**Core Concept**
Electrocardiogram (ECG) changes are a crucial diagnostic tool for assessing cardiac function and detecting various cardiac conditions. ECG changes can provide valuable information about the heart's electrical activity, including rhythm, conduction, and repolarization.

**Why the Correct Answer is Right**
ECG changes can be caused by various factors, including electrolyte imbalances, cardiac ischemia, and structural heart diseases. The P wave represents atrial depolarization, the QRS complex represents ventricular depolarization, and the T wave represents ventricular repolarization. Changes in these waves can indicate underlying cardiac conditions. For instance, a widened QRS complex may indicate ventricular conduction delay or bundle branch block. Similarly, T wave inversion can indicate cardiac ischemia or strain.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it doesn't specify a true ECG change. To be a correct option, it would need to describe a known ECG abnormality, such as a prolonged QT interval or a left bundle branch block.
**Option B:** This option is incorrect because it doesn't describe a true ECG change. A normal ECG has a normal PR interval, which is the time between the onset of the P wave and the start of the QRS complex. Prolongation of the PR interval can indicate first-degree atrioventricular (AV) block.
**Option C:** This option is incorrect because it doesn't describe a true ECG change. A normal ECG has a normal QRS complex duration, which is typically less than 120 milliseconds. Prolongation of the QRS complex can indicate ventricular conduction delay or bundle branch block.
**Option D:** This option is incorrect because it doesn't describe a true ECG change. A normal ECG has a normal T wave morphology, which is typically upright in leads I, II, and V2-V6. Inversion of the T wave can indicate cardiac ischemia or strain.

**Clinical Pearl / High-Yield Fact**
When interpreting ECG changes, it's essential to consider the clinical context and look for correlations between the ECG findings and the patient's symptoms and medical history. For example, a patient with chest pain and a widened QRS complex on ECG may have a diagnosis of acute coronary syndrome.

**Correct Answer: D.**