Parasystole

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Parasystole Classification and external resources
MeSH	D017574

Parasystole is a kind of arrhythmia caused by the presence and function of a secondary pacemaker in the heart, which works in parallel with the SA node. Parasystolic pacemakers are protected from depolarization by the SA node by some kind of entrance block. This block can be complete or incomplete.

Parasystolic pacemakers can exist in both the atrium or the ventriculus. Atrial parasystolia are characterized by narrow QRS complexes

[edit] ECG signals

On an ECG, parasystole may be recognized by:

• spotting ectopic P or QRS waves which either:
  • occur at regular intervals
  • the time between them is always exact multiple of the smallest time between such two occurrences
• spotting "fusioned" P or QRS complexes (sometimes rare)

Another feature is the varying coupling interval between sinus and ectopic beats.

[edit] External links

• ventricular parasystole
• atrial parasystole

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)