Pre-excitation syndrome

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Pre-excitation syndrome Classification and external resources
ICD-10	I45.6
ICD-9	426.7, 426.81
DiseasesDB	32903
MeSH	D011226

Pre-excitation syndrome is a condition where the the ventricles of the heart become depolarized too early, which leads to their partial premature contraction. Normally, the atria (chambers taking venous blood) and the ventricles (chambers pumping blood towards organs) 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.

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	yes

[edit] See also

• Electrical conduction system of the heart

v • d • e Cardiovascular disease: heart disease - Circulatory system pathology (I00-I52, 390-429) Ischaemic heart disease CHD: CAD - Coronary thrombosis - Coronary vasospasm - Coronary artery aneurysm Angina pectoris (Prinzmetal's angina) - Myocardial infarction (heart attack) Acute coronary syndrome - Myocardial rupture - Dressler's syndrome Pericardium Pericarditis (Acute pericarditis, Constrictive pericarditis) - Pericardial effusion - Cardiac tamponade Endocardium/ heart valves Endocarditis (Subacute bacterial endocarditis) mitral (regurgitation, prolapse, stenosis) - aortic (stenosis, insufficiency) - pulmonary (stenosis, insufficiency) - tricuspid (stenosis, insufficiency) Myocardium Myocarditis - Cardiomyopathy (Dilated cardiomyopathy, Hypertrophic cardiomyopathy, Loeffler endocarditis, Restrictive cardiomyopathy, Alcoholic cardiomyopathy) - Arrhythmogenic right ventricular dysplasia Electrical conduction/ arrhythmia heart block: AV (1°, 2°, 3°) - Bundle branch (Left, Right) - Bifascicular - Trifascicular - Sinoatrial - Sick sinus syndrome - Adams-Stokes syndrome pre-excitation syndrome: Wolff-Parkinson-White - Lown-Ganong-Levine tachycardia: Paroxysmal - Supraventricular (AV nodal reentrant, Accelerated idioventricular rhythm, Sinus) - Ventricular (Torsades de pointes) premature contraction: Atrial - Ventricular flutter/fibrillation: Atrial flutter - Ventricular flutter - Atrial fibrillation (Familial) - Ventricular fibrillation pacemaker: Wandering pacemaker - Ectopic pacemaker - Parasystole long QT syndrome: Romano-Ward syndrome - Andersen-Tawil syndrome - Jervell and Lange-Nielsen syndrome cardiac arrest: Sudden cardiac death Other Cardiomegaly - Ventricular hypertrophy (Left, Right) Cor pulmonale Heart failure - Rheumatic fever See also congenital (Q20-Q28, 745-747)