reported that ATs originated more frequently in the LA (69%) than the right atrium (RA 31%) and the most common arrhythmia mechanism was reentrant AT (70%). Surgical AF ablation is an alternative treatment for drug-refractory or even catheter ablation-refractory AF and ATs are often observed after surgical AF ablation. 37 Of all the LA macroreentrant ATs in CBA, perimitral flutter (45.5%) is the most common type, followed by roof flutter (27.3%) and septal flutter (9%). 37 The possible explanation is that CBA produced more extensive low LA voltage areas than RFCA, which might have contributed to LA macroreentrant ATs. reported that in the second procedure, higher LA flutter occurred in the CBA group than in the RFCA group (54.5% versus 12.5%). 30 In one study, the incidence of ATs after CBA was 3–11% and more than half of ATs were macroreentrant. 10,29 This indicates that more aggressive and extensive LA ablation lesions might easily produce ATs after the index procedure.Ĭryoballoon ablation (CBA) for PVI has safety and efficacy similar to those of radiofrequency catheter ablation (RFCA). 20 Complex atrial fractionated electrogram (EGM)-based ablation is associated with high AT incidence (26–36%). reported that nearly 60% of ATs after PVI had critical isthmus that localised to the mitral isthmus. 26,27 One cohort study conducted in the US demonstrated that ATs after PVI might be single AT or multiple ATs, and nearly 90% were reentrant and associated with gaps in the previous ablation line. 23–25 Linear ablation combined with PVI may result in reentrant ATs because of conduction gaps and non-transmural lesions caused by ablation lesions. ![]() 21 Focal ATs have frequently been observed from reconnected PVs after a segmental or circumferential PVI and account for up to 80% of AT occurrences, 17,22 whereas macroreentrant ATs have been noted after extensive LA ablation. ![]() reported that compared with segmental isolation (2%), circumferential PVI resulted in higher incidence of ATs (18%). 15,17–20 ATs after PVI can be due to a focal or macroreentrant mechanism. The incidence of AT after AF ablation varies from less than 5% to 40% and is associated with the index ablation strategy and duration of AF. In this review, we summarise the incidence, mechanism, mapping and ablation techniques, and outcomes of AT after AF ablation. 14–16 Therefore, the question of how these ATs can be effectively ablated has become a crucial issue in the era of AF ablation. 13 Notably, this AT can be classified into the following three categories: focal, macroreentrant and microreentrant AT. 9–12 However, atrial tachycardia (AT) occurring after AF ablation is often symptomatic, complex and poorly controlled by anti-arrhythmic agents. Therefore, although several multicentre randomised trials showed no difference between PVI alone and additional ablation within the left atrium (LA), various methods, including linear ablation and substrate modification, have been introduced to achieve favourable results. 7,8 Hence, catheter ablation has become widely used for treating symptomatic drug-refractory AF, even though the recurrence rates of AF ablation remain high, especially in persistent AF and longstanding persistent AF. In the Catheter Ablation Versus Anti-arrhythmic Drug Therapy for Atrial Fibrillation (CABANA) trial, the catheter ablation group had superior quality of life compared with the anti-arrhythmic drug group and less AF recurrence after blanking through intention-to-treat analysis. ![]() 4–6 The recent advances in mapping and ablation techniques have provided more efficient non-pharmacological therapies for AF. 2,3 Per the European and US AF guidelines, catheter ablation of AF is currently recommended as the first-line therapy if anti-arrhythmic agents fail to maintain sinus rhythm. 1 Triggers from the pulmonary vein (PV) have been identified as crucial ectopic sources that initiate AF and pulmonary vein isolation (PVI) is the cornerstone for catheter ablation of AF. AF is the most common clinical arrhythmia that causes severe adverse cardiovascular events, such as ischaemic stroke and acute heart failure.
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