**Core Concept**
The most common cause of sudden cardiac death in individuals without a prior history of heart disease is a fatal arrhythmia, often precipitated by a sudden increase in sympathetic activity. This can lead to a life-threatening rhythm disturbance, such as ventricular fibrillation.

**Why the Correct Answer is Right**
In the case of a 58-year-old man without a prior history of heart disease, the most likely cause of sudden cardiac death would be a coronary artery thrombosis. This is because coronary artery thrombosis can lead to a blockage of blood flow to the heart muscle, triggering a fatal arrhythmia. This can occur in the absence of any prior symptoms, making it a sudden and unexpected event.

**Why Each Wrong Option is Incorrect**
**Option A:** Sudden cardiac death due to aortic dissection is less likely in this scenario, as it typically presents with severe chest pain and a "tearing" sensation, which is not mentioned in the case description.

**Option B:** Myocardial infarction due to a spontaneous coronary artery dissection is a rare cause of sudden cardiac death, and would not be the most likely explanation for this individual without any prior symptoms.

**Option C:** Pulmonary embolism is a possible cause of sudden death, but it would typically present with symptoms such as shortness of breath, chest pain, and possibly a history of recent travel or immobility.

**Clinical Pearl / High-Yield Fact**
The most common cause of sudden cardiac death in individuals without a prior history of heart disease is a coronary artery thrombosis, often occurring without any prior symptoms.

**Correct Answer:** D.