Review Question - QID 212711

This patient has Wolff-Parkinson-White (WPW) syndrome (e.g., delta wave on ECG, intermittent heart palpitations, and syncopal episode). It is due to an aberrant conduction tract from the atria to the ventricles.

WPW is a syndrome of paroxysmal tachycardia due to an accessory pathway that directly connects the atria and the ventricles, thereby bypassing the atrioventricular node. Patients will have a short PR interval, a widened QRS complex, and a characteristic delta wave on their ECG. The majority of patients are asymptomatic, while a small percentage of patients will present with palpitations, and to a lesser extent, syncope and sudden cardiac death. The condition is usually diagnosed via ECG.

Figure/Illustration A demonstrates an electrocardiogram characteristic of Wolff-Parkinson-White syndrome. The arrow points to the delta wave.

Incorrect Answers:
Answer 2: Abrupt onset of intense fear or discomfort describes a panic attack, which can present with palpitations. However, it would not yield an ECG with delta waves.

Answer 3: Excessive production of thyroxine describes hyperthyroidism, which can lead to palpitations. However, it also does not result in the ECG pattern shown.

Answer 4: Neurologically induced drop in blood pressure in response to stress describes a vasovagal episode/syncope. This is within the differential as this patient describes lightheadedness and anxiety prior to her syncopal episode. However, vasovagal syncope does not present with the ECG shown.

Answer 5: Overingestion of caffeine can also present with heart palpitations. However, it does not result in the ECG pattern shown.

Bullet Summary:
Wolff-Parkinson-White syndrome is caused by an aberrant conduction tract from the atria to the ventricles.