Coronary Cameral Fistula

Coronary cameral fistulas are rare congenital medical conditions characterized by an abnormal connection between a coronary artery and a cardiac chamber. In contrast, coronary arteriovenous fistulas denote connections between a coronary artery and any part of the systemic or pulmonary circulation. Coronary cameral fistulas are categorized anatomically based on their connection—a direct link is termed an arterioluminal fistula, whereas a connection through a sinusoidal network is referred to as an arteriosinusoidal fistula. Most coronary arteries (90%) drain into right-sided chambers or great vessels, with drainage into left-sided chambers exceedingly rare (see  Cardiac Ultrasound of an Adult with a Coronary Cameral Fistula).  These fistulas can bypass the microcirculation, increasing 1-way blood flow between the connected structures. Although many cases are asymptomatic and discovered incidentally, larger coronary cameral fistulas can lead to complications such as arrhythmias, including atrial fibrillation; infective endocarditis; and, in rare cases, rupture or thrombosis of the fistula, which can result in sudden death. They can also cause myocardial ischemia due to a coronary steal phenomenon, leading to symptoms such as angina or heart failure. The presence of the steal phenomenon is considered a sign of the hemodynamically significant consequences of the fistula.  Each fistula is described by its site of origin and termination, with the most common type originating from the right coronary artery and draining into the right ventricle. Most fistulas terminate in the right ventricle or right atrium, with rare terminations in the left atrium or left ventricle.