All of the following are the electrocardiographic features of Hyperkalemia, except-
**Core Concept**
Hyperkalemia is a condition characterized by elevated potassium levels in the blood, which can lead to cardiac arrhythmias and even cardiac arrest. The electrocardiographic (ECG) features of hyperkalemia are a critical diagnostic tool for monitoring the severity of this condition.
**Why the Correct Answer is Right**
Hyperkalemia affects the cardiac conduction system, leading to characteristic ECG changes. The initial ECG changes in hyperkalemia include peaked T waves, which are thought to be due to the effects of potassium on the ST segment and the T wave. As the potassium levels rise, the ECG changes progress to a flat or inverted T wave, followed by a prolonged PR interval, and eventually, a widened QRS complex. The most severe manifestation of hyperkalemia on ECG is the appearance of a sine wave pattern, which is a precursor to cardiac arrest.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a known ECG feature of hyperkalemia. Peaked T waves are one of the earliest signs of hyperkalemia and are thought to be due to the effects of potassium on the ST segment and the T wave.
**Option B:** This option is incorrect because it is also a known ECG feature of hyperkalemia. A flat or inverted T wave is a progression of the initial peaked T wave and is a sign of more severe hyperkalemia.
**Option C:** This option is incorrect because it is not a known ECG feature of hyperkalemia. A U wave is typically seen in hypokalemia, not hyperkalemia.
**Clinical Pearl / High-Yield Fact**
The ECG changes in hyperkalemia can be remembered using the mnemonic "peaked T waves, then flat, then PR prolongation, then QRS widening, and finally, a sine wave pattern." This mnemonic helps to recall the progression of ECG changes in hyperkalemia.
**Correct Answer:** C. A U wave is typically seen in hypokalemia, not hyperkalemia.