Wolff-Parkinson- White Preexcitation Patterns Chapter 12

Artrioventricular Bypass Tract Accessory pathways form and fail to disappear during fetal development Formed near the mitral or tricuspid valves or interventricular septum An AV bypass tract is sometimes referred to as the bundle of Kent

Artrioventricular Bypass Tract From SA node directly to AV node AND ventricular myocardium Partially bypassing the bundle of His and purkinje fibers Figure 12-5

Wolff-White- Parkinson Wide QRS not due to a delay in depolarization due to an early depolarization Shortened PR interval Upstroke QRS complex is slurred; delta wave

Wolff-Parkinson- White Short PR interval Wide QRS Delta Waves

Wolff-Parkinson- White

Fig 12-3 and 12-4

Wolff-Parkinson- White Bypass tracts can be located: left lateral posterior right anteroseptal (anterior) F.Y.I.

Wolff-Parkinson- White As a general rule: the initial QRS complex (delta wave) vector will point away from the area of the ventricles that is first to be stimulated by the bypass tract F.Y.I.

Wolff-Parkinson- White left lateral negative delta waves in I and/or aVL and positive in V1 posterior positive delta waves in most of the precordial (chest) leads and negative in the inferior leads right negative delta waves in V1 and V2 and positive in I and V6 anteroseptal (anterior) negative delta waves in leads V1 and V2 F.Y.I.

Clinical Significance Prone to arrhythmias paroxysmal supraventricular tachycardia (PSVT) Figure 12-5 Mistaken for RBBB or MI LaMarcus Aldridge Update Forward LaMarcus Aldridge underwent a series of tests today at Providence St. Vincent’s Medical Center in Portland. He was diagnosed with Wolff-Parkinson-White Syndrome (WPW) and was treated for the condition by Dr. Daniel Oseran at St. Vincent’s. The procedure was successful. Aldridge will be monitored by a cardiologist and will miss the remainder of the season. He is expected to make a full recovery and be cleared to resume physical activity, including basketball, in the near future. Aldridge, complaining of dizziness, left Portland’s game against the Los Angeles Clippers at the Rose Garden on March 31 and has been sidelined since that time.

Accessory Pathways