Altered Repolarization Reserve in Failing Rabbit Ventricular Myocytes: Calcium and Beta-adrenergic Effects on Delayed and Inward Rectifier Potassium Currents

摘要

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