LBBB in Hyperkalæmia

Report:

Accelerated junctional rhythm 90 - 96/min

? Sinus rhythm with sino-ventricular conduction

Left bundle branch block

QRS 0.22”

Peaked T waves suggestive of hyperkalæmia

Comment:

The potassium rose to 8.0 mEq/L and probably higher.

The rhythm is uncertain; atrial paralysis in hyperkalæmia may have masked P (or other atrial) waves. Sinus P waves reappeared at potassium level 5.9 mEq/L the following day (Fig 2a) below); their amplitude was still small. The QRS duration is diminished to 0.16” and the T waves are less peaked.

Sinoventricular conduction is often thought of, but rarely documented.

Figure 2a. Reappearance of atrial waves, almost certainly sinus, the following day.

Fig 3. Postoperative ECG in a 27 year old man with replaced bicuspid aortic valve and repaired ascending aortic aneurysm.

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