Electrocardiogram QRS Complex Duration as a Predictor of Hospital Prognosis in Patients With COVID-19.

Aim      To determine the effect of major electrocardiographic (ECG) parameters on the prognosis of patients with COVID-19.Material and methods  One of systemic manifestations of COVID-19 is heart injury. ECG is the most simple and available method for diagnosing the heart injury, which influences the therapeutic approach. This study included 174 hospitalized patients with COVID-19. Major ECG parameters recorded on admission and their changes before the discharge from the hospital or death of the patient, were analyzed, and the effect of each parameter on the in-hospital prognosis was determined. Results were compared with the left ventricular ejection fraction (LV EF), laboratory data, and results of multispiral computed tomography (MSCT) of the lungs.Results ECG data differed on admission and their changes differed for deceased and discharged patients. Of special interest was the effect of the QRS complex duration at baseline and at the end of treatment on the in-hospital survival and mortality rate. The Cox regression analysis showed that the QRS complex duration (relative risk (RR) 2.07, 95% confidence interval (CI): 1.17-3.66; р=0.01), MSCT data (RR, 1.54; 95 % CI: 1.14-2.092; р=0.005), and glomerular filtration rate (GFR) (RR, 0.98; 95 % CI: 0.96-0.99; р=0.001) had the highest predictive significance. In further comparison of these three indexes, the QRS duration and GFR retained their predictive significance, and a ROC analysis showed that the cut-off QRS complex duration was 125 ms (р=0.001). Patients who developed left bundle branch block (LBBB) in the course of disease also had an unfavorable prognosis compared to other intraventricular conduction disorders (р=0.038). The presence of LBBB was associated with reduced LV EF (р=0.0078). The presence of atrial fibrillation (AF) significantly predetermines a worse outcome both at the start (р=0.011) and at the end of observation (р=0.034). A higher mortality was observed for the group of deceased patients with ST segment deviations, ST elevation (р=0.0059) and ST depression (р=0.028).Conclusion      Thus, the QTc interval elongation, LBBB that developed during the treatment, AF, and increased QRS complex duration are the indicators that determine the in-hospital prognosis of patients with COVID-19. The strongest electrocardiographic predictor for an unfavorable prognosis was the QRS complex duration that allowed stratification of patients to groups of risk.

Extracellular GC-rich DNA activates TLR9- and NF-kB-dependent signaling pathways in human adipose-derived mesenchymal stem cells (haMSCs).

INTRODUCTION: The content of GC-rich ribosomal repeats (rDNA) in cell-free DNA (cfDNA) of patients with various diseases is several times higher as compared with genomic DNA (gDNA) and cfDNA of healthy donors. rDNA may act as Toll-like receptor 9 (TLR9) ligands and affect human adipose-derived mesenchymal stem cells (haMSCs). Here we explore effects of human cfDNAs and model rDNA fragments on cultured haMSCs. AREAS COVERED: Both cfDNAs and cloned rDNA stimulate expression of TLR9 (qRT-PCR). Treatment with cloned rDNA leads to an increase in the number of TLR9(+) cells (FACS), expression levels for both TLR9 and Myd88, the translocation of nuclear factor-kappa B to the nuclei and up-regulation of TNFα and IL-10 cytokines (ELISA). As shown by an analysis of γH2AX-foci and MTT test, the preconditioning of haMSCs with cloned rDNA fragment increases the resistance of these cells to irradiation at 2Gy, while the treatments with control gDNA did not stimulate either TLR9- or NF-kB-dependent signaling pathways. EXPERT OPINION: GC-rich sequences present in cfDNA stimulate endogenous stems cells when body is exposed to adverse conditions. GC-rich fragments of human DNA may be used for preconditioning of therapeutic MSCs aiming at an increase in their survival in the ailing body.