Altered Repolarization Reserve in Failing Rabbit Ventricular Myocytes: Calcium and β-Adrenergic Effects on Delayed- and Inward-Rectifier Potassium Currents.

ABSTRACT:

Background

Electrophysiological remodeling and increased susceptibility for cardiac arrhythmias are hallmarks of heart failure (HF). Ventricular action potential duration (APD) is typically prolonged in HF, with reduced repolarization reserve. However, underlying K⁺ current changes are often measured in nonphysiological conditions (voltage clamp, low pacing rates, cytosolic Ca²⁺ buffers).

Methods and results

We measured the major K⁺ currents (I_Kr, I_Ks, and I_K1) and their Ca²⁺- and β-adrenergic dependence in rabbit ventricular myocytes in chronic pressure/volume overload-induced HF (versus age-matched controls). APD was significantly prolonged only at lower pacing rates (0.2-1 Hz

SUBMITTER: Hegyi B 

PROVIDER: S-EPMC5813707 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature