A 17-year-old with recurrent palpitations and near-syncope has a normal initial ECG. Which test is most appropriate to pursue for evaluation?

• A. Cardiac catheterization
• B. Tilt table testing
• C. Echocardiogram
• D. Holter monitoring

Answer: (D)

Intermittent symptoms like palpitations and near-syncope that aren’t shown on a single resting ECG are best evaluated by capturing the heart rhythm during the episodes. A Holter monitor provides continuous 24- to 48-hour ECG recording while the patient goes about daily activities, increasing the chance of correlating a transient arrhythmia with dizziness or near-syncope. This makes it the most direct way to diagnose paroxysmal tachyarrhythmias or other rhythm disturbances in this setting, especially in a young patient with a normal initial electrocardiogram.

Cardiac catheterization is invasive and reserved for suspected structural or ischemic disease needing intervention, which isn’t suggested here. Tilt-table testing is useful for neurocardiogenic (vasovagal) syncope but doesn’t identify arrhythmias during symptoms. An echocardiogram assesses heart structure and function but won’t capture transient rhythm events, though it can complement the assessment if structural disease is a concern. If symptoms persist without documentation on Holter, longer-term monitoring options like event recording or implantable loop recorders can be considered.