An asymptomatic 64-year-old man presented for cardiovascular evaluation due to a systolic murmur. Transthoracic echocardiogram with Doppler demonstrated flow in a tubular structure between the liver and the right ventricle in the subcostal view (arrow figure 1A), as well as abnormal flow into the coronary sinus (video 1 of the supplementary data). Cardiac computed tomography was performed for further evaluation. The multiplanar reconstruction, at a similar angle to the echocardiogram, showed a diffusely aneurysmal and tortuous right coronary artery (RCA) measuring up to 1.4cm in diameter with a fistulous connection to the coronary sinus at the entrance of the right atrium (arrow figure 1B). The posterior descending artery was normal in size without evidence of aneurysm (asterisk figure 1B). Volume rendering reconstructions (figure 1C,D) compare the aneurysmal and tortuous RCA to the normal left anterior descending artery (arrow figure 1C) and left circumflex artery (asterisk figure 1C). Cardiac magnetic resonance (CMR) was performed to evaluate the functional impact of the fistulous connection (video 2 of the supplementary data). Figure 1E and video 2 of the supplementary data show short-axis cine images with the aneurysmal proximal, mid, and distal segments of the RCA. Phase-contrast CMR demonstrated a pulmonary to systemic flow ratio (Qp/Qs) of 1.6 (blue circle figure 1F), consistent with a significant left-to-right shunt. At this time, the patient has received no treatment and is waiting for follow-up imaging.

Figure 1

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We present a very rare case of a fistula between an aneurysmal RCA and the coronary sinus with a multimodality evaluation integrating complex anatomy and function.