Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ ECG Findings ++ Normal P waves Shortened PR interval Prolonged QRS interval Delta waves (slurring of the initial upstroke of R wave) +++ Pearls ++ Accessory tracts from the atria to the ventricles lead to depolarization of ventricles without using the AV node as the primary connecting route. Tachycardia associated with WPW may be mistaken for VT. Suspect WPW if the QRS complex is wide and tachycardia is extreme (ventricular rate > 240). Do not treat irregular atrial tachycardias (atrial fibrillation) in the setting of WPW with AV nodal blocking agents (calcium channel blockers, β-blockers, digoxin). This may lead to unopposed ventricular stimulation through the accessory tract and may worsen the tachycardia. Procainamide and cardioversion are accepted methods for conversion of a tachycardia associated with WPW. Depolarization via the accessory pathway may produce “pseudo-Q waves.” ++ FIGURE 23.44A Wolff-Parkinson-White Syndrome. (ECG contributor: James V. Ritchie, MD.) Graphic Jump LocationView Full Size||Download Slide (.ppt) ++ FIGURE 23.44B The PR interval is shortened (double arrow) and a delta wave (upsloping initial QRS segment) is seen (arrow, shaded area). Graphic Jump LocationView Full Size||Download Slide (.ppt) Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Download the Access App: iOS | Android Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.