In the present study, we sought to investigate the agreement between late gadolinium enhancement (LGE) in cardiovascular magnetic resonance (CMR) and electro-anatomical maps (EAM) of patients with non-ischemic dilated cardiomyopathy (NIDCM) and how it relates with the procedural outcome after catheter ablation of ventricular arrhythmias (VA). We identified 50 patients with NIDCM who underwent CMR and ablation for VA. LGE was detected in 16 patients (32%), mostly in those presenting with sustained VT (15 patients). Low-voltage areas (<1.5 mV) were observed in 23 patients (46%), in 7 patients (14%) without evidence of LGE. Using a threshold of 1.5 mV, a good and partially good agreement between the bipolar EAM and LGE-CMR was observed in only 4 (8%) and 9 (18%) patients, respectively. With further adjustments of EAM to match the LGE, we defined new cut-off limits of median 1.5 mV and 5 mV for bipolar and unipolar maps, respectively. Most VT exits were found in areas with LGE (12 out of 16 patients). VT exits were found in segments without LGE in 2 patients with unsuccessful ablation as well as in 2 patients with successful ablation, P=0.77. In patients with VT recurrence, the LGE volume was significantly larger than in those without recurrence: 12.2 ± 5.8% vs. 6.9 ± 3.4%; P=0.049. Myocardial heterogeneity provides the electrophysiological substrate of ventricular arrhythmias in patients with myocardial infarction. Fibrosis and reduction in the number of gap junctions of surviving myocytes allow the occurrence of re-entry (23). However, the relationship between fibrosis and VA is complex and involves not only fixed anatomical barriers but also functional blocks caused by differences in the fiber orientation, myocardial thickness mismatch or connexin downregulation (24-26). Studies involving EAM in patients with scar-related VT demonstrated that homogenization of the low-voltage areas with elimination of the signals showing abnormal amplitude and fractionation was associated with improved acute and long-term success rates (27). On the other hand, animal studies showed that CMR can be useful to characterize LV fibrosis. Moreover, the amount of LGE has been associated with inducibility of VT and is considered a powerful and independent predictor of adverse prognosis, especially in myocardial infarction patients (28-29). In contrast to ischemic cardiomyopathy, LGE is infrequently found in patients with NIDCM. A previous study of 399 patients with NIDCM demonstrated that LGE was detected in approximately one-fourth of the patients and was associated with a 9-fold increase of risk for SCD (30). In accordance with these data, we observed LGE in approximately one third of the patients, and most of them had a history of spontaneous sustained VT. In contrast to the VT patients who have frequently LGE, all patients with ventricular premature beats but without any sustained VT did not show any evidence of LGE in CMR. These observations support the general understanding that the presence of LGE identifies more advanced cardiomyopathy as well as a higher risk for more malignant ventricular arrhythmias. Although myocardial fibrosis is associated with a higher likelihood for VT occurrence, the absence of LGE in CMR does not completely eliminate the risk for VT. Some patients had sustained ventricular arrhythmias even without detectable scar in CMR, which suggests a poorer negative predictive value for the LGE. Although CMR imaging is currently considered the reference standard for the detection of LV scar, it has a limited spatial resolution in vivo. Therefore, minute scars as well as diffuse fibrosis that can still trigger VA may remain undetected. The alternative approach to detect myocardial scar is to characterize the electrical properties of the myocardium by using bipolar EAM in order to find low-voltage areas and late potentials that are markers of abnormal tissue. However, abnormal fragmentation and amplitudes below 1,5 mV are less frequently found in NIDCM in comparison to post-myocardial infarction patients. These findings illustrate the downsides of the EAM in NIDCM. Moreover, numerous animal and clinical studies underlined other technical drawbacks of the EAM that can influence the size and the characteristics of the low-voltage areas such as mapping electrode size and spacing, the angle of contact with the underlying tissue, wave-front direction (31-33). Recently, Betensky and al. analyzed the agreement between CMR and EAM in patients with NIDCM and found a significant discordance between both approaches in 36% of the patients. Using lower signal intensity threshold of 2 standard deviations they increased the CMR-EAM agreement up to almost 90% (34). In contrast to Betensky, who used a simplified approach analyzing only the septal to lateral disagreement, we choose to perform more precise analysis using the 17 segments AHA model of the LV. We found 23 out of 50 patients with low-voltage areas and 15 (71.4%) of them had sustained VT. Moreover only 16 (32%) patients with low-voltage had also LGE in the CMR. In our study the basal inferolateral, inferior and infero-septal segments were most frequently affected by LGE in contrast to the basal anterior and anteroseptal segments affected in the EAM. However, in the LGE positive patients, the best pace-mapping sites of the clinical VT coincided with areas of LGE. One possible explanation for the low correlation between EAM and LGE-CMR is the non-transmurality of the fibrosis in patients with NIDCM. A previous study in post-infarct patients demonstrated that median bipolar voltage <1.5 mV was only found in segments demonstrating ≥75% infarct transmurality (35). In a recently published article, Zeppenfeld et al. found that EAM voltages showed a linear relationship with the LV wall thickness and the amount of fibrosis in patients with non-ischemic DCM. However, no cutoff value for the voltage could be found to reliably delineate fibrotic areas in NIDCM (36). Regarding the quantification of the arrhythmogenic substrate, we could not find any correlation between the amount of LGE and the size of the low-voltage areas (endo- or epicardial), which can be explained by the impact of LGE transmurality as well as the sparse distribution of the LV fibrosis. In this regard, an advantage of the LGE-CMR is that it can visualize the presence of intramyocardial and epicardial scar which are not visible by endocardial EAM. The reason is that the bipolar EAM has narrower field of view and proved insensitive to delineate scar that lies deeper within the myocardium (37). Previously, Hutchinson et al. reported that by using a unipolar 8.27 mV threshold endocardial it was possible to identify epicardial bipolar low-voltage areas consistent with macroscopic scarring in patients with NIDCM and normal endocardial bipolar voltage (38). However, we found that the agreement between LGE and unipolar maps using this cutoff of 8.27 mV was poor. After adjusting the unipolar and bipolar threshold on the basis of CMR, the resulting median thresholds for the bipolar and unipolar low-voltage maps were 1.5 mV and 5 mV respectively, which are close to those observed in a previous study (37). 4.1 Conclusions LGE was observed in approximately one-third of the patients with dilated cardiomyopathy of non-ischemic origin and ventricular arrhythmias. LGE was seen mainly in patients with sustained VT. The agreement between the distribution or the extent of LGE and bipolar low-voltage areas was fairly poor. No particular cutoff values for bipolar and unipolar electro-anatomical maps could be found. On the other hand, most VT exits in patient with sustained VT were found in areas of LGE. The procedural success after VA ablation were related to LGE volume only.

No description available.

The main goal of this dissertation was to assess prospectively the value of two cardiovascular magnetic resonance methodises (the transmural extent of an late gadolinium enhancement and the contractile reserve during low dose dobutamine administration) as predictors of left ventricular segmental and global functional recovery in patients with left ventricular systolic dysfunction undergoing surgical or percutaneous revascularisation. Taking into account previous studies, revascularisation of the viable myocardium results in an improvement of patient’s symptoms and prognosis. This finding emphasized the need for and importance of noninvasive tests to quantify the amount of viable myocardium in patients with left ventricular dysfunction in order to define the optimal management strategy. On the basis of the research described in the dissertation, the diagnostic value of different cardiovascular magnetic resonance based viability prediction methods was assessed. The superiority of combined viability prediction model incorporating an late gadolinium enhancement and the contractile reserve during low dose dobutamine administration was confirmed. The optimal predictors of the significant improvement of left ventricular ejection fraction were found: the percentage of viable segments from all dysfunctional and revascularised segments in a patient and the absolute value of left ventricular ejection fraction measured during low dose dobutamine administration. On the basis of the... [to full text] / Disertacijoje nagrinėta dviejų magnetinio rezonanso metodikų (vėlyvojo kontrastinės medžiagos kaupimo transmuralumo bei mažų dobutamino dozių sukeliamo miokardo kontraktilinio rezervo) bei šių metodikų derinio vertė, prognozuojant bendrosios bei segmentinės kairiojo skilvelio funkcijos atsistatymą po revaskuliarizacijos (perkutaninės vainikinių arterijų intervencijos ar vainikinių arterijų apeinamųjų jungčių suformavimo operacijos), pacientams, turintiems išeminės kilmės kairiojo skilvelio sistolinę disfunkciją. Kadangi yra nustatyta, jog sėkminga gyvybingo miokardo revaskuliarizacija pagerina kairiojo skilvelio sistolinę disfunkciją turinčių pacientų simptomus bei prognozę, todėl gyvybingo miokardo nustatymas yra svarbus, siekiant parinkti optimalią tokių pacientų gydymo taktiką. Disertacijoje aprašomo tyrimo pagalba buvo nustatyta širdies magnetinio rezonanso vertė, prognozuojant miokardo bendrosios bei segmentinės kontrakcijos atsistatymą bei pagrįsta vėlyvojo kontrastinės medžiagos kaupimo transmuralumo bei mažų dobutamino dozių sukeliamo kontraktilinio rezervo nustatymo metodikų derinimo nauda. Disertacijoje aptarti optimalūs reikšmingo bendrosios kairiojo skilvelio sistolinės funkcijos pagerėjimo prognostiniai rodikliai: gyvybingų segmentų procentas nuo visų išeityje disfunkcinių bei revaskuliarizuotų paciento segmentų bei absoliuti kairiojo skilvelio išstūmimo frakcija, išmatuota mažų dobutamino dozių skyrimo metu. Disertacijos rezultatų pagrindu buvo sukurtas... [toliau žr. visą tekstą]

Disertacijoje nagrinėta dviejų magnetinio rezonanso metodikų (vėlyvojo kontrastinės medžiagos kaupimo transmuralumo bei mažų dobutamino dozių sukeliamo miokardo kontraktilinio rezervo) bei šių metodikų derinio vertė, prognozuojant bendrosios bei segmentinės kairiojo skilvelio funkcijos atsistatymą po revaskuliarizacijos (perkutaninės vainikinių arterijų intervencijos ar vainikinių arterijų apeinamųjų jungčių suformavimo operacijos), pacientams, turintiems išeminės kilmės kairiojo skilvelio sistolinę disfunkciją. Kadangi yra nustatyta, jog sėkminga gyvybingo miokardo revaskuliarizacija pagerina kairiojo skilvelio sistolinę disfunkciją turinčių pacientų simptomus bei prognozę, todėl gyvybingo miokardo nustatymas yra svarbus, siekiant parinkti optimalią tokių pacientų gydymo taktiką. Disertacijoje aprašomo tyrimo pagalba buvo nustatyta širdies magnetinio rezonanso vertė, prognozuojant miokardo bendrosios bei segmentinės kontrakcijos atsistatymą bei pagrįsta vėlyvojo kontrastinės medžiagos kaupimo transmuralumo bei mažų dobutamino dozių sukeliamo kontraktilinio rezervo nustatymo metodikų derinimo nauda. Disertacijoje aptarti optimalūs reikšmingo bendrosios kairiojo skilvelio sistolinės funkcijos pagerėjimo prognostiniai rodikliai: gyvybingų segmentų procentas nuo visų išeityje disfunkcinių bei revaskuliarizuotų paciento segmentų bei absoliuti kairiojo skilvelio išstūmimo frakcija, išmatuota mažų dobutamino dozių skyrimo metu. Disertacijos rezultatų pagrindu buvo sukurtas... [toliau žr. visą tekstą] / The main goal of this dissertation was to assess prospectively the value of two cardiovascular magnetic resonance methodises (the transmural extent of an late gadolinium enhancement and the contractile reserve during low dose dobutamine administration) as predictors of left ventricular segmental and global functional recovery in patients with left ventricular systolic dysfunction undergoing surgical or percutaneous revascularisation. Taking into account previous studies, revascularisation of the viable myocardium results in an improvement of patient’s symptoms and prognosis. This finding emphasized the need for and importance of noninvasive tests to quantify the amount of viable myocardium in patients with left ventricular dysfunction in order to define the optimal management strategy. On the basis of the research described in the dissertation, the diagnostic value of different cardiovascular magnetic resonance based viability prediction methods was assessed. The superiority of combined viability prediction model incorporating an late gadolinium enhancement and the contractile reserve during low dose dobutamine administration was confirmed. The optimal predictors of the significant improvement of left ventricular ejection fraction were found: the percentage of viable segments from all dysfunctional and revascularised segments in a patient and the absolute value of left ventricular ejection fraction measured during low dose dobutamine administration. On the basis of the... [to full text]

No description available.

Amyloidosis is a term used for a whole group of diseases caused by deposition of a substance called amyloid into different tissues. Amyloid may be produced by a range of pathologic processes. Heart affliction is typical for only several types of amyloidoses. Heart involvement is then the patient`s prognosis major limiting factor. Diagnosis of heart amyloidosis is difficult especially for nonspecific symptoms and nonspecific findings obtained during common diagnostic procedures. The aim of this thesis was to evaluate usefulness of novel diagnostic methods, namely cardiac magnetic resonance with gadolinium enhancement and a simplified echocardiographic evaluation of left ventricular longitudinal strain, in diagnosing amyloid cardiomyopathy. In our first study we examined 22 patients with light chain amyloidosis by echocardiography and also with cardiac magnetic resonance with late gadolinium enhancement. We compared morphologic and functional parameters acquired by magnetic resonance examination, which is considered a gold standard for morphologic and functional measurements, with values obtained by echocardiographic measurement. Afterwards we evaluated the presence and eventually pattern of late gadolinium enhancement during cardiac magnetic resonance exam. From acquired data we conclude that the...

La première partie de cette thèse porte sur l'étude du no-reflow ou obstruction microvasculaire en IRM cardiaque. Dans une première étude, nous avons mesuré l'incidence du no-reflow dans une population de 25 patients pris en charge pour infarctus du myocarde sans sus-décalage du segment ST. Nous avons trouvé que 32% de ces patients présentaient un no-reflow et que la présence de no-reflow était associée à une taille d'infarctus significativement plus importante ainsi qu'une élévation plus importante des enzymes cardiaques. Dans une deuxième étude nous avons comparé la performance diagnostique du myocardial blush grade (MBG) pour le diagnostic du no-reflow avec l'IRM cardiaque sur les séquences de rehaussement tardif post-gadolinium. Cette étude a été réalisée dans une population de 39 patients pris en charge pour un premier épisode de STEMI. Nous avons trouvé que le MBG sous-estimait la présence de no-reflow à la phase aiguë de l'infarctus après reperfusion optimale en comparaison avec l'IRM. La deuxième partie de cette thèse concerne la quantification de l'infarctus du myocarde en IRM cardiaque de rehaussement tardif post-gadolinium. Nous avons comparé une technique d'évaluation semi-quantitative visuelle rapide avec la planimétrie manuelle classique sur une population de 103 patients pris en charge pour syndrome coronarien aigu. La taille de l'infarctus était évaluée par ces deux méthodes en IRM cardiaque réalisée 4 jours après admission. Nous avons trouvé une excellente corrélation et un bon niveau de concordance entre les deux méthodes d'évaluation de la taille d'infarctus, avec des temps de posttraitements beaucoup plus courts pour l'analyse visuelle rapide. Enfin, la troisième partie de cette thèse aborde le sujet de l'utilisation de l'IRM cardiaque comme outil de mesure dans les essais thérapeutiques sur la reperfusion myocardique. Nous avons utilisé l'IRM cardiaque pour évaluer l'efficacité de l'utilisation de la cyclosporine A à la phase aigüe de l'infarctus reperfusé et son effet sur remodelage ventriculaire à 6 mois. Dans cette étude 28 patients ont été étudiés en IRM cardiaque 5 jours et 6 mois après un infarctus du myocarde. Nous avons trouvé une persistance de la réduction significative de 23% de taille de l'infarctus à 6 mois dans le groupe traité par cyclosporine par rapport au groupe contrôle. Il n'y avait pas d'effet négatif de la cyclosporine A sur le processus de remodelage ventriculaire gauche / We assessed the presence and extent of microvascular obstruction (MVO) and its relationship with infarct size and left ventricular (LV) functional parameters after acute non-ST elevated myocardial infarction (NSTEMI). 25 patients with first acute NSTEMI underwent a complete cardio magnetic resonance (CMR) study 72 hours after admission. MO was detected in 32% of patients and was significantly associated with a larger infarct size. There were no significant difference between both groups for the LV functional parameters but patients with MO showed a higher troponin-I and CK release. We studied the relation between Myocardial Blush Grade (MBG) and gadolinium-enhanced CMR for the assessment of MVO in 39 patients with acute ST elevated myocardial infarction (STEMI) treated by primary PCI. No statistical relation was found between MBG and MVO extent at CMR (p=0.63). MBG underestimates MVO after an optimal revascularization in AMI compared to CMR.We compared the performance and post-processing time of a global visual scoring method to standard quantitative planimetry and we compared both methods to the peak values of myocardial biomarkers. 103 patients admitted with reperfused AMI to our intensive care unit had a complete CMR study 4±2 days after admission. There was an excellent correlation between quantitative planimetry and visual global scoring for the hyperenhancement extent’s measurement (r=0.94; y=1.093x+0.87; SEE=1.2; P<0.001) and there was also a good concordance between the two approaches with significantly shorter mean post-processing time for the visual scoring method. There was also significant levels of correlation between the enzymatic peak values and the visual global scoring method. The visual global scoring method allows a rapid and accurate assessment of the myocardial global delayed enhancement. This study examined the effect of a single dose of cyclosporine A used at the time of reperfusion, on LV remodeling and function by cardiac magnetic resonance (CMR) in the early days and 6 months after AMI.28 patients of the original cyclosporine A study had an acute (day 5) and a follow-up (6 months) CMR study. There was a persistent 23% reduction of the absolute infarct size at 6 months without any dementrial effect in the cyclosporine A group compared with the control group of patients. Cyclosporine A used at the moment of AMI reperfusion persistently reduces infarct size and does not have a detrimental effect on LV remodeling

Cette thèse porte sur la caractérisation cardiaque, qui représente un enjeu méthodologique et clinique important, à la fois pour améliorer le diagnostic des pathologies et optimiser les moyens de traitement. Des méthodes de recalage et de fusion de données sont proposées pour amener dans un même référentiel des images IRM, scanner, échographiques et électro-anatomiques et ainsi décrire le cœur suivant des caractéristiques anatomiques, électriques, mécaniques et tissulaires. Les méthodes proposées pour recaler des données multimodales reposent sur deux processus principaux : l'alignement temporel et le recalage spatial. Les dimensions temporelles des images considérées sont mises en synchronisées par une méthode de déformation temporelle dynamique adaptative. Celle-ci permet de compenser les modifications temporelles non-linéaires entre les différentes acquisitions. Pour le recalage spatial, des méthodes iconiques ont été développées pour corriger les artefacts de mouvements dans les séquences ciné-IRM, pour recaler les séquences ciné-IRM avec les séquences d'IRM de rehaussement tardif et pour recaler les ciné-IRM avec les images scanner. D'autre part, une méthode basée contours, développée dans un précédent travail, a été améliorée pour prendre en compte des acquisitions échographiques multi-vues. Ces méthodes ont été évaluées sur données réelles pour sélectionner les métriques les plus adaptées et pour quantifier les performances des approches iconiques et pour estimer la précision du recalage entre échographies et ciné-IRM. Ces méthodes sont appliquées à la caractérisation de cardiomyopathies hypertrophiques (CMH) et d'asynchronismes cardiaques. Pour la CMH, l'objectif était de mieux interpréter les données échographiques par la fusion de l'information de fibrose issue de l'IRM de rehaussement tardif avec l'information mécanique issue de l'échographie de speckle tracking. Cette analyse a permis d'évaluer le strain régional en tant qu'indicateur de la présence locale de fibrose. Concernant l'asynchronisme cardiaque, nous avons établi une description du couplage électromécanique local du ventricule gauche par la fusion de données échographiques, électro-anatomiques, scanner et, dans les cas appropriés, d'IRM de rehaussement tardif. Cette étude de faisabilité ouvre des perspectives pour l'utilisation de nouveaux descripteurs pour la sélection des sites de stimulation optimaux pour la thérapie de resynchronisation cardiaque. / This work concerns cardiac characterization, a major methodological and clinical issue, both to improve disease diagnostic and to optimize its treatment. Multisensor registration and fusion methods are proposed to bring into a common referential data from cardiac magnetic resonance (CMRI), dynamic cardiac X-ray computed tomography (CT), speckle tracking echocardiography (STE) and electro-anatomical mappings of the inner left ventricular chamber (EAM). These data is used to describe the heart by its anatomy, electrical and mechanical function, and the state of the myocardial tissue. The methods proposed to register the multimodal datasets rely on two main processes: temporal registration and spatial registration. The temporal dimensions of input data (images) are warped with an adaptive dynamic time warping (ADTW) method. This method allowed to handle the nonlinear temporal relationship between the different acquisitions. Concerning the spatial registration, iconic methods were developed, on the one hand, to correct for motion artifacts in cine acquisition, to register cine-CMRI and late gadolinium CMRI (LGE-CMRI), and to register cine-CMRI with dynamic CT. On the other hand, a contour-based method developed in a previous work was enhanced to account for multiview STE acquisitions. These methods were evaluated on real data in terms of the best metrics to use and of the accuracy of the iconic methods, and to assess the STE to cine-CMRI registration. The fusion of these multisensor data enabled to get insights about the diseased heart in the context of hypertrophic cardiomyopathy (HCM) and cardiac asynchronism. For HCM, we aimed to improve the understanding of STE by fusing fibrosis from LGE-CMRI with strain from multiview 2D STE. This analysis allowed to assess the significance of regional STE strain as a surrogate of the presence of regional myocardial fibrosis. Concerning cardiac asynchronism, we aimed to describe the intra-segment electro-mechanical coupling of the left ventricle using fused data from STE, EAM, CT and, if relevant, from LGE-CMRI. This feasibility study provided new elements to select the optimal sites for LV stimulation.