30-year old patient presenting with generalised weakness.
Describe and interpret this ECG
ECG ANSWER and INTERPRETATION
- The ECG shows widespread ST segment abnormalities.
- There is a biphasic appearance to the ST segments and T waves, with initial negative deflection (= ST segment depression / T wave inversion) followed by a terminal positive deflection (= U wave).
- All these waves merge into each other and it is difficult to tell where one wave ends and the other begins.
- There is gross prolongation of the QU interval (= time from onset of QRS complex to end of T/U wave).
The combination of…
- Widespread ST depression / T wave inversion
- Prominent U waves
- Long QU interval (> 500 ms)
…. is highly suggestive of severe hypokalaemia.
This patient had a serum K of 1.7 mmol/L in the context of decompensated Conn’s syndrome (primary aldosteronism).
The main differentiating factor (apart from the clinical picture) is the direction of the T waves:
- Wellens: – biphasic T waves go UP then DOWN.
- Hypokalaemia: – T waves go DOWN then UP.