Radiofrequency energy was applied to the cavotricuspid isthmus in a linear fashion during either induced or spontaneously occurring atrial flutter.Ĭases were then reviewed for (1) termination of atrial flutter with the last intracardiac electrogram of tachycardia occurring just lateral to the site of linear ablation and (2) a surface flutter wave at the moment of termination unobscured by either the QRS or the T wave.Īlthough Einthoven recorded an electrocardiogram of atrial flutter in 1906, Jolly and Ritchie first described the arrhythmia in 1911. A 7F ablation catheter with a 4 mm tip (EP Technologies Inc., San Jose, CA) was advanced through a long supporting sheath (Daig Corporation) and positioned in the cavotricuspid isthmus. In all patients, a 7F steerable catheter with 20 poles using 2/8mm spacing (Daig Corporation, Minnetonka, MN) was positioned around the tricuspid annulus with its tip in the coronary sinus. All patients provided informed consent as per New York University Medical Center policy.ĭiagnostic electrophysiologic catheters were positioned in standard positions for atrial flutter ablation. Cases were included if they met the customary surface electrocardiographic and intracardiac electrogram appearances of typical (counterclockwise) atrial flutter. We retrospectively reviewed 100 cases of typical atrial flutter referred to our laboratory for electrophysiologic study and radiofrequency ablation between July 1997 and June 1999. If this were true, we hypothesized that using radiofrequency energy to create a linear lesion across the cavotricuspid isthmus would result in termination of atrial flutter during the period of gradual decline on the surface electrocardiogram with no subsequent sharp flutter component. This would result in elimination of that component of the surface electrocardiogram reflective of left atrial depolarization. We speculated that interruption of the circuit of typical atrial flutter within the cavotricuspid isthmus would prevent the reentrant wavefront from penetrating the interatrial septum and the left atrium. It is widely believed that the main component of the wave, the sharp descent, represents passive left atrial depolarization in a caudal to cranial direction. In order to elucidate the origin of the sawtooth pattern of atrial flutter, we analyzed the electrocardiographic appearance of flutter waves during radiofrequency ablation. The arrowhead marks the gradual descent and the arrow marks the steep descent. The last generated wave lacked the sharp negative downstroke.Ĭonclusion: These results suggest that the sharp negative deflection of flutter waves likely correlates with the wavefront's penetration of the interatrial septum and passive depolarization of the left atrium.ġ2‐lead electrocardiogram of typical atrial flutter. Results: Seventeen of the 17 cases demonstrated a gradual negative deflection as the last discernible wave of atrial activity followed by an isoelectric period and resumption of normal sinus rhythm. All cases were reviewed for termination of atrial flutter with the last intracardiac electrogram just lateral to the site of linear ablation and surface flutter wave at the moment of termination not obscured by the QRS segment or the T‐wave. Ninety‐seven of the 100 were successfully ablated. Methods: We examined 100 cases of atrial flutter with the typical “sawtooth” pattern referred for radiofrequency ablation. We hypothesized that interruption of the circuit within the isthmus would prevent the reentrant wave from depolarizing the left atrium thus eliminating the component of the electrocardiogram reflecting left atrial depolarization. It has been suggested that the negative flutter wave is a result of passive depolarization of the left atrium. These electrical events are thought to be responsible for the classic “sawtooth” wave of atrial flutter seen on the surface electrocardiogram characterized by a gradual downward deflection followed by a sharp negative deflection. Background: Typical atrial flutter (AFL) is a macroreentrant arrhythmia characterized by a counterclockwise circuit that passes through the cavotricuspid isthmus with passive depolarization of the left atrium.
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