Fig 1; certain persistent left superior vena cava anatomic variations: a. Typical venous drainage into the right atrium.b. Persistent left superior vena cava and its tributaries draining into the coronary sinus. c. Persistent left superior vena cava draining into the left atrium by means of an
unroofed coronary sinus. d. Persistent left superior vena cava draining into the coronary sinus and also connected to the right superior vena cava by an innominate vein. e. Persistent left superior vena cava with an absent right superior vena cava[11]
PLSVC typically drains into the right atrium (RA) via the coronary sinus (CS), which can become enlarged due to volume overload [12 ]. This enlarged CS can complicate mapping and ablation procedures of supraventricular tachyarrhythmias (SVA) arising from the CS ostia, the triangle of Koch [13 ] and mitral annulus.
Also, excessive motion of a CS mapping catheter has been shown to preclude accurate electrogram localization [14 ]. Thus, the presence of PLSVC can impact the evaluation and treatment of SVAs [15 ].
In AVRT, a CS electrode catheter cannot be used for guidance during ablation of the left-sided accessory pathway and may not allow for a stable electrode position at an endocardial target site [16,17 ].
Despite these difficulties, successful catheter ablation of AVNRT and AVRT was performed in previous case reports. Therefore, catheter ablation can be a reasonable method in the treatment of AVNRT and AVRT patients with PLSVC.