ECG Case 027

Main Abnormalities

• Bizarre appearing complexes
• Marked T wave peaking in V2-6.
• Gross QRS prolongation (~200 ms)
• Some leads (I, aVR) are starting to take on a sine wave appearance

Diagnosis

The combination of…

• Bizarre complexes
• QRS prolongation
• Peaked T waves
• Sine wave appearance

… are all strongly suggestive of severe hyperkalemia.

This patient had a serum K of 9.2 mmol/L!

In this elderly patient with multiple medical problems, causes could include renal failure (e.g. due to diuretics, NSAIDs, intercurrent illness) or treatment with ACE-inhibitors, spironalactone or K-supplements.

The push-pull effect

• Hypokalaemia creates the illusion that the T wave is “pushed down”, with resultant T-wave flattening/inversion, ST depression, and prominent U waves
• In hyperkalaemia, the T wave is “pulled upwards”, creating tall “tented” T waves, and stretching the remainder of the ECG to cause P wave flattening, PR prolongation, and QRS widening

Further Reading

• Wiesbauer F, Kühn P. ECG Mastery: Yellow Belt online course. Understand ECG basics. Medmastery
• Wiesbauer F, Kühn P. ECG Mastery: Blue Belt online course: Become an ECG expert. Medmastery
• Kühn P, Houghton A. ECG Mastery: Black Belt Workshop. Advanced ECG interpretation. Medmastery
• Rawshani A. Clinical ECG Interpretation ECG Waves
• Smith SW. Dr Smith’s ECG blog.
• Wiesbauer F. Little Black Book of ECG Secrets. Medmastery PDF