Circulation. Arrhythmia and electrophysiology, Volume 11, Issue 2, 1 1 2018, Pages e006130 Response by Feola et al to Letter Regarding Article, "Localized Optogenetic Targeting of Rotors in Atrial Cardiomyocyte Monolayers". Feola I, Volkers L, Majumder R, Teplenin A, Schalij MJ, Panfilov AV, de Vries AAF, Pijnappels DA