Wolff-Parkinson-White syndrome classification scheme: Difference between revisions
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* Antegrade conduction: also known as manifest, responsible for the "pre-excitation" finding on ECG | * Antegrade conduction: also known as manifest, responsible for the "pre-excitation" finding on ECG | ||
* Retrograde conduction: also known as concealed | * Retrograde conduction: also known as concealed | ||
Most commonly, the accessory pathways conduct in both directions. Isolated retrograde conduction is less common | Most commonly, the accessory pathways conduct in both directions. Isolated retrograde conduction is less common. Isolated antegrade conduction is the least common and is usually associated with accessory pathways in the right side of the heart. | ||
===Classification Based on the Characteristics of Conduction=== | ===Classification Based on the Characteristics of Conduction=== | ||
Revision as of 15:12, 30 July 2014
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]
Overview
Classification
Classification Based on the Type of Conduction
The accessory pathway in WPW can be classified into:
- Antegrade conduction: also known as manifest, responsible for the "pre-excitation" finding on ECG
- Retrograde conduction: also known as concealed
Most commonly, the accessory pathways conduct in both directions. Isolated retrograde conduction is less common. Isolated antegrade conduction is the least common and is usually associated with accessory pathways in the right side of the heart.
Classification Based on the Characteristics of Conduction
- Decremental conduction (8% of the cases)
- Decremental conduction is the progressive delay in the conduction through the accessory pathway following an increase in the paced rates.
- Non-decremental conduction (92% of the cases)
Classification Based on the ECG Findings
WPW syndrome can be classified based on the location of the accessory pathway, right-sided vs left-sided. In 1945, Rosenbaum classified WPW syndrome into type A and type B based on the characteristic electrocardiographic findings of the right-sided and left-sided accessory pathway.[1]
- Type A: Pre-excitation of the left side of the heart (the accessory pathway communicates the left atrium with the left ventricle)
- Presence of upright delta wave in the precordial leads
- Small or absent S waves
- Generally V1 shows either a notched R wave or RS or Rsr' deflection
- Mimics a posterior MI, RVH
- Type B: Pre-excitation of the right side of the heart (the accessory pathway communicates the right atrium with the right ventricle)
- Negative delta wave
- Prominent S wave deflection in the right precordial leads, and upright R waves in the lateral precordial leads
- More common than type A
- May resemble an abnormal Q wave in the right precordial leads and be mistaken for an anterior MI
Classification Based on the Type of AVRT
The most common arrhythmia in WPW syndrome is atrioventricular reciprocating tachycardia. AVRT in WPW can be classified into:
- Orthodromic (most common): the antegrade electrical signal moves from the atria to the ventricles through the AV node, and then from the ventricles to the atria through the accessory pathway.
- Antidromic: the antegrade electrical signal moves from the atria to the ventricles through the accessory pathway, and then from the ventricles to the atria through either the AV node or a second accessory pathway.
Variants of WPW
Lown-Ganong-Levine Syndrome (LGL)
- There is a short PR interval, but no delta wave
- LGL is due to intranodal bypass tracts (i.e. there is conduction down the James fibers)
- Normal QRS duration
- PR less than 0.12 seconds
- Normal P wave
Mahaim Type Preexcitation
- This form of pre-excitation is due to nodoventricular, nodofascicular or fasciculoventricular connections
- The impulse may travel through the AV node normally and this may then be followed by premature conduction to the basal ventricular myocardium
- There is a delta wave with a normal PR interval
- Rarer than WPW or LGL
- In older patients there can be a prolonged conduction down the accessory pathway resulting in a normal PR interval in the presence of WPW which is tough to distinguish from Mahaim fibers
References
- ↑ Suzuki T, Nakamura Y, Yoshida S, Yoshida Y, Shintaku H (2014). "Differentiating fasciculoventricular pathway from Wolff-Parkinson-White syndrome by electrocardiography". Heart Rhythm. 11 (4): 686–90. doi:10.1016/j.hrthm.2013.11.018. PMID 24252285.