Radiofrequency catheter ablation for atrial tachycardia originating from the left atrial appendage

Atrial tachycardia from an unusual site-Left atrial appendage tachycardia: Challenges in ablation

Left atrial appendage (LAA) tachycardia are rarely encountered in clinical practice (2.1% of focal atrial tachycardia). Out of these, the ones arising from the distal part of LAA are difficult to ablate due to higher risk of LAA perforation and thromboembolism. We hereby present a patient with LAA tachycardia mapped to the tip of LAA with the help of the CARTO system and ablated. This case highlights the inherent challenges faced in such a scenario.

An electrocardiography algorithm combined with clinical features could localize the origins of focal atrial tachycardias in adjacent structures

AIMS

It is difficult to differentiate the origins of focal atrial tachycardias (ATs) in adjacent structures by electrocardiography (ECG) alone. The aim of this study was to evaluate whether the clinical features of these ATs may help differentiate their origins.

METHODS AND RESULTS

One hundred and ninety-four patients (mean age, 43.5 ± 17.9 years; male, 53.6%) who underwent electrophysiological study for focal AT were included. We evaluated accuracy in differentiating the origin of AT by using ECG alone as well as with the addition of the clinical features. Electrocardiographs of ATs originating from the left superior pulmonary vein (LSPV, n = 24) vs. the left atrial appendage (LAA, n = 6), and from the right superior pulmonary vein (RSPV, n = 14) vs. the superior vena cava (SVC, n = 8) showed similar patterns. However, while no ATs from the LAA were found to be related to paroxysmal atrial fibrillation, 22 out of 24 ATs from the LSPV were associated with this condition. After localizing AT by using ECG, this clinical feature helped differentiate the ATs from the LSPV vs. the LAA with 93% accuracy. Moreover, while an on-and-off tachycardia (initiated and terminated more than 10 times per day) was observed in 4 of 8 ATs from the SVC, this pattern was observed in 13 of 14 ATs from the RSPV. After localizing the ATs by using ECG, on-and-off tachycardia helped differentiate the ATs from the RSPV vs. the SVC with 82% accuracy.

CONCLUSION

The clinical features and Holter monitoring can give additional information for differentiating the focal ATs originating from the adjacent structures.

Localized reentry within the left atrial appendage: arrhythmogenic role in patients undergoing ablation of persistent atrial fibrillation

BACKGROUND

Left atrial appendage (LAA) is implicated in maintenance of atrial fibrillation (AF) and atrial tachycardia (AT) associated with persistent AF (PsAF) ablation, although little is known about the incidence and mechanism of LAA AT.

OBJECTIVE

The purpose of this study was to characterize LAA ATs associated with PsAF ablation.

METHODS

In 74 consecutive patients undergoing stepwise PsAF ablation, 142 ATs were encountered during index and repeat procedures. Out of 78 focal-source ATs diagnosed by activation and entrainment mapping, 15 (19%) arose from the base of LAA. Using a 20-pole catheter, high-density maps were constructed (n = 10; age 57 ± 6 years) to characterize the mechanism of LAA-AT. The LAA orifice was divided into the posterior ridge and anterior-superior and inferior segments to characterize the location of AT.

RESULTS

Fifteen patients with LAA AT had symptomatic PsAF for 17 ± 15 months before ablation. LAA AT (cycle length [CL] 283 ± 30 ms) occurred during the index procedure in four and after 9 ± 7 months in 11 patients. We could map 89% ± 8% AT CLs locally with favorable entrainment from within the LAA, which is suggestive of localized reentry with centrifugal atrial activation. ATs were localized to inferior segment (n = 4), anterior-superior segment (n = 5), and posterior ridge (n = 6) with 1:1 conduction to the atria. Ablation targeting long fractionated or mid-diastolic electrogram within the LAA resulted in tachycardia termination. Postablation, selective contrast radiography demonstrated atrial synchronous LAA contraction in all but one patient. At 18 ± 7 months, 13/15 (87%) patients remained in sinus rhythm without antiarrhythmic drugs.

CONCLUSION

LAA is an important source of localized reentrant AT in patients with PsAF at index and repeat ablation procedures. Ablation targeting the site with long fractionated or mid-diastolic LAA electrogram is highly effective in acute and medium-term elimination of the arrhythmia.