Abstract Body (Do not enter title and authors here): Introduction: Coronary artery fistulas are rare congenital anomalies that are usually incidentally discovered on cardiac imaging or coronary angiography. We present an extremely rare case of a large left main coronary artery (LMCA)/left circumflex artery (LCX) fistula to the superior vena cava (SVC) successfully managed by transcatheter closure through coil embolization.

Case Presentation: A 63-year-old male competitive bodybuilder, with no prior cardiac history, presented with lightheadedness and wide complex tachyarrhythmia at a heart rate over 240 beats per minute in the field, requiring two defibrillator shocks. His subsequent EKG demonstrated diffuse ST depressions. Coronary angiography revealed a large tortuous coronary fistula from the LMCA/LCX emptying into the SVC. Transthoracic echocardiogram showed a left ventricular (LV) ejection fraction of 56% and lateral LV wall hypokinesis. Cardiac MRI demonstrated an enlarged right ventricle without delayed myocardial enhancement. Given right sided enlargement and concerns for coronary steal, decision was made to intervene. The patient declined sternotomy to preserve his active lifestyle. Thus, a nonsurgical multi-disciplinary approach was planned for fistula closure. Vascular plug placement was attempted through retrograde venous and antegrade coronary wiring but was unsuccessful due to a narrow and fenestrated single fistula ostium opening and long and tortuous fistula length. From the coronary side, stasis was achieved in the fistula through embolization using 12 microcoils. An electrophysiology study was performed, and the patient’s arrhythmia was consistent with ventricular tachycardia. A subcutaneous implantable defibrillator was inserted for secondary prevention.

Discussion: This patient’s uniquely late presentation and resulting unstable arrhythmia, cardiac chamber enlargement and ischemia emphasizes the importance of identifying indications for fistula closure. Pre-procedure planning with various imaging modalities and collaboration of multiple specialties allows for productive discussion of both surgical and interventional options.

Conclusion: A multidisciplinary heart team is essential in successfully treating complex arteriovenous malformations.