Sirs:Catheter-interventional closure of a secundum atrial septal defect (ASD II) is a common procedure. Most of the defects are suitable for this technique. A variety of different occluders and sizes are available. In the presence of additional congenital cardiac malformations the intervention may be problematic or even inappropriate. As a congenital anomaly, the left main coronary artery (LCA) may arise near or out of the ostium of the right coronary artery (RCA). The localization of the LCA may then be in the anterior or posterior wall around the aortic valve (AV) annulus/aortic root. The coexistence of this anomaly with a secundum atrial septal defect is rare. To close the ASD under this condition [1,2], surgery is the most common procedure. The alternative catheter-interventional closure is rarely performed, because a partly or even complete compression of the LCA may occur as the occluder may rest at or on the aortic wall and therefore also on the LCA [3]. However, interventional closure may be an alternative [4,5], if there is enough distance between defect/occluder and the LCA. Contrary to ASD closure in normal coronary morphologies, it is of utmost importance that in this special case no part of the occluder touches the LCA when approaching the defect or is placed close to or even on the aortic wall. This is to prevent compression of the LCA, ending up in a coronary occlusion [4,5]. While pushing the catheter/sheath forward, attention should be paid to the angle between catheter/sheath and the interatrial septum to avoid touching the LCA with the catheter tip to prevent coronary spasm [6] or even rupture. Additionally, maneuvering the catheter within the left atrium may also be critical for the same reasons when retracting the sheath with the partly developed occluder from the pulmonary vein area towards the defect [7].We report on a 60-year-old male patient with an ASD II (Fig. 1a, b). The diameter of the defect is 16 mm, left-toright shunting 58 %, the rate of pulmonary/systemic flow is (Qp/Qs) 3.7/1. The pulmonary vascular resistance is normal. As additional anomaly a right-sided origin of the LCA was found (Fig. 1c, d). The LCA proceeded posteriorly around the aortic valve (AV) annulus.The patient's clinic included right heart overload, vertigo, chronic atrial fibrillation, complete right bundle branch block, no cardiac decompensation.Transoesophageal echocardiography (TEE) was performed under local anaesthesia and mild sedation. Balloonsizing using the shunt-flow-stop technique revealed a defect width of 22 mm. To keep the size of the occluder as small as possible to prevent touching or compressing the LCA, a non-oversized ASD occluder (Amplatzer ASD occluder, 22 mm, St. Jude Medical Inc., St. Paul, USA) was implanted. The procedure was performed carefully under permanent monitoring of the LCA using 2D-/3D-TEE and angiography to avoid compression of the LCA by the occluder during or after implantation. While retracting the developed left-sided part of the occluder towards the septum (IAS), the LCA wa...