length.

Below (Fig 53a) there are two more instances of supernormal conduction.

Fig 53a. Supernormal conduction (if this is what it is) has significance only as a conversation point.

Fig 54. 48 year old lady admitted for cholecystectomy.

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