![]() Focal atrial tachycardia as the sole mechanism for supraventricular tachycardia is relatively rare accounting for 10-15% of cases referred for catheter ablation. Repeat echocardiography demonstrated normalization of his LVEF.ĭespite an irregularly irregular rhythm, the patient in our case suffers from a focal atrial tachycardia. He remains free from tachycardia three months post ablation. The patient was then observed overnight and discharged on 25mg of long acting metoprolol. We then started isoproternol up to 10mcg/min with no induction of atrial tachycardia or atrial fibrillation. Within several seconds of ablation, there was complete cessation of tachycardia. We decided to ablate in this region, which was anatomically on the mid posterior wall of the left atrium at the os of the left superior pulmonary vein. The left superior pulmonary vein demonstrated the earliest potentials 40msec in advance of the surface p wave (Figure 3). The circular catheter was then placed at the os of each pulmonary vein. We then accessed the left atrium through a standard double trans-septal access. We performed electro-anatomic mapping in the right atrium with demonstration of late activation times. The patient was taken to the electrophysiologic laboratory. Figure 2 is a continuous strip from a Holter tracing (lead II). He was interested in catheter ablation due to intolerance of medications, and was referred to our facility.įigure 1 is a 12-lead ECG demonstrating bursts of atrial tachycardia. This study noted “disorganized atrial activity with earliest activation in the left atrium consistent with atrial fibrillation/flutter.” Given the left sided location, the treating physicians decided to pursue medical management with beta blockers and a class Ic antiarrhythmic. He underwent electrophysiologic study at an outside institution. The patient did not demonstrate signs or symptoms of heart failure, and regularly exercised. Further diagnostic testing included a 2D echocardiogram demonstrating evidence of globally depressed left ventricular (LV) function with an ejection fraction (EF) of 33%. Prior Holter monitoring demonstrated episodes of atrial fibrillation as well as an atrial tachycardia. 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.A 50-year old-male is referred to our electrophysiologic service for evaluation of palpitations. 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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