Cryoballoon ablation using the sheath-in-sheath technique in a patient with a tortuous common iliac vein.

The sheath-in-sheath technique, utilizing a 15Fr cryoballoon delivery sheath inserted into a 25 cm 16Fr sheath, effectively navigates tortuous iliac veins during cryoballoon ablation for atrial fibrillation, ensuring safe delivery and maintaining essential device performance without complications.