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1.
Circ Arrhythm Electrophysiol ; 8(5): 1080-7, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26297786

RESUMO

BACKGROUND: Pulmonary vein isolation (PVI) is still associated with a substantial number of arrhythmia recurrences in paroxysmal atrial fibrillation (AF). This prospective, randomized study aimed to compare 2 different procedural strategies. METHODS AND RESULTS: A total of 152 patients undergoing de novo ablation for paroxysmal AF were randomized to 2 different treatment arms. The procedure in group A consisted of PVI exclusively. In this group, all isolated PVs were challenged with adenosine to reveal and ablate dormant conduction. In group B, PVI was performed with the patient either in spontaneous or in induced AF. If AF did not terminate with PVI, ablation was continued by targeting extra-PV AF sources with the desired procedural end point of termination to sinus rhythm. Primary study end point was freedom from arrhythmia during 1-year follow-up. In group A, adenosine provoked dormant conduction in 31 (41%) patients with a mean of 1.6±0.8 transiently recovered PVs per patient. Termination of AF during PVI was observed in 31 (65%) patients, whereas AF persisted afterward in 17 (35%) patients. AF termination occurred in 13 (76%) patients by AF source ablation. After 1-year follow-up, significantly more group B patients were free of arrhythmia recurrences (87 versus 68%; P=0.006). During redo ablation, the rate of PV reconduction did not differ between both groups (group A: 55% versus group B: 61%; P=0.25). CONCLUSIONS: Elimination of extra-PV AF sources after PVI is superior to sole PV isolation with the adjunct of abolishing potential dormant conduction. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02238392.


Assuntos
Fibrilação Atrial/cirurgia , Ablação por Cateter/métodos , Veias Pulmonares/cirurgia , Adenosina/administração & dosagem , Idoso , Antiarrítmicos/administração & dosagem , Fibrilação Atrial/fisiopatologia , Eletrocardiografia , Determinação de Ponto Final , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Veias Pulmonares/fisiopatologia , Recidiva , Resultado do Tratamento
2.
J Cardiovasc Electrophysiol ; 26(9): 956-962, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26062031

RESUMO

INTRODUCTION: Open irrigated radiofrequency (RF) ablation catheters with a porous tip (56 holes, TC-SF) permit delivering RF energy in a temperature-controlled mode without temperature rise. This prospective observational study investigated the association of different catheter parameters on the occurrence of audible steam pops during left atrial (LA) ablation. METHODS AND RESULTS: A total of 226 patients underwent TC-SF catheter ablation for atrial fibrillation. RF power delivery, impedance and catheter tip temperature were continually recorded throughout the ablation. Pulmonary vein isolation was performed with a maximum of 27 W and LA electrogram-guided or linear ablation with a maximum of 30 W. A total of 59 audible steam pops occurred, 2 of them resulting in pericardial tamponade. In the initial 89 patients, with an irrigation flow rate of 10 mL/min, 18 steam pops with one tamponade occurred in 12 (14%) patients. Subsequently, the irrigation flow rate was increased to 20 mL/min in the following 137 patients, resulting in the occurrence of 41 steam pops including one case of tamponade in a total of 30 (22%) patients. The maximal power was significantly higher in RF applications associated with a pop than those that did not. In only 12 (20%) steam pops, a significant impedance change occurred immediately before pop occurrence (4 [7%] impedance rise >10 ohm, 8 [13%] impedance drop >15 ohm). CONCLUSIONS: The TC-SF catheter does not provide sufficient feedback from the ablated tissue to prevent steam popping.

3.
J Cardiovasc Electrophysiol ; 25(8): 889-895, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24654876

RESUMO

INTRODUCTION: Implantable cardioverter defibrillators (ICD) may have the capacity to provoke or worsen ventricular tachyarrhythmias (VT). It has been reported that ICD shocks by itself can increase mortality. This study aimed to determine the role of back-up pacing-induced VT (PIT) in the overall ICD shock burden by avoiding pause-related ventricular back-up pacing. METHODS AND RESULTS: A population of 550 single-chamber ICD patients was studied. Of them, 17 (3%, 69 ± 16 years, 14 male) patients had documented episodes of PIT. A total of 431 VT episodes were documented including 89 (21%) due to PIT. In 3 patients, VT events were exclusively PITs. After ≥2 documented PITs, the pacing output for VVI pacing was set to a subthreshold level resulting in noncapturable ventricular back-up pacing. All other device parameters remained unchanged to prove a potential proarrhythmic effect of pause related back-up pacing. During a follow-up of 99 ± 39 months after reducing the pacing output to a subthreshold level, no further episodes of PIT were observed (P < 0.001). Moreover, with the prevention of PITs, the ICD shock burden decreased significantly (pre: 150 vs. post: 18, P < 0.001). However, a single event of pause-induced VT occurred due to missing back-up pacing. CONCLUSIONS: PIT is a frequent mechanism of VTs in ICD patients resulting in a substantially increased shock burden. Elimination of pause-related back-up pacing by subthreshold pacing output effectively abolishes PIT and thus significantly reduces ICD shock burden.


Assuntos
Estimulação Cardíaca Artificial , Desfibriladores Implantáveis , Cardioversão Elétrica/instrumentação , Marca-Passo Artificial , Falha de Prótese , Taquicardia Ventricular/etiologia , Idoso , Idoso de 80 Anos ou mais , Estimulação Cardíaca Artificial/efeitos adversos , Cardioversão Elétrica/efeitos adversos , Técnicas Eletrofisiológicas Cardíacas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Desenho de Prótese , Fatores de Risco , Taquicardia Ventricular/diagnóstico , Taquicardia Ventricular/fisiopatologia , Taquicardia Ventricular/terapia , Fatores de Tempo , Resultado do Tratamento
4.
Pacing Clin Electrophysiol ; 35(4): 403-8, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22309354

RESUMO

BACKGROUND: This study aimed to describe the influence on dual-chamber devices' expected longevity of devices' settings. METHODS: Data from patients implanted with dual chamber devices (Symphony™, SORIN CRM SAS, Clamart, France) from 2003 to 2006 were collected in registries. Programmer files were retrieved: device-estimated longevity, assessed through algorithm prediction, was analyzed according to device settings. RESULTS: One thousand sixty-eight recipients of dual chamber pacemaker in sinus rhythm (75.3±11.1 years, 54.5% male, ventricular block 30%, brady-tachy syndrome 21%, and sinus node dysfunction 49%) were followed up to 14.2±12.1 months (ranging from first quartile Q1: 2.9 months to fourth quartile Q4: 49.3 months) after implantation. DDD with automatic mode conversion and minimized ventricular pacing (SafeR) modes were programmed in 34.3%, 2.9%, and 62.8% of the patients, respectively. The mean total longevity estimated by the device was 134.1±31.5 months (11.2±2.6 years). Significant increase in longevity was observed in devices undergoing at least one reprogramming (134.4±31.4 months) versus device presenting no reprogramming (103.4±32.3 months, P=0.0005). The parameters associated with the major increase in mean longevity were the mode (mean longevity increase of +23.9 months in SafeR as compared to DDD mode, P<0.0001) and the atrial (A) and ventricular (V) amplitudes (mean longevity increase of +29.6 and +26.9 months for a decrease of less than 1V in A and V outputs respectively, P<0.0001). CONCLUSION: This study provides information on dual chamber pacemakers' longevity and highlights the impact of devices' reprogramming on expected longevities.


Assuntos
Marca-Passo Artificial , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Bradicardia/terapia , Estimulação Cardíaca Artificial/métodos , Feminino , Bloqueio Cardíaco/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Síndrome do Nó Sinusal/terapia , Síndrome , Taquicardia/terapia
5.
J Heart Lung Transplant ; 28(11): 1119-26, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19782587

RESUMO

BACKGROUND: Cardiac allografts are known to develop myocardial fibrosis, which may be a cause of progressive cardiac dysfunction. Apart from the renin-angiotensin and transforming growth factor-beta system, hypoxia has been proposed as an important player in the pathogenesis of fibrosis, but its significance remains unclear. This study examines the degree of myocardial fibrosis, cellular remodeling and hypoxic signaling over a time-course of 10 years after human cardiac allograft transplantation. METHODS: Serial right ventricular biopsies of 57 patients were collected in 6-month intervals after cardiac transplant surgery for a total of 10 years to allow a retrospective longitudinal analysis. Over this period, tissue remodeling, including interstitial fibrosis and cellular changes, were determined morphometrically. Immunohistochemistry (IHC) was used to analyze expression of the following hypoxia-related proteins: hypoxia-induced factor 1-alpha (HIF1alpha); the oxygen sensor prolyl hydroxylase 3 (PHD3); and vascular endothelial growth factor (VEGF). RESULTS: Fibrosis increased significantly from 12.6 +/- 6.5% at the point of transplantation throughout follow-up to 28.8 +/- 7.7% at 10 years. The DNA content and number of nuclei changed over the period of follow-up, displaying signs of cellular hypertrophy and a loss of myocytes. Whereas HIF1alpha expression revealed a U-shaped pattern with both early and late elevation during fibrogenesis, PHD3 and VEGF expression patterns showed a gradual increase with PHD3 decreasing again in later fibrogenesis. CONCLUSIONS: In cardiac allografts, extensive and progressive tissue remodeling is present. Hypoxia may play a role in this process by up-regulating HIF1alpha and leading to differential regulation of pro-angiogenic signals.


Assuntos
Cardiopatias/epidemiologia , Transplante de Coração/efeitos adversos , Hipóxia/etiologia , Remodelação Ventricular/fisiologia , Fibrose Endomiocárdica/epidemiologia , Fibrose Endomiocárdica/patologia , Feminino , Seguimentos , Transplante de Coração/patologia , Ventrículos do Coração/patologia , Humanos , Hipertensão/epidemiologia , Hipóxia/epidemiologia , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Transplante Homólogo
6.
Herz ; 34(3): 176-85, 2009 May.
Artigo em Alemão | MEDLINE | ID: mdl-19444401

RESUMO

This review gives an integrated summary of the three old and two new ECG algorithms for the differential diagnosis of monomorphic regular tachycardias with broad QRS complex. Several studies have provided evidence that a ventricular tachycardia was diagnosed correctly by doctors on call and emergency physicians only in 35-50% of cases. Whether an algorithm may really improve diagnosis in everyday clinical practice and whether the algorithms are feasible for physicians, has not yet been clarified.The algorithms possess a high sensitivity of 88-95%, but only a satisfactory specificity of 73-80%. The values of all algorithms are similar. In the hands of physicians with little experience, the incidence of correct diagnoses is likely to be markedly lower. The algorithms have considerable limitations, especially with regard to the application of the "morphology criteria". As the nondetection of a ventricular tachycardia can have fatal consequences for the patient, any tachycardia with broad QRS complex should be treated as ventricular tachycardia in emergencies. In hemodynamically stable patients, the administration of adenosine for diagnostic purposes should immediately lead to a correct diagnosis. Based on the study situation, a schematic representation for the differential diagnosis has been created which follows very simple ECG criteria identifiable by any physician.


Assuntos
Algoritmos , Diagnóstico por Computador/métodos , Eletrocardiografia/métodos , Serviços Médicos de Emergência/métodos , Taquicardia Ventricular/diagnóstico , Diagnóstico Diferencial , Emergências , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
7.
Drugs Today (Barc) ; 45(11): 807-24, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20126673

RESUMO

Atrial and ventricular arrhythmias are associated with substantial morbidity and mortality and thus are a significant economic burden for healthcare systems. Currently available pharmacological agents have limited efficacy or the risk of relevant side effects, such as drug toxicity and proarrhythmic potential. Recent scientific developments have added new aspects and approaches to this field meriting a fresh review of treatment options. These include novel ion-channel blockers (e.g. dronedarone, celivarone, vernakalant, ranolazine), non-ion channel blockers (e.g. GsMtx4) such as gap junction modulators (rotigaptide) and drugs antagonizing the angiotensin system (ACE-inhibitors, angiotensin II receptor blockers), which appear to have various effects on cardiac electrophysiology. Special emphasis is placed on new antiarrhythmic drugs (e.g. dantrolene) targeting molecular, proarrhythmogenic and structural remodeling. Finally, new developments in the prevention of thromboembolic complications of atrial fibrillation are discussed (dabigatran).


Assuntos
Antiarrítmicos/uso terapêutico , Arritmias Cardíacas/tratamento farmacológico , Sistemas de Liberação de Medicamentos , Animais , Antiarrítmicos/efeitos adversos , Antiarrítmicos/farmacologia , Arritmias Cardíacas/complicações , Arritmias Cardíacas/fisiopatologia , Fibrilação Atrial/complicações , Fibrilação Atrial/tratamento farmacológico , Fibrilação Atrial/fisiopatologia , Efeitos Psicossociais da Doença , Humanos , Tromboembolia/etiologia , Tromboembolia/prevenção & controle , Resultado do Tratamento
8.
Europace ; 9(7): 534-9, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17440005

RESUMO

AIMS: The purpose of this prospective, randomized, multicentre study was to investigate whether the incidence of ventricular tachyarrhythmia can be reduced in standard implantable cardioverter/defibrillator (ICD) patients by implanting a dual-chamber ICD capable of atrial therapy delivery. METHODS AND RESULTS: A Jewel AF or GEM III AT ICD (Medtronic Inc., Minneapolis, MN, USA) was implanted in 122 patients (62.3 +/- 10.5 years; 84.4% male; coronary artery disease 71.3%; left ventricular ejection fraction 39.7 +/- 13.6%; secondary ICD indication 91%). Overall, 31.2% of the patients had paroxysmal atrial fibrillation (AF)/atrial tachycardia (AT) before ICD implantation (n = 38). Implantable cardioverter/defibrillator therapies for AT/AF were activated and de-activated every 3 months in a cross-over study design. The mean follow-up was 18.5 +/- 7.7 months (6.29 +/- 2.2 cross-over/patient). Overall, there were 684 episodes of ventricular tachyarrhythmias in 48.4% of patients (n = 59). In 33.6% of patients (n = 41), 532 supraventricular tachyarrhythmias occurred. Activation of ICD therapies for AT/AF did not result in a reduction of ventricular tachyarrhythmias (P = 0.92). Patients with monomorphic ventricular tachycardias (mVTs) as index arrhythmia for ICD implantation or inducible mVTs in the electrophysiological study had the highest probability of recurrences of ventricular tachyarrhythmias. CONCLUSION: For patients with standard indications for ICD therapy and no indication for cardiac pacing, a dual-chamber ICD capable of atrial tachyarrhythmia treatment offers no benefit concerning a reduction of ventricular tachyarrhythmias.


Assuntos
Fibrilação Atrial/terapia , Desfibriladores Implantáveis , Taquicardia Ventricular/prevenção & controle , Estimulação Cardíaca Artificial , Feminino , Alemanha , Humanos , Masculino , Pessoa de Meia-Idade , Distribuição de Poisson , Estudos Prospectivos , Resultado do Tratamento
9.
Europace ; 8(1): 65-9, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16627412

RESUMO

AIMS: This study evaluated the acute clinical performance of a new ventricular automatic capture algorithm developed to work with all lead types and pacing vectors. METHODS AND RESULTS: During regular pacemaker implant or replacement, AutoThreshold and manual threshold tests were performed in ventricular unipolar (UP) and bipolar (BP, if applicable) pacing using a customized external prototype INSIGNIA pacemaker. The success rate and accuracy of two different modes (commanded and ambulatory) of the automatic capture algorithm were used to evaluate the performance. Loss-of-capture events (two consecutive non-captured beats without backup pacing) were used to assess safety. Data of 53 patients (33 DDD/20 VVI) from four medical centres were analysed. Tested leads included 43 BP and 10 UP from nine manufacturers, and seven had electrodes with low polarization. The rate of successful commanded and ambulatory AutoThreshold tests was 96 and 94%, respectively, with an average absolute threshold difference compared with manual threshold of < 0.1 V at 0.4 ms (commanded 0.07 +/- 0.07 V and ambulatory 0.08 +/- 0.07 V). There was no significant difference in performance between UP/BP pacing, polarization, and lead type. No loss-of-capture event was observed. CONCLUSION: When successful, the ventricular automatic capture algorithm accurately determined pacing thresholds in either a UP or BP pacing configuration among all leads tested.


Assuntos
Algoritmos , Ventrículos do Coração , Marca-Passo Artificial , Adulto , Idoso , Idoso de 80 Anos ou mais , Eletrocardiografia Ambulatorial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Telemetria
10.
Europace ; 8(5): 371-6, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16635998

RESUMO

AIMS: An algorithm that alerts implantable cardioverter-defibrillator (ICD) patients, in case of abnormal lead impedance (Patient Alerttrade mark, Medtronic), may help to recognize lead dysfunction. We aimed to determine the utility of Patient Alert for ICD lead-failure detection in a prospective study. METHODS AND RESULTS: Three hundred and sixty ICD patients were followed for 22+/-14 months. Patient Alert was active for pacing impedance <200 and >2000-3000 Omega, and high-voltage conductor impedance <10-20 and >200 Omega. Ten alert events and a total of 29 severe system complications occurred. Patient Alert detected three of 10 ICD lead failures, with a positive predictive value (PPV) of 77.8% for any severe system complication. Retrospective analysis identified 23 patients with a sensing integrity counter (SIC) >300 and revealed an additional four prior undetected lead defects. SIC detected ICD lead failure with 92.9% sensitivity and a PPV of 59.1%. Eight of nine patients with a false-positive SIC had an integrated bipolar lead. Patient Alert combined with SIC detected all ICD lead failures and 71.4% of all severe lead complications. CONCLUSIONS: Patient Alert, based on daily lead-impedance measurement, detected one-third of all ICD lead failures. Combined use with continuous lead integrity monitoring (SIC) increased sensitivity to 100%. Integrated bipolar leads may yield a false-positive SIC. Incorporating SIC and automated pace/sense threshold measurement may improve Patient Alert sensitivity for severe lead complications.


Assuntos
Algoritmos , Desfibriladores Implantáveis , Idoso , Impedância Elétrica , Falha de Equipamento , Segurança de Equipamentos , Reações Falso-Positivas , Feminino , Humanos , Masculino , Valor Preditivo dos Testes , Estudos Prospectivos , Sensibilidade e Especificidade
11.
Circulation ; 108(2): 192-7, 2003 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-12835212

RESUMO

BACKGROUND: We sought to determine the potential of right ventricular VVI backup pacing to induce ventricular tachyarrhythmias in patients with implanted cardioverter-defibrillators. METHODS AND RESULTS: All consecutive patients presenting exclusively with pacemaker-induced tachycardias (PITs) were included in a prospective study using a crossover protocol. Patients were randomized to either group 1 (augmentation of the baseline frequency of the pacemaker to 60 bpm) or group 2 (pacemaker turned off) and were followed up for 1 year and then crossed over to the other programming, looking for reoccurrence of PIT. Of 150 consecutive patients, 39 (26%) had PIT, 13 of them exclusively (8.6%). Forty of 1063 analyzed tachyarrhythmias of all the patients were PIT (3%). Before inclusion in the study, the patients had 2.7+/-0.9 PITs in 11+/-6.5 months with their pacemakers programmed empirically at 42.3 bpm. During the study phase, no PIT occurred while the pacemaker was turned off, whereas programming to 60 bpm led to the recurrence of PIT in 5 of 6 patients (1.4+/-0.6 per patient). At the end of the study, 9 patients underwent a prolonged follow-up with their pacemakers turned off, resulting in spontaneous episodes of ventricular tachycardia/fibrillation in 5 patients, but PITs were no longer observed. CONCLUSIONS: This crossover protocol proves the potential proarrhythmic effect of pacemaker stimulation in implantable cardioverter-defibrillator patients. Resulting PITs led to clinical symptoms and antitachycardia therapy by the implantable cardioverter-defibrillator. Thus, in patients presenting with PIT but without a pacemaker indication, the pacemaker feature should be turned off, or, alternatively, the longest possible escape interval should be programmed.


Assuntos
Arritmias Cardíacas/etiologia , Estimulação Cardíaca Artificial/efeitos adversos , Desfibriladores Implantáveis/efeitos adversos , Marca-Passo Artificial/efeitos adversos , Taquicardia/etiologia , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/terapia , Estimulação Cardíaca Artificial/métodos , Estudos Cross-Over , Eletrocardiografia , Seguimentos , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Prevenção Secundária , Volume Sistólico , Taquicardia/diagnóstico , Taquicardia/terapia , Fatores de Tempo , Resultado do Tratamento
12.
Pacing Clin Electrophysiol ; 25(7): 1079-86, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12164450

RESUMO

Dual chamber ICDs are increasingly implanted nowadays, mainly to improve discrimination between supraventricular and ventricular arrhythmias but also to maintain AV synchrony in patients with bradycardia. The aim of this study was to investigate a new single pass right ventricular defibrillation lead capable of true bipolar sensing and pacing in the right atrium and integrated bipolar sensing and pacing in the right ventricle. The performance of the lead was evaluated in 57 patients (age 61 +/- 12 years; New York Heart Association 1.9 +/- 0.6, left ventricular ejection fraction 0.38 +/- 0.15) at implant, at prehospital discharge, and during a 1-year follow-up. Sensing and pacing behavior of the lead was evaluated in six different body positions. In four patients, no stable position of the atrial electrode could intraoperatively be found. The intraoperative atrial sensing was 2.3 +/- 1.6 mV and the atrial pacing threshold 0.8 +/- 0.5 V at 0.5 ms. At follow-up, the atrial sensing ranged from 1.5 mV to 2.2 mV and the atrial pacing threshold product from 0.8 to 1.7 V/ms. In 11 patients, an intermittent atrial sensing problem and in 24 patients an atrial pacing dysfunction were observed in at least one body position. In 565 episodes, a sensitivity of 100% and a specificity of 96.5% were found for ventricular arrhythmias. In conclusion, this single pass defibrillation lead performed well as a VDD lead and for dual chamber arrhythmia discrimination. However, loss of atrial capture in 45% of patients preclude its use in patients depending on atrial pacing.


Assuntos
Desfibriladores Implantáveis , Eletrocardiografia/instrumentação , Eletrodos Implantados , Marca-Passo Artificial , Taquicardia Supraventricular/terapia , Fibrilação Ventricular/terapia , Idoso , Europa (Continente) , Feminino , Átrios do Coração/fisiopatologia , Ventrículos do Coração/fisiopatologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Taquicardia Supraventricular/fisiopatologia , Fibrilação Ventricular/fisiopatologia
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