Friday, July 2, 2021

This ECG Pattern Told the Story When the Patient Could Not

 Submitted by Spencer Lord MD, written by Alex Bracey with edits by Meyers and Smith

A patient presents as a transfer from an outside facility. On arrival, he appeared air hungry, volume overloaded, and agitated. EMS was not available for a history at the time and the patient was unable to provide any details regarding his circumstances. During the initial minutes of his resuscitation the following ECG was performed:

This ECG is pathognomonic. What is it?

Sinus bradycardia with first degree AV block
Wide, bizarre QRS complexes with STE in V1 and aVR
Peaked T waves in I, II, V4-V6
QRS duration is nearly 200 ms.
There is a large R-wave in aVR and V1 (RBBB pattern)
There is ST Elevation in V1, V2, and aVR
There is upsloping ST depression in V4-V6 with a wide and peaked T-wave

Recall the ECG findings of hyperkalemia (aka the "Killer B's") summarized in this graphic created by Pendell Meyers:

The treating emergency physician immediately recognized this to be representative of hyperkalemia. He initiated treatment with calcium gluconate 2g calcium gluconate, insulin, bicarbonate, and lasix with modest improvement in his symptoms. Approximately 20 minutes later a repeat ECG was performed:

Similar to initial ECG with more prominent P waves.

The similarities between these two ECGs is likely due to underdosing of calcium. The minimum dose of calcium gluconate required to rapidly stabilize the myocardium in hyperkalemia is 3g of calcium gluconate or 1g of calcium chloride (calcium chloride has 3x as much elemental calcium as calcium gluconate). More calcium than this minimum is often required. Importantly, there is no upper limit to the amount of calcium that can be administered in severe hyperkalemia and the dose is the amount required to normalize ECG abnormalities, improve hemodynamics, or achieve ROSC in cases of cardiac arrest.

Upon thorough examination of the patient, the emergency staff identified an upper extremity fistula and began arranging for emergent dialysis. He continued to be symptomatic, with periods of bradycardia to the 30s. The patient was treated with calcium gluconate nearly every 15 minutes for these persistent symptoms and albuterol was administered. Dialysis was emergently performed, and this ECG was performed 30 minutes in to the session:

Sinus rhythm with resolution of bizarre, broad QRS complexes and peaked T waves

The potassium level resulted at 9.4 mEq/L.

The patient required two full sessions of hemodialysis but made a full recovery and was discharged without complication following a brief hospital course.

Teaching points:

  • You must be able to instantly recognize hyperkalemia on ECG
  • Hyperkalemia is the great mimicker and will regularly have ST elevation as an ECG manifestion; therefore, one must maintain a high level of suspicion for hyperkalemia with unusual appearing ECGs
  • Know the "Killer B's of HyperK:" Brady, Broad, Bizarre, Block (and peaked T waves)
  • The minimum amount of calcium required to treat severe hyperkalemia is 3g of calcium gluconate or 1g of calcium chloride. Higher doses are often required.
  • There is no upper limit to the amount of calcium that can be administered for severe hyperkalemia. Give the amount required to stabilize the patient while arranging for definitive management (e.g., dialysis)
There have been many other cases of hyperkalemia elsewhere on the blog. Here are several links to prior posts:

1 comment:

DEAR READER: I have loved receiving your comments, but I am no longer able to moderate them. Since the vast majority are SPAM, I need to moderate them all. Therefore, comments will rarely be published any more. So Sorry.

Recommended Resources