Resynchronization Therapy in a Rarest of Rare Coronary Venous Sinus Anomaly (JACC Case Reports August 2025)-Article: Resynchronization Therapy in a Rarest of Rare Coronary Venous Sinus Anomaly

Article: Resynchronization Therapy in a Rarest of Rare Coronary Venous Sinus Anomaly

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This case report describes a rare congenital anomaly involving the coronary venous sinus (CS), a major cardiac vein responsible for venous drainage and a crucial structure in electrophysiological interventions like cardiac resynchronization therapy (CRT). The anomaly involved an interrupted coronary sinus with the proximal segment draining normally into the right atrium and the distal segment draining into a common channel that connected to the left subclavian vein via a persistent left superior vena cava (PLSVC). Uniquely, flow in the PLSVC was retrograde (heart to left subclavian vein), contrary to the usual antegrade flow observed in typical PLSVC cases, thus evading detection on conventional left axillary and subclavian vein angiography.<br /><br />Initial suspicion arose during levo-phase coronary sinus angiography and was confirmed with computed tomography and direct coronary sinus angiography, which also revealed collateral vessels bridging the interrupted segments. This case represents, to the authors’ knowledge, the first documented implantation of a cardiac resynchronization therapy device in such interrupted coronary sinus anatomy.<br /><br />The CRT device was successfully implanted with right atrial and ventricular leads placed via the normal superior vena cava, and the left ventricular lead inserted through the PLSVC into the posterior lateral vein. This approach underlines the necessity of comprehensive preprocedural imaging and understanding of coronary sinus anatomy variations to ensure procedural success and patient safety.<br /><br />Key take-home points emphasize the importance of awareness of coronary sinus anomalies, thorough evaluation prior to intervention, and recognition that PLSVC may present atypically with flow reversal, necessitating advanced imaging beyond conventional venography for accurate diagnosis.<br /><br />This case highlights how detailed anatomical knowledge and tailored procedural strategy facilitate successful device implantation in complex cardiac venous anomalies, advancing the field of cardiac electrophysiology interventions.

Keywords

coronary venous sinus anomaly

interrupted coronary sinus

persistent left superior vena cava (PLSVC)

retrograde flow

cardiac resynchronization therapy (CRT)

coronary sinus angiography

computed tomography imaging

collateral vessels

left ventricular lead placement

cardiac electrophysiology interventions