title: The Major Role ofIK1in Mechanisms of Rotor Drift in the Atria: A Computational Study.
abstract: Maintenance of paroxysmal atrial fibrillation (AF) by fast rotors in the left atrium (LA) or at the pulmonary veins (PVs) is not fully understood. This review describes the role of the heterogeneous distribution of transmembrane currents in the PVs and LA junction (PV-LAJ) in the localization of rotors in the PVs. Experimentally observed heterogeneities inIK1,IKs,IKr,Ito, andICaLin the PV-LAJ were incorporated into models of human atrial kinetics to simulate various conditions and investigate rotor drifting mechanisms. Spatial gradients in the currents resulted in shorter action potential duration, less negative minimum diastolic potential, slower upstroke and conduction velocity for rotors in the PV region than in the LA. Rotors under such conditions drifted toward the PV and stabilized at the less excitable region. Our simulations suggest thatIK1heterogeneity is dominant in determining the drift direction through its impact on the excitability gradient. These results provide a novel framework for understanding the complex dynamics of rotors in AF.
authors.affiliation: Center for Arrhythmia Research, Internal Medicine and Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Omer
authors.initials: O
authors.lastname: Berenfeld
keywords: atrial fibrillation; computer modeling; drift; ionic currents; rotors