Paradoxical generator impedance behavior during catheter ablation in a patient with severe polycythemia

Abstract

An extremely high generator impedance in the blood pool can be observed in a patient with severe polycythemia. However, ablation can be performed safely as long as the generator impedance during contact with the myocardial tissue is within acceptable limits.

Keywords: Ebstein's anomaly; atrial flutter; congenital heart disease; generator impedance; polycythemia.

FIGURE 1

A schema of the great vessels and cardiac chambers after the last operation. The % values mean the oxygen saturation of each chamber and vessel acquired after the ablation procedure under 35% of FiO₂. ASD, atrial septum defect; IVC, inferior vena cava; LPA, left pulmonary artery; RPA, right pulmonary artery; RPV, right pulmonary vein; SVC, superior vena cava; TV, tricuspid valve.

FIGURE 2

(A) Snapshots from the video during the atrial flutter mapping. Upper panel: The catheter tip is in the blood pool (0 g of contact force, 261 ohms of GI). Lower panel: The catheter tip contacting the CTI area (9 g of contact force, 156 ohms of GI). (B) The activation maps (coherent map) of the atrial flutter. The atrial flutter presented a counter‐clockwise activation pattern around the closed TV (dotted arrow). (C) The voltage maps of the atrial flutter. The maps showed scars in the closed TV and incisioned right atrial free wall. CF, contact force; CTI, cavotricuspid isthmus; GI, generator impedance; IVC, inferior vena cava; PPI, post‐pacing interval; TCL, tachycardia cycle length; TV, tricuspid valve.

FIGURE 3

Generator impedance and contact force behavior during the ablation at the top of the Eustachian ridge. Left panel: Catheter position. Right panel: Graphs of generator impedance (green), contact force (blue), power (yellow), and temperature (red).