Precipitating factors of bradycardia after remdesivir administration: ICU admission and cutoff value for declining heart rate.

BACKGROUND: Despite increasing concerns about the association between remdesivir and bradycardia in severe coronavirus disease 2019 (COVID-19) patients receiving remdesivir, information on its clinical course and precipitating factors is limited. Our aim was to investigate possible triggers of bradycardia after remdesivir administration. METHODS: We retrieved the medical records of hospitalized severe and critical COVID-19 patients who received remdesivir from May 1, 2021 to June 30, 2021. Bradycardia was defined as two episodes of a heart rate (HR) < 60 bpm in 24 h. Receiver operating characteristic (ROC) curve analysis was conducted to evaluate the discriminability of heart rate pattern on the occurrence of bradycardia. The precipitating factors of bradycardia were examined by a logistic regression model. RESULTS: Regardless of bradycardia status, the median heart rate dropped during remdesivir treatment (from 85 to 72 bpm, p < 0.001), with the heart rate dropping considerably within the first two days of remdesivir treatment. Among various heart rate descriptors, HR ratiomin (d2-d1) had the best discrimination (AUC = 0.7336), and a reduction in HR ratiomin (d2-d1) by 14.65% was associated with bradycardia. Intensive care unit (ICU) admission was associated with an increased risk of bradycardia (odds ratio: 3.41; 95% CI: 1.12-10.41). CONCLUSIONS: In severe COVID-19 patients receiving remdesivir, the risks of bradycardia were influenced by a substantial reduction in heart rate during the first two days of remdesivir treatment and ICU admission. These findings suggest that clinical practitioners should intensively monitor heart rates during remdesivir treatment.

Molecular Doping Inhibits Charge Trapping in Low-Temperature-Processed ZnO toward Flexible Organic Solar Cells.

There has been a growing interest in the development of efficient flexible organic solar cells (OSCs) due to their unique capacity to provide energy sources for flexible electronics. To this end, it is required to design a compatible interlayer with low processing temperature and high electronic quality. In this work, we present that the electronic quality of the ZnO interlayer fabricated from a low-temperature (130 °C) sol-gel method can be significantly improved by doping an organic small molecule, TPT-S. The doped TPT-S, on the one hand, passivates uncoordinated Zn-related defects by forming N-Zn bonds. On the other hand, photoinduced charge transfer from TPT-S to ZnO is confirmed, which further fills up electron-deficient trap states. This renders ZnO improved electron transport capability and reduced charge recombination. By illuminating devices with square light pulses of varying intensities, we also reveal that an unfavorable charge trapping/detrapping process observed in low-temperature-processed devices is significantly inhibited after TPT-S doping. OSCs based on PBDB-T-2F:IT-4F with ZnO:TPT-S being the cathode interlayer yield efficiencies of 12.62 and 11.33% on rigid and flexible substrates, respectively. These observations convey the practicality of such hybrid ZnO in high-performance flexible devices.