Institute for Clinical and Experimental Medicine IKEM

Prague, Czech Republic

Institute for Clinical and Experimental Medicine IKEM

Prague, Czech Republic
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Kuck K.-H.,Abt. Kardiologie | Reddy V.Y.,Mount Sinai School of Medicine | Schmidt B.,Abt. Kardiologie | Natale A.,The Texas Institute | And 9 more authors.
Heart Rhythm | Year: 2012

The aim of this multicenter study was to evaluate the device- and procedure-related safety of a novel force-sensing radiofrequency (RF) ablation catheter capable of measuring the real-time contact force (CF) and to present CF data and its possible implications on patient safety. The clinical outcome of RF ablation for the treatment of cardiac arrhythmias may be affected by the CF between the catheter tip and the tissue. Insufficient CF may result in an ineffective lesion, whereas excessive CF may result in complications. Seventy-seven patients (43 with right-sided supraventricular tachycardia [SVT] and 34 with atrial fibrillation [AF]) received percutaneous ablation with the novel studied catheter. The CF applied and safety events related to the procedure were reported. CF values at mapping ranged from 8 ± 8 to 60 ± 35 g and from 12 ± 10 to 39 ± 29 g in the SVT group and the LA group, respectively, showing a significant interinvestigator variability (P <.0001). High transient CFs (>100 g) were noted in 27 patients (79%) of the LA group. One device-related complication (tamponade, 3%) occurred in the AF group. Catheter ablation using real-time CF technology is safe for the treatment of SVT and AF. High CFs may occur during catheter manipulation and not just during ablation, suggesting that measuring CF may provide additional useful information to the operator for safe catheter manipulation. In the future, CF-sensing catheters may also increase the effectiveness of RF ablations by allowing better control of the RF lesion size.

Reddy V.Y.,Mount Sinai School of Medicine | Shah D.,University of Geneva | Kautzner J.,Institute for Clinical and Experimental Medicine IKEM | Schmidt B.,The Texas Institute | And 10 more authors.
Heart Rhythm | Year: 2012

Background: The clinical efficacy of catheter ablation of paroxysmal atrial fibrillation (AF) remains limited by difficulty in achieving durable pulmonary vein isolation (PVI). Suboptimal catheter tip-to-tissue contact force (CF) during lesion delivery is believed to reduce clinical efficacy. Objective: To determine the relationship between catheter CF during irrigated catheter ablation for AF and clinical recurrences during follow-up. Methods: Thirty-two patients with paroxysmal AF underwent PVI by using a radiofrequency ablation catheter with a CF sensor integrated at its tip, and they were followed for 12 months. The relationship between the CF and clinical outcomes was determined. Results: Acute PVI was achieved in 100% of the veins. Thirty-five percent (351 of 1017) of the applications were placed with an average CF of <10 g (low CF). All patients treated with an average CF of <10 g (5 of 5 patients) experienced recurrences, whereas 80% of the patients treated with an average CF of >20 g (8 of 10 patients) were free from AF recurrence at 12 months. The analysis of the average force-time integral showed that 75% of the patients treated with <500 gs were recurrent whereas only 31% of the patients treated with >1000 gs had recurrences at 12 months. Conclusions: The CF during catheter ablation for AF correlates with clinical outcome. Arrhythmia control is best achieved when ablation lesions are placed with an average CF of >20 g, and clinical failure is universally noted with an average CF of <10 g.

Kautzner J.,Institute for Clinical and Experimental Medicine IKEM | Neuzil P.,Na Homolce Hospital | Lambert H.,St. Jude Medical | Peichl P.,Institute for Clinical and Experimental Medicine IKEM | And 7 more authors.
Europace | Year: 2015

Aims A challenge of pulmonary vein isolation (PVI) in catheter ablation for paroxysmal atrial fibrillation (PAF) is electrical reconnection of the PV. EFFICAS I showed correlation between contact force (CF) parameters and PV durable isolation but no prospective evaluation was made. EFFICAS II was a multicentre study to prospectively assess the impact of CF guidance for an effective reduction of PVI gaps. Methods and results Pulmonary vein isolation using a radiofrequency (RF) ablation catheter with an integrated force sensor (TactiCath™) was performed in patients with PAF. Operators were provided EFFICAS I-based CF guidelines [target 20 g, range 10-30 g, minimum 400 g s force-time integral (FTI)]. Conduction gaps were assessed by remapping of PVs after 3 months, and gap rate was compared with EFFICAS I outcome. At follow up, 24 patients had 85% of PVs remaining isolated, compared with 72% in EFFICAS I (P = 0.037) in which CF guidelines were not used. The remaining 15% of gaps correlated to the number of catheter moves at creating the PVI line, quantified as Continuity Index. For PV lines with contiguous lesions and low catheter moves, durable isolation was 81% in EFFICAS I and 98% in EFFICAS II (P = 0.005). At index procedure, the number of lesions was reduced by 15% in EFFICAS II vs. EFFICAS I. Conclusion The use of CF with the above guidelines and contiguous deployment of RF lesions in EFFICAS II study resulted in more durable PVI in catheter ablation of PAF. © 2015 The Author 2015. Published by Oxford University Press on behalf of the European Society of Cardiology.

Neuzil P.,Na Homolce Hospital | Reddy V.Y.,Mount Sinai School of Medicine | Kautzner J.,Institute for Clinical and Experimental Medicine IKEM | Petru J.,Na Homolce Hospital | And 6 more authors.
Circulation: Arrhythmia and Electrophysiology | Year: 2013

Background-Pulmonary vein isolation is the most prevalent approach for catheter ablation of paroxysmal atrial fibrillation. Long-term success of the procedure is diminished by arrhythmia recurrences occurring predominantly because of reconnections in previously isolated pulmonary veins. The aim of the EFFICAS I multicenter study was to demonstrate the correlation between contact force (CF) parameters during initial procedure and the incidence of isolation gaps (gap) at 3-month follow-up. Method and Results-A radiofrequency ablation catheter with integrated CF sensor (TactiCath, Endosense, Geneva, Switzerland) was used to perform pulmonary vein isolation in 46 patients with paroxysmal atrial fibrillation. During the ablation procedure, the operator was blinded to CF information. At follow-up, an interventional diagnostic procedure was performed to assess gap location as correlated to index procedure ablation parameters. At follow-up, 65% (26/40) of patients showed ≥1 gaps. Ablations with minimum Force-Time Integral (FTI) <400 gs showed increased likelihood for reconnection (P<0.001). Reconnection correlated strongly with minimum CF (P<0.0001) and minimum FTI (P=0.0007) at the site of gap. Gap occurrence showed a strong trend with lower average CF and average FTI. CF and FTI are generally higher on the right side, although the left anterior segment presents a unique challenge to achieve stable position with good CF. Conclusions-Minimum CF and minimum FTI values are strong predictors of gap formation. Optimal CF parameter recommendations are a target CF of 20 g and a minimum FTI of 400 gs for each new lesion. © 2013 American Heart Association, Inc.

Melenovsky V.,Mayo Medical School | Melenovsky V.,Institute for Clinical and Experimental Medicine IKEM | Andersen M.J.,Mayo Medical School | Andersen M.J.,Aarhus University Hospital | And 3 more authors.
European Journal of Heart Failure | Year: 2015

Aims The goal of the study was to examine the prognostic impact, haemodynamic and clinical features associated with lung congestion in patients with chronic heart failure (HF). Methods and results HF patients (n = 186) and HF-free controls (n = 21) underwent right heart catheterization, echocardiography, pulmonary function testing and chest radiography that was blindly scored for the presence and severity of lung oedema. Lung congestion correlated directly with pulmonary vascular resistance (PVR, P = 0.004) and inversely with pulmonary artery (PA) compliance (P < 0.001) and the diffusion limit for carbon monoxide (DLCO, P = 0.009). Compared with dry lung HF, wet lung HF patients (congestion score > median) had 25% lower PA compliance and 25-35% higher PVR, transpulmonary gradients and PA pressures (40 vs. 32 mmHg, P < 0.001) despite marginally higher PA wedge pressure (PAWP; 22 vs. 19 mmHg, P = 0.002). Wet lung HF patients displayed more right ventricular (RV) dilatation and dysfunction, more restrictive ventilation and greater reduction of DLCO. The strongest correlates of lung congestion were NT-proBNP, haemoglobin, albumin, and glomerular filtration, all surpassing PAWP. After a median of 333 days (interquartile range 80-875), 59 patients (32%) died. Lung congestion was associated with reduced survival (P < 0.0001), even after adjusting for PAWP, NT-proBNP, anaemia, CAD and renal dysfunction. Conclusion Interstitial lung oedema is associated with pulmonary vascular disease, RV overload and dysfunction and increased mortality in HF. These data reinforce the importance of aggressive decongestion in HF and suggest that novel agents aimed at reducing lung water may help to deter progression of pulmonary vascular disease and biventricular HF. © 2015 The Authors. © 2015 European Society of Cardiology.

Sekerkova A.,Institute for Clinical and Experimental Medicine IKEM | Polackova M.,Faculty Hospital Bulovka
International Archives of Allergy and Immunology | Year: 2011

Background: Birch pollen belongs to the major allergen triggers in the spring season in Europe. Our rapidly expanding knowledge of the allergenic molecules enables us to better recognize the individual differences between the reactivity of specific IgE antibodies of individual patients and allergic populations living in various regions of the world. Method: In a group of birch pollen-allergic patients living in the Czech Republic (107 children, 71 adults) we detected the presence of Bet v1, Bet v2 and Bet v4 specific IgE antibodies. Results: Bet v1 specific IgE antibodies were identified in most patients without any significant differences between children and adults. Bet v2 positivity was found more frequently in the group of children than in adults (p = 0.02). In most adult patients Bet v1 monospecificity was more expressed as compared to the pediatric group. More allergic subjects reacted against minor birch allergens in the pediatric group (p = 0.02). Specific IgE antibodies against Bet v1 were not detected in 10% of the tested patients. In this group, 5% of birch pollen-allergic patients were found to not have specific IgE antibodies against any of the tested recombinant allergens. Conclusion: The investigation of specific IgE antibodies against Bet v1, Bet v2 and Bet v4 demonstrated that the specificity of allergen-induced IgE antibodies in birch pollen-allergic individuals is dependent not only on the region in which a patient lives but also on age. Especially in children, there is an increase in the number of allergic subjects who do not react exclusively against the major allergen. The question is whether some allergen-specific IgE antibodies will disappear depending on age or on the contrary whether their synthesis will be increased. Copyright © 2010 S. Karger AG.

Aldhoon B.,Institute for Clinical and Experimental Medicine IKEM | Wichterle D.,Institute for Clinical and Experimental Medicine IKEM | Peichl P.,Institute for Clinical and Experimental Medicine IKEM | Cihak R.,Institute for Clinical and Experimental Medicine IKEM | Kautzner J.,Institute for Clinical and Experimental Medicine IKEM
Europace | Year: 2013

AimsCatheter ablation (CA) for atrial fibrillation (AF) is a complex procedure that is associated with higher risk of complications. This study aimed at exploring the complication rate and corresponding risk factors in a high-volume centre with routine use of intracardiac echocardiography (ICE).Methods and resultsIn total 1192 consecutive AF ablation procedures (100% ICE-guided; 96.4% 3D-navigated; point-by-point radiofrequency ablation with open-irrigated tip catheter; 22.4% robotic navigation; 25.4% repeated ablation) were performed in 959 patients (aged 58 ± 9 years; 70.8% males; 35.9% persistent AF) between March 2006 and December 2010. Ablation endpoint in paroxysmal AF was complete electrical pulmonary vein isolation (PVI). Complex ablation was defined as PVI plus stepwise strategy for left atrial substrate ablation (43.5%) in persistent AF. Forty major complications (3.3%) during the procedure or within the 3 month follow-up were observed. No death or atrioesophageal fistula occurred. Three patients (0.25%) had cardiac tamponade/hemopericardium and five patients (0.42%) had cerebrovascular embolic event. Vascular injury was the most frequent (2.3%) complication. Low body weight was the only significant risk factor with 0.8% increase of complication rate per 10 kg of body weight decrease (P = 0.013). A trend for increase in complication rate was also observed for advanced age, female gender, and complex procedure.ConclusionAtrial fibrillation ablation procedures guided by ICE in a high-volume centre are associated with low rate of serious complications. The composite risk score consisting of body weight, age, gender, and complexity of procedure predicted complications. © The Author 2012.

Sramko M.,Institute for Clinical and Experimental Medicine IKEM | Wichterle D.,Institute for Clinical and Experimental Medicine IKEM | Kautzner J.,Institute for Clinical and Experimental Medicine IKEM
PLoS ONE | Year: 2016

This study evaluated hemodynamic feasibility and reproducibility of a new method for in vivo simulation of human atrial fibrillation (AF). The method was tested during sinus rhythm in 10 patients undergoing catheter ablation for AF. A simple electronic device was assembled that allowed triggering a cardiac stimulator by predefined series of RR intervals. Irregular RR interval sequences with a mean heart rate of 90/min and 130/min were obtained from ECG recordings of another patients with AF. Simultaneous atrioventricular pacing was delivered by catheters placed inside the coronary sinus and at the His bundle region. Hemodynamic effect of the simulated AF was assessed by invasive measurement of the left ventricular (LV) pressure, dP/dt, and Tau. Compared to regular pacing at the same mean heart rate, the simulated AF significantly impaired the LV both systolic and diastolic function. Repeated AF pacing in the same patients generated similar LV hemodynamics. The proposed method provides a realistic and reproducible in-vivo model of AF. It can be exploited for investigation of the hemodynamic consequences of AF in various patient populations. © 2016 Sramko et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Kleissner M.,Institute for Clinical and Experimental Medicine IKEM | Sramko M.,Institute for Clinical and Experimental Medicine IKEM | Kohoutek J.,Institute for Clinical and Experimental Medicine IKEM | Kautzner J.,Institute for Clinical and Experimental Medicine IKEM | Kettner J.,Institute for Clinical and Experimental Medicine IKEM
Resuscitation | Year: 2015

Background: Timing of coronary angiography (CAG) is still controversial in the out-of-hospital cardiac arrest survivors who present without ST-segment elevation. Methods and results: We analysed a prospective registry of 158 comatose survivors of out-of-hospital cardiac arrest. For further analysis, we included 99 patients without ST-segment elevation on the initial electrocardiogram. All patients underwent temperature management. Urgent CAG (<2. h from admission) was performed in 25% of the patients. A definite cause of the cardiac arrest could be identified during the index hospitalization in 82 patients: 36 had a non-ST-segment elevation acute coronary syndrome (NSTE-ACS) and 46 had a non-ACS diagnosis. Eighty-seven patients (88%) survived the index hospitalization and 65 (66%) were alive at six months. A favourable neurological status (cerebral performance category ≤2) was observed in 56% of the patients at discharge and in 56% after six months of follow-up. Neither the survival nor the neurological outcome differed between the patients in whom the CAG was performed urgently upon the admission and the patients in whom the CAG was initially not performed, regardless of the aetiology of the cardiac arrest. On the other hand, performing an urgent CAG was safe and it did not prolong the average time to achieve an effective hypothermia. Conclusions: Performing an urgent CAG in comatose cardiac arrest survivors without ST-segment elevation was not associated with better clinical and neurological outcome as compared to the initially conservative approach. © 2015 Elsevier Ireland Ltd.

Kautzner J.,Institute for Clinical and Experimental Medicine IKEM | Peichl P.,Institute for Clinical and Experimental Medicine IKEM
Journal of Atrial Fibrillation | Year: 2014

The efficacy of catheter ablation of atrial fibrillation (AF) remains limited. Increase of success would require more durable lesions without increased risk steam pop and cardiac perforation. Recently, novel technologies have been developed to estimate real-time catheter-tissue contact force (CF). This paper reviews three available tools for assessment of CF and data on experimental or clinical experience. Experimental data with open-irrigated catheter showed that lesion size was greater with applications of lower power (like 30 W) and greater CF (e.g. 30 to 40 g) than with high power and low CF. Impedance drop in the first 5 seconds was significantly correlated to catheter CF. Perforation was achieved more rapidly with the ablation catheter in a sheath despite the same CF because the sheath prevents catheter buckling. Clinical experience confirmed poor relationship between CF and either unipolar amplitude, bipolar amplitude, or impedance. Within the left atrium, the most common high CF site was found at the anterior/rightward LA roof, directly beneath the ascending aorta. Importantly, several studies showed that the use of CF leads to shorter procedure with less fluoroscopy time and less RF applications. CF assessment was also found to be associated with higher proportion of durable lesions. Finally, pilot studies showed that CF measurement could be associated with better clinical efficacy AF ablation.

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