Effect of amiodarone on the isthmus between V. cava inf. and tricuspid valve annulus in patients with atrial flutter. Skinner JR, Hebe J, Volkmer M, Ouyang F, Braun E, Cappato R, Siebels J, Kuck KH (1997) Z. Kardiol. 86 Suppl. 2: 12   The effects of i.v. amiodarone on the isthmus between the vena cava inferior and the tricuspid valve annulus were studied in 5 patients with atrial flutter. In contrast to patients not given antiarrhythmic therapy, in 4/5 patients given chronic amiodarone there was a displacement of conduction in the posterior isthmus.