Excerpt

An 84-year-old man with shortness of breath and palpitation was admitted to our hospital. Physical examination revealed bilateral leg edema, but no cardiac murmur. His heart rate was irregular at 68 beats/min and blood pressure was 111/86 mmHg. The electrocardiogram showed atrial fibrillation. Cardiac dilatation with bilateral pleural effusion was noted on his chest X-ray. His transthoracic echocardiography showed a dilated left atrium (LA) of 59 mm in diameter and slightly enlarged right-sided chambers with a prominent coronary sinus (CS) (Fig. 1a). Left ventricular function was normal (diastolic diameter was 45 mm and ejection fraction was 59%) with mild-to-moderate mitral and tricuspid regurgitations. Transesophageal echocardiography (TEE) revealed a defect between the LA and a dilated CS (Fig. 1b), but a shunt flow across the defect was difficult to confirm. We could not identify a persistent left superior vena cava (PLSVC) by contrast echocardiography. Cardiac multi-detector computed tomography (MDCT) showed a communication between the mid-CS and the LA (Fig. 1c). Its size was 8 mm × 18 mm. Subsequent CS angiography disclosed a defect in the mid-portion of the CS with a slow shunt flow (Fig. 1d). On intracardiac echo catheterization (a commercially available AcuNaV, ICE), we visualized clearly the defect and bidirectional shunting (Fig. 1e, f). His Qp/Qs was 1.27. He started taking diuretics and anticoagulants, resulting in a disappearance of symptoms. An unroofed CS is an uncommon congenital heart anomaly, which is often associated with a PLSVC [1] or rarely isolated [2]. 2D or 3D TEE is the most widely used imaging modality for this disease [3] but in our case it was limited in its ability to visualize a shunt flow not along the ultrasonic beam probably because of its defect in the mid-CS in a limited cross-sectional plane. MDCT is useful for providing the anatomy of the CS [4] but it cannot reveal real-time information and hemodynamic evaluation. On the other hand, ICE, which is commonly used in catheter-based procedures including ablation [5], has a higher resolution than TEE or CT, and provides a color flow imaging within the right atrium and its surrounding structures including the CS. There is no reported case to demonstrate a shunt in an unroofed CS by ICE. ICE was a useful modality to demonstrate the portion of the defect and flow direction clearly using color and pulsed wave Doppler echocardiography.

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