The Cause of the ST-Segment Elevation

Kyuhyun Wang, MD


March 10, 2008

Answer and Discussion

Answer: B. Hyperkalemia causing the Brugada electrocardiographic (ECG) pattern.

In leads V1-2, the ST segment is elevated, which begins from the top of the R' wave and is downsloping, ending with an inverted T wave. These findings are characteristic of the Brugada ECG pattern. In the tracing, QRS complexes are widened, and T waves are tall, pointed, and tented. The P waves are flat and the PR interval is prolonged. All of these are characteristics of hyperkalemia. By inactivating the sodium channel, hyperkalemia can cause ST-segment elevation in V1-2, which is also a feature of Brugada syndrome.

In acute anterior infarct with right bundle branch block, the downstroke of the R' wave and the beginning of the ST segment have a distinct transition, and the ST segment is horizontal or upsloping, not downsloping, as it is in this case. There is a P wave in front of every QRS complex indicating the rhythm is sinus rhythm, not accelerated idioventricular rhythm.