[Efficiency and safety of allapinin in short- and long-term treatment of patients with normal heart and ventricular premature beats]

Allapinin, class 1C antiarrhythmic drug, is highly effective in treatment of patients with ventricular premature beats (VPB). The purpose of work was retrospective assessment of efficacy and safety of allapinin in patients with benign ventricular arrhythmias. 73 patients with VPB and no structural heart disease were selected from a database. In short course allapininin in dose of 75-150 mg per os daily decreased the number of VPB for more than 90% in 46,6% of patients. In 34,4% cases tolerable drug side effects were observed. Among patients with VPB burden of 10% and higher allapinin reduced this quantity below the indicated value in 76% of cases with tolerable drug side effects in 38,6% of cases. In long treatment study antiarrhythmic effect of allapinin persisted and no other side effects of the drug were documented.

CONCLUSION

Allapinin is highly effective in treatment of patients with VPB without structural heart disease.

[Significance of Tp-Te interval for risk stratification of ventricular premature contractions in children]

OBJECTIVE

To investigate the significance of Tp-Te interval for risk stratification of ventricular premature contractions (VPC) in children.

METHODS

A total of 120 children with VPC were divided into benign VPC (n=40), organic disease (n=40) and ventricular parasystole groups (n=40) according to the etiology of VPC; another 40 children who underwent physical examination were selected as the normal control group. The four groups were compared in terms of Tp-Te intervals and Tp-Te/QT ratios in leads V3, V4 and V5.

RESULTS

The Tp-Te interval in lead V3 was significantly longer in the organic disease group than in the other groups (P<0.05), the benign VPC group had a significantly shorter Tp-Te interval in lead V4 than the normal control and organic disease groups (P<0.05), and the organic disease group had a significantly longer Tp-Te interval in lead V5 than the benign VPC group (P<0.05). The Tp-Te/QT ratios in leads V3-V5 were significantly higher in the organic disease group than in the other groups (P<0.05). The Tp-Te/QT ratios in leads V4 and V5 showed significant differences between the ventricular parasystole and benign VPC groups (P<0.05).

CONCLUSIONS

Tp-Te interval is susceptible to changes in heart rate, and it is of little value for the risk stratification of VPC in children. Tp-Te/QT ratio, however, may be used as an important non-invasive index for clinical risk stratification of VPC in children and is worthy of further study.

Suppression of ventricular fibrillation by electrical modification of the Purkinje system in hypertrophic cardiomyopathy

A 56-year-old man in hypertrophic cardiomyopathy had an electrical storm caused by ventricular fibrillation (VF). Mapping during the initiation of the VF triggered by a premature ventricular contraction (PVC1), with right bundle branch block (RBBB)-like morphology and superior axis, demonstrated a prominent Purkinje-muscle junction (PMJ) delay at the distal portion of the left posterior fascicle. Delivery of radiofrequency (RF) energy to this area abolished the VF triggered by the PVC1. However, VF emerged by triggering another PVC (PVC2) with RBBB-like morphology and inferior axis. Similarly, the initiation of VF was associated with the PMJ delay at the peripheral left anterior fascicle, where RF delivery completely suppressed the VF. The PMJ delay and subsequent Purkinje-muscle reentry-like activity could be essential for the initiation of the Purkinje-related VF.

Radiofrequency ablation can reverse the structural remodeling caused by frequent premature ventricular contractions originating from the right ventricular outflow tract even in a "normal heart"

OBJECTIVE

The aim of this study was to evaluate whether frequent premature ventricular contractions originating from the right ventricular outflow tract remodel the cardiac structure and function in patients with a "seemingly normal heart" and whether radiofrequency ablation can reverse this remodeling.

METHODS

Sixty-eight patients with idiopathic frequent premature ventricular contractions originating from the right ventricular outflow tract and normal heart structure and function were enrolled in this study. The patients were divided into three groups according to the therapeutic method: radiofrequency ablation group (24 cases), anti-arrhythmia drug group (26 cases), and control group (18 cases without any treatment). Clinical Registration number: ChiCTR-ONRC-12002834 RESULTS: The basic patient characteristics were comparable between the three groups, except for the premature ventricular contraction rate, which was significantly lower in the control group. After six months of follow up, the premature ventricular contraction rate was significantly reduced in the radiofrequency ablation group, which was accompanied by a significant decrease in the following cardiac cavity inner diameters, as determined by echocardiography: right atrium (33.33±3.78 vs. 30.05±2.60 mm, p = 0.001), right ventricle (23.24±2.40 vs. 21.05±2.16 mm, p = 0.020), and left ventricle (44.76±4.33 vs. 41.71±3.44 mm, p = 0.025). These results were similar in the anti-arrhythmia drug group, although this group exhibited a smaller extent of change (right atrium: 33.94±3.25 vs. 31.27±3.11 mm, p = 0.024; right ventricle: 22.97±3.09 vs. 21.64±2.33 mm, p = 0.049; left ventricle: 45.92±6.38 vs. 43.84±5.67 mm, p = 0.039), but not in the control group (p>0.05). There was a tendency toward improvement in the cardiac functions in both the radiofrequency ablation and anti-arrhythmia drug groups. However, these differences were not statistically significant (p>0.05).

CONCLUSIONS

These results indicate that radiofrequency ablation can potentially reverse the cardiac remodeling caused by frequent premature ventricular contractions even in structurally normal hearts and that frequent premature ventricular contractions should be abated even in structurally normal hearts.

Parathyroidectomy eliminates arrhythmic risk in primary hyperparathyroidism, as evaluated by exercise test

OBJECTIVE

To investigate whether parathyroidectomy (PTx) reverses risk factors for arrhythmias related to the QT dynamic changes evaluated during bicycle ergometry exercise test (ET).

METHODS

Twenty-four postmenopausal women with primary hyperparathyroidism (PHPT) (mean age 60.08.4 years) and 30 sex- and age-matched controls underwent ET, echocardiography, and biochemical evaluation. The following stages were considered during ET: rest, peak exercise, and recovery. The patients were randomized to two groups: 12 underwent PTx (group A) and 12 were followed-up conservatively (group B). After 6 months, the patients were studied again.

RESULTS

Groups A and B showed no differences in mean baseline biochemical values, echocardiographic parameters, and QTC interval. PHPT patients showed an increased occurrence of ventricular premature beats (VPBS) during ET compared with controls (37.0 vs 6.6%, P=0.03). Serum calcium level was a predictor of VPBS (P=0.05). Mean value of QTC was in the normal range at baseline (Group A: 401±16.9; group B: 402.25±13.5 ms) but significantly lower than controls (417.8±25.1 ms, P<0.01). A negative correlation was found between QTc and calcium values (P=0.03). Physiological reduction of QTc interval from rest to peak exercise was not observed in PHPT patients before surgery. After PTx, group A had a significant reduction in VPBs compared with baseline (at baseline, 5 of 12 vs none of 12 patients after PTx, P=0.03) and a restored normal QT adaptation during ET. Group B showed no significant changes after a 6-month period.

CONCLUSIONS

PTx reduces the occurrence of VPBs and restored the QTc adaptation during ET.

Noninvasive cardiac activation imaging of ventricular arrhythmias during drug-induced QT prolongation in the rabbit heart

BACKGROUND

Imaging myocardial activation from noninvasive body surface potentials promises to aid in both cardiovascular research and clinical medicine.

OBJECTIVE

To investigate the ability of a noninvasive 3-dimensional cardiac electrical imaging technique for characterizing the activation patterns of dynamically changing ventricular arrhythmias during drug-induced QT prolongation in rabbits.

METHODS

Simultaneous body surface potential mapping and 3-dimensional intracardiac mapping were performed in a closed-chest condition in 8 rabbits. Data analysis was performed on premature ventricular complexes, couplets, and torsades de pointes (TdP) induced during intravenous administration of clofilium and phenylephrine with combinations of various infusion rates.

RESULTS

The drug infusion led to a significant increase in the QT interval (from 175 ± 7 to 274 ± 31 ms) and rate-corrected QT interval (from 183 ± 5 to 262 ± 21 ms) during the first dose cycle. All the ectopic beats initiated by a focal activation pattern. The initial beat of TdPs arose at the focal site, whereas the subsequent beats were due to focal activity from different sites or 2 competing focal sites. The imaged results captured the dynamic shift of activation patterns and were in good correlation with the simultaneous measurements, with a correlation coefficient of 0.65 ± 0.02 averaged over 111 ectopic beats. Sites of initial activation were localized to be ~5 mm from the directly measured initiation sites.

CONCLUSIONS

The 3-dimensional cardiac electrical imaging technique could localize the origin of activation and image activation sequence of TdP during QT prolongation induced by clofilium and phenylephrine in rabbits. It offers the potential to noninvasively investigate the proarrhythmic effects of drug infusion and assess the mechanisms of arrhythmias on a beat-to-beat basis.

[Effect of clopidogrel and aspigrel on ectopic cardiac activity in patients with unstable angina pectoris]

The coronary circulation dysfunction in patients with unstable angina pectoris causes development of ventricular and supraventricular cardiac rhythm disorders. Findings from the current study suggest that antianginal therapy of patients with acute coronary syndrome which includes antiaggregant and anticoagulant is effective in the treatment of extrasystolic arrhythmias.

Autonomic involvement in idiopathic premature ventricular contractions

OBJECTIVE

To investigate autonomic involvement in different types of idiopathic premature ventricular contractions (PVCs) grouped by heart rate (HR) dependency.

METHODS

One hundred and sixty PVC patients and 31 controls were enrolled. Holter ECG was used to evaluate PVC occurrence, and spectral analysis of heart rate variability (HRV) was calculated to represent cardiac autonomic control. PVCs were divided into fast rate-dependent (F-PVC), slow rate-dependent (S-PVC), and HR-independent PVC (I-PVC) based on the relationship between hourly PVC density and hourly HR. HRV among different types of PVCs were compared, and the association between PVC density with HR and HRV were analyzed. Furthermore, autonomic changes assessed by consecutive 5-min HRV in 30 min before PVC episodes were investigated.

RESULTS

In 160 subjects, there were 73 F-PVC, 56 S-PVC, and 31 I-PVC. Hourly PVC density was positively associated with sympathetic indice (LF/HF) and negatively related to vagal indices (HF and HFnu) in F-PVC, and this trend was reversed in S-PVC. During 30 min before PVC onset, RR interval and HFnu decreased significantly with LF/HF showing an increasing trend in F-PVC, while in S-PVC both RR interval and HF increased significantly. It was noted that those changes were most evident during the last 5 min before PVC onset. In addition, PVC density in F-PVC was significantly decreased by β-blocker treatment.

CONCLUSIONS

HR dependency reflected autonomic modulation of idiopathic PVCs. F-PVC and S-PVC might be facilitated by sympathetic activation and vagal activation, respectively. HR dependency and the related autonomic mechanisms should be considered when treating idiopathic PVCs.

[Preferential conduction to right ventricular outflow track leads to left bundle-branch block morphology in patient with premature ventricular contraction originating from the aortic sinus cusp]

OBJECTIVE

The purpose of this study was to explore the relationship between originate and breakout and radiofrequency catheter ablation strategy in patients undergoing radiofrequency ablation for premature ventricular contractions originating from the aortic sinus cusp (ASC) using 3-dimensional electro anatomic mapping.

METHODS

This study included 21 consecutive patients (10 male) underwent ablation for frequent PVCs originating from ASC in our hospital between May 2009 and February 2012. Electro anatomic mapping and ablation of right ventricular outflow track (RVOT) and left ventricular outflow track (LVOT) were performed with the 7F 4-mm-tip ablation catheter from right femoral vein and artery. Activation mapping and pacing mapping were performed in all patients.

RESULTS

Ablation was successful in all 21 patients successful ablation target in left coronary sinus cusp (LCC, n = 17), in right coronary sinus cusp (RCC, n = 2) and in noncoronary sinus cusp (NCC, n = 2). Seven patients showed a RBBB morphology (group A) and 14 patients showed a LBBB morphology (group B). In group A, earliest ventricular activation (EVA) was recorded 22 - 34 (27.4 ± 4.6) ms earlier before QRS at the site of catheter ablation in ASC. In group B, EVA was later in RVOT than that in ASC in 5 patients and EVA at the site of catheter ablation in RVOT and ASC was 22 - 28 (25.2 ± 2.7) ms and 26 - 40 (32.8 ± 5.2) ms, respectively (t = -3.6, P = 0.024) while EVA was earlier in the remaining 9 patients and EVA recorded in RVOT and ASC was 22 - 38 (28.7 ± 5.9) ms and 18 - 28 (22.7 ± 3.6) ms, respectively (t = 3.8, P = 0.005).

CONCLUSION

Patients with premature ventricular contractions originating from the ASC often show preferential conduction to the RVOT, which may explain the LBBB morphology of ECG in these patients.

Effects of catheter ablation of "asymptomatic" frequent ventricular premature complexes in patients with reduced (<48%) left ventricular ejection fraction

Frequent ventricular premature complexes (VPCs), particularly those without troublesome palpitations, are often regarded as a benign arrhythmia and are not treated other than with reassurance. However, VPCs can contribute to left ventricular (LV) dysfunction in the absence of symptoms. The present study was designed to investigate whether catheter ablation of VPCs can improve LV dysfunction in patients with and without troublesome palpitations. Of 80 consecutive patients who underwent catheter ablation of frequent VPCs, 24 (aged 60 ± 15 years) were found to have a reduced LV ejection fraction at baseline (<48%) and included in the present study. No important procedure-related complications occurred in these patients. During a median follow-up of 8 months, the VPC burden after ablation had decreased from 15 ± 6% to 1 ± 1% (p <0.001), and the left ventricular ejection fraction had increased from 32 ± 15% to 43 ± 14% (p <0.001). Ten patients (42%) had no palpitations before ablation. In the other 14 patients, the palpitations were improved or entirely resolved after ablation. No significant difference was found in the extent of LV ejection fraction improvement after ablation between patients with and without palpitations (+11 ± 12% vs +11 ± 11%, p = 0.941) or between patients with different locations of VPC origin. In conclusion, VPCs might not necessarily be associated with palpitations in many patients with LV dysfunction. Successful ablation of frequent VPCs in these "asymptomatic" patients is associated with an improvement in LV function similar to that observed in "symptomatic" patients.

[Effectiveness of RF ablation of ventricular ectopic beats from the right and (or) left ventricle]

There are few studies on the immediate and long term efficacy of ablation of ventricular ectopic beat (VEB) using different mapping systems arrhythmia. The aim of the study was to evaluate the efficacy of intraoperative, immediate and late outcome of RF ablation ventricular arrhythmias and a comparison of methods for identification and ablation of arrhythmia substrate.

MATERIAL AND METHODS

In 88 patients, average age 50,8+/-17,8 years old (16 to 90) with performed RF ablation of VEB from the left ventricular and (or) right ventricular. We retrospectively evaluated surgical reports and clinical records. The number of applications, energy, temperature, duration of application, impedance, radiation exposure to X-ray and the presence of obesity, myocardial infarction were evaluated. RF ablation was performed using the method of Carto or Carto and Pace mapping stimulation or Pace mapping stimulation alone. Patients were divided into 3 groups: group A - long result was positive after ablation, group B - treatment was ineffective, group C - ad hoc and postoperative result were positive but long result was negative.

RESULTS

The observation time was 30+/-11 months (3-48). An ad hoc positive end point of VEB ablation was 86%, postoperative 74%, and a distant 60%, respectively. There was 13% ineffective treatments. Carto system was used in 53 patients. In 6 (11%, group B) treatment was ineffective, the remaining 47 patients achieved complete success in 31 (58%, group A) cases, while temporary success in 16 (30%, group C) cases. The relationship between the average temperature of 57 Celcius degree during ablation (HR = 1.148, regression = 0.138, p < 0.039) and the effectiveness of treatment was found. No statistical significance between the assessment of the effectiveness of ablation of arrhythmias and the location of the substrate were found but there was no statistical difference between the analyzed parameters and the technical and clinical effectiveness of ablation in the method of localization of arrythmia. The highest percentage of ablation failures in follow-up concerned the technique Carto alone (34%), the most effective was combined techniques adding Pace mapping plus Carto (76% succes rate long after ablation).

CONCLUSIONS

To find substrate of arrhythmia to ablate operator should be guided by stimulation mapping and electroanatomical map in order to achieve distant effect of operation. The only significant parameter correlating with the distant ablation efficacy was the mean temperature of the ablation. While using Carto to ablate arrythmia most important role is played by the precise location of the arrhythmia substrate rather than increasing the temperature during ablation.

Direct effects of arsenic trioxide on action potentials in isolated cardiac tissues: importance of the choice of species, type of cardiac tissue and perfusion time

INTRODUCTION

The aim of the present study was to evaluate direct/acute effects of arsenic trioxide on action potentials (APs) in isolated cardiac tissues, and to investigate if the choice of species and tissue and the duration of the perfusion play a role in arsenic-induced acute/direct prolongation of AP/QT.

METHODS AND RESULTS

Direct electrophysiological effects of arsenic trioxide were measured in cardiac tissues isolated from four different species using micro-electrode recording. Arsenic (after 30 to 95 min perfusion at 10 μM) significantly prolonged APD(90), increased triangulation of the AP and elicited early afterdepolarizations (EADs) only in isolated guinea-pig and dog Purkinje fibers but not in rabbit and porcine (minipig) Purkinje fibers. Arsenic induced a prolongation of the APD(90) and increases in triangulation and the occurrence of EADs was not observed in papillary muscles of guinea-pigs and rabbits. Arsenic at 4 increasing concentrations from 0.1 μM to 10 μM at the standard perfusion-time of 15 min per concentration, and after a continuous 90-min perfusion at 1 μM and 1 Hz did not induce these direct effects on APD(90), triangulation and EADs in isolated guinea-pig Purkinje fibers, but it at 1 µM elicited EADs in 2 out of 7 preparations after 90 min at 0.2 Hz.

DISCUSSION

The present study demonstrates that the choice of species and cardiac tissue as well as perfusion-time play important roles in arsenic-induced direct/acute effects on APD(90) and induction of EADs in vitro.

[Antiarrhythmic therapy of paroxysmal tachycardias and extrasystoles in patients with sinus node dysfunction]

Antiarrhythmic therapy of patients with disturbed automatism of the sinus node and impaired atrioventricular conductance may be complicated by hemodynamically significant bradycardias and contraindications for implantation of a cardiac electrical stimulator This study aimed at estimating effect of antiarrhythmic therapy with allapinin on the function of sinus and atrioventricular nodes. It included 20 patients (mean age 37.5+-2.3 years) with disturbed cardiac rhythm and sinus node dysfunction treated with allapinin (37.5 - 50 mg/d per os). This therapy had well apparent antiarrhythmic effect manifest as improvement of supraventricular and ventricular ectopic activities in the absence of negative influence on the function of sinus and atrioventricular nodes.

[Association of parameters of heart rate variability with severity of bronchial obstruction and presence of pulmonary hypertension in patients with chronic obstructive pulmonary disease]

With the aim of assessing parameters of heart rate variability (HRV) and heart rhythm turbulence (HRT) in patients with chronic obstructive pulmonary disease (COPD) in dependence on severity of the course of this disease and presence of pulmonary hypertension (PH) we examined 73 patients (28 with COPD and 45 healthy subjects). Invasive measurement of central hemodynamics was conducted. Compared with the control group in patients with COPD we revealed lowering of temporal as well as frequency HRV parameters. No significant changes of HRV parameters depended on severity of COPD course. However a tendency to maximal lowering of HRV parameters was noted in the group of patients with COPD with first sec forced expiratory volume &lt;50%. Comparison of patients with and without PH with controls revealed tendency to maximal lowering of HRV parameters in the PH group. Thus measurement of HRV can be used for supplementary assessment of severity of the disease and detection of PH.

[Disturbances of heart rhythm in patients after myocardial infarction with obstructive sleep apnea during outpatient rehabilitation]

We studied specific features of heart rhythm disturbances observed during outpatient rehabilitation of 432 patients after first myocardial infarction. In 94 of these patients (21.8%) we diagnosed obstructive sleep apnea syndrome (OSAS). We noted substantial preponderance of pathologic ectopy related to OSAS with most significant detection of frequent ventricular extrasystoles. Their paired variant and polymorphic forms in patients with OSAS were 3.4 and 7.4 times, respectively, more frequent than in patients without OSAS. Frequency of ventricular ectopy rose with increase of severity of OSAS and was maximal during nocturnal hours. Analysis of correlations revealed association between OSAS and frequencies of ventricular and supraventricular extrasystoles.

CONCLUSION

After myocardial infarction patients should be thoroughly examined for timely detection of OSAS and corresponding correction of their rehabilitation program.