de Groot, Joris R

Increased epicardial adipose tissue attenuation on CT images was associated with the presence and recurrence of atrial fibrillation in studies using consistent or corrected tube voltage settings, suggesting its potential as a prognostic marker.

Abstract Background Patients with atrial fibrillation (AF) are at increased risk of stroke, often arising from a thrombus in the left atrial appendage (LAA). In selected cases, left atrial appendage occlusion or closure is an alternative for stroke prevention with oral anticoagulation. To assess the risk of stroke and the benefit of LAA closure and to select the appropriate device, it is crucial to quantify the morphology and dynamics of the left atrial appendage (LAA). To date, much about LAA dynamics in this setting is unknown, and subsequently the risk of embolic stroke and inappropriate device positioning is insufficiently explored. Purpose We describe the morphological and dynamic differences of the left atrium (LA) and LAA in high risk AF patients compared to controls undergoing trans catheter aortic valve implantation (TAVI). Methods Our study population consists of 14 patients, seven with AF and seven without AF, undergoing TAVI, since dynamic computed tomography (CT) angiography scans are performed in the standard of care in these patients. The scans were acquired every 5% of the cardiac cycle (i.e., R-R interval on the ECG) (Figure 1a). The LA and LAA were semi-automatically segmented (Figure 1b) to determine the following parameters across the entire cardiac cycle: LA volume; LAA volume, depth, height, and length; and ostium area, eccentricity, and diameter. Results AF patients had a significantly larger LA volume (108 mL vs 68 mL, p=0.03), while the LA volume change throughout the cardiac cycle was similar in AF patients and controls. Both groups had an LA volume change of 35mL on average. Figure 1cd shows the LA and LAA volume curves of a patient with and without AF. The LAA ostium size and volume of AF patients exhibited larger dynamic variations than those from non-AF patients, while the ostium eccentricity in AF patients showed less variation and the ostium shape was rounder. Conclusions We found differences in morphologic and dynamic parameters of the LA and LAA between AF and non-AF patients. The morphology and dynamics of the LAA can increase the understanding of LAA thrombus formation. Moreover, it may have implications for the risk of embolic stroke and may assist in the selection of the optimal LAA closure device type and size.

Background : Modulation of the cardiac autonomic nervous system (ANS) is a promising adjuvant therapy in the treatment of atrial fibrillation (AF). In pre-clinical models, pulsed field (PF) energy has the advantage of selectively ablating the epicardial ganglionated plexi (GP) that govern the ANS. Objective: This study aims to demonstrate the feasibility and safety of epicardial ablation of the GPs with PF during cardiac surgery with a primary efficacy outcome of prolongation of the atrial effective refractory period (AERP). Methods : In a single-arm, prospective analysis, patients with or without a history of AF underwent epicardial GP ablation with PF during coronary artery bypass grafting (CABG). AERP was determined immediately pre- and post- GP ablation to assess cardiac ANS function. Holter monitors were performed to determine rhythm status and Heart Rate Variability (HRV) at baseline and at 1 month post-procedure. Conclusions : This study demonstrates the safety and feasibility of epicardial ablation of the GP using PF to modulate the ANS during cardiac surgery. Large, randomized analyses are necessary to determine whether epicardial PF ablation can offer a meaningful impact on the cardiac ANS and reduce AF. Results : Of 24 patients, 23 (96%) received the full ablation protocol. No device-related adverse effects were noted. GP ablation resulted in a 20.7% ± 19.9% extension in AERP (P < 0.001). Post-operative AF was observed in 7 (29%) patients. Holter monitoring demonstrated an increase in mean heart rate (74.0±8.7 vs 80.6±12.3, P=0.01). There were no significant changes in HRV. There were no study-related complications.