Despite evolving success of mini-invasive techniques in treating cardiac arrhythmias in children, pharmaceuticals remain the cornerstone therapeutic option. Beyond conventional antiarrhythmic agents such as amiodarone, local anesthetics, tranquilizers, anticonvulsants, and neuroleptics exhibit antiarrhythmic properties. H(1)-histamine receptor blockers are widely used in treating allergies in children. Observational studies suggest efficacy of these agents for treating or preventing tachyarrhythmias, although prolongation of QT interval, and ventricular arrhythmias occur. We determined safety and efficacy of antihistamine, quifenadine, versus conventional amiodarone on cardiac rhythm in children with frequent premature beats (PB). One hundred and four patients (mean age 10.8 +/- 3.2 years) with ventricular (n = 65), supraventricular (n = 39) PB were randomized 1:1 to quifenadine (2 mg kg(-1) day(-1); n = 54), or amiodarone (9 mg kg(-1) day(-1), n = 50) arms. Both groups were treated for 2 weeks. All patients underwent 24-hour Holter monitoring 3 times: before at 14-28 days after randomization, and during the follow up at 2-3 months. The mean frequency of PB in quifenadine group was 562 +/- 61 per hour and 597 +/- 78 per hour in the amiodarone-treated children. Full antiarrhythmic efficacy (PB < 75% from baseline) has been achieved in 23/54 (43%) of quifenadine-treated patients, which was less than after amiodarone treatment (37/50, 74%, P = 0.02). Quifenadine was mostly beneficial in children with supraventricular PB and/or bradycardia than in those with ventricular PB; it was associated with a trend toward increased heart rate during day (88.5 +/- 8.4 beats/min) and night (67.3 +/- 6.2) compared with amiodarone (79.6 +/- 7.8 and 56.1 +/- 5.7 beats/min, respectively; P = 0.04). The incidence of side effects in quifenadine group (drowsiness and headache) was low (2%) in contrast to the alarming 40% risk associated with amiodarone therapy. Quifanidine exhibits antiarrhythmic activity in children with frequent PB, without significant QT prolongation, or sinus node depression. Although, H(1)-histamine receptor blocker is less potent than amiodarone, much better safety profile of quifenadine is advantageous, especially in children. Future large trials with proving novel antihistamines pleiotropy are warranted.

Despite the mass population immunization, the total spread of the COVID-19 pandemic once again made scientists around the world doubt the effectiveness of currently existing methods of prevention and treatment of a novel coronavirus infection. The rationale for a potentially new approach to the preventive therapy of COVID-19 using probiotic bacterial strains was the presence of a bidirectional “gut-lung” axis, which interacts between these organs through transported soluble microbial metabolites in blood. The study aimed to determine the relationship between the correction of the gut microbiota with the polycomponent synbiotic Maxilac® and clinical and laboratory markers of the severity of the new coronavirus infection. During the open-label, prospective, observational study 60 patients with a confirmed diagnosis of COVID-19, a moderate severity and the presence of gastrointestinal symptoms were divided into 2 groups: the 1st performed the outpatient complex standard treatment with the addition of synbiotic, the 2nd - without addition. All patients of group 1 showed positive dynamics of clinical and laboratory indicators of COVID-19 severity, compared with group 2, where 2 patients needed hospitalization due to the aggravation of the course of novel coronavirus infection. A reduction in the duration of clinical symptoms and the duration of outpatient treatment was revealed in a group of patients taking Maxilac®. The dynamics of clinical and laboratory indicators reflecting the course of COVID-19 indicate the effectiveness of symbiotic’s usage as adjuvant therapy and the possibility of recommending its use in the complex treatment of patients with a novel coronavirus infection.