[Comparative efficacy and safety of enoxaparin followed by warfarin and rivaroxaban monotherapy in the treatment of venous thrombosis in patients after intracardiac catheter interventions].

AIM: to compare two anticoagulant therapy (ACT) regimens in the treatment of venous thrombosis (VT) in patients after catheter interventions - electrophysiological studies (EFIs) and ablations: enoxaparin followed by warfarin, and rivaroxaban monotherapy. MATERIALS AND METHODS: The study included patients from 18 years and older with heart rhythm disorders and planned catheter ablation. When parietal venous thrombosis (VT) were detected at the femoral vein puncture site, all patients were randomly assigned to two treatment groups. In group I enoxaparin 1 mg/kg was prescribed every 12 hours with switching to warfarin after 7 days with maintenance of the target INR values (2.0-3.0). In group II rivaroxaban therapy was started at a dose of 15 mg twise/day for 21 days with a further transition to a dose of 20 mg/day. The total period of observation and treatment of patients was at least 3 months. RESULTS: 408 patients were observed, 42 (10.3%) patients with parietal VT were divided into two treatment groups. In group I (n=16) complete lysis of VT was noted by the 7th day of treatment in 7 (58.3%) patients, however this scheme was associated with a greater risk of complications (р=0.003) at the puncture site in the form of arteriovenous fistulae (n=1; 8.3%) and intermuscular hematomas (n=4; 25%). In group II (n=26), no complications were noted, the lysis time of VT was on average 21 days (n=18; 69.2%). Complete lysis of VT was noted in both groups at the time of the control observation point (3rd month). CONCLUSION: The efficiency of the two VT treatment regimens was comparable. Enoxaparin therapy is associated with a high risk of local complications, namely intermuscular hematomas (n=4; 25%) and arteriovenous fistulas (n=1; 8.3%). Rivaroxaban monotherapy is safer (p=0.003); in Group II none of the patients had any complications.

[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.

[Successful midodrin treatment for vasovagal syncopes accompanied by asystole]. / Uspechnoe lechenie midodrinom vazovagal'nykh obmorokov, protekaiushchikh s asistoliei.

Vasovagal syncopes (WS) are fainting fits whose manifestations are systemic vasodilation and bradycardia. The development of WS is frequently accompanied by short-term cardiac arrest. Recent data show that implantation of a cardiac pacemaker fails to prevent the development of fainting fits in these patients. On the basis of the pathogenesis of WS, the use of alpha-adrenomimetic midodrine is justifiable. The presented case demonstrates the successful use of the agent in the treatment of vasovagal syncope accompanied by asystole.

[Electrophysiological experimental study of a novel class III antiarrhythmic drug RG-2]. / Eksperimental'noe élektrofiziologicheskoe issledovanie preparata III klassa RG-2.

The electrophysiologic effects of a new drug, RG-2 were studied on anesthetized open-chest dogs and on rabbit right atrial tissue. RG-2 was manufactured in Chemical-Pharmaceutical Institute in Moscow. Dogs (n=12) were anesthetized with sodium pentobarbital (30 mg/kg, i.v.). An ECG lead II, arterial blood pressure, His bundle electrogram, atrial and ventricular bipolar electrograms were continuously monitored, recorded and then analyzed by a computerized complex for electrophysiological study. Electrophysiological variables, ECG parameters, atrioventricular conduction (His electrogram) and blood pressure were determined after sequential i.v. administration of 1, 5, 10, 20, 40 and 80 ug/kg of RG-2. Interval between injections was 60 min. RG-2 had no significant effect on PQ, QRS, S-A, A-H and H-V intervals, but the drug caused dose-dependent increase of R-R and QT intervals. Moreover, RG-2 dose-dependently increased the atrial and ventricular effective refractory periods (AERP and VERP). Maximal increases of AERP and VERP registered at 5 min after administration of RG-2 (40 microg/kg) were 46+/-2% (p<0.001 vs control) and 23+/-6% (p<0.05 vs control), respectively. In the isolated rabbit right atrial tissue RG-2 (0.01 to 1 microM) had no effects on maximal diastolic potential, action potential amplitude and Vmax, but revealed concentration-dependent increase of action potential duration at 90% repolarization level (APD90%). The maximal effects on APD90% obtained after RG superfusion at 1 microM were 26+/-7% (p<0.001 vs control). We conclude that RG-2 has significant effects of class III antiarrhythmic drugs in vivo and in vitro.

[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.

[A comparison of the results of endocardial and transesophageal electrostimulation of the heart in assessing sinus node function and atrioventricular conduction]. / Sravnenie rezul'tatov éndokardial'noi i chrespishchevodnoi élektrostimuliatsii serdtsa pri otsenke funktsii sinusovogo uzla i predserdno-zheludochkovogo provedeniia.

Forty five patients with cardiac arrhythmias were included in this study (20 had paroxysmal atrial fibrillation, 19, supraventricular tachycardias; 11 had sick sinus syndrome). In all patients endocardial electrophysiological study and transesophageal atrial pacing were performed in order to study sinus node function and atrioventricular conduction. The results of two methods of investigation have a high correlation. Quantitative criteria were developed for defining normal parameters of sinus node function and atrioventricular conduction during transesophageal atrial pacing.

[Potentials and limits of transesophageal electrical stimulation of the heart in diagnosing supraventricular tachyarrhythmias]. / Vozmozhnosti i ogranicheniia chrespishchevodnoi élektricheskoi stimuliatsii serdtsa v diagnostike nadzheludochkovykh takhiaritmii.

The results of intracardiac electrophysiological examination were compared to those of transesophageal electrostimulation of the left atrium in combination with the recording of its electrical activity in 48 patients with paroxysms of reciprocal supraventricular tachycardia and in 28 patients with paroxysms of ciliary arrhythmia. In order to diagnose a form of tachyarrhythmia using the latter method some criteria were revealed. Transesophageal electrostimulation of the left atrium was shown to be quite an informative method to be widely used in clinical practice for the diagnosis of paroxysmal supraventricular tachyarrhythmia.

[Method of evaluating antiarrhythmic therapy in patients with paroxysms of supraventricular tachycardia]. / Sposob otsenki antiaritmicheskoi terapii u bol'nykh s paroksizmami nadzheludochkovoi takhikardii.

Potentialities of the non-invasive method of trans-esophagus electrostimulation of the heart were studied with regard to the selection and assessment of the effectiveness of antiarrhythmic therapy in 16 patients with paroxysms of supraventricular reciprocal tachycardia. The antiarrhythmic therapy selected by this method proved effective in 13 patients following a prolonged course of treatment. The method was highly informative in predicting the efficacy of the systemic course treatment of patients with supraventricular tachycardia paroxysms.