48 research outputs found

    Algoritmos de Detecçao de Taquicardias Incorporado a Desfibriladores Automáticos Implantáveis. 1) Desfibriladores Monocamerais

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    Diversos algoritmos foram incorporados aos cardioversores-desfibriladores automáticos implantáveis (CDIs) para identificar os distúrbios do ritmo ventricular e, sobretudo, para os diferenciar de taquicardias supraventriculares que nao necessitam terapia. Esses benefícios também sao encontrados nos CDIs bicamerais que têm como benefício a detecçao atrial acoplada à detecçao do ventrículo. O objetivo dos algoritmos é de identificar todas as arritmias ventriculares (sensibilidade de 100%), para que sejam tratadas corretamente. Devem ainda evitar erros de identificaçao de arritmias supraventriculares (especificidade máxima). Infelizmente, nao é possível alcançar 100% de sensibilidade e especificidade. Além disso, todo aumento da especificidade será acompanhado por uma diminuiçao da sensibilidade. Essa diminuiçao de especificidade pode conduzir a falha na detecçao dos distúrbios do ritmo ventricular, e como conseqüência, isto é pior que o tratamento inadequado de uma taquicardia sinusal ou supraventricular

    Algoritmos de Detecçao de Taquicardias Incorporado a Desfibriladores Automáticos Implantáveis. 1) Desfibriladores Monocamerais

    Get PDF
    Diversos algoritmos foram incorporados aos cardioversores-desfibriladores automáticos implantáveis (CDIs) para identificar os distúrbios do ritmo ventricular e, sobretudo, para os diferenciar de taquicardias supraventriculares que nao necessitam terapia. Esses benefícios também sao encontrados nos CDIs bicamerais que têm como benefício a detecçao atrial acoplada à detecçao do ventrículo. O objetivo dos algoritmos é de identificar todas as arritmias ventriculares (sensibilidade de 100%), para que sejam tratadas corretamente. Devem ainda evitar erros de identificaçao de arritmias supraventriculares (especificidade máxima). Infelizmente, nao é possível alcançar 100% de sensibilidade e especificidade. Além disso, todo aumento da especificidade será acompanhado por uma diminuiçao da sensibilidade. Essa diminuiçao de especificidade pode conduzir a falha na detecçao dos distúrbios do ritmo ventricular, e como conseqüência, isto é pior que o tratamento inadequado de uma taquicardia sinusal ou supraventricular

    Radio-frequency ablation as primary management of well-tolerated sustained monomorphic ventricular tachycardia in patients with structural heart disease and left ventricular ejection fraction over 30%.

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    AIMS: Patients with well-tolerated sustained monomorphic ventricular tachycardia (SMVT) and left ventricular ejection fraction (LVEF) over 30% may benefit from a primary strategy of VT ablation without immediate need for a 'back-up' implantable cardioverter-defibrillator (ICD). METHODS AND RESULTS: One hundred and sixty-six patients with structural heart disease (SHD), LVEF over 30%, and well-tolerated SMVT (no syncope) underwent primary radiofrequency ablation without ICD implantation at eight European centres. There were 139 men (84%) with mean age 62 ± 15 years and mean LVEF of 50 ± 10%. Fifty-five percent had ischaemic heart disease, 19% non-ischaemic cardiomyopathy, and 12% arrhythmogenic right ventricular cardiomyopathy. Three hundred seventy-eight similar patients were implanted with an ICD during the same period and serve as a control group. All-cause mortality was 12% (20 patients) over a mean follow-up of 32 ± 27 months. Eight patients (40%) died from non-cardiovascular causes, 8 (40%) died from non-arrhythmic cardiovascular causes, and 4 (20%) died suddenly (SD) (2.4% of the population). All-cause mortality in the control group was 12%. Twenty-seven patients (16%) had a non-fatal recurrence at a median time of 5 months, while 20 patients (12%) required an ICD, of whom 4 died (20%). CONCLUSION: Patients with well-tolerated SMVT, SHD, and LVEF > 30% undergoing primary VT ablation without a back-up ICD had a very low rate of arrhythmic death and recurrences were generally non-fatal. These data would support a randomized clinical trial comparing this approach with others incorporating implantation of an ICD as a primary strategy

    Design and evaluation of an abbreviated pixelwise dynamic contrast enhancement analysis protocol for early extracellular volume fraction estimation

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    International audienceIntroduction: T1-based method is considered as the gold standard for extracellular volume fraction (ECV) mapping. This technique requires at least a 10 min delay after injection to acquire the post injection T1 map. Quantitative analysis of Dynamic Contrast Enhancement (DCE) images could lead to an earlier estimation of an ECV like parameter (2 min). The purpose of this study was to design a quantitative pixel-wise DCE analysis workflow to assess the feasibility of an early estimation of ECV.Methods: Fourteen patients with mitral valve prolapse were included in this study. The MR protocol, performed on a 3 T MR scanner, included MOLLI sequences for T1 maps acquisition and a standard SR-turboFlash sequence for dynamic acquisition. DCE data were acquired for at least 120 s. We implemented a full DCE analysis pipeline with a pre-processing step using an innovative motion correction algorithm (RC-REG algorithm) and a post-processing step using the extended Tofts Model (ECVETM). Estimated ECVETM maps were compared to standard T1-based ECV maps (ECVT1) with both a Pearson correlation analysis and a group-wise analysis.Results: Image and map quality assessment showed systematic improvements using the proposed workflow. Strong correlation was found between ECVETM, and ECVT1 values (r-square = 0.87).Conclusion: A DCE analysis workflow based on RC-REG algorithm and ETM analysis can provide good quality parametric maps. Therefore, it is possible to extract ECV values from a 2 min-long DCE acquisition that are strongly correlated with ECV values from the T1 based method

    Relationship between the morphology of myocardial infarction scar border assessed by cardiacmagnetic resonance and the inducibility of ventricular tachycardia

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    International audienceP5887 Relationship between the morphology of myocardial infarction scar border assessed by cardiac magnetic resonance and the inducibility of ventricular tachycardi

    A Stepwise Approach to the Management of Postinfarct Ventricular Tachycardia Using Catheter Ablation as the First-Line Treatment: A Single-Center Experience

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    International audienceBACKGROUND:The occurrence of ventricular tachycardia (VT) after myocardial infarction is associated with poorer prognosis. In such patients, implantable cardioverter-defibrillators are recommended. Catheter ablation of VT is currently recommended only as an adjunctive therapy. Whether a successful VT ablation alone might be a viable strategy in some of these patients, however, remains unknown. The aim of the present study was to evaluate this strategy.METHODS AND RESULTS:Between January 2002 and December 2011, 189 patients with cardiomyopathy underwent 259 VT ablations in our center. Forty-five patients (mean age, 65.2±9.6 years; 91% men) with a history of myocardial infarction and mean left ventricular ejection fraction of 39.7±9.7% matched the study criteria and were included in this analysis. Acute success was obtained in 40 of 45 patients (88.9%). During a follow-up, on the basis of our stepwise algorithm (using acute success, repeat electrophysiological study, and recurrence of VT), 19 of 45 patients (42.2%) underwent implantable cardioverter-defibrillators implantation. During a median follow-up of 4.5 (interquartile range, 2.1-7.0) years, all-cause mortality occurred in 14 of 45 patients (31.1%). Using multivariate Cox regression analysis, age (hazard ratio, 1.13; 95% confidence interval, 1.03-1.22; P=0.007) was the only independent predictor of mortality, whereas implantable cardioverter-defibrillators implantation was not (hazard ratio, 0.54; 95% confidence interval, 0.18-1.64; P=0.28)CONCLUSIONS:Our results suggest that a stepwise approach to the management of VT with ablation as a first-line treatment in postinfarct patients presenting with VT might be a reasonable option. Further studies are required to confirm these results

    Electroanatomic characterization of post-infarct scars comparison with 3-dimensional myocardial scar reconstruction based on magnetic resonance imaging.

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    International audienceOBJECTIVES: This study was designed to compare electroanatomic mapping (EAM) and magnetic resonance imaging (MRI) with delayed contrast enhancement (DCE) data for delineation of post-infarct scars. BACKGROUND: Electroanatomic substrate mapping is an important step in the post-infarct ventricular tachycardia (VT) ablation strategy, but this technique has not yet been compared with a gold-standard noninvasive tool informing on the topography and transmural extent of myocardial scars in humans. METHODS: Ten patients (9 men, age 71 +/- 10 years) admitted for post-infarct VT ablation underwent both a left ventricle DCE MRI and a sinus-rhythm 3-dimensional (3D) (CARTO) EAM (Biosense Webster, Johnson & Johnson, Diamond Bar, California). A 3D color-coded MRI-reconstructed left ventricular endocardial shell was generated to display scar data (intramural location and transmural extent). A matching process allocated any CARTO point to its corresponding position on the MRI map. Electrogram (EGM) characteristics were then evaluated in relation to scar data. RESULTS: A spiky EGM morphology, a reduced unipolar or bipolar EGM voltage amplitude (56 ms) independently correlated with the presence of scar whatever its intramural position. Endocardial scars had a larger degree of signal reduction than intramural or epicardial scars. None of the parameters was correlated with transmural scar depth. A clear mismatch in infarct surface between CARTO and MRI maps was observed in one-third of infarct zones. CONCLUSIONS: Sinus-rhythm EAM helps identify the limits of post-infarct scars. However, the accuracy of EAM for precise scar delineation is limited. This limit might be circumvented using anatomical information provided by 3D MRI data
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