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1.
Europace ; 21(Supplement_1): i34-i42, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30801126

RESUMO

AIMS: A novel measure of local impedance (LI) has been found to predict lesion formation during radiofrequency current (RFC) catheter ablation. The aim of this study was to investigate the utility of this novel approach, while comparing LI to the well-established generator impedance (GI). METHODS AND RESULTS: In 25 consecutive patients with a history of atrial fibrillation, catheter ablation was guided by a 3D-mapping system measuring LI in addition to GI via an ablation catheter tip with three incorporated mini-electrodes. Local impedance and GI before and during RFC applications were studied. In total, 381 RFC applications were analysed. The baseline LI was higher in high-voltage areas (>0.5 mV; LI: 110.5 ± 13.7 Ω) when compared with intermediate-voltage sites (0.1-0.5 mV; 90.9 ± 10.1 Ω, P < 0.001), low-voltage areas (<0.1 mV; 91.9 ± 16.4 Ω, P < 0.001), and blood pool LI (91.9 ± 9.9 Ω, P < 0.001). During ablation, mean LI drop (△LI; 13.1 ± 9.1 Ω) was 2.15 times higher as mean GI drop (△GI) (6.1 ± 4.2 Ω, P < 0.001). Baseline LI correlated with △LI: a mean LI of 99.9 Ω predicted a △LI of 12.9 Ω [95% confidence interval (12.1-13.6), R2 0.41; P < 0.001]. This relationship was weak for baseline GI predicting △GI (R2 0.06, P < 0.001). Catheter movements were represented by rapid LI changes. The duration of an RFC application was not predictive for catheter-tissue coupling with no further change of △LI (P = 0.247) nor △GI (P = 0.376) during prolonged ablation. CONCLUSION: Local impedance can be monitored during ablation. Compared with the sole use of GI, baseline LI is a better predictor of impedance drops during ablation and may provide useful insights regarding lesion formation. However, further studies are needed to investigate if this novel approach is useful to guide catheter ablation.


Assuntos
Fibrilação Atrial/fisiopatologia , Fibrilação Atrial/cirurgia , Ablação por Cateter/métodos , Impedância Elétrica , Idoso , Mapeamento Epicárdico , Feminino , Humanos , Masculino , Projetos Piloto , Ondas de Rádio
2.
J Cardiovasc Electrophysiol ; 28(10): 1127-1136, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28635023

RESUMO

INTRODUCTION: The need for transesophageal echocardiography (TEE) before catheter ablation of atrial fibrillation (CA-AF) is still being questioned. The aim of this study is to analyze patients' (patients) risk factors of left atrial appendage thrombus (LAAT) prior to CA-AF in daily clinical practice, according to oral anticoagulation (OAC) strategies recommended by current guidelines. METHODS AND RESULTS: All patients scheduled for CA-AF from 01/2015 to 12/2016 in our center were included and either treated with NOACs (novel-OAC; paused 24-hours preablation) or continuous vitamin K antagonists (INR 2.0-3.0). All patients received a preprocedural TEE at the day of ablation. Two groups were defined: (1) patients without LAAT, (2) patients with LAAT. The incidence of LAAT was 0.78% (13 of 1,658 patients). No LAAT was detected in patients with a CHA2 DS2 -VASc score of ≤1 (n = 640 patients) irrespective of the underlying AF type. Independent predictors for LAAT are: higher CHA2 DS2 -VASc scores (odds ratio [OR] 1.54, 95%-confidence interval [CI]: 1.07-2.23, P = 0.0019), a history of nonparoxysmal AF (OR 7.96, 95%-CI: 1.52-146.64, P = 0.049), hypertrophic cardiomyopathy (HCM; OR 9.63, 95% CI: 1.36-43.05, P = 0.007), and a left ventricular ejection fraction (LVEF) < 30% (OR 8.32, 95% CI: 1.18-36.29, P = 0.011). The type of OAC was not predictive (P = 0.70). CONCLUSIONS: The incidence of LAAT in patients scheduled for CA-AF is low. Therefore, periprocedural OAC strategies recommended by current guidelines seem feasible. Preprocedural TEE may be dispensed in patients with a CHA2 DS2 -VASc score ≤1. However, a CHA2 DS2 -VASc score ≥2, reduced LVEF, HCM, or history of nonparoxysmal AF are independently associated with an increased risk for LAAT.


Assuntos
Apêndice Atrial/diagnóstico por imagem , Fibrilação Atrial/diagnóstico por imagem , Fibrilação Atrial/terapia , Ablação por Cateter/métodos , Ecocardiografia Transesofagiana/métodos , Trombose/diagnóstico por imagem , Idoso , Antiarrítmicos/uso terapêutico , Anticoagulantes/uso terapêutico , Fibrilação Atrial/epidemiologia , Cardiomiopatia Hipertrófica/complicações , Cardiomiopatia Hipertrófica/diagnóstico por imagem , Estudos de Coortes , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Medicina de Precisão , Valor Preditivo dos Testes , Medição de Risco , Volume Sistólico , Trombose/tratamento farmacológico , Trombose/epidemiologia , Resultado do Tratamento , Vitamina K/antagonistas & inibidores
3.
J Cardiovasc Electrophysiol ; 28(3): 258-265, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27925337

RESUMO

INTRODUCTION: Despite a rising demand for catheter ablation (CA) of atrial fibrillation (AF) in an elderly population, complication and success rates are not fully elucidated. We sought to compare complication rates of CA of AF in patients ≥75 versus <75 years of age. METHODS AND RESULTS: Patients with symptomatic, drug-refractory AF were prospectively enrolled from January 2007 to 2010 in this multicenter study. A total of 4,449 patients, group 1 ≥75 years and group 2 <75 years (n = 227, age 77.3 ± 2.2 vs. 59.7 ± 9.8 years, 52.0% vs. n = 4,222, 68.9% male, CHA2 DS2 -VASc-Score 3.7 ± 1.0 vs. 1.7 ± 1.2; P < 0.001, respectively), with paroxysmal AF (59.9% in group 1 vs. 63.3% in group 2, P = 0.30), and persistent AF (34.8% in group 1 vs. 29.4% in group 2, P = 0.082) underwent CA of AF. A centralized follow-up was obtained in 4,347 patients by the Institute for Myocardial Infarction Research (IHF, Ludwigshafen). There was a significant difference between periprocedural stroke rates in the elderly versus the younger cohort (1.3% vs. 0.1%, P < 0.01). In-hospital severe nonfatal complications did not differ significantly between the groups (4.4% vs. 2.7%, P = 0.14). Other procedure-related, in-hospital complications were not significantly different. After a mean follow-up of 472 ± 99 days (group 1) and 477 ± 94 days (group 2), no differences were found in complication rates. CONCLUSION: CA of AF in patients ≥75 years is associated with higher in-hospital stroke rates. In a 1-year follow-up, complication rates do not differ between the groups.


Assuntos
Fibrilação Atrial/cirurgia , Ablação por Cateter/efeitos adversos , Veias Pulmonares/cirurgia , Acidente Vascular Cerebral/etiologia , Potenciais de Ação , Fatores Etários , Idoso , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/fisiopatologia , Intervalo Livre de Doença , Feminino , Alemanha , Frequência Cardíaca , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Veias Pulmonares/fisiopatologia , Sistema de Registros , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
4.
PLoS One ; 11(10): e0164236, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27780243

RESUMO

BACKGROUND: Electrogram-based identification of the regions maintaining persistent Atrial Fibrillation (AF) is a subject of ongoing debate. Here, we explore the concept of local electrical dyssynchrony to identify AF drivers. METHODS AND RESULTS: Local electrical dyssynchrony was calculated using mean phase coherence. High-density epicardial mapping along with mathematical model were used to explore the link between local dyssynchrony and properties of wave conduction. High-density mapping showed a positive correlation between the dyssynchrony and number of fibrillatory waves (R2 = 0.68, p<0.001). In the mathematical model, virtual ablation at high dyssynchrony regions resulted in conduction regularization. The clinical study consisted of eighteen patients undergoing catheter ablation of persistent AF. High-density maps of left atrial (LA) were constructed using a circular mapping catheter. After pulmonary vein isolation, regions with the top 10% of the highest dyssynchrony in LA were targeted during ablation and followed with ablation of complex atrial electrograms. Catheter ablation resulted in termination during ablation at high dyssynchrony regions in 7 (41%) patients. In another 4 (24%) patients, transient organization was observed. In 6 (35%) there was no clear effect. Long-term follow-up showed 65% AF freedom at 1 year and 22% at 2 years. CONCLUSIONS: Local electrical dyssynchrony provides a reasonable estimator of regional AF complexity defined as the number of fibrillatory waves. Additionally, it points to regions of dynamical instability related with action potential alternans. However, despite those characteristics, its utility in guiding catheter ablation of AF is limited suggesting other factors are responsible for AF persistence.


Assuntos
Fibrilação Atrial/cirurgia , Ablação por Cateter/métodos , Mapeamento Epicárdico/métodos , Átrios do Coração/fisiopatologia , Idoso , Fibrilação Atrial/fisiopatologia , Terapia Combinada , Feminino , Átrios do Coração/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Teóricos , Projetos Piloto , Resultado do Tratamento
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