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Supraventricular Arrhythmias

Terms in this set (37)

Rapid, Regular, atrial rhythm at an atrial rate of 200-400 beats/min.
Sawtooth-like oscillations
Ventricular response is commonly 2:1, but may be 4:1,3:1, and rarely 1:1
2:1 meaning that for every 2 P-waves, there is a QRS
1:1 conduction leads to hemodynamic instability.
Flutter waves best seen in II, III, aVF and V1

Atrial flutter is a type of supraventricular tachycardia caused by a re-entry circuit within the right atrium.
The length of the re-entry circuit corresponds to the size of the right atrium, resulting in a fairly predictable atrial rate of around 300 bpm (range 200-400). Ventricular rate is determined by the AV conduction ratio ("degree of AV block"). The commonest AV ratio is 2:1, resulting in a ventricular rate of ~150 bpm. Higher-degree AV blocks can occur — usually due to medications or underlying heart disease — resulting in lower rates of ventricular conduction, e.g. 3:1 or 4:1 block. Atrial flutter with 1:1 conduction can occur due to sympathetic stimulation or in the presence of an accessory pathway — especially if AV-nodal blocking agents are administered to a patient with WPW. Atrial flutter with 1:1 conduction is associated with severe haemodynamic instability and progression to ventricular fibrillation.

Atrial Flutter orginates in an atrial automaticity focus. The rapid succession of identical, back-to-back atrial depolarization waves, "flutter" waves, suggest a reentry origin to some experts. In atrial flutter an extremely irritable atrial automaticity focus fires at a rate of 250-300 per minute, producing rapid series of atrial depolarizations. On EKG, atrial flutter is characterized by consecutive identical "flutter" waves in rapid back-to-back succession. The baseline appears to vanish between the back to back flutter waves.