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Implantation of cardioverter defibrillators with minimal fluoroscopy using a three-dimensional navigation system: a feasibility study.

AIMS
Fluoroscopy is necessary to implant cardioverter defibrillators using the conventional approach. Modern electroanatomic navigation systems allow the visualization of multiple catheters and, as they are capable of rendering precise geometrical reconstructions of cardiac chambers, have been used for fluoroscopy-free electrophysiological procedures. The aim of our study was to assess the feasibility of non-fluoroscopic implants using a three-dimensional navigation system.


METHODS AND RESULTS
The NavX system was used to create the virtual anatomies of heart chambers and thoracic veins. Defibrillator leads were placed at stable positions using exclusively the electrical and anatomical information provided by the navigator. A single fluoroscopy shot confirmed final lead positions. Thirty-five consecutive patients had 30 single-chamber and 5 dual-chamber defibrillators implanted. Cardiac chambers geometries were developed in 10 ± 4.3 min. Ventricular and atrial leads were implanted, with suitable positions and electrical parameters being achieved, in 18 ± 22 and 16 ± 9 min, respectively. The final confirmatory shot was the only fluoroscopy needed in 31 (89%) cases. Two patients needed fluoroscopy-guided relocation of the ventricular lead due to high defibrillation threshold and a breakdown of the active-fixation mechanism, respectively. In one patient the ventricular lead was totally extracted and reimplanted because a loop has formed in the vena cava, and one patient required fluoroscopy-guided subclavian puncture. In five cases (16%), the position of the proximal defibrillation coil was minimally modified with fluoroscopy due to incomplete geometric reconstruction of the superior vena cava.


CONCLUSION
Fluoroscopy-free defibrillators implantation is feasible using a navigation system. Suitable placement of the proximal coil is a critical stage and requires a reliable and complete reconstruction of the superior vena cava.