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Abstract: Introduction: Levels of cardiac necroenzymes, high-sensitive troponin (hsTnT) and creatine kinase muscle-brain (CKMB) increase as a result of a myocardial damage following catheter ablation. Aim: To analyze the mid-term alteration of hsTnT and CKMB levels following radiofrequency ablation (RFCA) for atrial fibrillation (AF), atrial flutter (AFlu), AV-nodal reentry tachycardia (AVNRT) and electrophysiological studies (EPS) without ablation. Method: Patients undergoing RFCA for various indications and EPS were consecutively enrolled in our prospective study. Concentrations of hsTnT and CKMB were measured from serial blood samples directly before and after the procedure, 4 and 20 hours later and at 3 months follow-up. Results: Forty-seven patients (10 EPS, 12 AVNRT, 13 AFlu, 12 AF) with mean age of 55 ± 13 were included. hsTnT levels increased significantly in all groups after the procedures, while CKMB changed only in the AF group. hsTnT exceeded the reference value in all patients with ablation and in 80% of patients with EPS 4 hours post-ablation. Peak average hsTnT levels for EPS, AVNRT, AFlu were 24 ± 11, 260 ± 218 and 541 ± 233 ng/L, respectively. The highest hsTnT level was measured in the AF group (799 ± 433 ng/L). We found a positive correlation between hsTnT levels and ablation time after RFCA. Conclusions: The hsTnT levels significantly change after EPS and RFCA, in all patients who underwent ablation, and in 80% of those with EPS had hsTnT positivity in the early post-procedural phase. hsTnT levels depended significantly on the type of the subgroups and correlated with the ablation time. Awareness of those observations is essential to correctly interpret elevated hsTnT levels following RFCA. Orv Hetil. 2019; 160(14): 540–548.

INTRODUCTION AND OBJECTIVES Cardiac resynchronization therapy (CRT) is beneficial for selected heart failure (HF) patients, although nonresponse to therapy is still prevalent. We investigated a set of novel biomarkers associated with various pathophysiological pathways of HF. Our purpose was to assess their ability to predict clinical outcomes after CRT. METHODS We studied 136 chronic HF patients undergoing CRT. We measured the plasma levels of fractalkine, pentraxin-3, hepatocyte growth factor (HGF), carbohydrate antigen-125, and matrix metalloproteinase-9 before and 6 months after CRT. The primary endpoint of the study was 5-year all-cause mortality, and we considered the absence of 6-month reverse remodelling (defined as at least a 15% decrease in end-systolic volume) as a secondary endpoint. RESULTS Fifty-eight patients died during the 5-year follow-up period and 66 patients were categorized as nonresponders. In multivariable models, only an increased HGF was an independent predictor of both mortality (HR, 1.35; 95%CI, 1.11-1.64; P=.003; per 1 standard deviation increase) and the absence of reverse remodelling (OR, 1.83; 95%CI, 1.10-3.04; P=.01; per 1 standard deviation increase). Applying HGF to the basic multivariable model of both mortality (net reclassification improvement=0.69; 95%CI, 0.39-0.99; P

BACKGROUND: Despite significant improvements in cardiac output and functional capacity with cardiac resynchronization therapy (CRT), incidence of sudden cardiac death still remains high. Reversal of physiological myocardial activation sequence during epicardial pacing increases the transmural dispersion of repolarization (TDR). The aim of this study was to compare the effects of endocardial and epicardial biventricular pacing on repolarization parameters in the same patient group. METHODS: Seven patients who had transseptal endocardial left ventricle (LV) lead placement, in whom epicardial CRT had failed due to coronary sinus (CS) lead dislodgement after successful implantation, were admitted to the study. LV endocardial leads were implanted through the inter-atrial septum in a lateral position. ECGs were scanned before and after successful epicardial and endocardial biventricular pacing and analyzed using digital callipers. ECG markers of TDR (TpTe and TpTe/QT ratio) were measured and compared. RESULTS: Baseline QRS durations (161.7+/-15.9 vs 162.2+/-17.8 ms, p = 0.95), TpTe values (107.1+/-20.5 vs 108.5+/-17.6 ms, p = 0.89) and TpTe/QT ratios (0.24+/-0.05 vs 0.24+/-0.03, p = 0.88) were similar before epicardial and endocardial CRT. QRS interval reduction was similar (-28.3+/-11.6 vs -29.1+/-11.4 ms, p = 0.89) in both groups. Compared to transseptal endocardial CRT, epicardial CRT was associated with a significant increase in TpTe (17.1+/-19.5 vs -12.6+/-18.9 ms, p = 0.01) and TpTe/QT ratio (0.03+/-0.04 vs -0.02+/-0.03, p = 0.04). CONCLUSION: Transseptal LV endocardial pacing is associated with significant reduction in TDR characteristics compared to epicardial pacing in CRT. Further studies are warranted to determine whether these effects may contribute to reduction of arrhythmias in patients with CRT. This article is protected by copyright. All rights reserved.

Aims Data on longer right to left ventricular activation delay (RV-LV AD) predicting clinical outcome after cardiac resynchronization therapy (CRT) by left bundle branch block (LBBB) are limited. We aimed to evaluate the impact of RV-LV AD on N-terminal pro–B-type natriuretic peptide (NT-proBNP), ejection fraction (EF), and clinical outcome in patients implanted with CRT, stratified by LBBB at baseline. Methods and results Heart failure (HF) patients undergoing CRT implantation with EF ≤ 35% and QRS ≥ 120 ms were evaluated based on their RV-LV AD at implantation. Baseline and 6-month clinical parameters, EF, and NT-proBNP values were assessed. The primary endpoint was HF or death, the secondary endpoint was all-cause mortality. A total of 125 patients with CRT were studied, 62% had LBBB. During the median follow-up of 2.2 years, 44 (35%) patients had HF/death, 36 (29%) patients died. Patients with RV-LV AD ≥ 86 ms (lower quartile) had significantly lower risk of HF/death [hazard ratio (HR): 0.44; 95% confidence interval (95% CI): 0.23–0.82; P = 0.001] and all-cause mortality (HR: 0.48; 95% CI: 0.23–1.00; P = 0.05), compared with those with RV-LV AD < 86 ms. Patients with RV-LV AD ≥ 86 ms and LBBB showed the greatest improvement in EF (28–36%; P

Aims There are limited and contradictory data on the effects of CRT with implantable cardioverter defibrillator (CRT-D) on mortality as compared with CRT with pacemaker (CRT-P). Methods and results We evaluated the long-term outcome of patients implanted with a CRT-D or CRT-P device in our high-volume single-centre experience. Data on all-cause mortality were derived from clinic visits and the Hungarian National Healthcare Fund Death Registry. Kaplan–Meier survival analyses and multivariate Cox regression models were used to evaluate all-cause mortality in patients with CRT-D vs. CRT-P, stratified by the aetiology of cardiomyopathy. From 2000 to 2011, 1122 CRT devices, 693 CRT-P (LVEF 28.2 ± 7.4%) and 429 CRT-D (LVEF 27.6 ± 6.4%), were implanted at our centre. During the median follow-up of 28 months, 379 patients died from any cause, 250 patients (36%) with an implanted CRT-P and 129 patients (30%) with an implanted CRT-D. There was no evidence of mortality benefit in patients implanted with a CRT-D compared with a CRT-P in the total cohort [hazard ratio (HR) 0.98, 95% confidence interval (CI) 0.73–1.32, P = 0.884]. In patients with ischaemic cardiomyopathy, CRT-D treatment was associated with a significant 30% risk reduction in all-cause mortality compared with an implanted CRT-P (HR 0.70, 95% CI 0.51–0.97, P = 0.03). In non-ischaemic patients, there was no mortality benefit of CRT-D over CRT-P (HR 0.98, 95% CI 0.73–1.32, P = 0.894, interaction P-value = 0.15). Conclusions In heart failure patients with ischaemic cardiomyopathy, CRT-D was associated with a mortality benefit compared with CRT-P, but no benefit of CRT-D over CRT-P in mortality was observed in non-ischaemic cardiomyopathy.

Early recognition of ventricular tachycardias (VTs) with epicardial circuits is crucial. Surface electrocardiogram (ECG) suggesting an epicardial origin could guide ablation procedures and increase success rates. A 35-year-old female patient with VT treated by combined epicardial and endocardial ablation approach is presented in this report, and the role of surface electrocardiogram and timing of epicardial access is discussed.

The chronic inflammation plays an important role in heart failure and complement components might be useful markers of the prognosis. We set out to evaluate their predictive value in the clinical outcomes of patients with cardiac resynchronization therapy (CRT).We determined the complement levels C3, C3a, sC5b-9 and also the N-terminus of the prohormone brain natriuretic peptide (NT-proBNP) of 126 heart failure patients in a prospective, single-center observational study before and 6 months after CRT implantation.CRT reduced the C3a [212.5 (148.2-283.6) vs. 153 (119.8-218.3) ng/mL, p 0.0001] and the sC5b-9 levels [296.9 (234.2-358.8) vs. 255.1 (210.1-319.0) ng/mL, p = 0.0006], but not the total C3 levels [1.43 (1.26-1.61) vs. 1.38 (1.23-1.57) g/L, p = 0.57]. C3a predicted the 5-year mortality of the patients [C3a 165 ng/mL hazard ratio = 4.21 (1.65-10.72), p = 0.003] independent of the NT-proBNP and other factors. After reclassification, we observed a significant net reclassification improvement [NRI = 0.71 (0.43-0.98), p 0.0001] and integrated discrimination improvement [IDI = 0.08 (0.03-0.12), p = 0.0002].In patients with CRT, elevated C3a levels increase the risk of mortality independent of the NT-proBNP levels or other factors. CRT exerts anti-inflammatory effect by reducing the complement activation.

The aim of our investigation was to test the suitability of a novel method for the analysis of the integrity of an explanted pacemaker lead stabilized by a stent. A coronary sinus lead has been explanted 27 months after implantation and has been examined by optical-, confocal-, x-ray-, and scanning electron microscopy. Several surface injuries were found on the insulation. Based on the surface characteristics, it is possible to define and differentiate the source of damages as well as to measure the extent of injuries. Impedance of the explanted lead has also been measured and electronic integrity has been verified. (PACE 2013; 36:e27–e30)

Idiopathic fascicular ventricular tachycardia is an important and not very rare cardiac arrhythmia with specific electrocardiographic features and therapeutic options. Ventricular tachycardia is characterized by relatively narrow QRS complex and right bundle branch block pattern. The QRS axis depends on which fascicle is involved in the re-entry. Left axis deviation is noted with left posterior fascicular tachycardia and right axis deviation with left anterior fascicular tachycardia. A left septal fascicular tachycardia with normal QRS axis is also possible. Idiopathic fascicular tachycardia is usually seen in individuals without structural heart disease. Response to verapamil is an important feature of fascicular tachycardia. In some cases intravenous adenosine may also terminate the arrhythmia. During electrophysiology study, presystolic or diastolic potentials precede the QRS, presumed to originate from the Purkinje fibers. The potentials can be recorded during sinus rhythm and ventricular tachycardia in many patients with fascicular tachycardia. This potential (so-called Purkinje potential) has been used as a guide to catheter ablation. Correct diagnosis of fascicular tachycardia is very important because catheter ablation is very effective in the treatment of this type of ventricular tachycardia. In this review, we describe three patients with idiopathic ventricular tachycardia and their successful catheter ablation, and summarize the actual knowledge of the diagnosis and management of this special ventricular tachycardia.

Introduction: Coronary sinus (CS) leads used for cardiac resynchronization have undergone development in the last years. However, dislocation rate remained high (5–9%). The aim of this study was to investigate the effectiveness and safety of stent implantation in a CS side vein to stabilize the left ventricular lead position after postoperative or intraoperative dislocation of the electrode. Methods and Results: Thirty-six patients (age: 64 ± 9.7 years, 19 primary, 17 ischemic cardiomyopathy, NYHA class III: 30, IV: 6) were treated with stenting. The procedure was performed because of postoperative dislocation in seven patients, while dislocation was observed during the implantation in 29 cases. The electrode was repositioned into the desired position and a bare metal coronary stent was introduced via another guide wire. The stent was deposited at 5- to 15-mm proximal to the tip of the electrode with a pressure of 6 to 14 atmospheres. Control angiography showed no blood flow compromise in any of the side branches or in the coronary sinus. Control echocardiography did not show pericardial effusion due to stenting. During follow-up (11.5 ± 5.5, 2–23 months), left ventricular pacing threshold increased from 2.2 to 5.6 V in one patient, but dislocation was not found by fluoroscopy. Clinically important pacing threshold increase was not detected in the other cases. Impedance measurements did not suggest lead insulation failure. Conclusion: Stent implantation to stabilize the left ventricular lead position seems to be a useful and safe procedure in the treatment of patients with complicated coronary sinus anatomy or lead instability.

Introduction Although macroreentrant atrial tachycardia (MRAT) and focal atrial tachycardia (FAT) can be successfully cured by catheter ablation, the proper diagnosis and treatment of these arrhythmias can still be challenging. Aim The objective of this study is to develop an algorithm allowing rapid diagnosis of the mechanism and the chamber of origin of atrial tachycardia based on intracardiac catheter recordings from the right atrium and the coronary sinus (CS). Methods A 2-stepped algorithm was designed: (1) The time of biatrial activation expressed as a percentage of the tachycardia cycle length served to discriminate FAT from MRAT. (2) In FAT, the direction of activation of the CS catheter and the earliest atrial activation were used to define the chamber of origin. In MRAT, the time of right atrium activation was determined or entrainment was used at different sites. Thirty-two intracardiac recordings were reviewed off-line after the algorithm by 4 electrophysiologists blinded to the mechanism and the chamber of origin. The results of their analysis were compared with the intraoperative diagnosis. Results The algorithm correctly identified 11 (100%) of 11 FATs and 19 (90.4%) of 21 MRATs. The site of origin was correctly identified in 8 (72.7%) of 11 FATs and in 20 of 21 (95.2%) MRATs. The site of origin was misidentified in 3 FATs, all arising from the CS ostium. Conclusions This algorithm allows rapid discrimination between FAT and MRAT. The chamber of origin is detected with a high accuracy in MRAT. However, the earliest atrial activation taken as an isolated event is not a good predictor for the chamber of origin in FAT arising from the ostium of the CS.

Objective.To identify early echocardiographic abnormalities at the time of diagnosis of polymyositis (PM) and dermatomyositis (DM) and follow the echocardiographic findings during the first 3 months of therapy.Methods.We included 30 PM/DM patients (23/7) with a mean age of 42.3 ± 1.6 years and without cardiovascular symptoms. Age-matched healthy patients served as controls. Clinical characteristics were recorded. Traditional echocardiography and tissue Doppler imaging (TDI) were performed to measure systolic [ejection fraction, right ventricular fractional area change (RV FAC), lateral and tricuspid annulus s velocities] and diastolic echocardiographic variables (mitral inflow velocities: E, A; deceleration time: DT; lateral and tricuspid annulus e′, a′ velocities, lateral E/e′).Results.The left and right ventricular systolic dysfunction detected by TDI at the time of the PM/DM diagnosis improved, and characteristic values at the end of the followup period were comparable to those of the controls (lateral s: 10.6 ± 0.2, 8.7 ± 0.4, 9.6 ± 0.3, 11.3 ± 0.2 cm/s; RV FAC: 45.2 ± 2.3, 36.9 ± 1.5, 42.2 ± 1.3, 46.9 ± 1.2%; tricuspid s: 13.3 ± 0.2, 9.5 ± 0.4, 10.3 ± 0.3, 11.6 ± 0.5 cm/s; control, 0, 1, and 3 mos, respectively). Measurements indicated the development of diastolic dysfunction at 3 mos (E/A: 1.4 ± 0.1, 1.29 ± 0.05, 1.03 ± 0.05, 0.92 ± 0.05; DT: 148.6 ± 3.6, 157.3 ± 5.7, 168.3 ± 6.0, 184.3 ± 6.2 ms; lateral e′: 12.8 ± 0.3, 12.1 ± 0.5, 10.2 ± 0.6, 10.8 ± 0.8 cm/s; E/e′: 5.6 ± 0.1, 5.0 ± 0.22, 6.92 ± 0.46, 7.64 ± 0.47; control, 0, 1, and 3 mos, respectively).Conclusion.TDI is a useful method to detect early cardiac abnormalities complementing the conventional echocardiographic measurements. LV and RV systolic dysfunction found in the acute phase significantly improved during the first 3 months of therapy; however, deterioration of diastolic dysfunction was also observed.

Radiofrequency (RF) catheter ablation guided by electroanatomic mapping systems is an effective therapy for atrial fibrillation. However, it may be affected by respiration movements. The aim of this study was to determine the impact of respiratory gating on procedural parameters in patients undergoing catheter ablation of atrial fibrillation (AF).One-hundred forty consecutive patients undergoing pulmonary vein isolation were admitted to study. Respiratory gating module (AccuResp algorithm, Carto3, Biosense Webster) was enabled in 70 patients and disabled in 70 patients during procedures. Successful pulmonary vein isolation and sinus rhythm were obtained in all patients. A significant reduction in total procedure times [median 77, interquartile range (IQR 66-95) min vs median 82 (IQR 72-104) min, p0.05] and fluoroscopy times [median 14 (IQR 9-17) min vs median 16 (IQR 12-22) min, p0.05] were observed in the respiratory gated group. Although ablation times (duration between the first and last ablation) were significantly shorter in respiratory gated group [median 37 (IQR 32-53) min vs median 48 (IQR 39-65) min, p0.05], total RF application durations were not different between two groups [median 1,554 (IQR 1,213-2,196) s vs median 1,802 (IQR 1,344-2,448) s, p = 0.11]. Difference in electroanatomical map reconstruction times was not significant [median 14 (IQR 12-16) min in gated group vs median 13 (IQR 10-18) min in nongated group, p = 0.19].Respiratory gating significantly improves fluoroscopy and ablation times during electroanatomic mapping guided AF ablation. Respiratory gated maps may provide uninterrupted continuous ablation applications. Furthermore, using automatic respiratory gating module does not prolong mapping times.

Both myocardial infarction and ischemic stroke are rare in the young. Yet a 15-year-old male patient suffered a myocardial infarction and later an ischemic stroke despite uninterrupted antiplatelet therapy. His medical history involved the surgical correction of an incomplete atrioventricular canal defect at the age of 13 years. No cardiovascular risk factors other than elevated lipoprotein(a) level could be identified. His antithrombin (AT) activity was decreased and DNA sequence analysis revealed heterozygosity for AT Basel (p.Pro41Leu), a variant with impaired heparin binding. This report supports a possible additional pathophysiological role for AT Basel and elevated lipoprotein(a) level in arterial thrombogenesis.

Aim Failure rate to implant left ventricular (LV) lead transvenously is 4-8% in cardiac resynchronization therapy (CRT) patients. Epicardial lead placement is an alternative method and if not applicable case reports and small series showed the feasibility of endocardial LV lead implantation. Electroanatomical mapping might be a useful tool to guide this procedure. Methods and results Four patients had undergone endocardial LV lead implantation after unsuccessful transvenous implantation or epicardial LV lead dysfunction using the transseptal approach. Electroanatomical mapping was used to mark the location of the transseptal puncture. This location point guided the mapping catheter from the subclavian access and facilitated positioning of the LV lead at the adjacent latest activation area of the left ventricle detected by activation mapping. Endocardial active fixation LV leads were successfully implanted in all patients with stable electrical parameters immediately after implantation and over a mean follow-up of 18.3 months (lead impedance 520 ± 177 vs. 439 ± 119 Ω and pacing threshold 0.8 ± 0.2 V, 0.5 ms vs. 0.6 ± 0.1 V, 0.5 ms, respectively). Patients were maintained on anticoagulation therapy with a target international normalized ratio of 3.5-4.5 and did not show any thromboembolic, haemorrhagic events, or infection. Echocardiography showed significant improvement of LV systolic function with marked improvement of the functional status. Conclusions Electroanatomical mapping is a useful technical tool to guide endocardial LV lead implantation. It helps to identify the location of the transseptal puncture and the use of activation mapping might facilitate location of the optimal lead positions during CRT.

A 29-year-old male was admitted to our outpatient clinic because of palpitation and documented narrow QRS arrhythmia. Based on the ECG, supraventricular tachycardia was diagnosed, electrophysiological examination was indicated and ablation therapy was recommended. During positioning of the catheter the patient developed arrhythmia. On the coronary sinus catheter the activation spread from distal to proximal electrodes, suggesting left atrial origin. During atrial entrainment pacing long return cycle was observed and distal coronary sinus pacing resulted in a 15 ms longer cycle length than the arrhythmia. Therefore, the left atrial origin of the arrhythmia was confirmed and double transseptal puncture was performed. Lasso and irrigated tip catheter were introduced into the left atrium and electroanatomical mapping was performed with CARTO3 system. After electroanatomical mapping the origin of tachycardia was located proximally in the left superior pulmonary vein. Ablation was started at the earliest activation point, where acceleration was observed and the arrhythmia stopped after the first ablation. Pulmonary vein isolation was completed, and bidirectional block could be confirmed. After 30 minutes the arrhythmia was not inducible. During follow-up, Holter-examination was negative and the patient remained asymptomatic. The pulmonary vein tachycardia is a supraventricular arrhythmia that can occur at any age, but the diagnosis based on the ECG is not always simple. Detailed electroanatomical mapping is very important in the diagnosis of this type of arrhythmia, although it can be verified with conventional electrophysiological methods as well. Focal ablation may be a therapeutic option; however, total isolation of pulmonary veins can be more effective. Orv. Hetil., 2011, 152, 1374–1378.

Cardiac resynchronization therapy (CRT) is an important breakthrough for the drug-refractory heart failure patients with reduced left ventrical ejection fraction (LVEF: 120 ms). The primary objecive of CRT is the coordination of the myocardial contraction with a right atrial (RA), right ventrical (RV) and a left ventrical (LV) lead and a biventricular device. The standard approach for implantation of the LV lead is transvenous epicardial approach through the subclavian vein to the lateral or posterolateral sidebranch of the coronary sinus. The average implantation time of CRT in high volume centers is under 120 minutes. Nowadays the procedural success ranges between 87% and 96% (Alonso, 2009). Early complications were seen in 10% and late complications were reported in further 5.5% (Khan et al., 2009). However we do not have all the evidence based predicting criterias to select the CRT responders and the different definitions of responders are numerous (Paul et al., 2009), the basics of all comparison is the successful left and right ventricular lead implantation. The growing numbers of heart failure patients recieving CRT and the limitation of the first line transvenous approach enhanced the evolution of alternative techniques. In this chapter we focus on the advanced CRT techniques which might help to reach the optimal lead positions and increase the success rate of implantations. The standard transvenous approach unfortunately has significant drawbacks as it is totally dependent on the inconsistent venous anatomy. The tributaries of the coronary sinus is usually visualised by the late phase of left coronarography, direct contrast injecion or by inserting an occlusion balloon into the coronary sinus (CS). Several reasons can cause the inabilty to reach the desired sidebrach and to insert the LV lead. The main reasons are: inability to cannulate the CS caused by dilatated right atrium, atypical orifice of CS, prominent Thebesian valve, small vessel size of the CS, severe kinking of the vein or venous valve in the CS. The secondary reasons are the high pacing threshold or phrenic nerve stimulation at the optimal site, inability to fixate the lead at the desired position and the insuffitient experience of the implanters. Stenosis or occlusion of the subclavian vein, or presence of a persistent left superior vena cava might be the cause for alternative LV implantations. Small or occluded sidebranches or tortuous branches and CS dissection or perforations might overcome with advanced transvenous techniques. The selection of the optimal site is an unsettled debate. Several noninvasiv and invasive techniques were investigated to confirm the optimal site, but no clear proven evidence is shown for the selection. However there is a consesus that the lateral and posterolateral veins are preferable rather than the anterior or apical veins. The anterolateral vein might be selected as a last resort in the absence of lateral and posterolateral veins. The identification of the veins

Aims Phrenic nerve stimulation (PNS), which is often intolerable for the patient, is a known complication of resynchronization therapy. We describe a new, minimal invasive method for treating PNS. Methods and results Untreatable PNS was found in nine cardiac resynchronization therapy patients with distal coronary sinus (CS) lead position 6 ± 6 (0.5–17) months after the implantation. Ablation catheter and Amplatz Left 2 type guiding catheter were introduced into the right atrium via the right femoral vein. Coronary sinus was cannulated with the Amplatz catheter, and on a normal guide wire, a coronary stent was introduced beside the lead into the side branch in seven cases or a bigger stent into the CS in two patients. The ablation catheter was looped around the CS lead in the atrium with bent tip and was drawn backward together with the CS electrode. New lead positions were evaluated with electrophysiological measurements, and the suitable position was stabilized with inflation of the stent. Pericardial effusion was not detected on post-operative echocardiography. After repositioning, suitable pacing parameters were registered (threshold: 1.6 ± 1.1 V; 0.5 ms, impedance: 565 ± 62 ohm). Phrenic nerve stimulation was not found with 7.5 V; 1.5 ms pacing. During follow-up (7.7 ± 4.6 months), stable pacing threshold and impedance values were measured; transient and reprogrammable PNS was present in only one patient. Conclusion Coronary sinus electrode reposition using the femoral approach seems to be a safe and effective procedure, which means smaller burden for the patients compared with the established reposition operation. The technique can be used successfully if the CS lead is in a distal position.

We describe a case of a 56-year-old male patient, who developed refractory dilated cardiomyopathy 5 years after heart transplantation. An atriobiventricular pacemaker was implanted when indication criteria of cardiac resynchronization therapy (CRT) were seen. The intraventricular dyssynchrony was significant before CRT, while synchronous contraction was demonstrated later with the beneficial reverse remodelling of the left ventricle. Resynchronization therapy resulted in significant improvement of the patient's clinical parameters. The success of this therapy points out the possible role of CRT in the treatment of chronic allograft failure after heart transplantation.

Several methods are being used to induce atrial fibrillation (AF) in experimental investigations, which may affect the electrophysiologic parameters of the induced arrhythmia. The aim of our study was the investigation of temporal characteristics of AF during and after electrical induction. Direct current and high-frequency stimulation was used for induction in bipolar biatrial, right and left atrial appendage configurations in 6 dogs. Atrial and ventricular electrical activity was recorded near the bundle of His. Seven statistical parameters were calculated to analyze the temporal characteristics of electrical activity of both chambers. The induction method affected 5 atrial and no ventricular electrophysiologic parameters during stimulation, and the effect disappeared after ceasing induction, during the induced transient or persistent AF. Electrical stimulation affects the properties of the induced arrhythmia during the induction; thus, the investigation of AF is recommended only after ceasing the induction to avoid bias.

We characterized the Ca2+-sensitizing and phosphodiesterase (PDE)-inhibitory potentials of levosimendan and enoximone to assess their contributions to the positive inotropic effects of these drugs. In guinea pig hearts perfused in the working-heart mode, the maximal increase in cardiac output (55%, P

Endothelin-1 (ET-1) is a potent endogenous arrhythmogenic substance. The aim of our study was to investigate the changes of serum ET-1 and big-endothelin levels in patients suffering from spontaneous, incessant ventricular tachyarrhythmias. The 11 consecutive patients' (mean age, 59 +/- 11 years) underlying diseases were ischemic heart disease, valvular heart disease, dilated cardiomyopathy, primary electrical disease, and arrhythmogenic right ventricular dysplasia in five cases, three cases, one case, one case, and one case, respectively. The mean ejection fraction was 39 +/- 14%, New York Heart Association functional status was I, II, and III in two cases, four cases, and five cases, respectively. Ventricular tachycardias (VT) were detected in five patients, ventricular fibrillation (VF) in three patients, and VT + VF in three patients. VTs terminated spontaneously in two cases. Six patients required multiple external cardioversion/defibrillation shocks, while implantable cardioverter defibrillators terminated all sustained arrhythmias successfully in four cases. Blood samples were collected during arrhythmias and 24 hours (control) following the last VT/VF episode. Serum ET-1 and big-endothelin levels were measured with western blot analysis after immunoprecipitation. Serum ET-1 and big-endothelin levels were significantly higher during the last VT/VF compared with the control period (ET-1, 65.8 +/- 26.8 fmol/mL versus 53.9 +/- 22.3 fmol/mL, P < 0.05; big-endothelin, 115.2 +/- 39.3 fmol/mL versus 89.2 +/- 25.1 fmol/mL, P < 0.05). There was a negative correlation between the age and big-endothelin level measured at both times (during VT/VF, r = 0.94, P < 0.05; control, r = 0.91, P < 0.05). In conclusion, serum big-endothelin and ET-1 levels were significantly higher during incessant VT/VF, which can be a cause of multiple arrhythmia recurrence.