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Journal of Cardiovascular Electrophysiology 08/2012; 23(10):E100. · 3.06 Impact Factor
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ABSTRACT: A growing number of patients with advanced heart failure fulfill a primary-prevention indication for an implantable cardioverter-defibrillator (ICD). This study seeks to identify new predictors of overall mortality in a Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT)-like collective to enhance risk stratification.
An impaired renal function and severely depressed left ventricular ejection fraction pose relevant risk factors for mortality in primary prevention ICD recipients.
Ninety-four consecutive ICD patients with New York Heart Association class II-III heart failure and depressed left ventricular function (left ventricular ejection fraction [LVEF] ≤35%) with no history of malignant ventricular arrhythmias were followed for 34 ± 20 months.
During this period, 30 patients died (32%). Deceased patients revealed a significantly worse renal function before ICD implantation (1.55 ± 0.7 mg/dL vs 1.1 ± 0.4 mg/dL; P = 0.007), suffered more often from coronary artery disease (53 vs 29; P = 0.006), and were older (69.5 ± 8 y vs 67 ± 12 y; P = 0.0002) than surviving patients. Furthermore, increased serum creatinine at baseline (2 mg/dL vs 1 mg/dL; odds ratio [OR]: 3.96, 95% confidence interval [CI]: 1.2-13.04, P = 0.02), presence of coronary artery disease (OR: 8.6, 95% CI: 1.1-65, P = 0.036), and low LVEF (OR per 5% baseline LVEF deterioration: 1.4, 95% CI: 1-1.8, P = 0.034) represented strong and independent predictors for overall mortality.
Impaired renal function, the presence of coronary artery disease, and reduced LVEF before implantation represent independent predictors for mortality in a cohort of patients with advanced systolic heart failure. These conditions still bear a high mortality risk, even if ICD implantation effectively prevents sudden arrhythmic death. Indeed, in patients suffering from several of the identified "high-risk" comorbidities, primary-prevention ICD implantation might have a limited survival benefit. The possible adverse effects of these comorbidities should be openly discussed with the potential ICD recipient and his or her close relatives. Clin. Cardiol. 2012 doi: 10.1002/clc.22018 The authors have no funding, financial relationships, or conflicts of interest to disclose.
Clinical Cardiology 06/2012; 35(9):575-9. · 2.15 Impact Factor
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ABSTRACT: AIMS: The current study includes all consecutive patients with advanced heart failure and cardiac resynchronization therapy (CRT) with an implantable cardioverter defibrillator (ICD) over a 10-year period in a tertiary referral centre. It aims at identifying independent risk factors for mortality during CRT-defibrillator (CRT-D) treatment.METHODS AND RESULTS: This study includes 239 consecutive patients who had undergone implantation of a CRT-D system (ejection fraction 25.9 ± 8%; 139 patients with ischaemic, 100 patients with non-ischaemic cardiomyopathy). Enrolment took place between 2001 and 2010, resulting in a median follow-up of 43 ± 30 months. During follow-up, 59 patients (25%) died. An impaired baseline kidney function [hazard ratio (HR) 1.98; 95% confidence interval (CI) 1.7-3; P< 0.0001], appropriate ICD therapy during follow-up (HR 2.1; CI 1.1-3.4; P= 0.001), lack of beta-blocker therapy (HR 2.3; CI 1.6-3.8; P= 0.004), and intake of amiodarone (HR 2; CI 1.8-4.1; P< 0.0001) were identified as predictors of overall mortality.CONCLUSION: This study demonstrates the benefit of beta-blocker therapy also in patients on long-term CRT-D treatment. It confirms the prognostic significance of impaired renal function and the occurrence of appropriate ICD therapies also in CRT-D patients. It argues for an intensified follow-up regimen and adjustment of heart failure treatment whenever these prognostic markers are identified in a patient treated with CRT-D.
Europace 05/2012; · 1.98 Impact Factor
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ABSTRACT: In order to optimize power delivery into the myocardium during radiofrequency ablation (RFA) without overheating the electrode tip, active cooling of the tip electrode as well as electrode tips made of gold have evolved. Recently, an externally irrigated gold tip electrode ablation catheter has been developed to combine the advantages of these 2 technologies. We sought to investigate the procedural parameters tip temperature, delivered power and cooling flow requirements of the irrigated gold tip catheter in comparison to the conventional irrigated platinum iridium (Pt) tip catheter in pulmonary vein isolation (PVI) and cavotricuspid isthmus (CTI) ablation.
Sixty patients referred for first PVI were randomized into ablation with irrigated gold tip catheter versus irrigated Pt tip catheter. Forty-nine patients received ablation of CTI following PVI. Mean and standard deviation from all measurements were calculated for each patient. During RFA of pulmonary veins, mean catheter tip temperature was significantly lower in the gold group (35.4 ± 0.9 °C vs 38.2 ± 0.8 °C, P < 0.001), and total amount of delivered energy was higher (1303.1 ± 81.1 W vs 1223.7 ± 115.6 W, P = 0.004). During CTI ablation, necessary saline flow was almost 2.5-fold lower in the gold group (22.5 ± 5.9 mL/min vs 52.5 ± 9.7 mL/min, P < 0.001), accompanied by significantly lower tip temperature (39.1 ± 0.6 °C vs 40.5 ± 1.4 °C, P < 0.001).
The irrigated gold tip electrode allows to deliver significantly more energy at a lower electrode tip temperature in RFA of PV and CTI in comparison to the irrigated Pt tip electrode. The required saline flow during CTI ablation is much lower than in Pt.
Journal of Cardiovascular Electrophysiology 03/2012; 23(7):717-21. · 3.06 Impact Factor
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ABSTRACT: Beta-adrenoceptors (β-AR) play an important role in the neurohumoral regulation of cardiac function. Three β-AR subtypes (β(1), β(2), β(3)) have been described so far. Total deficiency of these adrenoceptors (TKO) results in cardiac hypotrophy and negative inotropy. TKO represents a unique mouse model mimicking total unselective medical β-blocker therapy in men. Electrophysiological characteristics of TKO have not yet been investigated in an animal model.
In vivo electrophysiological studies using right heart catheterisation were performed in 10 TKO mice and 10 129SV wild type control mice (WT) at the age of 15 weeks. Standard surface ECG, intracardiac and electrophysiological parameters, and arrhythmia inducibility were analyzed.
The surface ECG of TKO mice revealed a reduced heart rate (359.2±20.9 bpm vs. 461.1±33.3 bpm; p<0.001), prolonged P wave (17.5±3.0 ms vs. 15.1±1.2 ms; p = 0.019) and PQ time (40.8±2.4 ms vs. 37.3±3.0 ms; p = 0.013) compared to WT. Intracardiac ECG showed a significantly prolonged infra-Hisian conductance (HV-interval: 12.9±1.4 ms vs. 6.8±1.0 ms; p<0.001). Functional testing showed prolonged atrial and ventricular refractory periods in TKO (40.5±15.5 ms vs. 21.3±5.8 ms; p = 0.004; and 41.0±9.7 ms vs. 28.3±6.6 ms; p = 0.004, respectively). In TKO both the probability of induction of atrial fibrillation (12% vs. 24%; p<0.001) and of ventricular tachycardias (0% vs. 26%; p<0.001) were significantly reduced.
TKO results in significant prolongations of cardiac conduction times and refractory periods. This was accompanied by a highly significant reduction of atrial and ventricular arrhythmias. Our finding confirms the importance of β-AR in arrhythmogenesis and the potential role of unspecific beta-receptor-blockade as therapeutic target.
PLoS ONE 01/2012; 7(11):e49203. · 4.09 Impact Factor
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Revista Espa de Cardiologia 06/2011; 64(9):840-1. · 2.53 Impact Factor
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Markus Linhart,
Jörg O Schwab,
Barbara Bellmann,
Jan W Schrickel,
Jens Kreuz,
Osman Balta,
Claas P Naehle,
Katharina Strach,
Christian Schneider,
Bahman Esmailzadeh,
Rolf Fimmers,
Georg Nickenig,
Lars M Lickfett
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ABSTRACT: Little is known about the prevalence of upper extremity vein obstruction or anomalies in patients before first implantation of implantable cardioverter defibrillator (ICD). It remains unclear in which patients contrast venography is warranted before implantation procedure.
Results of clinical data and contrast venography of 302 consecutive patients scheduled for first ICD implantation were analyzed.
Prevalence of upper vein obstruction was 6.6% (20/302 patients) in a typical patient population undergoing first ICD implantation. Age, left ventricular ejection fraction, underlying heart disease, prior open-heart surgery, or cardiopulmonary resuscitation were not predictors of obstruction. Patients with previous cardiac pacemaker implantation had a higher rate of obstruction, though this was not statistically significant (20% vs 15.7%, P = 0.54). Persistent left vena cava was found in 0.7%.
There is no clinical parameter sufficient enough to predict upper extremity venous obstruction. Contrast venography may be considered in patients with previous pacemaker placement but should not be a routine diagnostic tool in unselected patients prior to first ICD-implantation procedure.
Pacing and Clinical Electrophysiology 02/2011; 34(6):684-9. · 1.35 Impact Factor
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ABSTRACT: Malignant ventricular arrhythmias and inappropriate therapies represent unsolved problems in patients with implantable cardioverter/defibrillator (ICD) for primary prevention. This study focuses on the incidence of such therapies and thereby seeks to identify new predictors of adverse events to enhance risk stratification.
Ninety-four consecutive patients with mild-to-moderate heart failure (NYHA II-III) and depressed left ventricular function (≤35%) were followed for 34 ± 20 months. Two hundred and ninety-one malignant ventricular arrhythmias were documented in 51 patients (54%). Eighteen patients (19%) received inappropriate ICD therapies (e.g. atrial fibrillation, sinus tachycardia, etc.). Patients with malignant arrhythmia (1.34 ± 0.44 vs. 1.16 ± 0.4 mg/dL, P = 0.017) and patients suffering from inappropriate ICD therapies (1.54 ± 0.48 vs. 1.2 ± 0.38 mg/dL; P = 0.007) revealed a significantly worse renal function before ICD implantation than participants without any therapy. An increased serum creatinine at baseline (2 vs. 1 mg/dL; odds ratio (OR) 3.96; P = 0.02; 95% CI: 1.2-13.04) and NHYA class III compared with II (OR: 2.96; P = 0.02; 95% CI: 1.16-7.48) represent strong and independent predictors for the occurrence of ventricular arrhythmias. Moreover, an impaired renal function is identified as an independent risk factor for inappropriate therapies (OR: 5.6; P = 0.004; 95% CI: 1.72-18.22).
An impaired renal function and advanced heart failure before ICD implantation for primary prevention are identified as independent predictors for the incidence of appropriate ICD interventions. With regard to current guidelines and economical aspects, patients suffering from an impaired renal function or advanced heart failure seem to benefit most from ICD therapy.
Europace 10/2010; 12(10):1439-45. · 1.98 Impact Factor
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Jan Wilko Schrickel,
Florian Stöckigt,
Wieslaw Krzyzak,
Denise Paulin,
Zhenlin Li,
Indra Lübkemeier,
Bernd Fleischmann,
Philipp Sasse, Markus Linhart,
Thorsten Lewalter,
Georg Nickenig,
Lars Lickfett,
Rolf Schröder,
Christoph Stephan Clemen
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ABSTRACT: Desmin mutations in humans cause desmin-related cardiomyopathy, resulting in heart failure, atrial and ventricular arrhythmias, and sudden cardiac death. The intermediate filament desmin is strongly expressed in striated muscle cells and in Purkinje fibers of the ventricular conduction system. The aim of the present study was to characterize electrophysiological cardiac properties in a desmin-deficient mouse model.
The impact of desmin deficiency on cardiac electrophysiological characteristics was examined in the present study. In vivo electrophysiological studies were carried out in 29 adult desmin deficient (Des-/-) and 19 wild-type (Des+/+) mice. Additionally, epicardial activation mapping was performed in Langendorff-perfused hearts.
Intracardiac electrograms showed no significant differences in AV, AH, and HV intervals. Functional testing revealed equal AV-nodal refractory periods, sinus-node recovery times, and Wenckebach points. However, compared to the wild-type situation, Des-/- mice were found to have a significantly reduced atrial (23.6+/-10.3 ms vs. 31.8+/-12.5 ms; p=0.045), but prolonged ventricular refractory period (33.0+/-8.7 ms vs. 26.7+/-6.5 ms; p=0.009). The probability of induction of atrial fibrillation was significantly higher in Des-/- mice (Des-/-: 38% vs. Des+/+: 27%; p=0.0255), while ventricular tachycardias significantly were reduced (Des-/-: 7% vs. Des+/+: 21%; p<0.0001). Epicardial activation mapping showed slowing of conduction in the ventricles of Des-/- mice.
Des-/- mice exhibit reduced atrial but prolonged ventricular refractory periods and ventricular conduction slowing, accompanied by enhanced inducibility of atrial fibrillation and diminished susceptibility to ventricular arrhythmias. Desmin deficiency does not result in electrophysiological changes present in human desminopathies, suggesting that functional alterations rather than loss of desmin cause the cardiac alterations in these patients.
Journal of Interventional Cardiac Electrophysiology 04/2010; 28(2):71-80. · 1.17 Impact Factor
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Katharina Strach,
Claas Philip Naehle,
Artur Mühlsteffen,
Michael Hinz,
Adam Bernstein,
Daniel Thomas, Markus Linhart,
Carsten Meyer,
Sascha Bitaraf,
Hans Schild,
Torsten Sommer
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ABSTRACT: The number of low-field (<0.5 T) magnetic resonance (MR) scanners installed worldwide is increasing due to a favourable cost and safety profile and improved patient comfort using an open-scanner design. Therefore, the aim of our study was to evaluate a strategy for the safe performance of magnetic resonance imaging (MRI) at a field strength of 0.2 T, in pacemaker (PM) patients without limitations on scan region, PM dependency, or the presence of abandoned leads.
One hundred and fourteen PM patients, including PM-dependent patients and patients with abandoned leads, examined at a 0.2 T MR scanner due to an urgent clinical need for an MRI examination, were evaluated. All PMs were reprogrammed before MRI: if heart rate was <60 bpm, the asynchronous mode (with a rate of 80 bpm) was programmed to avoid MR-induced inhibition; if heart rate was >60 bpm, sense-only mode (ODO/OVO/OAO) was used to avoid MR-induced competitive pacing and potential proarrhythmia. Patients were monitored with electrocardiogram (ECG) and pulse oximetry. All PMs were interrogated before and after MRI, including measurement of lead impedance, pacing capture threshold (PCT), and battery voltage. All MRI scans were completed safely. No induction of arrhythmias or inhibition of PM output occurred. There were no statistically significant changes in lead impedance, PCT, or battery voltage (P>0.05).
Low-field MRI of PM patients, including high-risk PM patients and MRI scan regions, can be performed with an acceptable risk-benefit ratio under controlled conditions.
Europace 03/2010; 12(7):952-60. · 1.98 Impact Factor
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Jan Wilko Schrickel,
Lars Lickfett,
Thorsten Lewalter,
Erica Mittman-Braun,
Stephanie Selbach,
Katharina Strach,
Claas P Nähle,
Jörg Otto Schwab, Markus Linhart,
Rene Andrié,
Georg Nickenig,
Torsten Sommer
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ABSTRACT: Left atrial catheter ablation of the pulmonary veins (PV) has evolved as an important therapeutic option for the treatment of atrial fibrillation (AF). We aimed to investigate the incidence and predictors of silent cerebral embolism associated with PV catheter ablation, detected by diffusion-weighted magnetic resonance imaging (DW-MRI).
We performed a prospective analysis of 53 consecutive patients with persistent or paroxysmal AF that underwent PV ablation and post-procedural cerebral MRI 1 day after lasso catheter-guided ostial PV ablation. Patients were analysed for possible demographical, medical, echocardiographical, and procedural predictors of embolic events. A mean of 3.5 +/- 0.5 PVs were ablated per patient. In six patients, DW-MRI depicted new clinically silent microembolism after PV ablation (11%). The number of ineffective medical antiarrhythmic agents prior to ablation procedure was significantly higher in the embolism group (3.3 +/- 0.5 vs. 2.2 +/- 1.4, P = 0.014). Coronary heart disease (CAD) was more frequent in patients with cerebral embolisms (33 vs. 2%, P = 0.031); left ventricular volume (130 +/- 12 vs. 103 +/- 26 mL, P = 0.002), and septal wall thickness (13.0 +/- 1.4 vs. 7.9 +/- 4.8 mm, P = 0.025) were significantly increased.
This study shows a high incidence of silent micro-embolic events after PV ablation. CAD, left ventricular dilatation, and hypertrophy were potential predictors of this complication.
Europace 11/2009; 12(1):52-7. · 1.98 Impact Factor
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Julia Otten,
Peter F M van der Ven,
Padmanabhan Vakeel,
Stefan Eulitz,
Gregor Kirfel,
Oliver Brandau,
Michael Boesl,
Jan W Schrickel, Markus Linhart,
Katrin Hayess,
Francisco J Naya,
Hendrik Milting,
Rainer Meyer,
Dieter O Fürst
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ABSTRACT: Xin is a striated muscle-specific F-actin binding protein that has been implicated in cardiomyopathies. In cardiomyocytes, Xin is localized at intercalated discs (IDs). Mice lacking only two of the three Xin isoforms (XinAB(-/-) mice) develop severe cardiac hypertrophy. To further investigate the function of Xin variants in the mammalian heart, we generated XinABC(-/-) mice deficient in all Xin isoforms.
XinABC(-/-) mice showed a very mild phenotype: heart weight, heart weight to tibia length ratios, and cardiac dimensions were not altered. Increased perivascular fibrosis was only observed in hearts of young XinABC(-/-) mice. Striking differences were revealed in isolated cardiomyocytes: XinABC(-/-) cells demonstrated a significantly increased number of non-terminally localized ID-like structures. Furthermore, resting sarcomere length was increased, sarcomere shortening, peak shortening at 0.5-1 Hz, and the duration of shortening were decreased, and shortening and relengthening velocities were accelerated at frequencies above 4 Hz in XinABC(-/-) cardiomyocytes. ECG showed a significantly shorter HV interval and a trend towards shorter QRS interval in XinABC(-/-) mice, suggesting a faster conduction velocity of the ventricular-specific conduction system. In human cardiac tissue, expression of XinC protein was detected solely in samples from patients with cardiac hypertrophy.
Total Xin deficiency leads to topographical ID alterations, premature fibrosis and subtle changes in contractile behaviour; this is a milder cardiac phenotype than that observed in XinAB(-/-) mice, which still can express XinC. Together with the finding that XinC is detected solely in cardiomyopathic human tissues, this suggests that its expression is responsible for the stronger dominant phenotype in XinAB(-/-) mice. Furthermore, it indicates that XinC may be involved in the development of human cardiac hypertrophy.
Cardiovascular research 10/2009; 85(4):739-50. · 5.80 Impact Factor
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ABSTRACT: Our aim was to establish and evaluate a strategy for safe performance of magnetic resonance imaging (MRI) at 1.5-T in patients with implantable cardioverter-defibrillators (ICDs).
Expanding indications for ICD placement and MRI becoming the imaging modality of choice for many indications has created a growing demand for MRI in ICD patients, which is still considered an absolute contraindication.
Non-pacemaker-dependent ICD patients with a clinical need for MRI were included in the study. To minimize radiofrequency-related lead heating, the specific absorption rate was limited to 2 W/kg. ICDs were reprogrammed pre-MRI to avoid competitive pacing and potential pro-arrhythmia: 1) the lower rate limit was programmed as low as reasonably achievable; and 2) arrhythmia detection was programmed on, but therapy delivery was programmed off. Patients were monitored using electrocardiography and pulse oximetry. All ICDs were interrogated before and after the MRI examination and after 3 months, including measurement of pacing capture threshold, lead impedance, battery voltage, and serum troponin I.
Eighteen ICD patients underwent a total of 18 MRI examinations at 1.5-T; all examinations were completed safely. All ICDs could be interrogated and reprogrammed normally post-MRI. No significant changes of pacing capture threshold, lead impedance, and serum troponin I were observed. Battery voltage decreased significantly from pre- to post-MRI. In 2 MRI examinations, oversensing of radiofrequency noise as ventricular fibrillation occurred. However, no attempt at therapy delivery was made.
MRI of non-pacemaker-dependent ICD patients can be performed with an acceptable risk/benefit ratio under controlled conditions by taking both MRI- and pacemaker-related precautions. (Implantable Cardioverter Defibrillators and Magnetic Resonance Imaging of the Heart at 1.5-Tesla; NCT00356239).
Journal of the American College of Cardiology 09/2009; 54(6):549-55. · 14.16 Impact Factor
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ABSTRACT: Ablation of pulmonary veins (PV) is an established therapeutic option for patients with symptomatic drug-refractory paroxysmal atrial fibrillation (AF). Radiofrequency (RF) is currently the most widespread energy source for PV ablation. Cryothermal energy applied with a cryoballoon technique as an alternative has recently evolved.
In a case-control setting, we compared 20 patients with paroxysmal AF who underwent their first PV ablation with the cryoballoon technique to 20 matched patients with conventional RF ablation. In the case of persistent electrical potentials after cryoballoon ablation, it was combined with ablation with a conventional cryocatheter. All patients performed daily event recording for 3 months after ablation procedure. Ablation parameters and success rate after 3 and 6 months were compared. In the cryoballoon group, the overall success rate was 55% (50% in the cryoballoon only group [14 patients] and 66% in the combination group [6 patients]), as opposed to the RF group with 45%. AF episode burden was lower after cryoballoon ablation. There was no significant difference between cryoballoon and RF ablation regarding procedure parameters. In the cryoballoon group, 3 phrenic nerve palsies occurred using the 23 mm balloon that resolved spontaneously.
PV ablation with the cryoballoon technique is feasible and seems to have a similar success rate in comparison to RF ablation. Procedure- and fluoroscopy duration are not longer than in conventional RF ablation.
Journal of Cardiovascular Electrophysiology 08/2009; 20(12):1343-8. · 3.06 Impact Factor
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ABSTRACT: Connexin (Cx) 30.2, Cx40 and Cx45 containing gap junctional channels contribute to electrical impulse propagation through the mouse atrioventricular node (AV-node). The cross talk in between these Cxs may be of great importance for AV-nodal conduction. We generated Cx30.2/Cx40 double deficient mice (Cx30.2(LacZ/LacZ)Cx40(-/-)) and analyzed the relative impact of Cx30.2 and Cx40 on cardiac conductive properties in vivo by use of electrophysiological examination. Cx30.2(LacZ/LacZ)Cx40(-/-) mice exhibited neither obvious cardiac malformations nor impaired contractile function. In surface-ECG analyses, Cx30.2(LacZ/LacZ)Cx40(-/-) and Cx40 deficient animals (Cx40(-/-)) showed significantly longer P-wave durations, PQ-intervals and prolonged QRS-complexes relative to wildtype littermates (WT). Cx30.2-deficient mice (Cx30.2(LacZ/LacZ)) developed shorter PQ-intervals as compared to WT, Cx40(-/-) or Cx30.2/Cx40 double deficient mice. Intracardiac evaluation of the atria-His (AH) and His-ventricle (HV) intervals representing supra and infra-Hisian conduction yielded significant acceleration of supra-Hisian conductivity in Cx30.2(LacZ/LacZ) (AH: 28.2+/-4.3 ms) and prolongation of infra-Hisian conduction in Cx40(-/-) mice (HV: 13.7+/-2.6 ms). These parameters were unchanged in the Cx30.2(LacZ/LacZ)Cx40(-/-) mice (AH: 37.3+/-5.5 ms, HV: 11.7+/-2.6 ms), which exhibited AV-nodal and ventricular conduction times similar to WT animals (AH: 35.9+/-4.4 ms, HV: 10.5+/-1.9 ms). We conclude that the remaining Cx45 gap junctional channels are sufficient to maintain electrical coupling and cardiac impulse propagation in the AV-node and proximal ventricular conduction system in mice. We suggest that Cx30.2 and Cx40 act as counterparts in the AV-node and His-bundle, decreasing or increasing, respectively, electrical coupling and conduction velocity in these areas.
Journal of Molecular and Cellular Cardiology 03/2009; 46(5):644-52. · 5.17 Impact Factor
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Markus Linhart,
Hanke Mollnau,
Alexander Bitzen,
Sabine Wurtz,
Jan W Schrickel,
René Andrié,
Florian Stöckigt,
Christian Weiss,
Georg Nickenig,
Lars M Lickfett,
Thorsten Lewalter
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ABSTRACT: We compared a newly developed irrigated gold tip electrode ablation catheter and a gold tip 4 and 8 mm catheter with the corresponding platinum-iridium (Pt) tip catheters in an in vitro setting.
In a flow chamber simulating physiological flow conditions, radiofrequency catheter ablation was performed on tissue samples of porcine endomyocardium and liver. Lesion depth, energy and temperature delivery, and popping frequency were determined. Two hundred and fifty-three ablations were conducted. Four and eight millimetre, gold tip electrode catheters produced significantly deeper lesions compared with the Pt tip electrode (liver 4 mm: 4.67 +/- 1.7 vs. 2.9 +/- 1.0 mm, P < 0.0001; endomyocardium 4 mm: 3.88 +/- 1.1 vs. 2.81 +/- 0.7 mm, P < 0.001; liver 8 mm: 3.98 +/- 1.0 vs. 2.03 +/- 1.1 mm, P < 0.001; endomyocardium 8 mm: 4.00 +/- 0.9 vs. 3.39 +/- 0.8 mm, P < 0.001) and correlated with the amount of energy delivery. Popping frequency was significantly higher in gold tip electrodes. In irrigated tip electrodes, there was no difference in the lesion depth comparing gold with Pt (liver: 5.18 +/- 0.7 vs. 5.01 +/- 0.7 mm, P = ns; endomyocardium: 4.89 +/- 0.7 vs. 4.78 +/- 0.8 mm, P = ns). There was a trend towards less popping in the gold tip electrode.
Both 4 and 8 mm not-irrigated gold tip catheters produced deeper lesions than the corresponding Pt tip catheter. In irrigated tip catheters, gold and Pt tip material did not show differences in the lesion depth.
Europace 02/2009; 11(5):565-70. · 1.98 Impact Factor
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Alexander Bitzen,
Karsten Sternickel,
Thorsten Lewalter,
Jörg Otto Schwab,
Alexander Yang,
Jan Wilko Schrickel, Markus Linhart,
Christian Wolpert,
Werner Jung,
Peter David,
Berndt Lüderitz,
Georg Nickenig,
Lars Lickfett
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ABSTRACT: Patients with atrial fibrillation (AF) often exhibit abnormalities of P wave morphology during sinus rhythm. We examined a novel method for automatic P wave analysis in the 24-hour-Holter-ECG of 60 patients with paroxysmal or persistent AF and 12 healthy subjects.
Recorded ECG signals were transferred to the analysis program where 5-10 P and R waves were manually marked. A wavelet transform performed a time-frequency decomposition to train neural networks. Afterwards, the detected P waves were described using a Gauss function optimized to fit the individual morphology and providing amplitude and duration at half P wave height.
>96% of P waves were detected, 47.4 +/- 20.7% successfully analyzed afterwards. In the patient population, the mean amplitude was 0.073 +/- 0.028 mV (mean variance 0.020 +/- 0.008 mV(2)), the mean duration at half height 23.5 +/- 2.7 ms (mean variance 4.2 +/- 1.6 ms(2)). In the control group, the mean amplitude (0.105 +/- 0.020 ms) was significantly higher (P < 0.0005), the mean variance of duration at half height (2.9 +/- 0.6 ms(2)) significantly lower (P < 0.0085).
This method shows promise for identification of triggering factors of AF.
Annals of Noninvasive Electrocardiology 10/2007; 12(4):306-15. · 1.10 Impact Factor
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Alexander Bitzen M.D,
Karsten Sternickel Ph.D,
Thorsten Lewalter M.D,
Jörg Otto Schwab M.D,
Alexander Yang M.D,
Jan Wilko Schrickel M.D,
Markus Linhart M.D,
Christian Wolpert M.D,
Werner Jung M.D,
Peter David Ph.D, [......],
Jörg Otto Schwab,
Alexander Yang,
Jan Wilko Schrickel, Markus Linhart,
Christian Wolpert,
Werner Jung,
Peter David,
Berndt Lüderitz,
Georg Nickenig,
Lars Lickfett
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ABSTRACT: Background: Patients with atrial fibrillation (AF) often exhibit abnormalities of P wave morphology during sinus rhythm. We examined a novel method for automatic P wave analysis in the 24-hour-Holter-ECG of 60 patients with paroxysmal or persistent AF and 12 healthy subjects.Methods: Recorded ECG signals were transferred to the analysis program where 5–10 P and R waves were manually marked. A wavelet transform performed a time-frequency decomposition to train neural networks. Afterwards, the detected P waves were described using a Gauss function optimized to fit the individual morphology and providing amplitude and duration at half P wave height.Results: >96% of P waves were detected, 47.4 ± 20.7% successfully analyzed afterwards. In the patient population, the mean amplitude was 0.073 ± 0.028 mV (mean variance 0.020 ± 0.008 mV2), the mean duration at half height 23.5 ± 2.7 ms (mean variance 4.2 ± 1.6 ms2). In the control group, the mean amplitude (0.105 ± 0.020 ms) was significantly higher (P < 0.0005), the mean variance of duration at half height (2.9 ± 0.6 ms2) significantly lower (P < 0.0085).Conclusions: This method shows promise for identification of triggering factors of AF.
Annals of Noninvasive Electrocardiology 09/2007; 12(4):306 - 315. · 1.10 Impact Factor
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ABSTRACT: Atrial flutter is a relatively frequent macro-reentrant tachycardia that can be caused by a variety of structural and functional atrial changes. Cardiac lymphoma is rare and usually carries a poor prognosis. It preferentially involves the right atrium. This report describes a patient with cardiac follicular B-cell lymphoma who developed paroxysmal atrial flutter. The large tumor mass created a macroscopic substrate for an area of slow conduction which is essential for atrial flutter. It also caused sinus arrest and intermittent obstruction of the tricuspid valve inlet.
Pacing and Clinical Electrophysiology 07/2006; 29(6):682-4. · 1.35 Impact Factor
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Thorsten Lewalter,
Alexander Yang,
Dietrich Pfeiffer,
Jaap Ruiter,
Götz Schnitzler,
Tilmann Markert,
Mogens Asklund,
Oliver Przibille,
Armin Welz,
Bahman Esmailzadeh, Markus Linhart,
Berndt Lüderitz
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ABSTRACT: The VIP registry investigated the efficacy of preventive pacing algorithm selection in reducing atrial fibrillation (AF) burden.
There are few data identifying which patients might benefit most from which preventive pacing algorithms.
Patients, with at least one documented AF episode and a conventional antibradycardia indication for pacemaker therapy, were enrolled. They received pacemakers with AF diagnostics and four preventive algorithms (Selection and PreventAF series, Vitatron). A 3-month Diagnostic Phase with conventional pacing identified a Substrate Group (>70% of AF episodes with <2 premature atrial contractions [PACs] before AF onset) and a Trigger Group (< or =70% of AF episodes with <2 PACs before AF onset). This was followed by a 3-month Therapeutic Phase where in the Trigger Group algorithms were enabled aimed at avoiding or preventing a PAC and in the Substrate Group continuous atrial overdrive pacing was enabled.
One hundred and twenty-six patients were evaluated. In the Trigger Group (n = 73), there was a statistically significant 28% improvement in AF burden (median AF burden: 2.06 hours/day, Diagnostic Phase vs 1.49 hours/day, Therapy Phase; P = 0.03304 signed-rank test), and reduced PAC activity. There was no significant improvement in AF burden in the Substrate Group (median AF burden: 1.82 hours/day, Diagnostic Phase vs 2.38 hours/day, Therapy Phase; P = 0.12095 signed-rank test), and little change in PAC activity.
We identified a subgroup of patients for whom the selection of appropriate pacing algorithms, based on individual diagnostic data, translated into a reduced AF burden. Trigger AF patients were more likely responders to preventive pacing algorithms as a result of PAC suppression.
Pacing and Clinical Electrophysiology 02/2006; 29(2):124-34. · 1.35 Impact Factor
