Markers of coronary sinus accessory pathways in pediatrics

Coronary sinus accessory pathways (CSAPs), atrioventricular connections formed by the coronary sinus myocardial coat, have been described in adult patients, but not systematically described in pediatric patients.

Patients who underwent CSAP ablation were compared to patients with right posteroseptal (RPS) pathway ablation (control group) from November 2004 to June 2007. Retrospective reviews of preablation 12-lead electrocardiogram (EKG), fluoroscopic, and intracardiac electrogram data were then performed to identify electrophysiologic markers of CSAP.

A total of 23 patients were identified: 13 with CSAP and 10 with RPS pathways. Preablation EKGs demonstrated preexcitation in 8/10 (80%) patients with RPS pathways versus 9/13 (69%) patients with CSAP (P = 0.66). Preexcitation with a negative delta wave in lead II was seen in 5/9 (56%) patients with CSAP versus 0/8 in RPS (P = 0.029), and preexcitation with a positive delta wave in augmented vector right (aVR) was seen in 9/9 (100%) patients with CSAP versus 3/8 (37.5%) with RPS (P = 0.009). Accessory pathway (AP) potentials were seen on the coronary sinus (CS) catheter in 6/13 (46%) of CSAP and in 0 RPS ablations (P = 0.019). Recurrence of tachycardia occurred in 5/13 (38%) of patients with CSAP and 1/10 (10%) of patients with RPS pathways (P = 0.18).

CSAPs should be considered when preablation EKG demonstrates preexcitation with a negative delta wave in lead II and a positive delta wave in aVR, and if an AP potential is seen on the CS catheter. Recurrence of tachycardia postablation or the need for multiple ablations should raise suspicion for a CSAP.