Mapping and Ablation
Nineteen of the 20 patients underwent ablation successfully, while one patient with RBBB presented with transient complete AVB at the beginning of RF ablation. The procedure was discontinued without further ablation. SAM can be observed in all patients on ICE with the AML either touching or nearly touching the interventricular septum. For patient No. 12, an extraordinarily long and flexible mitral leaflet was observed with real-time ICE. The AML was reflexed and attached to the IVS during systole (Figure 2D). RF energy was delivered only in the same region where the AML flapped. Trans-atrial septal access was used in 5 patients to achieve more stable catheter-tissue contact. After ablation, significant tissue edema can be observed on the real-time ICE image (Figure 1E). Invasive resting LVOT gradients were measured before and after the procedure and decreased significantly from 88.9 ± 30.5 mmHg to 33.5 ± 30.1 mmHg (p < 0.001). The mean procedure time was 208.4 ± 49.4 min and the mean X-ray exposure time was 13.9 ± 7.2 min. A mean of 15.2 ± 8.1 min of RF energy was applied. Ablated area was 2.9 ± 1.4 cm2, representing 12.7 ± 5.6 % of total septum endocardial surface (Figure 1D).