Which ECG finding might suggest the presence of Wolff-Parkinson-White syndrome?

The finding that suggests the presence of Wolff-Parkinson-White syndrome is the delta wave. Wolff-Parkinson-White syndrome is characterized by the presence of an accessory pathway that causes premature depolarization of the ventricles, leading to a unique ECG appearance. The delta wave is a slurred upstroke seen at the beginning of the QRS complex, indicative of this early ventricular depolarization due to the accessory pathway (also known as the Bundle of Kent). This alteration in the conduction system causes a shortened PR interval and a characteristic appearance on the ECG that can help in the identification of this syndrome.

In contrast, a prolonged PR interval is often associated with other types of heart block rather than Wolff-Parkinson-White syndrome. A shortened QT interval can be seen in various conditions but is not indicative of this syndrome. Dropped beats would point towards other arrhythmias, not the specific features characteristic of Wolff-Parkinson-White syndrome. Thus, the delta wave is a key electrocardiographic marker that clinicians use to identify this condition.