Hypokalemia promotes late phase 3 early afterdepolarization and recurrent ventricular fibrillation during isoproterenol infusion in Langendorff perfused rabbit ventricles.

ABSTRACT:

Background

Hypokalemia and sympathetic activation are commonly associated with electrical storm (ES) in normal and diseased hearts. The mechanisms remain unclear.

Objective

The purpose of this study was to test the hypothesis that late phase 3 early afterdepolarization (EAD) induced by IKATP activation underlies the mechanisms of ES during isoproterenol infusion and hypokalemia.

Methods

Intracellular calcium (Cai) and membrane voltage were optically mapped in 32 Langendorff-perfused normal rabbit hearts.

Results

Repeated episodes of electrically induced ventricular fibrillation (VF) at baseline did not result in spontaneous VF (SVF). During isoproterenol infusion, SVF occurred in 1 of 15 hearts (7%) studied in normal extracellular potassium ([K(+)]o, 4.5 mmol/L

SUBMITTER: Maruyama M 

PROVIDER: S-EPMC3996562 | biostudies-literature | 2014 Apr

REPOSITORIES: biostudies-literature