Response to Letter Regarding Article, "Upregulation of K2P3.1 K+ Current Causes Action Potential Shortening in Patients With Chronic Atrial Fibrillation".

We thank Dr Olschewski and colleagues for their interest in our article,1 and we appreciate their recapitulation of 2 key findings of our work: (1) the identification of increased atrial K2P3.1 (TASK-1) K+ channel expression, I K2P3.1 upregulation, and action potential shortening as substrate in patients with chronic atrial fibrillation (AF); and (2) the presentation of K2P3.1 current inhibition and resulting action potential prolongation as mechanism-based therapeutic paradigm in this subentity of the arrhythmia. Our study focused on the mechanistic contribution of K2P3.1 channels to human atrial electrophysiology and action potential regulation, with particular emphasis on pathophysiological dysregulation in AF. Based on mechanistic data presented in the study, functional correction of atrial ionic remodeling through the suppression of atrial K2P3.1 current emerged as a novel antiarrhythmic option for AF management. We agree with Olschewski et al that efficacy and safety require in-depth preclinical evaluation before transfer of novel therapeutic principles into human application. In their letter, the authors highlight their findings of K2P3.1 expression and functional …