Thrombus Formation in Isolated Left Atrial Appendage After Multiple Atrial Fibrillation Ablations Despite Oral Anticoagulation Followed by Percutaneous Appendage Closure

Durable LAA isolation combining pulsed field ablation and radiofrequency linear lesions in a patient with a therapy refractory left atrial appendage tachycardia

BACKGROUND

Treating atrial tachycardia (AT) originating from left atrial appendage (LAA) needs sometimes electrical isolation of LAA. We report a case of AT originating from LAA successfully treated with electrical isolation using the novel lattice-tip pulsed-field/radiofrequency ablation (PFA/RFA) catheter. A 55-year-old female patient with a history of three focal ablative attempts for a highly symptomatic AT originating from the LAA in different centers was admitted to our department for the recurrence of the clinical tachycardia. Electrical isolation of the LAA (LAAEI) was successfully performed with a lattice-tip PFA/RFA ablation catheter. Six weeks after the procedure, an invasive re-mapping study indicated a durable electrical LAA isolation; therefore, a 24-mm-sized LAA occlusion device (WATCHMAN FLX device, Boston Scientific, Plymouth, MN, USA) was implanted.

DISCUSSION

In this case, we successfully treated an atrial tachycardia originating from LAA using the recently approved lattice-tip PFA/RFA ablation catheter. The combination between two energy sources during the same procedure could potentially improve lesions transmurality offering a new promising solution for the treatment of complex atrial tachycardias.

Evolving Role of Catheter Ablation for Atrial Fibrillation: Early and Effective Rhythm Control

Catheter Ablation (CA) is an effective therapeutic option in treating atrial fibrillation (AF). Importantly, recent data show that CA as a rhythm control strategy not only significantly reduces AF burden, but also substantially improves clinical hard endpoints. Since AF is a progressive disease, the time of Diagnosis-to-Intervention appears crucial. Recent evidence shows that earlier rhythm control is associated with a lower risk of adverse cardiovascular outcomes in patients with early AF. Particularly, CA as an initial first line rhythm control strategy is associated with significant reduction of arrhythmia recurrence and rehospitalization in patients with paroxysmal AF. CA is shown to significantly lower the risk of progression from paroxysmal AF to persistent AF. When treating persistent AF, the overall clinical success after ablation remains unsatisfactory, however the ablation outcome in patients with "early" persistent AF appears better than those with "late" persistent AF. "Adjunctive" ablation on top of pulmonary vein isolation (PVI), e.g., ablation of atrial low voltage area, left atrial posterior wall, vein of Marshall, left atrial appendage, etc., may further reduce arrhythmia recurrence in selected patient group. New ablation concepts or new ablation technologies have been developing to optimize therapeutic effects or safety profile and may ultimately improve the clinical outcome.

[Atrial fibrillation and the limits of oral anticoagulation: for whom are left atrial appendage occluders suitable?]

BACKGROUND

Patients with atrial fibrillation are at a significantly increased risk of thromboembolic events, especially ischemic strokes. Oral anticoagulation reduces this risk, but cannot be used in some patients for various reasons and is associated with a relevantly increased risk of bleeding. As an alternative for prophylaxis of thromboembolic events in patients with atrial fibrillation, there are different options of left atrial appendage closure.

AIM

This article explains the possibilities of interventional atrial occlusion as well as the suitable patient clientele using an overview of the currently available systems for atrial occlusion, a guideline for patient selection and a summary of the current scientific data.

CONCLUSION AND AVAILABLE SCIENTIFIC DATA

In carefully selected patients suffering from atrial fibrillation with relative or absolute contraindications for oral anticoagulation, interventional closure of the atrial appendage is a safe alternative for prophylaxis against thromboembolic events. The currently available scientific evidence from randomized controlled trials is sparse. Nevertheless, extensive amounts of registry study data suggest a benefit, while the results of several large randomized controlled trials are expected in the coming years.

Comparison of Left Atrial Appendage Occlusion versus Non-Vitamin-K Antagonist Oral Anticoagulation in High-Risk Atrial Fibrillation: An Update

Transcatheter left atrial appendage occlusion (LAAO) is non-inferior to vitamin K antagonists (VKAs) in preventing thromboembolic events in atrial fibrillation (AF). Non-vitamin K antagonists (NOACs) have an improved safety profile over VKAs; however, evidence regarding their effect on cardiovascular and neurological outcomes relative to LAAO is limited. Up-to-date randomized trials or propensity-score-matched data comparing LAAO vs. NOACs in high-risk patients with AF were pooled in our study. A total of 2849 AF patients (LAAO: 1368, NOACs: 1481, mean age: 75 ± 7.5 yrs, 63.5% male) were enrolled. The mean CHA2DS2-VASc score was 4.3 ± 1.7, and the mean HAS-BLED score was 3.4 ± 1.2. The baseline characteristics were comparable between the two groups. In the LAAO group, the success rate of device implantation was 98.8%. During a mean follow-up of 2 years, as compared with NOACs, LAAO was associated with a significant reduction of ISTH major bleeding (p = 0.0002). There were no significant differences in terms of ischemic stroke (p = 0.61), ischemic stroke/thromboembolism (p = 0.63), ISTH major and clinically relevant minor bleeding (p = 0.73), cardiovascular death (p = 0.63), and all-cause mortality (p = 0.71). There was a trend toward reduction of combined major cardiovascular and neurological endpoints in the LAAO group (OR: 0.84, 95% CI: 0.64-1.11, p = 0.12). In conclusion, for high-risk AF patients, LAAO is associated with a significant reduction of ISTH major bleeding without increased ischemic events, as compared to "contemporary NOACs". The present data show the superior role of LAAO over NOACs among high-risk AF patients in terms of reduction of major bleeding; however, more randomized controlled trials are warranted.