Coronary artery fistulae may sometimes be asymptomatic and may spontaneously close, but they may also cause angina, myocardial infarction, endocarditis, atrial fibrillation and heart failure. Therefore, in patients with big or symptomatic fistulae, intervention is mandatory. In the literature, most of the patients who underwent transcatheter coil embolization of coronary artery fistulae were children; this is because of the early onset of symptoms in the most severe cases, but also because many adult patients are usually referred to surgery. We describe the case of an adult patient presenting with heart failure and a giant tortuous coronary fistula, with high shunt flow from right coronary artery to right atrium, which was successfully treated with transcatheter closure with free embolization coils. The most challenging technical aspect of transcatheter coil embolization is the precise release of the spirals.