A 69 year old male patient, no history of structural heart disease, presented with frequent, symptomatic PVC bigeminus (see panel A). 12-lead ECG showed spot diagnosis of summit region as PVC origin. 3D mapping using Abott Ensite-Precision^©system confirmed an exit from the anterior region of the coronary sinus, confirmed by pacemap. 

The coronary sinus is an epicardial structure opening from the right atrium. It is known to have close vicinity to the coronary arteries. After reaching the origin via the CS, coronary angiogram was performed. In addition to confirm the exact PVC origin and its relation to the coronary arteries, we performed 3D mapping of the left main, LAD and RCX artery using an isolated guidewire just sparing the distal 15mm (Visionwire^©Biotronik) in the coronary arteries connected to the Precision^© system. This method was feasible, safe and has not been described before. It showed a reliable and stable map, defining non fluoroscopic, very close relationship between PVC origin and the coronary artery (see panel D). 

Ablation of PVC origin being so close to a coronary artery is of high risk of an acute coronary syndrome due to thermic lesions and/or acute thrombus formation leading to ST-elevation myocardial infarction.   

Ablation procedure (25 W, 60 s) with an irrigated 4mm catheter (Cool-Flex M^©, Abbott) could be performed within the coronary sinus and protected Coronary arteries by two coated wires (see panel C for position of ablation catheter). 

In the short term follow up after successful ablation during holter-ECG monitoring no significant PVC could be detected, also there were no ECG changes regarding cardiac ischemia due to vascular injury of the circumflex artery. 

Conclusion: In this for the first time described visualisation of the coronary arteries by connecting an isolated guidewire with the Ensite-Precision^© System we were able to show the vicinity of coronary arteries and CS in an electroanatomical fashion. This technique could be very helpful in the future, especially when ablating in the epicardium and to avoid fluoroscopy and the use of contrast agent.