Contact (St Jude Medical) System uses a novel impedance- based measure of
Electrical Coupling Index (ECI) to assess the quality of catheter tip to
endocardium contact. We sought to establish average ECI measurements during
pulmonary vein (PV) isolation procedures.
patients undergoing PV isolation for atrial fibrillation (AF) were studied.
‘Non-contact’ and upper range ‘in-contact’ catheter positioning was performed
for system calibration. ECI measurements were recorded pre-ablation at 14
standardized locations around the PV antra.
mean ECI non-contact value was 77 ± 11 (range 63–107); the mean upper range
in-contact value was 111 ± 16 (range 81–145). Mean ECI values pre-ablation
around the PV antra ranged from 85 ± 18 to 107 ± 19. A trend towards higher
mean ECI values was noted with increasing body mass index (BMI). Pre-ablation
mean ECI values were 92 ± 10 (BMI 20-25), 95 ± 12 (BMI 26-30) and 104 ± 11 (BMI
>30)(p< 0.01 for 20-25 vs. >30). A positive correlation was noted for
mean pre-ablation ECI values and BMI (r=0.50).
expected range of ECI values during PV isolation has been documented in this
study. Observed ECI values correlate with patient BMI. The potential
limitations of the current generation Contact System are discussed.
Credits: Daniel T Walker; Karen P Phillips