[Cardiac magnetic resonance imaging with contrast enhancement in treatment of atrial fibrillation].

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.

[Novel class III antiarrhythmic agent niferidile: review of experimental and clinical studies].

This article reviews experimental and clinical studies of a novel antiarrhythmic agent niferidile. Niferidile, a class III antiarrhythmic agent, blocks potassium outward currents, prolongs repolarization and refractory periods predominantly in atria than in ventricles. Intravenous Niferidile was efficient for interruption of AV-nodal and orthodromic re-entrant tachycardias with rates of 75% to 80%. Niferidile had a conversion rate of up to 87.3% in persistent atrial fibrillation and up to 100% in persistent atrial flutter. Proarrhythmic action of niferidil administration manifested as nonsustained torsade de pointes and monomorphic ventricular tachycardia in 1.2 and 3.7% of cases, respectively. Niferidile can be used for pharmacological cardioversion of persistent atrial fibrillation and flutter as an alternative to electrical cardioversion.

[Electrophysiological effects and antiarrhythmic activity of novel domestic class III antiarrhythmogenic drug niferidil administered in patients with paroxismal supraventricular tachycardia].

Intracardiac electrophysiological effects and antiarrhythmic activity of novel domestic class III antiarrhythmogenic drug niferidil has been studied in a group of 25 patients with paroxismal supraventricular tachycardia (PSVT) diagnosis. The drug was administered in a dose of 20 mg/kg (i.v.). Niferidil injections increased the refractory periods in both right and left atrium (by 22 and 20%, respectively, p < 0.001), right ventricle (12%, p < 0.01), and the His-Purkinje system (34%, p < 0.001) and improved additional anterograde and retrograde conduction (by 22 and 31%, respectively, p < 0.001), while not influencing the conduction via excitable cardiac tissues. Elongation of the QTc interval (22%, p <0.05) in one case was accompanied by an arrythmogenic effect (induction of short-term polymorphous ventricular tachycardia of the "torsade de pointes" type. Niferidil arrested PSVT in 78% cases and prevented PSVT development in response to endocardial stimulation in 86% of patients.

[New class III antiarrhythmic drugs for treatment of atrial fibrillation].

Last two decades have been dedicated to intensive search for new class III antiarrhythmic drugs, especially for atrial fibrillation. Here we present a review of the status this problem. Influence on transmembranous ion currents and mechanisms of antiarrhythmic action are described. Results of experimental and clinical studies are reviewed. Possible perspectives of newest atrial-selective medications are discussed. Russia's class III antiarrhythmic drugs are of special interest of the article. First data on efficacy and safety of newest agent niferidil are presented. This drug undergoes clinical testing at present time.

[First experience of clinical use of new class III antiarrhythmic agent niferidil in patients with persistent atrial fibrillation and flutter].

The aim of the study was to evaluate the efficacy and safety of administered intravenously niferidil in doses 10, 20 and 30 mkg per kg in patients with persistent atrial fibrillation (AF) and flutter (AFL) for pharmacological cardioversion. The study included 30 patients (22 male) with persistent AF (n = 28) and AFL (n = 2) without structural heart diseases with median arrhythmia duration 6.1 +/- 4.8 months (2 weeks to 24 months). Niferidil was administered as 3 bolus injections (10 mkg per kg each) performed with the interval of 15 minutes. Antiarrhythmic efficacy of niferidil in dose of 10 mkg per kg was 60%, in dose of 20 mkg per kg it was 70%, and in dose of 30 mkg per kg reached 90% prespectively. The part of the patients, in whom QTc prolongation exceeded potentionally dangerous value of 500 mc, was 22.2% (6 of 27). None of the patients developed proarrhythmic side effect as torsade de pointes.

[The efficacy and safety of nibentan for pharmacological cardioversion in patients with persistent atrial fibrillation and flutter: the role of dose limitation and magnesium sulfate administration].

The aim of the study was to evaluate the influence of magnesium sulfate on the efficacy and safety of pharmacological cardioversion with nibentan (NB) in doses up to 0,125 mg/kg in patients with persistent atrial fibrillation (AF) and flutter (AFL). Calculated dose of NB was 0.125 mg/kg. It was administered as 2 bolus injections (0.0625 mg/kg each) performed with the interval of 15 minutes. The study included 64 patients (pts) (45 male, age 54+/-9,9 years) with persistent AF (n=56) and AFL (n=8) with median arrhythmia duration 6,7+/-6,8 months (8 days to 36 months). Pts were divided into two groups. In the first (I) group NB was used without preliminary magnesium sulfate administration, in the second group (II) magnesium sulfate was injected in a dose of 50 mg/kg, followed by 0.83 mg/kg/min infusion before NB administration. There was no difference between groups in conversion rates of atrial arrhythmias: 74% and 69%, in groups I and II, respectively (p>0.4). Mean effective dose of NB was the same in investigated groups - 0.09 mg/kg. Administration of initial dose of NB (0.0625 mg/kg) converted AF/AFL to sinus rhythm within 15-min interval in 29.7% of patients. Efficacy of full dose of NB (0.125 mg/kg) was 100% in AFL, 68% in AF. No side effects were registered after initial injection of 0.0625 mg/kg. After administration of 2 boluses (0.125 mg/kg) "torsade de pointes" developed in 2 pts (3%). Magnesium sulfate administration had no influence on NB efficacy and rate of its proarrhythmic events. Limitation of NB total dose to

[Dynamics of parameters of heart rate variability after radiofrequency ablation in patients with paroxysmal supraventricular tachycardia: holter ECG monitoring data].

Changes of parameters of heart rate variability (HRV) in patients with supraventricular tachycardia (SVT) immediately after radiofrequency ablation (RFA) have been demonstrated earlier. However dynamics of HRV parameters after RFA has not been sufficiently studied. For elucidation of dynamics of HRV parameters in patients with SVT after RFA we conducted analysis of HRV basing on data of 24 hour Holter ECG monitoring before RFA, on day 2, in 1 week and 1 month after intervention in 27 patients with paroxysmal SVT. Statistically significant lowering of temporal (SDNNi, RMSSD, NN50, pNN50) and spectral (VLF, LF, HF) HRV parameters were found on day 2 and in 1 week after RFA compared with data obtained before intervention. In 1 month after RFA the studied parameters of HRV did not differ from baseline values. Reversible changes of HRV parameters evidencing for transitory autonomic dysfunction are observed after RFA.

[Efficiency of antiarrhythmic therapy and resistance to it in patients with malignant ventricular tachyarrhythmias: formulation of prognosis]. / Effektivnost' antiaritmicheskoi terapii i refrakternost' k nei u bol'nykh so zlokachestvennymi zheludochkovymi takhiaritmiiami: postroenie prognoza.

AIM: To study feasibility of predicting results of drug antiarrhythmic therapy in patients with malignant ventricular arrhythmias (MVA) basing on the results of clinical and device examinations. MATERIALS AND METHODS: 136 patients with documented MVA entered the study. 100 patients were in the retrospective analysis group, 36 patients comprised the study group. All the patients underwent physical examination, resting ECG, chest x-ray, radionuclide ventriculography. Intracardiac electrophysiological examination, Holter 24-h ECG monitoring and bicycle exercise provided data for diagnosis of MVA and control over effects of antiarrhythmic drugs. The mathematical model was derived using discriminant analysis. RESULTS: Significant differences were obtained in patients with positive and negative results of drug testing by the number and recurrence time of ventricular tachycardia (VT) for 3 years, survival, cardiac and sudden death, some other parameters. A mathematic model has been designed which allows prognosis of the results of antiarrhythmic therapy (AAT) in patients with MVA. 7 independent predictors of AAT efficiency are shown: left ventricular ejection fraction, duration of P-Q interval, cardiac failure, left ventricular aneurysm, age, number of VT morphologies, insufficiency of aortic valve. Verification of the model on the study group patients showed that prognostic accuracy of the model was 82%. CONCLUSION: The results of the drug tests predict life span of MVA patients. The developed mathematical model allows prediction of AAT results in such patients before the pharmacological test with accuracy 82-87%. The model can help objectivize indications to use of non-pharmacological methods for each patient basing on prognosis of resistance to drug AAT.

[The first original Russian class-III antiarrhythmic nibentan]. / Pervyi original'nyi otechestvennyi antiaritmik III klassa nibentan.

The paper presents experimental and clinical findings of the new antiarrhythmic drug nibentan. The agent was found to be a class-III antiarrhythmic agent in terms of its electrophysiological effects and an inhibitor of the delayed rectifier potassium current in terms of its effects on the ionic channels of cardiomyocytes. The clinical trial of nibentan shows that the drug is highly effective (in 70-100% of cases) in patients with atrial flutter and fibrillation and in those with supraventricular tachycardia and it is less effective in suppressing ventricular premature contractions and tachycardia. The rate of arrhythmogenic effects produced by the drug was inversely related to its antiarrhythmic action. Nibentan has been approved for clinical use.

[Permanent repetitive nonparoxysmal ventricular tachycardia. I. The electrocardiographic manifestations and possible mechanisms of its occurrence]. / Nepreryvno retsidiviruiushchaia neparoksizmal'naia zheludochkovaia takhikardiia. Soobshchenie I. Elektrokardiograficheskie proiavleniia i vozmozhnye mekhanizmy vozniknoveniia.

A total of 20 patients (16 males and 4 females) with repetitive nonparoxysmal ventricular tachycardia (RNVT) underwent Holter monitoring of ECG, bicycle exercise test, intracardiac electrophysiological measurements. The findings evidence for a principal difference of this tachycardia form from paroxysmal ventricular tachycardia by trigger mechanism. All the tests performed showed rhythm-dependence of RNVT, tachycardia cannot be initiated by electrocardiostimulation, but can be stopped after intravenous introduction of finoptin. It is evident that this form of cardiac arrhythmia is due to the mechanism of pathological ectopic automatism represented, most likely, by trigger activity, but not re-entry, as it is in the majority of patients with paroxysmal ventricular tachycardia.

[Permanent repetitive nonparoxysmal ventricular tachycardia. II. The results of using anti-arrhythmia preparations and the characteristics of its long-term course]. / Nepreryvno retsidiviruiushchaia neparoksizmal'naia zheludochkovaia takhikardiia. Soobshchenie II. Rezul'taty primeneniia antiaritmicheskikh preparatov i osobennosti dlitel'nogo techeniia.

A total of 20 patients with repetitive nonparoxysmal ventricular tachycardia (RNVT) underwent Holter ECG monitoring to test efficacy of successive oral antiarrhythmic drugs. The response was recorded in 50% of the patients. Although the effect of the drugs persisted for a few months only, RNVT ran without severe symptoms, in contrast to paroxysmal ventricular tachycardia. Long-term course of RNVT is characterized by dilatation of the left ventricular compartment under increasing ejection fraction and absence of cardiac insufficiency. A close relationship exists between the end-diastolic volume, ejection fraction of the left ventricle and RNVT duration. This is attributed to heart adaptation to long-term activity in the conditions of tachycardia.