Arrhythmia Disorder

Atrioventricular nodal reentry tachycardia, a form of supraventricular tachycardia, is the most common narrow-complex tachycardic arrhythmia in healthy individuals and only second to atrial fibrillation and atrial flutter in the general population.

Beta-blockers antagonize beta-1 and beta-2 receptors which are the usual targets of the sympathetic nervous system, including epinephrine and norepinephrine.

Slow ventricular tachycardia is also known as an “accelerated idioventricular rhythm” or “AIVR” and is a common rhythm after an MI. An idioventricular rhythm — not accelerated — has a heart rate of < 60 beats per minute.

Atrial tachycardia is a form of supraventricular tachycardia that occurs when one focus in the atria begins to fire rapidly, overwhelming the sinoatrial node.

Ashman phenomenon (Ashman beat) occurs when a premature supraventricular beat occurs before the right bundle branch has recovered from its refractory period.

Ajmaline is a class IA antiarrhythmic drug used diagnostically (not used therapeutically) to elicit ECG changes in patients suspected to have Brugada syndrome.

Sinus arrhythmia refers to a changing sinus node rate with the respiratory cycle, on inspiration and expiration.

Adenosine is a short-acting endogenous molecule that is a purine nucleoside. The half-life is 6 seconds. Adenosine receptor activation results in multiple different actions depending on the location.

Antiarrhythmic drugs act on the electrical conduction system of the heart. The most common use of these drugs is as part of a rhythm control strategy to maintain sinus rhythm. The Vaughan Williams classification system divides these agents based on their mechanisms of action at the cell membrane ― ion channels and sympathetic receptors ― and their effects on the action potential. The classification includes four broad classes, with further subdivisions.

Atrial flutter is similar to atrial fibrillation in that the rhythm originates in the atrium and causes a narrow complex tachycardia, which carries thromboembolic risk.