LAUSR

We read with great interest the report by Thomas et al describing the use of leadless left ventricular (LV) endocardial pacing in a patient with coronary sinus (CS) atresia. The technique they used was highly sophisticated but necessitated, besides implantation of the LV receiver-electrode, an ultrasound source for energy transmission and a separate battery pack for the ultrasound source. In our 17-year experience with cardiac resynchronization therapy, we have encountered CS ostial atresia in 4 patients. In the first patient we performed a left coronary artery angiogram to visualize the venous phase and the anatomy of the CS. This angiogram revealed a coronary venous system but with runoff in an upward direction toward the pectoral area. Subsequent contrast injection into the subclavian vein showed a persistent left superior vena cava (PLSVC) that gave access to the CS. It is therefore our opinion that if the CS cannot be intubated from the right atrium, a contrast injection in the proximal subclavian vein can elucidate the presence of a PLSVC; flow of contrast from the PLSVC toward the subclavian vein confirms the atresia of the CS. CS anatomy can be visualized by a selective angiogram and the decision can be made to proceed to a CS implant or to use an alternative implantation as described by Thomas et al. In our experience so far, all 4 patients had a successful CS lead implantation via the PLSVC with standard equipment and a more complicated approach could be avoided. Two of our patients have been described in case reports.