Tips & Tricks with Halo catheter

• what is the recommended position of Halo catheter
• how to interpret signals
• when CTI is blocked

Using a Halo catheter for the diagnosis of typical atrial flutter is a frequently used approach that gives great understanding of the arrhythmia and the progress of ablation. This long catheter mostly consists of 20 electrodes (duo deca polar) that should be placed around the tricuspid valve. You should pay attention that poles 1/2 are placed in or in vicinity of CS ostium.
The activation pattern from pole 19/20 towards 1/2 indicates most typical counter-clockwise type of flutter (90% of cases) while propagation from 1/2 in direction of 19/20 an uncommon reverse typical or clockwise flutter (10%). In most cases the PPI during entrainment maneuver from halo catheter is identical with the CL of flutter. This indicates that the catheter is positioned within the circuit of the arrhythmia.
During pacing from the CS ostium region (regularly pole 1/2) a pattern with interrupted conduction at the level of ablation line (in most cases pole 9/10) should be easily recognizable   if a complete CTI block has been achieved.