**Core Concept**
Pseudo-P-pulmonale refers to the electrocardiographic (ECG) pattern of tall P waves, mimicking right atrial enlargement. However, this pattern is not due to true right atrial enlargement but rather due to other underlying conditions.

**Why the Correct Answer is Right**
Pseudo-P-pulmonale is often seen in conditions that lead to high vagal tone, such as hypothyroidism. In these cases, the tall P waves are due to increased parasympathetic activity on the sinoatrial (SA) node, causing it to fire more rapidly. This results in the characteristic tall P waves seen on the ECG.

**Why Each Wrong Option is Incorrect**
**Option A:** Cor pulmonale, a condition characterized by right ventricular enlargement due to pulmonary hypertension, is a true cause of P-pulmonale, not pseudo-P-pulmonale.
**Option B:** Left ventricular hypertrophy can also cause P-pulmonale due to increased left atrial pressure and subsequent right atrial enlargement, but this is not a pseudo-P-pulmonale.
**Option C:** Acute pericarditis can cause widespread ECG changes, including tall P waves, but these are not typically referred to as pseudo-P-pulmonale.

**Clinical Pearl / High-Yield Fact**
It's essential to differentiate between true and pseudo-P-pulmonale, as the underlying cause has significant implications for diagnosis and management. A thorough medical history and physical examination can help guide the diagnosis.

**Correct Answer: D. Hypothyroidism.**