The coronary sinus (CS) normally drains into the right atrium (RA). We report a rare case of anomalous CS drainage into the left atrium (LA). A middle-aged lady underwent coronary computed tomography angiography (CCTA) for evaluation of dyspnea. An earlier transthoracic echocardiogram showed normal chamber sizes and function. The CCTA revealed severe left anterior artery stenosis as well as an anomalous drainage of a normal sized CS into the LA. A small fistula from the CS also communicated with RA. These findings were confirmed during invasive angiography. No further intervention was offered as this was unlikely to be of hemodynamic significance. Nevertheless, understanding of this unusual anatomy will be of importance when planning for electrophysiological or pacing procedures.

The coronary sinus (CS) normally drains into the right atrium (RA). We report a rare case of anomalous CS drainage into the left atrium (LA). A middle-aged lady underwent coronary computed tomography angiography (CCTA) for evaluation of dyspnea. An earlier transthoracic echocardiogram showed normal chamber sizes and function. The CCTA revealed severe left anterior artery stenosis as well as an anomalous drainage of a normal sized CS into the LA. A small fistula from the CS also communicated with RA. These findings were confirmed during invasive angiography. No further intervention was offered as this was unlikely to be of hemodynamic significance. Nevertheless, understanding of this unusual anatomy will be of importance when planning for electrophysiological or pacing procedures.

The coronary sinus (CS) normally drains into the right atrium (RA). We report a rare case of anomalous CS drainage into the left atrium (LA). A middle-aged lady underwent coronary computed tomography angiography (CCTA) for evaluation of dyspnea. An earlier transthoracic echocardiogram showed normal chamber sizes and function. The CCTA revealed severe left anterior artery stenosis as well as an anomalous drainage of a normal sized CS into the LA. A small fistula from the CS also communicated with RA. These findings were confirmed during invasive angiography. No further intervention was offered as this was unlikely to be of hemodynamic significance. Nevertheless, understanding of this unusual anatomy will be of importance when planning for electrophysiological or pacing procedures.

The coronary sinus (CS) normally drains into the right atrium (RA). We report a rare case of anomalous CS drainage into the left atrium (LA). A middle-aged lady underwent coronary computed tomography angiography (CCTA) for evaluation of dyspnea. An earlier transthoracic echocardiogram showed normal chamber sizes and function. The CCTA revealed severe left anterior artery stenosis as well as an anomalous drainage of a normal sized CS into the LA. A small fistula from the CS also communicated with RA. These findings were confirmed during invasive angiography. No further intervention was offered as this was unlikely to be of hemodynamic significance. Nevertheless, understanding of this unusual anatomy will be of importance when planning for electrophysiological or pacing procedures.