Results
Altogether 949 TSPs were performed during 586 procedures in 524 patients. Patient characteristics are shown in Table 1. The majority of procedures were performed for AF or atypical atrial flutter. However, TSPs in other left-sided arrhythmias were also assessed: VT (5.6%), AT (4.6%), AP mediated tachycardia and AVNRT with left sided location of the slow pathway (12.8%). Procedural characteristics are shown in Table 2. 57 patients had two (46 for AF, 3 for atypical atrial flutter, 5 for AP mediated tachycardia, 2 for focal AT, 1 for VT) and 5 patients had three procedures (3 for AF, 1 for and 1 for AP mediated tachycardia). Double TSPs were performed in majority of procedures for AF or atypical atrial flutter (350/451, 78%) and in a minority of procedures for focal atrial tachycardia (8/27, 30%) and VT (5/33, 15%). There were no double TSPs in patients treated for AP mediated tachycardia and AVNRT.
Only few procedures (41/586, 7%) were performed under general anesthesia; in pediatric patients who were under 14 years of age (22 procedures) and in patients undergoing hybrid ablation for persistent atrial fibrillation (19 procedures).
Only two TSPs were unsuccessful (2/949, 0.2%), both in patients with AF. In one patient with prior surgical removal of myxoma the operator was unable to puncture through the stiff IAS. The transseptal access was later successfully performed using RF needle technique. In the second unsuccessful TSP the presence of inferior vena cava filter precluded the femoral venous access. Subsequently right transjugular access was attempted but the operator was unable to insert a steerable or non-steerable long sheath into the left atrial cavity due to acute angle between the superior vena cava (SVC) and the IAS. Two procedures in patients with AF were aborted due to a visible mobile structure on the wire/long sheath/dilator assembly (2/586, 0.3%). In all cases, mapping and ablation parts of the procedure after successful TSP were performed completely without the use of fluoroscopy.