**Core Concept**
Electrocardiography (ECG) and Holter monitoring are commonly used tests to diagnose arrhythmias and cardiac conduction disorders, which can cause syncope. However, other tests like exercise stress testing may not be suitable for patients with a history of syncopal attacks, especially if they have had a recent episode.

**Why the Correct Answer is Right**
Exercise stress testing involves physical exertion to assess cardiac function, but it may exacerbate underlying cardiac conditions, leading to another syncopal episode. This is particularly concerning in patients with unexplained syncope, where the underlying cause may be a potentially life-threatening cardiac condition. Exercise stress testing is contraindicated in patients with recent syncope, especially if it is unexplained.

**Why Each Wrong Option is Incorrect**
**Option A:** ECG is a useful test in evaluating patients with a history of syncopal attacks, as it can identify arrhythmias and cardiac conduction disorders.
**Option B:** Holter monitoring can be useful in patients with recurrent syncope to identify arrhythmias that may be causing symptoms.
**Option C:** Tilt table testing can be used to diagnose vasovagal syncope, which is a common cause of syncope.

**Clinical Pearl / High-Yield Fact**
In patients with unexplained syncope, it is essential to perform a thorough cardiac evaluation, including ECG and Holter monitoring, to rule out underlying cardiac conditions.

**Correct Answer:** C. Tilt table testing can be used to diagnose vasovagal syncope.