The administration of AV-nodal blocking agents to a patient with Wolff-Parkinson-White syndrome can precipitate this Atrial flutter with 1:1 conduction can occur due to sympathetic stimulation, or in the presence of an accessory pathway.Higher-degree blocks can occur - usually due to medications or underlying heart disease - resulting in lower rates of ventricular conduction, e.g.The most common AV ratio is 2:1, resulting in a ventricular rate of ~150 bpm Ventricular rate is determined by the AV conduction ratio (“degree of AV block”).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) A number of experimental animal studies have reinforced the critical importance of the natural anatomical barriers in typical atrial flutter and found that surgical incisions and suture lines could facilitate IART, especially the crista terminalis, as well as potentially prevent inducibility of IART.Atrial flutter is a form of supraventricular tachycardia caused by a re-entry circuit within the right atrium. Many of these abnormalities may even be present before any of their operations.

This liability is likely due surgically created atrial discontinuities focal atrial scarring and conduction block associated with suture lines atrial fibrosis and thickening caused by pericardial inflammation and abnormal wall stress abnormal atrial size and anatomy increased atrial refractoriness associated with sinus node dysfunction and prolonged duration of atrial activation. Clinical intracardiac electrophysiologic studies have confirmed the vulnerability of patients for IART after the Senning, Mustard, and Fontan procedures. The atria of patients with heart disease are also often subjected to increased pressure and volume loads, resulting in progressive fibrosis and changes in the electrophysiological properties. In contrast to typical atrial flutter, incisional IART may involve not only the anatomically fixed structural barriers but also incisions, suture lines, patches, and baffles within the atria, as well as areas of fibrosis. The primary difference between the typical form of atrial flutter and incisional IART is the nature of the barriers around which the reentry impulse circulates. The upright P-waves imply superior to inferior atrial activation typically with a clockwise rotation around the tricuspid valve still passing through the cavo-tricuspid isthmus. A second form, atypical atrial flutter, has positive P-waves in leads II, III, and AVF, and usually has slower atrial rates around 200 bpm. There is usually variable atrioventricular (AV) conduction yielding a pulse rate of near 150 bpm in clinical practice, a fixed heart rate of 120–150 bpm strongly suggests the presence of atrial flutter with 2:1 AV block (Fig. Atrial rates in older children and adults are usually around 300 bpm (range: 240–350 bpm). In infants, these rates are typically very fast, ranging from 350 to 500 bpm (Fig. The anatomic barriers are the tricuspid valve annulus, coronary sinus, inferior and superior vena cavae, and crista terminalis (Fig. Type I atrial flutter has characteristic inverted “saw tooth” P-waves in leads II, III, and AVF, implying inferior to superior atrial activation typically the reentrant loop consists of a counterclockwise rotation around the tricuspid valve through the cavo-tricuspid isthmus.

Typical atrial flutter and ecg