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Aim      Evaluating the efficacy and safety of early administration of antirecurrence antiarrhythmic therapy (AAT) following restoration of sinus rhythm (SR) with refralon.Aim      Evaluating the efficacy and safety of early administration of antirecurrence antiarrhythmic therapy (AAT) following restoration of sinus rhythm (SR) with refralon.Material and methods  The study included 247 patients with atrial fibrillation/atrial flutter (AF/AFL) (142 men) who underwent pharmacological cardioversion (PCV) with refralon. A 4-step schedule of drug administration was used (successive intravenous infusions at doses of 5, 5, 10, and 10 µg/kg; maximum total dose was 30 µg/kg). Patients who recovered SR and had no contraindications were prescribed antirecurrence AAT in the early (≤24 h; n=101) or delayed (≥24 h; n=95) period. Lappaconitine hydrobromide, propafenone, and sotalol were administered orally as the antirecurrence therapy. The decision on the time of initiating ATT and the choice of the drug and its dose was taken by the attending physician individually. The safety criteria included a prolonged PQ interval >200 ms; second- or third-degree atrioventricular block; QRS complex duration >120 ms; QT prolongation >500 ms; and heartbeat pauses >3 s. The efficacy criteria included the absence of sustained recurrence of AF/AFL after initiation of AAT and the duration of hospitalization after PCV. Patients were followed up during the study until they were discharged from the hospital.Results SR was recovered in 229 (92.7 %) patients. In the group of early AAT initiation, a PQ duration >200 ms was observed in 8 (7.9 %) patients, whereas in the group of delayed AAT initiation, in 7 patients (7.4 %; p=1.000). A wide QRS complex >120 ms was recorded in 1 (1.1 %) patient of the delayed AAT initiation group and in none of the patients of the early AAT initiation group (p=0.485). Ventricular arrhythmogenic effects and QT prolongation >500 ms were not detected in any patient. Numbers of early AF recurrence did not differ in the groups of early and delayed AAT initiation: 6 (5.9 %) vs. 5 (5.3 %), respectively (p=1.000). Median duration of hospitalization after PCV was 4 days in the group of early AAT initiation and 5 days in the group of delayed AAT initiation (р=0.009).Conclusion      Early initiation of the refralon AAT does not increase the risk of drug adverse effects and reduces the duration of stay in the hospital.

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We studied the frequency dependence of the effects of the novel Russian class III antiarrhythmic drug refralon on the duration of action potentials (AP) in rabbit ventricular myocardium. The absence of an inverse frequency dependence of AP prolongation was demonstrated: the effects of refralon at stimulation frequency of 1 Hz were stronger than at 0.1 Hz. The patch-clamp experiments with recording of rapid delayed rectifier potassium current IKr in a heterologous expression system showed that the blocking effect of refralon developed significantly faster at 2 Hz depolarization frequency than at 0.2 Hz. This feature of refralon distinguishes it among the majority of other class III drugs (sotalol, dofetilide, E-4031) and explains the relatively high safety of this drug together with its high efficacy.

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Catheter ablation is presently the main method for interventional treatment of atrial fibrillation (AF). Despite improvements of the method and accumulation of personnel's experience, incidence of recurrent AF following catheter interventions remains high. This review addresses a possibility of using contrast-enhanced cardiac magnetic resonance imaging to increase the effectiveness of interventional treatment of arrhythmia.

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PURPOSE: to assess cardiac electrophysiological parameters in patients with paroxysmal atrial fibrillation (AF), lone or with concomitant arterial hypertension (AH), and their prognostic significance relative to treatment effectiveness. MATERIALS AND METHODS: We included in this study 184 patients with paroxysmal AF (84 with concomitant AH and 100 with presumed lone AF). Cardiac electrophysiological study was performed in accordance with standardized protocol that included assessment of sinus node recovery time, sinoatrial, intraatrial and interatrial conduction time, and effective refractory periods (ERP) of right and left atria and atrioventricular node. Patients with inducible supraventricular reentrant arrhythmias that could potentially trigger AF underwent catheter radiofrequency ablation of those arrhythmias. Other patients received either antiarrhythmic drug therapy (AAD; n=79) or catheter cryo-ablation (CBA; n=81). Treatment was considered ineffective in case of any symptomatic or asymptomatic AF episode documented by ECG or Holter ECG within 12 months of follow-up. RESULTS: Patients with lone AF compared with those with AH had shorter ERP of the right atrium (219±21 ms vs. 253±44 ms, respectively, p<0.05) and more prominent dispersion of ERP of right and left atria (median 40 ms, interquartile range 10-50 ms vs. median 20 ms, interquartile range 10-22.5 ms, respectively, p<0.05). There was no statistically significant difference in other electrophysiology parameters between the groups. Sustained supraventricular reentrant arrhythmias were induced in 9% (9 of 100) patients with presumed lone AF and in 1.2% (1 of 84) patients with AH (p<0.05). All these arrhythmias were successfully ablated, and patients had no AF recurrence during 12-month follow-up. Among other patient treatment (CBA n=81, AAD n=79) was effective in 64% of those with lone AFib and in 34% - with AH (p<0.05). In multivariate multiple regression analysis, none of electrophysiological parameters could be assumed as a factor associated with the efficacy of CBA or AAD. CONCLUSION: Patients with lone AF had more prominent atrial electrophysiological inhomogeneity compared with patients with concomitant AH. Cardiac electrophysiological parameters had no influence on effectiveness of antiarrhythmic treatment.

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In this brief review we focus on major updates and key points of 2017 American Heart Association/American College of Cardiology/Heart Rhythm Society (AHA/ACC/HRS) guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death.

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Abnormalities in cardiac conduction can occur due to a variety of factors. So called "idiopathic", conduction system degeneration develops without evident causes and may have hereditary basis. In the majority of cases it has no clinical manifestation, do not require treatment and have overall good prognosis. In this review we focus on congenital complete atrioventricular block and progressive cardiac conduction defect - rare but malignant and potentially lethal conditions that can be caused by genetic mutations and may be isolated or associated with structural heart disease. Cardiac involvement is relatively common in rare hereditary diseases - myodystrophies and mitochondrial cytopathies. Conduction abnormalities are among the most severe manifestations that may determine prognosis in these rare genetic disorders. These conditions deserve special consideration because of rapid progression of conduction defects and high prevalence of sudden cardiac death if no appropriate treatment applied.

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AIM: To evaluate the efficacy and safety of refralon (niferidil), a new class III antiarrhythmic agent whose activity is related to the block of delayed rectifying potassium current and to the prolongation of atrial and ventricular action potential and refractory periods, when it is used as an agent for pharmacological cardioversion for atrial fibrillation (AF) and atrial flutter (AFL). SUBJECTS AND METHODS: The efficacy of the drug as 3 intravenous boluses of 10 µg/kg was evaluated in 134 patients (90 men; 57.8 ± 11 years) with a mean AF duration of 3 (1.5; 6) months. Its effect was controlled by 24-hour Holter ECG monitoring. The criterion for its antiarrhythmic effect was 24-hour sinus rhythm (SR) recovery. RESULTS: Niferidil restored SR in 47.7% of the patients with AF after administration of bolus 1, in 62% after bolus 2, and in 84.6% after bolus 3. SR was restored in all 100% patients with AFL. With the AF duration of less than 3 months, the efficacy of niferidil was 91.8%. There was nonsustained polymorphic ventricular tachycardia (VT) (torsade de pointes) in 1 (0.7%) patient and nonsustained monomorphic VT was stated in 5 (3.7%) patients. CONCLUSION> Pharmacological cardioversion with niferidil for persistent AF and VT may be regarded as a possible alternative to electrical cardioversion.

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We report a case of bundle-branch reentrant ventricular tachycardia as a first and severe manifestation of myotonic dystrophy. Progressive cardiac conduction disturbances and cardiac arrhythmias are well-known features of myotonic dystrophy, although they are commonly found in late stage of disease in patients with established diagnosis. We review clinical manifestations, diagnostics, management, and prognostic value of cardiac involvement in myotonic dystrophy.

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