**Core Concept**
Ischemic cardiac myocytes undergo a series of pathophysiological changes in response to reduced blood flow. The earliest event in this process is a critical step in determining the outcome of ischemia. This event is related to the disruption of cellular homeostasis and the initiation of cell injury.

**Why the Correct Answer is Right**
The earliest event in ischemic cardiac myocytes is the disruption of the sodium-potassium pump. This leads to an influx of sodium ions into the cell, causing a rapid increase in intracellular sodium concentration. The sodium-calcium exchanger, which normally removes calcium ions from the cell in exchange for sodium ions, becomes overloaded and begins to pump calcium ions into the cell. This influx of calcium ions triggers the release of stored calcium from the sarcoplasmic reticulum, leading to an increase in intracellular calcium concentration. The elevated intracellular calcium concentration activates various cellular enzymes and pathways, ultimately leading to cell injury and death.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the early events in ischemic cardiac myocytes.
* **Option B:** While the release of stored calcium from the sarcoplasmic reticulum is an important event, it is not the earliest event in ischemic cardiac myocytes.
* **Option D:** This option is not a correct description of the earliest event in ischemic cardiac myocytes.

**Clinical Pearl / High-Yield Fact**
The disruption of the sodium-potassium pump is a critical early event in ischemic cardiac myocytes, and it is often referred to as the "sodium paradox" or "sodium overload." This event is a key step in the development of ischemic cell injury and death.

**Correct Answer:** C. Disruption of the sodium-potassium pump.