Which pattern shows a short PR interval with a delta wave and a wide QRS complex?

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A pattern with a short PR interval, a delta wave, and a wide QRS is Wolff-Parkinson-White pattern. The key idea is pre-excitation from an accessory pathway, such as the Bundle of Kent, that bypasses the usual slow conduction of the AV node. Because ventricular activation starts early through this pathway, the time from atrial to ventricular activation is shortened, giving a PR interval that is brief. The early depolarization via the accessory pathway creates a slurred upstroke at the beginning of the QRS, called a delta wave. Since part of the ventricle is activated earlier through the extra pathway while the rest follows the normal conduction system, the overall QRS becomes wider than normal. So you see a short PR, a delta wave, and a widened QRS in this pattern. The other options don’t fit this combination: first-degree AV block has a prolonged PR with normal delta wave and typically normal QRS width; atrial fibrillation is irregular with absent discrete P waves and no delta wave; sinus tachycardia has a normal PR and QRS unless there’s another issue.