Compatibility of electroanatomical mapping systems with a concurrent percutaneous axial flow ventricular assist device.

BACKGROUND

Hemodynamic instability hinders activation and entrainment mapping during ventricular tachycardia ablation. The Impella 2.5 microaxial flow device (MFD; Abiomed Inc., Danvers, MA, USA) is used to prevent hemodynamic instability during electrophysiologic study. However, electromagnetic interference (EMI) generated by this device can preclude accurate electroanatomic mapping.

METHODS

Impella was placed in the left ventricle of 7 canines for circulatory support. Electroanatomic mapping during sinus rhythm, ventricular pacing, and ventricular fibrillation (VF) was performed using magnet- (CARTO3, Biosense Webster Inc., Diamond Bar, CA, USA) and impedance- (EnSite Velocity System/EnSite NavX, St. Jude Medical Inc., St. Paul, MN, USA) based systems. Distance from device to points with severe EMI precluding acquisition was compared to points with mild/no EMI. Two methods were used to reduce EMI: (1) titration of MFD performance, and (2) impedance-only mapping combined with manual annotation of activation.

RESULTS

Severe EMI did not occur during impedance-based mapping. Severe EMI was observed using CARTO3 at 9.4% of all points attempted at maximum performance level (P8) of device. Severe EMI occurred at points closer to device (40.1 ± 16.8 mm) versus (55.5 ± 20.0 mm) for mild/no EMI, P < 0.0001. Severe EMI using CARTO3 was resolved by either (1) reduction of performance from P8 to P6 or (2) impedance-only mapping with manual annotation.

CONCLUSION

Concurrent use of MFD caused EMI to prevent acquisition of points with magnet-based mapping. Predictors for EMI were distance from device and performance level. Temporary reductions to P6 or impedance-only mapping are 2 methods to resolve EMI.