{'fraction_non_alphanumeric': 0.023677395486496486, 'fraction_numerical': 0.007399186089530152, 'mean_word_length': 5.793969849246231, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Atrial Tachyarrhythmias After Atrial Fibrillation Ablation Procedures: Trading One Tachycardia for Another?

Treatment of atrial fibrillation through the creation of left atrial lesions surrounding the pulmonary veins has received a great deal of attention recently due to the development of catheter-based techniques. However, surgical treatments for atrial fibrillation preceded the current catheter-based methods by more than a decade.1 The initial “maze” procedure involved complex incisions made in both atria, and the success of this procedure was reported to be extremely high. Initial reports of clinical follow-up after the surgical maze noted atrial flutter in 14% of patients.2 This procedure has evolved over the years, and surgical atrial fibrillation ablation (SAFA) techniques at many centers now employ radiofrequency, microwave, or cryoablation lesions in the left atrium surrounding each pulmonary vein and extending to the mitral annulus and across the posterior wall.3,4 These lesions are similar to catheter-based methods, particularly anatomical left atrial catheter ablation.5 Both techniques aim to create lines of conduction block in the posterior left atrium surrounding the pulmonary veins. Extension of these lines to the mitral annulus, left atrial appendage, and across the roof of the left atrium is performed to create further anatomic lines of block and prevent the development of reentrant arrhythmias. “Atrial flutter” is a well-recognized complication of atrial fibrillation ablation procedures. Since “atrial flutter” implies a macroreentrant mechanism, and many of these arrhythmias appear to be focal, we prefer the general term “left atrial tachycardia” for regular atrial tachyarrhythmias at rates less than 300 beats per minute. Clinical studies of both surgical and catheter-based anatomical radiofrequency ablation of the left atrium have reported postprocedure “atrial flutter” in 4–20% of patients.4,6-8 One study, in which patients underwent intensive electrophysiologic follow-up, reported a 96% incidence of “atrial flutter” after a novel SAFA technique.9 This remarkable variability in outcomes highlights a controversial issue in clinical studies of atrial fibrillation ablation procedures—the follow-up of postprocedure arrhythmias. Most clinical studies rely on patient-reported symptoms and periodic electrocardiograms to diagnose recurrent atrial fibrillation or new-onset atrial tachycardias. However, studies using ambulatory arrhythmia monitoring have demonstrated that over one-third of patients with recurrent atrial tachyarrhythmias after atrial fibrillation ablation will be asymptomatic.8 Therefore, it is quite likely that the incidence of