![]() ![]() Less frequently, the direction of wavefront propagation in this large right atrial circuit is reversed (“clockwise” flutter proceeding cephalad up the right atrial free wall and caudad down the septum, with upright flutter waves in the inferior leads Fig. Locations for RF delivery can be guided anatomically or electrophysiologically. Typically, this is across the isthmus of atrial tissue between the inferior vena caval orifice and the tricuspid annulus (the cavotricuspid isthmus), a relatively narrow point in the circuit. Ablating tissue in a line between any two anatomic barriers that transects a portion of the circuit necessary for perpetuation of reentry can be curative. Reentry in the right atrium, with the left atrium passively activated, constitutes the mechanism of the typical electrocardiographic variety of atrial flutter, with caudocranial activation along the right atrial septum and craniocaudal activation of the right atrial free wall ( Fig. The success rate is approximately 60%, and it is more effective than procainamide, sotalol, or amiodarone. Intravenous ibutilide is a first-line medication for pharmacologic cardioversion of atrial flutter in patients with normal systolic function and QT intervals. However, the recurrence rate is substantial, perhaps 50% at 1 yr. The rate of recurrence of atrial flutter with cardioversion alone is difficult to determine because most published data combine atrial flutter with atrial fibrillation. In general, atrial flutter is more difficult to rate-control than atrial fibrillation. Atrial flutter may spontaneously convert to normal sinus rhythm with this strategy. ĪV blocking agents such as calcium channel blockers, beta-blockers, and digitalis (second-line treatment) may all be used for rate control.In the hemodynamically stable patient, assess the need for anticoagulation and proceed with rate control or rhythm control strategy. If the patient is unstable, proceed directly to electrical cardioversion. Table 3 summarizes atrial flutter therapy. 4 describes an acute treatment of atrial flutter algorithm. Atypical atrial flutter originates from the left atrium or areas in the right atrium, such as surgical scars, and has a variable appearance on ECG in regards to the flutter waves.Treatment choices are based on clinical circumstances. This appears as positively-directed flutter waves in the inferior leads. This results in negatively-directed flutter waves in the inferior leads.Īt times, the direction of the circuit can reverse, causing clockwise atrial flutter from the same anatomical location. ![]() Typical atrial flutter rotates counterclockwise in direction, from a reentrant circuit around the tricuspid valve annulus and through the cavo-tricuspid isthmus. Also, atrial flutter can be described as “clockwise” or “counterclockwise” depending on the direction of the circuit. In this situation, giving adenosine will transiently slow the ventricular rate, unmasking the atrial flutter waves and allowing a more definitive diagnosis to be made.Ītrial flutter can described as “typical” (type I) or “atypical” (type II) based on the anatomic location from which it originates. When the heart rate is significantly elevated - that is, greater than 150 bpm - it is often difficult to determine atrial flutter from atrial fibrillation, atrial tachycardia or atrioventricular nodal reentrant tachycardia, or AVNRT. This results in the rhythm becoming “irregularly irregular.” There are only two other rhythms that are commonly irregularly irregular, including atrial fibrillation and multifocal atrial tachycardia, or MAT. In this situation, there may be three P waves to one QRS complex, then a quick change to two P waves to one QRS complex, and so on any combination of P waves to QRS complexes can occur. The regularity of the QRS complexes frequently present with atrial flutter helps to distinguish it from atrial fibrillation, though atrial flutter with variable conduction of the P waves can also occur. In this situation, the ventricular (QRS) rate will be exactly 150 bpm and regular.ĬLINICAL PEARL: A narrow complex tachycardia at a ventricular rate of exactly 150 bpm is very commonly atrial flutter. Typically, the atrial rate will be about 300 bpm, and only every other atrial depolarization will be conducted through the AV node. Just as in atrial fibrillation, not all of the P waves are able to conduct through the atrioventricular node, and thus the ventricular rate will not be as fast as the atrial rate. ![]()
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