- Aberrant connection from the atria to the ventricles through an accessory pathway (AP)
- Classic EKG pattern in sinus rhythm (Figure 17-1): short P–R interval (due to conduction over the faster AP) and a slurred upstroke of the QRS—“delta wave” (due to fusion of impulses that pass through AV node and those that pass via the AP)
- Patients with Wolff–Parkinson–White (WPW) syndrome can present in sinus rhythm or with reentrant narrow complex tachycardias (orthodromic reciprocating tachycardia [ORT]), wide complex tachycardias (antidromic reciprocating tachycardia [ART]), and atrial fibrillation (AF)
- AF with WPW pattern has classic EKG pattern (Figure 17-2) and can degenerate into VF
Figure 17-1. Classic WPW Pattern on EKG in Sinus Rhythm
Slurring of the upstroke of the QRS. Reproduced from Knoop KJ, Stack LB, Storrow AB, Thurman RJ. The Atlas of Emergency Medicine. 3rd ed. Figure 23-42A. Available at: www.accessmedicine.com. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.
Figure 17-2. Atrial Fibrillation in a Patient with WPW
Note wide, bizarre, and irregular QRS complexes. Reproduced from Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson JL, Loscalzo J. Harrison’s Principles of Internal Medicine. 18th ed. Figure E30-21. Available at: www.accessmedicine.com. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.
- Perform EKG: WPW is diagnosed by history and EKG findings
- Consider referral to electrophysiologist for possible preoperative ablation
- Management of paroxysmal tachycardia associated with WPW is similar to that of other SVTs. Treatment is required when there is clinical poor tolerance
- Be cautious when administering anesthetics that cause an increase in sympathetic tone or the production of extrasystoles that may precipitate tachycardia:
- Desflurane is sympathomimetic and can increase AV nodal conduction time, which may result in greater conduction via the AP and tachycardias
- Atropine, glycopyrrolate, ketamine can resulting in PSVT or AF and should be avoided
- Neostigmine slows AV nodal conduction and facilitates AP conduction. Therefore, it should be avoided
- Patients who develop an atrial arrhythmia intraoperatively (AF or atrial flutter) and have underlying WPW should not be given nodal blockers (including adenosine, calcium channel blockers, beta-blockers, or digoxin) or carotid sinus massage. Nodal blockers slow AV nodal conduction and allow for greater conduction through the faster conducting AP. This promotes degeneration of AF to VF:
- Cardioversion and/or sodium channel blockers (i.e., procainamide) are first-line therapy for patients with AF and WPW. Sodium channel blockers block the AP
- However, patients who develop a narrow complex arrhythmia such as ORT can be given nodal blockers to slow the rate
Table 17-1 Drugs to Be Avoided in WPW |Favorite Table|Download (.pdf)
Table 17-1 Drugs to Be Avoided in WPW
- Nodal blockers (e.g., diltiazem, verapamil, metoprolol, adenosine, ...
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