Categorization of accessory pathway regions/types
The AP categorization is illustrated by the diagram on Figure 1and explained in detail below. For anatomic localization of the ablation
site, fluoroscopic imaging or electroanatomic 3D maps were used in
various projections, especially the left anterior oblique projection of
35 degree (LAO).
- Parahisian (PHIS) localization was diagnosed when a His bundle
potential was recorded at the site of successful ablation.
- Right midseptal (RMS) region was defined as below the PHIS region and
above the roof of the coronary sinus ostium.
- Right posteroseptal (RPS) region was defined as below the roof of the
coronary sinus ostium, including the periostial region (but less than
1 cm inside the coronary sinus) and extending to 5.00 o’clock on the
tricuspid annulus in LAO.
- Right posterior (RP) region was defined as between 5.00 and 7.00
o’clock on the tricuspid annulus in LAO.
- Right posterolateral (RPL) region was defined as between 7.00 and 8.00
o’clock on the tricuspid annulus in LAO.
- Right lateral region (RL) region was defined as between 8.00 and 10.00
o’clock on the tricuspid annulus in LAO.
- Right anterolateral (RAL) region was defined as between 10.00 and
11.00 o’clock on the tricuspid annulus in LAO.
- Right anterior (RA) region was defined as between 11.00 and 12.30
o’clock on the tricuspid annulus in LAO.
- Right anteroseptal (RAS) region was defined as between 12.30 o’clock
on the tricuspid annulus in LAO and the PHIS region.
- Epicardial (EPI) AP was diagnosed when the successful ablation had to
be performed within the coronary sinus (> 1 cm from the
ostium) including cardiac veins and coronary sinus diverticula.
- Atriofascicular (MAHAIM) AP was diagnosed per the recognized
electrophysiological criteria for such AP, regardless of the actual
position of successful ablation site on the tricuspid annulus.
- Fasciuloventricular (FASC-VENT) AP was diagnosed with HV <
35 ms and fixed preexcitation during incremental pacing, adenosine
administration and/or extrastimulus testing.
- Left midseptal (LMS) AP was diagnosed when successful ablation was on
the mitral anulus just below the His bundle potential region –
corresponding in LAO to the right midseptal region.
- Left posteroseptal (LPS) region was defined as just below the aorta on
the mitral annulus between 7.00 – 8.00 o’clock in LAO.
- Left posterior (LP) region was defined as between 5.00 – 7.00 o’clock
on the mitral annulus in LAO.
- Left posterolateral (LPL) region was defined as between 4.00 – 5.00
o’clock on the mitral annulus in LAO.
- Left lateral (LL) region was defined as between 2.00 – 4.00 o’clock
on the mitral annulus in LAO.
- Left anterolateral (LAL) region was defined as between 12.30 – 2.00
o’clock on the mitral annulus in LAO.
- Left anterior (LA) region (including aortomitral continuity), was
defined as between 11.00-12.30 o’clock on the mitral annulus in LAO.