A 46-year-old physician with an intermediate pretest probability but strong family history of premature coronary artery disease was referred for cardiac computed tomography angiography. While the cardiac computed tomography angiography did not demonstrate significant atherosclerotic coronary artery disease, the right coronary artery (RCA) was noted to have an anomalous intracavitary course within the right atrium over a 2.5 cm segment (Figures 1 to 3).
DiscussionThe presence of an intracavitary course of an intact epicardial coronary artery is rarely encountered. To date, two variants have been described: an intracavitary course of the proximal left anterior descending artery into the right ventricle, which is more common and estimated to occur in less than 0.3% of the population, and an intracavitary course of the RCA into the right atrium in less than 0.1% of the population (1,2). Although believed to be clinically benign, these variants impose a myriad of potential challenges around invasive cardiac procedures. Inadvertent disruption of an intracavitary artery resulting in left-to-right shunting or distal myocardial ischemia can occur at the time of invasive coronary angiography, pacemaker implantation, right heart catheterization or invasive electrophysiology testing (1-5). Indeed, the complex and multifaceted nature of invasive electrophysiology procedures puts an intra-atrial coronary artery at significant risk of disruption, in which damage to an intracavitary coronary artery may occur during Congenital coronary artery anomalies have been reported in fewer than 1.3% of patients undergoing coronary angiography. Most commonly, they take the form of an anomalous origin of one of the major epicardial vessels or variations in their epicardial course. The presence of an intracavitary course of an intact epicardial coronary artery is a particularly rare entity with two distinct variants described in the literature. While the majority of previous reports were incidentally encountered at the time of open heart surgery or on autopsy, the detection of these abnormalities is likely to significantly increase with the widespread use of advanced cardiac imaging. Although usually clinically benign, these variants impose a myriad of challenges around invasive cardiac procedures. The presence of an intramural or intracavitary course can complicate coronary artery bypass surgery, leading to difficulties in vessel localization as well as bypass grafting. In addition, it is of upmost importance that interventional cardiologists and electrophysiologists are aware of this anomaly because inadvertent disruption of an intracavitary artery can occur at the time of invasive coronary angiography, pacemaker implantation, right heart catheterization or electrophysiology procedure. Electrophysiologists, invasive cardiologists and cardiothoracic surgeons all need to be aware of this anomaly and the implications of this anatomical variant on procedural risk and planning.