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International journal of cardiology 05/2013; · 7.08 Impact Factor
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ABSTRACT: Resistant hypertension remains a challenging issue even for modern medicine. Therefore, research is focusing on the development of new technologies to optimize the treatment of this condition. It has been demonstrated that the dysfunction of the sympathetic nervous system is crucial in the development and maintenance of advanced stages of hypertension. Based on these findings, clinical trials have recently shown that catheter-based percutaneous renal denervation therapy is safe and effective in the treatment of resistant hypertension. This review discusses the current scientific knowledge of renal denervation therapy in resistant hypertension, including the different methods that have been described in the literature so far, as well as limitations of the available data. Furthermore, new potential targets for this fascinating therapy will be addressed.
Expert Review of Medical Devices 03/2013; 10(2):247-256. · 2.63 Impact Factor
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International journal of cardiology 10/2012; · 7.08 Impact Factor
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Biomedizinische Technik/Biomedical Engineering 09/2012; · 0.53 Impact Factor
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Biomedizinische Technik/Biomedical Engineering 08/2012; · 0.53 Impact Factor
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International journal of cardiology 04/2012; 157(3):447-8. · 7.08 Impact Factor
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ABSTRACT: Heart rate turbulence, deceleration capacity (DC), and symbolic dynamics (SD) are promising novel domains of autonomic indices representing the multidimensional qualities of autonomic heart rate dynamics.
The aim of this study was to test the impact of these novel indices in predicting early AF recurrence within the first month after electrical cardioversion (CV).
In 45 patients with AF, standard Holter recordings were commenced immediately after CV. Holter-based indices were retrospectively analyzed using computerized algorithms. The best indices were applied in a multivariate model to select the optimal combination set that correctly classified patients who developed early AF recurrence.
Early AF recurrence occurred in 25 vs 20 patients with stable sinus rhythm. The set with the highest predictive power consisted of DC, turbulence onset, VLF/P, and PTH19 as a parameter of SD. The receiver operating curve analysis applied to this optimum set produced an area under the curve of 0.86, thus correctly classifying patients with 95.0% specificity and 76.0% sensitivity.
The analysis of novel multidimensional Holter-based autonomic indices after CV appears of clinical value because the procedure identifies patients with high risk of early AF recurrence. Furthermore, it indicates a substantial alteration of autonomic regulation.
Journal of electrocardiology 03/2012; 45(2):116-22. · 1.08 Impact Factor
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ABSTRACT: The endovascular application of low-dose radiofrequency (RF) energy to the renal arteries results in effective ablation of sympathetic nerve fibres leading to a significant lowering of blood pressure (BP). This study aims to examine the feasibility and safety of renal denervation by the use of a standard electrophysiology (EP) catheter.
Twelve patients (mean age 62±14 years, nine male) with drug resistant hypertension despite medical treatment with at least four antihypertensive drugs underwent renal denervation by using a standard steerable RF ablation catheter with a 7 Fr diameter (Marinr®; Medtronic Inc., Minneapolis, MN, USA). Low-power RF applications have been applied along the length of both renal arteries, consecutively. Assessment of 24 hour ambulatory BP was done at baseline, at one, and at three months following RF ablation. The mean reduction of 24 hour ambulatory BP was -11/-7 mmHg at one month and -24/-14 mmHg at three months (p<0.01 for systolic and p<0.03 for diastolic blood pressure) with unchanged medication. No vascular complications have been observed in the short-term follow-up. The renal function as assessed by serum creatinine and proteinuria remained unchanged from baseline.
Our preliminary results indicate that the use of a standard RF ablation catheter is feasible and safe for sympathetic renal denervation as shown by a significant lowering of mean 24 hour ambulatory BP in comparison to baseline during short-term follow-up. Whether the use of a standard EP catheter for sympathetic renal denervation indeed improves the long-term outcome in resistant hypertension, however, remains to be investigated.
EuroIntervention: journal of EuroPCR in collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology 09/2011; 7(9):1077-80. · 3.29 Impact Factor
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ABSTRACT: It is not clear whether cardiac resynchronization therapy (CRT) should only be optimized at rest or whether it is necessary to perform CRT optimization during exercise. Our study aims to answer this question by using an inert gas rebreathing method (Innocor®).
Twenty-seven patients with congestive heart failure and implanted CRT devices were included in the study. The aetiology of the heart failure was ischaemic in nine (33%) patients. Patients had low left ventricular ejection fraction (29 ± 8%) and enlarged LV end-diastolic diameters (63 ± 7 mm). Atrioventricular delay (AVD) was optimized at rest according to cardiac index (CI), measured by inert gas rebreathing (Innocor®). Thereafter, patients performed standardized, steady-state bicycle exercise at 30 W in sitting body position. Three AVDs were tested during exercise in a random sequence: optimized resting AVD (AVD(opt)) according to baseline measurement; AVD(opt) - 30 ms; and AVD(opt) + 30 ms. Cardiac index was measured in each AVD by inert gas rebreathing. Cardiac index increased significantly during exercise. However, neither AVD(opt) shortening nor prolongation during exercise had significant effect on CI (shortening of AVD(opt) - 30 ms was accompanied by a reduction of CI of 4.8%, prolongation of AVD(opt) + 30 ms was accompanied by a reduction of CI of 7.7%).
Shortening or lengthening of the AVD during exercise has no impact on CI in CRT patients. On the basis of our results, we conclude that in CRT patients the AVD should be programmed, fixed even during exercise.
Europace 09/2011; 14(2):249-53. · 1.98 Impact Factor
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ABSTRACT: QRS duration (QRSd) and prolonged corrected QT interval (QTc) are associated with ventricular arrhythmic events. This study was designed to determine whether CRT by means of biventricular pacing alters the QTc and QRSd, and whether such changes are related to the risk of sustained ventricular tachyarrhythmias (sVTA).
A total of 127 patients (102 men, mean age 63.9 +/- 8.9 years) with drug-resistant heart failure and QRS duration > or = 130 ms underwent CRT/CRT-ICD. The aetiology of the heart failure was ischaemic in 41 patients (32.3%). After a median follow-up of 24 months, 42 sVTA occurred in 35 patients (27.6%). Twenty-nine patients had a single sVTA, in five patients two sVTA and in one patient three sVTA occurred. The paced QTc was longer in sVTA patients (505 +/- 55 ms) compared with no sVTA patients (486 +/- 44 ms, P < or = 0.003). Similar responses for paced QRSd were observed (182 +/- 27 ms in sVTA patients vs 167 +/- 27 ms in no-sVTA patients, P < or = 0.03). This effect was independent from intrinsic QTc and QRSd and the aetiology of the heart failure. The mortality rate was significantly higher in patients with ventricular fibrillation and fast VT (P < or = 0.004) who experienced shock therapies. However, the sVTA were not the immediate cause of death.
A pacing-induced increase in QTc and QRSd is related to sVTA in patients with CRT. Further studies are needed to determine whether optimization of CRT with the goal to achieve a narrow paced QRSd can reduce the occurrence of sVTA.
Acta cardiologica 08/2011; 66(4):415-20. · 0.61 Impact Factor
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ABSTRACT: Myocarditis is an injury of the myocardium caused by a variety of agents. Conduction disturbances such as complete atrioventricular block (AV block) may occur as an infrequent but serious complication of myocarditis. Early detection and accurate diagnosis of myocarditis are still unresolved challenges. We present 2 cases of otherwise mild myocarditis complicated by high-degree AV block in combination with isolated delayed uptake of contrast at the septal regions in the cardiac magnetic resonance imaging. Because the AV block was persistent in both cases, permanent pacemaker implantation was necessary. Delayed enhancement in the septal area in myocarditis might be predictive of infra-Hisian AV block.
Journal of electrocardiology 07/2011; 45(2):161-3. · 1.08 Impact Factor
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ABSTRACT: We investigated whether the use of therapeutic hypothermia improves the outcome after cardiac arrest (CA) under routine clinical conditions.
In a retrospective study, data of CA survivors treated from 2003 to 2010 were analysed. Of these, 143 patients were treated with hypothermia at 33 ± 0.5°C for 24h according to predefined inclusion criteria, while 67 who did not fulfil these criteria received comparable therapy without hypothermia.
210 patients were included, 143 in the hypothermia group (HG) and 67 in the normothermia group (NG). There was no significant difference in mortality between the groups; 69 (48.2%) in the HG died in the first four weeks, compared to 30 patients (44.8%) in the NG (p=0.659). Patients in the NG were older and more seriously ill, and CA occurred more often in-hospital. Binary logistic regression revealed ventricular fibrillation (p=0.044), NSE serum level < 33 ng ml⁻¹ (p<0.001), age (p=0.035) and witnessed cardiac arrest (p=0.043) as independent factors significantly improving survival after CA, whereas hypothermia was not (p=0.69). The target temperature was maintained for a significantly longer time (19.5h vs. 15.2h; p=0.003) in hypothermia patients with a favourable outcome than in those with an unfavourable outcome.
There was no improvement in survival rates when hypothermia was added to standard therapy in this case series, as compared to standard therapy alone. The time at target temperature may be of relevance. We need better evidence in order to expand the recommendations for hypothermia after CA.
Resuscitation 06/2011; 82(9):1168-73. · 3.60 Impact Factor
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Clinical Research in Cardiology 11/2009; 99(2):129-31. · 2.95 Impact Factor
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ABSTRACT: Voltage-gated Na+ channels mediate the rapid upstroke of the action potential in excitable tissues. Na(v)1.5, encoded by the SCN5A gene, is the predominant isoform in the heart. Mutations in SCN5A are associated with distinct cardiac excitation disorders often resulting in life-threatening arrhythmias. This review outlines the currently known SCN5A mutations linked to three distinct cardiac rhythm disorders: long QT syndrome subtype 3 (LQT3), Brugada syndrome (BS), and cardiac conduction disease (CCD). Electrophysiological properties of the mutant channels are summarized and discussed in terms of Na+ channel structure-function relationships and regarding molecular mechanisms underlying the respective cardiac dysfunction. Possible reasons for less convincing genotype-phenotype correlations are suggested.
Progress in Biophysics and Molecular Biology 12/2008; 98(2-3):120-36. · 3.20 Impact Factor
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ABSTRACT: The aim of the present study was to elucidate the molecular mechanism underlying the concomitant occurrence of cardiac conduction disease and long QT syndrome (LQT3), two SCN5A channelopathies that are explained by loss-of-function and gain-of-function, respectively, in the cardiac Na+ channel.
A Caucasian family with prolonged QT interval, intermittent bundle-branch block, sudden cardiac death, and syncope was investigated. Lidocaine (1 mg/kg i.v.) normalized the prolonged QT interval and rescued bundle-branch block. An SCN5A mutation analysis was performed that revealed a C-to-A mutation at position 4859 (exon 28), predicted to change a highly conserved threonine for a lysine at position 1620. Mutant channels were characterized both in Xenopus oocytes and HEK293 cells. The T1620K mutation remarkably altered the properties of Nav1.5 channels. In particular, the voltage-dependence of the current decay time constants was largely lost. As a consequence, mutant channels inactivated faster than wild-type channels at potentials negative to -30 mV, resulting in less Na+ inward current (loss-of-function), but significantly slower at potentials positive to -30 mV, resulting in an increased Na+ inward current (gain-of-function). Moreover, we found a hyperpolarized shift of steady-state activation and an accelerated recovery from inactivation (gain-of-function). At the same time, channel availability was significantly reduced at the resting membrane potential (loss-of-function).
We conclude that lysine at position 1620 leads to both loss-of-function and gain-of-function properties in hNav1.5 channels, which may consequently cause in the same individuals impaired impulse propagation in the conduction system and prolonged QTc intervals, respectively.
Cardiovascular Research 04/2008; 77(4):740-8. · 6.06 Impact Factor
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Matthias Heinke,
Helmut Kühnert, Ralf Surber,
Peter Osypka,
Hans Gerstmann,
Jens Haueisen,
Tobias Heinke,
Dirk Reinhard,
Dirk Prochnau,
Gudrun Dannberg,
Hans R Figulla
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ABSTRACT: INTRODUCTION: The purpose of this study was to evaluate termination of atrial flutter (AFL) by directed rapid transesophageal atrial pacing (TAP) with and without simultaneous transesophageal echocardiography (TEE) performed using a novel TEE tube electrode. MATERIALS AND METHODS, AND RESULTS: A total of 16 AFL patients (age 63+/-12 years; 13 males) with mean AFL cycle length of 224+/-24 ms (n=12) and mean ventricular cycle length of 448+/-47 ms (n=12) were analyzed using either an esophageal TO electrode (n=10) or a novel TEE tube electrode consisting of a tube with four hemispherical electrodes that is pulled over the echo probe (n=6). AFL could be terminated by directed rapid TAP using an esophageal TO electrode, leading to induction of atrial fibrillation (AF) (n=6), induction of AF and spontaneous conversion to sinus rhythm (SR) (n=3), and with conversion to SR (n=1). AFL could also be terminated by directed rapid TAP using the TEE tube electrode, with induction of AF (n=3) or induction of AF and spontaneous conversion to SR (n=3). CONCLUSION: AFL can be terminated by directed rapid TAP with hemispherical electrodes with and without simultaneous TEE. TAP with the directed TEE tube electrode is a safe, simple, and useful method for terminating AFL.
Biomedizinische Technik 02/2007; 52(2):180-4. · 0.86 Impact Factor
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ABSTRACT: INTRODUCTION: Biventricular (BV) pacing is an established therapy for heart failure (HF) patients with intraventricular conduction delay, but not all patients improved clinically. We investigated the interventricular delay (IVD) by means of the transesophageal left ventricular posterior wall potential (LVPWP). MATERIALS AND METHODS, AND RESULTS: A total of 18 HF patients (age 62+/-9 years; 15 males) with NYHA class 3.1+/-0.3, LV ejection fraction 22+/-7%, left bundle branch block and a QRS duration (QRSD) of 171+/-27 ms were analyzed using transesophageal LVPWP before implantation of a BV pacing device. The median follow up was 14+/-14 months. In 14 responders, IVD was 81+/-25 ms with a QRSD/IVD ratio of 2.2+/-0.3 with reclassification of NYHA class 3.1+/-0.3 to 2.0+/-0.5 (p<0.001) and an increase in LV ejection fraction from 22+/-7% to 36+/-11% (p=0.001) during long-term BV pacing. In four non-responders, transesophageal IVD was significantly smaller at 30+/-11 ms (p=0.001). CONCLUSION: Transesophageal IVD may be a useful method to detect responders to BV pacing. Transesophageal LVPWP may be a simple and useful technique to detect clinical responders to BV pacing in HF patients.
Biomedizinische Technik 01/2007; 52(2):173-9. · 0.86 Impact Factor
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ABSTRACT: We applied the novel ProteinChip technology (SELDI-MS) to investigate and identify differentially regulated proteins upon myocardial remodelling in different heart regions. Tissue samples were isolated from the atria, the interventricular septum, and the right and left ventricles three months after surgically-induced myocardial infarction (MI) in rats. Corresponding protein extracts from control versus MI hearts were analysed on two different ProteinChip surfaces. In each of the functionally distinct cardiac regions, we obtained specific protein profile alterations upon myocardial remodelling. Most alterations were observed in the non-infarcted right ventricle, where down-regulation occurred more frequently than up-regulation of protein expression. Three of the differentially regulated proteins were identified: the metabolic enzyme triosephosphate isomerase (TIM), the cell signalling protein Raf-1 kinase inhibitory protein (RKIP), also known as phosphatidylethanolamine binding protein (PEBP), and the small heat shock protein alphaB-crystallin. These proteins showed a pronounced tissue-dependent regulation. TIM was down-regulated only in the atrium and in the left ventricle, RKIP/PEBP was down-regulated only in the right ventricle and in the interventricular septum, and alphaB-crystallin was up-regulated only in the right and in the left ventricle. A simple correlation of peak intensity changes using two of the identified peaks demonstrated the diagnostic potential of SELDI-MS. We conclude that this novel proteomic method is a powerful high-throughput tool for the fast detection of region-specific cardiac protein profiles in small biopsy samples, and that SELDI-MS may become a useful complementary technique for the diagnosis and prognosis of cardiac diseases.
International Journal of Molecular Medicine 01/2007; 18(6):1207-15. · 1.98 Impact Factor
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ABSTRACT: Chronic total coronary occlusions (CTOs) with angiographically well-developed collaterals may be considered to provide sufficient blood supply to the occluded segment, and the indication for revascularization may be questioned. Therefore, the collateral function and functional reserve in patients with a CTO without a prior Q-wave myocardial infarction (MI) were assessed.
Invasive assessment of collateral function was done during successful percutaneous coronary intervention in 107 patients with a CTO and no prior Q-wave MI. Intracoronary Doppler flow velocity and pressure recordings were obtained distal to the occlusion before the first balloon inflation and collateral function indexes calculated. In 62 patients, additional pharmacological stress testing was done by intravenous adenosine (140 microg/kg/min) to assess the collateral flow reserve. Patients with normal and impaired regional dysfunction were compared. Collateral function was similar in patients with and without regional left ventricular (LV) dysfunction. In both groups, 78% collaterals provided a collateral pressure index at baseline > 0.3, sufficient to prevent ischaemia during a balloon occlusion, with a minimum of 0.2 in those with preserved LV function. A Doppler-derived function index showed a wider variation due to the high prevalence of microvascular dysfunction in CTOs. Only 7% of patients had an increase in collateral flow reserve > 2.0 during pharmacological stress, whereas coronary steal occurred in one-third independent of regional LV function.
A limited increase in collateral flow and the high prevalence of coronary steal during stress underscore the functional limitation of collaterals in CTOs without prior Q-wave MI. Even presumably 'well-collateralized' CTOs may benefit from a revascularization.
European Heart Journal 10/2006; 27(20):2406-12. · 10.48 Impact Factor
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ABSTRACT: Previous studies of biventricular (BV) pacing for treatment of heart failure (HF) patients with left bundle branch block (LBBB) evaluated responders to BV pacing with acute transvenous left ventricular (LV) pacing and arterial pulse pressure (PP). The aim of this study was to assess transoesophageal LV pacing in evaluation of the haemodynamic response with a view to upgrading responders from permanent right ventricular (RV) pacing to BV pacing.
Ten HF patients (age 62+/-8 years; one female, nine males) in NYHA III, LV ejection fraction 24+/-9% and permanent RV pacing by means of an implanted pacemaker or ICD were tested using transoesophageal LV pacing and PP. Permanently RV-paced HF patients were analysed with transoesophageal atrial sensed LV pacing in VAT mode with a different AV delay (n = 6) and with transoesophageal LV pacing in V00 mode during atrial fibrillation (n = 4). In five responders, PP was higher during transoesophageal LV pacing than PP during RV pacing (74+/-42 versus 57+/-31 mmHg, P = 0.015). Responders were upgraded by means of an LV lead via the coronary sinus in the posterior (n = 1) or posterolateral (n = 4) walls and after attaining a high LV pacing threshold with an epicardial LV lead on the anterior (n = 1) or anterolateral (n = 1) walls. NYHA class improved from 3 to 2+/-0.3 (P = 0.003) during 204+/-120 days follow-up and cardiac output increased from 4.4+/-1.5 to 5.6+/-1.7 l/min (P = 0.027) when comparing BV pacing and optimal AV delay with RV pacing. In five nonresponders, PP was not higher during transoesophageal LV pacing than during RV pacing.
Transoesophageal LV pacing may be a useful technique to detect responders to BV pacing in permanently RV-paced HF patients.
Europace 12/2005; 7(6):617-20. · 1.98 Impact Factor
