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Pathology
Atrioventricular block
Bundle branch block
Pulseless electrical activity
Atrial fibrillation
Atrial flutter
Atrioventricular nodal reentrant tachycardia (AVNRT)
Premature atrial contraction
Wolff-Parkinson-White syndrome
Brugada syndrome
Long QT syndrome and Torsade de pointes
Premature ventricular contraction
Ventricular fibrillation
Ventricular tachycardia
Cardiac tumors
Shock
Arterial disease
Aneurysms
Aortic dissection
Angina pectoris
Coronary steal syndrome
Myocardial infarction
Prinzmetal angina
Stable angina
Unstable angina
Abetalipoproteinemia
Familial hypercholesterolemia
Hyperlipidemia
Hypertriglyceridemia
Coarctation of the aorta
Conn syndrome
Cushing syndrome
Hypertension
Hypertensive emergency
Pheochromocytoma
Polycystic kidney disease
Renal artery stenosis
Hypotension
Orthostatic hypotension
Lymphangioma
Lymphedema
Peripheral artery disease
Subclavian steal syndrome
Nutcracker syndrome
Superior mesenteric artery syndrome
Angiosarcomas
Human herpesvirus 8 (Kaposi sarcoma)
Vascular tumors
Behcet's disease
Kawasaki disease
Vasculitis
Chronic venous insufficiency
Deep vein thrombosis
Thrombophlebitis
Acyanotic congenital heart defects: Pathology review
Aortic dissections and aneurysms: Pathology review
Atherosclerosis and arteriosclerosis: Pathology review
Cardiac and vascular tumors: Pathology review
Cardiomyopathies: Pathology review
Coronary artery disease: Pathology review
Cyanotic congenital heart defects: Pathology review
Dyslipidemias: Pathology review
Endocarditis: Pathology review
Heart blocks: Pathology review
Heart failure: Pathology review
Hypertension: Pathology review
Pericardial disease: Pathology review
Peripheral artery disease: Pathology review
Shock: Pathology review
Supraventricular arrhythmias: Pathology review
Valvular heart disease: Pathology review
Vasculitis: Pathology review
Ventricular arrhythmias: Pathology review
Atrioventricular nodal reentrant tachycardia (AVNRT)
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The atria are the heart’s upper chambers; the ventricles are the lower chambers. Reentrant tachycardias are fast heart rates caused by electrical signals that loop back on themselves.
Normally, an electrical signal starts at the sinoatrial or SA node in the right atrium and propagates out through both atria, including bachmann’s bundle in the left atrium, and then contracts both atria. It’s then delayed just a little bit as it goes through the atrioventricular, or AV node, before it passes through the Bundle of His and on to the Purkinje fibers of the left and right ventricles, causing them to contract as well.
Usually, the only place where a signal can go from the atria to the ventricles is at the AV node, and once that signal gets to the purkinje fibers, it stops and the heart tissue waits for another signal from the SA node. With an atrioventricular reentrant tachycardia, or AVRT, the electrical signal actually uses a separate accessory pathway to get back up from the ventricles to the atria, which causes the atria to contract before the SA node sends out another signal. The signal then moves back down the AV node to the ventricles and purkinje fibers, contracts the ventricles, and goes back up that accessory pathway. This cycle repeats, which is why AVRT can result in rates as high as 200-300 bpm. This type of tachycardia is known as a supraventricular tachycardia because the signal causing the fast rate originates above the ventricles. The most common type of AVRT is Wolff-Parkinson-White syndrome, where the accessory pathway is called the Bundle of Kent. This type of reentry is known as an anatomical reentrant circuit because the accessory pathway is a fixed, anatomically-defined pathway.
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