**Core Concept**
Cor pulmonale refers to the alteration of the structure and function of the right ventricle of the heart due to a primary disorder of the respiratory system. This condition often results from chronic high blood pressure in the pulmonary arteries, which increases the workload on the right ventricle and leads to its hypertrophy and eventual failure.

**Why the Correct Answer is Right**
The correct answer is a condition characterized by chronic high blood pressure in the pulmonary arteries, which is a classic cause of cor pulmonale. This high blood pressure is often due to lung diseases such as chronic obstructive pulmonary disease (COPD), pulmonary embolism, or interstitial lung disease. The increased pressure in the pulmonary arteries leads to the right ventricle working harder to pump blood through the lungs, resulting in right ventricular hypertrophy and eventually failure.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because cor pulmonale is not directly related to left ventricular failure, although the two conditions can coexist. Left ventricular failure is a different condition that affects the left side of the heart.
**Option B:** This option is incorrect because pulmonary edema is a complication of left ventricular failure, not a primary cause of cor pulmonale. Pulmonary edema is characterized by fluid accumulation in the lungs, which can be caused by left ventricular failure.
**Option C:** This option is incorrect because cardiac tamponade is a condition where fluid accumulates in the pericardial sac, compressing the heart and impeding its function. While cardiac tamponade can affect both ventricles, it is not a primary cause of cor pulmonale.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that cor pulmonale often presents with signs of right-sided heart failure, such as jugular venous distension, peripheral edema, and hepatomegaly. These signs are a result of the increased pressure in the pulmonary arteries and the resulting hypertrophy and failure of the right ventricle.

**Correct Answer:** D. Chronic high blood pressure in the pulmonary arteries.