From the Guidelines
The Bundle of Kent in WPW syndrome is typically located between the atria and ventricles, and WPW does not always cause a broad QRS complex. In Wolff-Parkinson-White (WPW) syndrome, the Bundle of Kent is an accessory pathway that connects the atria and ventricles, bypassing the normal AV node conduction delay, as described in the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1. The location of the Bundle of Kent can vary, but it is typically found between the left atrium and left ventricle or the right atrium and right ventricle. The classic ECG finding in WPW is a short PR interval (less than 120 ms) with a delta wave (slurred upstroke of the QRS complex), as defined in the guideline 1. While the delta wave often widens the QRS complex beyond the normal 120 ms threshold, this is not always the case. Some key points to consider in WPW syndrome include:
- The degree of QRS widening depends on how much of the ventricular activation occurs through the accessory pathway versus the normal conduction system.
- The accessory pathway may conduct only minimally, resulting in a small delta wave with minimal QRS widening.
- The accessory pathway may conduct intermittently, leading to variable ECG findings. Understanding these variations is important for accurate diagnosis and management of patients with WPW syndrome, as emphasized in the guideline 1.
From the Research
Location of the Bundle of Kent in WPW Syndrome
- The bundle of Kent is located in the left lateral AV sulcus, as determined by preoperative and intraoperative electrophysiological assessment 2.
- The location of the bundle of Kent can vary, with posteroseptal, left lateral, right lateral, and anteroseptal localizations reported in different studies 3.
- Left lateral bundles of Kent are detected more frequently in patients over 60 years old than in those under 60 years of age 4.
WPW Syndrome and Broad QRS
- WPW syndrome is characterized by ventricular pre-excitation, which can lead to a broad QRS complex on the electrocardiogram (ECG) 5.
- However, not all patients with WPW syndrome have a broad QRS complex, as the degree of pre-excitation can vary depending on the location and conduction properties of the accessory pathway 5, 4.
- The presence of a broad QRS complex is not a universal feature of WPW syndrome, and other diagnostic criteria, such as the presence of a delta wave and shortened PR interval, are also important for diagnosis 5, 6.