# Wolff-Parkinson-White Syndrome > Wolff-Parkinson-White syndrome for NEET-PG Medicine covers delta wave recognition, pre-excited atrial fibrillation, drugs to avoid and curative ablation. - Canonical URL: https://prepelephant.com/topics/neet-pg/medicine/wolff-parkinson-white-syndrome - Exam / course: NEET-PG · Subject: Medicine - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-08 - Last updated: 2026-10-08 - Reference basis: Harrison's Principles of Internal Medicine; Braunwald's Heart Disease; ESC Guidelines on supraventricular tachycardia - How to cite: "Wolff-Parkinson-White Syndrome", PrepElephant, https://prepelephant.com/topics/neet-pg/medicine/wolff-parkinson-white-syndrome ## Direct answer Wolff-Parkinson-White syndrome is pre-excitation through an accessory atrioventricular connection, producing a short PR interval, a delta wave and a wide QRS on the electrocardiogram. Its clinical importance lies in atrial fibrillation conducting rapidly to the ventricles through the accessory pathway, so AV nodal blockers such as verapamil, diltiazem, digoxin and beta blockers are avoided, procainamide or synchronised cardioversion is used instead, and catheter ablation offers cure. ## What you must remember - **ECG triad:** PR interval under 120 ms, a delta wave with a slurred QRS upstroke, and a wide QRS with secondary ST-T change. - **Accessory pathway:** the bundle of Kent is the classical connection; it bypasses the AV node's delay, so ventricular rates in atrial fibrillation can exceed 250 beats per minute. - **Dangerous AF:** pre-excited atrial fibrillation gives irregular, wide, rapid complexes that can degenerate into ventricular fibrillation. - **Drugs to avoid:** verapamil, diltiazem, digoxin and beta blockers in pre-excited atrial fibrillation, because they block the AV node and favour conduction down the accessory pathway (verapamil and digoxin also shorten its refractory period); adenosine is avoided because it can provoke rapid atrial fibrillation. - **Drug of choice:** intravenous procainamide for stable pre-excited atrial fibrillation, with ibutilide as an alternative where available. - **Unstable patients:** synchronised DC cardioversion without delay. - **Ablation:** radiofrequency ablation of the accessory pathway is curative in most patients; electrophysiological study identifies high-risk pathways with a shortest pre-excited RR interval in atrial fibrillation of about 250 ms or less (a short accessory pathway refractory period). - **Mimic:** Lown-Ganong-Levine syndrome gives a short PR interval without a delta wave and is a disputed, separate entity not associated with the same pre-excited atrial fibrillation risk. ## A student with palpitations and a delta wave A 24-year-old student is found on routine ECG to have a short PR interval and a delta wave in sinus rhythm, with no symptoms. Months later she presents with a fast irregular palpitation, blood pressure 100 over 70 mmHg and an ECG showing irregular, wide complexes at around 220 beats per minute. The diagnosis is pre-excited atrial fibrillation, and the first decision is to avoid AV nodal blockers. A previous prescription of digoxin or verapamil for the palpitations must be recognised as dangerous here. Because she is stable, intravenous procainamide is given with continuous monitoring, and the rhythm usually slows as the accessory pathway refractoriness lengthens. If she becomes hypotensive, synchronised cardioversion is performed without delay. Once rhythm is controlled, referral for electrophysiological study and ablation is arranged, since a pathway with a short refractory period carries a risk of sudden death, and ablation removes that risk. The case shows why the delta wave matters even when the patient feels well, which is the principle examiners test. ## Where the exam tries to catch you Examiners set the drug trap repeatedly: a candidate treating pre-excited atrial fibrillation with verapamil, digoxin or adenosine has chosen the wrong drug in every version. Adenosine is safe for orthodromic narrow-complex tachycardia, but not for pre-excited atrial fibrillation, and this distinction separates strong candidates from weak ones. The second trap is confusing WPW with Lown-Ganong-Levine syndrome, which has a short PR but no delta wave and is not linked to the same arrhythmic risk. The third trap is asymptomatic WPW. A candidate who ignores an incidental delta wave has missed the point, since risk stratification with electrophysiological study is needed to identify the minority who have high-risk pathways. Indian viva questions often pair this with occupational counselling, particularly for pilots and those in safety-critical work, where ablation or risk assessment is advised. ## Frequently asked questions ### Which drugs are contraindicated in atrial fibrillation with WPW? Digoxin, verapamil, diltiazem, beta blockers and adenosine are avoided in atrial fibrillation with Wolff-Parkinson-White syndrome. They accelerate conduction down the accessory pathway, which can precipitate ventricular fibrillation. ### What is the drug of choice for stable pre-excited atrial fibrillation? Intravenous procainamide is the drug of choice for stable pre-excited atrial fibrillation, slowing conduction through the accessory pathway. Ibutilide is an alternative where available, and synchronised cardioversion is used if the patient is unstable. ### Which ECG features define Wolff-Parkinson-White syndrome? The ECG shows a short PR interval under 120 ms, a delta wave with a slurred upstroke of the QRS, and a wide QRS with secondary ST-T change. These features occur in sinus rhythm and reflect pre-excitation through an accessory pathway. ### Which electrophysiological finding signals high risk of sudden death in WPW? A short accessory pathway refractory period, with a shortest pre-excited RR interval of about 250 ms or less in atrial fibrillation, identifies high risk of sudden death in Wolff-Parkinson-White syndrome. Patients with this finding are usually referred for catheter ablation.