Aims: We sought to evaluate feasibility and efficacy of a very high-power short-duration (vHP-SD, 90 W/4 sec) temperature-controlled radiofrequency (RF) cavotricuspid isthmus (CTI) ablation for typical right atrial flutter (AFL) utilizing a novel vHP-SD contact force (CF) sensing ablation catheter with micro-electrodes.

Background: Catheter ablation for AFL provides an effective treatment option associated with encouraging clinical outcome. The novel micro-electrode ablation catheter allows vHP-SD ablation and potentially offers the ability to perform a safe, effective and faster CTI ablation.

Methods: Fifteen consecutive patients (median age 75 years (interquartile range, IQR: 67, 79), 67 % male) with documented typical AFL were prospectively enrolled and underwent vHP-SD based CTI ablation (90 W/4 sec). Durability of CTI block was proven by pacing maneuvers from both sides of the ablation line. 

Results: Complete CTI block utilizing a vHP-SD ablation was achieved in all patients (Figure 1). A continuous ablation line (tricuspid valve to inferior vena cava) with proven CTI block after the first ablation line (fist-line isthmus block, FLIB) was accomplished in 9/15 (60 %). At median 23 (IQR 20; 39) vHP-SD RF applications over a median RF ablation time of 92 (IQR 78, 154) seconds were applied. It was not necessary to switch to the standard temperature-controlled mode to achieve durable CTI block. No periprocedural complications, no charring and no steam pops were observed.

Conclusions: Very high-power short-duration (90 W/4 sec) CTI ablation for treatment of typical AFL is feasible and efficient. Effective CTI block can be achieved in about 1.5 minutes of RF time.

Figure 1:  Very high-power short-duration based ablation of typical cavotricuspid isthmus (CTI) depending atrial flutter

Three-dimensional electroanatomic reconstruction (CARTO 3, UNIVIEW module, Biosense Webster) of the right atrium (RA) of case #5 in RAO and LAO view. The local activation time (LAT) map shows typical cavotricuspid isthmus (CTI) depending atrial flutter. Note the ablation line (highlighted by white arrows) at the CTI depicted through red-white tags created by radiofrequency ablation utilizing 90 W/4 sec very high-power short-duration ablation.