Radiofrequency Ablation of a Focal Atrial Tachycardia Originating From the Marshall Ligament as a Trigger for Atrial Fibrillation
A 66-year-old woman with a history of typical atrial flutter and atrial fibrillation was referred to our institution for radiofrequency ablation. In 1997, her atrial flutter was successfully ablated. During the next 4 years, she remained free of both arrhythmias. In 2001, the patient presented again with atrial fibrillation. During the subsequent electrophysiological study, the index arrhythmia was an incessant atrial tachycardia (AT), 170 bpm (Figure 1, left). A 3-dimensional electroanatomic map (CARTO; Biosense Webster, Inc) of the right atrium (RA) during tachycardia clearly demonstrated a tachycardia originating in the left atrium (LA) (Figure 2). Mapping of the LA through a transseptal puncture revealed an AT arising from a posterolateral LA focus, between the left superior pulmonary vein ostium and the atrioventricular groove (Figure 2). Endocardial recordings during AT from this region showed a discrete electrical potential (Marshall potential) preceding the atrial electrogram (Figure 1, right). Radiofrequency ablation targeting this area of early activation was successfully performed. The patient remains free of atrial arrhythmias at 3-month follow-up. This case indicates that in this particular patient, 2 triggers for atrial fibrillation were documented: an isthmus-dependent atrial flutter and an AT originating from the Marshall ligament.
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke’s Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
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