key: cord-0880984-ntugabm7
authors: Geiger, Robert M.; Klein, Michael G.; Fatima, Naheed; Goldstein, Robert E.; Krantz, Mori J.; Haigney, Mark C.; Flagg, Thomas P.
title: Rapid Assessment of Proarrhythmic Potential Using Human iPSC-Derived Cardiomyocytes
date: 2020-12-24
journal: JACC Clin Electrophysiol
DOI: 10.1016/j.jacep.2020.08.034
sha: 535a9f6dacf05c332c865bb409da18edfed872b2
doc_id: 880984
cord_uid: ntugabm7

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The extracellular field potential duration and amplitude of the early spike (P Max ) reflect the mean action potential duration and sodium (Na) conductance, respectively, analogous to the QT interval and QRS complex assessed in a surface electrocardiogram. We also measured the local extracellular action potential FPD over a similar range of concentrations, as did azithromycin, but with 4-fold lower sensitivity.

Although hydroxychloroquine-dependent block of potassium channels received the most attention, we also observed a decrease in the depolarization spike amplitude by hydroxychloroquine and azithromycin (P Max ) ( Figure 1C) , which suggested that both drugs also inhibit depolarizing I Na or I Ca equally. Proarrhythmic activity was also observed in LEAP recordings during prolonged exposure ( Figure 1D ). 

Where's the Scar?

We read with great interest the paper by Boukens 

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