Percutaneous left atrial appendage closure (LAAC) has become a commonly used alternative for stroke prevention worldwide in patients with non-valvular atrial fibrillation, who are not eligible for oral anticoagulation (c
lass IIb recommendation) [
1]. Large multicenter trials such as PROTECT AF, PREVAIL, or PRAGUE-17 have already shown that LAAC provides comparable stroke prevention to vitamin K antagonists (VKAs) or novel oral anticoagulants (NOACs), with a reduction in complications such as bleeding or mortality [
2,
3]. Periprocedural imaging is essential when performing LAAC due to the considerable differences in size, shape, and relationship to neighboring structures such as left pulmonary artery, left upper pulmonary vein, and circumflex artery [
4]. Besides, percutaneous interventions involve challenges such as navigation of the catheter and implantation of the device on a beating heart as well as the learning curve of the interventionalists [
5]. Recent studies demonstrated that by improving the aspects such as design of the devices, periprocedural imaging, and the experience of cardiologists, the complication rate of periinterventional life-threatening events such as pericardial effusion with cardiac tamponade, ischemic stroke, arrhythmias, bleeding, and increased 30-day mortality was significantly reduced [
6]. Intraprocedural steps such as a transseptal puncture (TSP), optimal device sizing, and ultimately the implantation of the occlude device require great precision, because underestimation can lead to dislocation of the occluder device or peri-device leak, and oversizing may cause tamponade or embolization as well [
7,
8]. Thus, optimizing the interventionalist’s learning curve is of foremost importance as emphasized by current European and American expert consensus [
9,
10]. Previous studies have shown that the performance and safety of percutaneous LAAC have steadily improved with operator experience, and that 30 procedures are required to reach proficiency and optimize clinical outcomes [
11,
12]. It is recommended to perform procedural imaging with transoesophageal echocardiography (TEE) or intracardiac echocardiography (ICE) [
6,
13]. Unfortunately, although TEE allows visualization of the soft tissues of the cardiac structures, there are limitations in the visualization of the catheter systems and devices used, therefore the simultaneous use of fluoroscopy is indispensable [
14]. Through the application of fusion imaging (FI), the interventionalist no longer needs to mentally combine information from both imaging modalities, which can be very complex and require a good spatial imagination [
15]. Instead, they are fused in real-time and displayed on one screen and on the same image. This, guidance and navigation of catheters or devices while performing procedures can be facilitated [
16]. We recently demonstrated the procedural advantages of FI for LAAC [
17]: It reduces the procedure time, the time to transseptal puncture, and the periprocedural amount of contrast agent. Data about real-time echocardiography-fluoroscopy fusion imaging´s (FI) impact on the interventionalist’s learning curve during LAAC are lacking. Therefore, we aimed to evaluate its impact on an interventional cardiologist’s (IC) learning curve.