Pre-excitation syndrome

Pre-excitation syndrome

Electrical conduction system of the heart. (Accessory pathways not shown.)


1. Sinoatrial node
2. Atrioventricular node
3. Bundle of His
4. Left bundle branch
5. left posterior fascicle


6. left-anterior fascicle
7. Left ventricle
8. Ventricular septum
9. Right ventricle
10. Right bundle branch

Classification and external resources
Specialty cardiology
ICD-10 I45.6
ICD-9-CM 426.7, 426.81
DiseasesDB 32903
MeSH D011226

Pre-excitation syndrome is a condition in which the ventricles of the heart become depolarized too early, which leads to their partial premature contraction.

Pathophysiology

Normally, the atria and the ventricles are electrically isolated, and electrical contact between them exists only at the "atrioventricular node". In all pre-excitation syndromes, at least one more conductive pathway is present. Physiologically, the normal electrical depolarization wave is delayed at the atrioventricular node to allow the atria to contract before the ventricles. However, there is no such delay in the abnormal pathway, so the electrical stimulus passes to the ventricle by this tract faster than via normal atrioventricular/bundle of His system, so the ventricles are depolarized (excited) before (pre-) normal conduction system.

Types

Several different types have been described.[1]

Type Conduction pathway PR interval QRS interval Delta wave?
Wolff-Parkinson-White syndrome Bundle of Kent (atria to ventricles) short long yes
Lown-Ganong-Levine syndrome "James bundle" (atria to bundle of His) short normal no
Mahaim-type Mahaim fibers normal long no

See also

References

This article is issued from Wikipedia - version of the Friday, April 22, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.