[Cardiology: what's new in 2023]. / Cardiologie: ce qui a changé en 2023.

The year 2023 has been extremely rich in new publications in the various subfields of cardiology. Furthermore, the European Society of Cardiology (ESC) has issued revised guidelines focused on the management of acute coronary syndrome (ACS) and endocarditis, as well as an update on the recommendations for the management of heart failure and cardiovascular prevention. The most significant updates according to the Cardiology Department of CHUV are summarized in this review article.

L'année 2023 a été extrêmement riche en nouvelles publications dans les différents sous-domaines de la cardiologie. De plus, la Société européenne de cardiologie (ESC) a formulé des directives révisées axées sur le management du syndrome coronarien aigu (SCA) et de l'endocardite ainsi qu'une mise à jour des recommandations sur la prise en charge de l'insuffisance cardiaque et la prévention cardiovasculaire. Les nouveautés les plus importantes selon l'équipe du Service de cardiologie du CHUV sont résumées dans cet article de synthèse.

Myocardial Fibrosis at Cardiac MRI Helps Predict Adverse Clinical Outcome in Patients with Mitral Valve Prolapse.

Background Patients with mitral valve prolapse (MVP) may develop adverse outcomes even in the absence of mitral regurgitation or left ventricular (LV) dysfunction. Purpose To investigate the prognostic value of mitral annulus disjunction (MAD) and myocardial fibrosis at late gadolinium enhancement (LGE) cardiac MRI in patients with MVP without moderate-to-severe mitral regurgitation or LV dysfunction. Materials and Methods In this longitudinal retrospective study, 118 144 cardiac MRI studies were evaluated between October 2007 and June 2020 at 15 European tertiary medical centers. Follow-up was from the date of cardiac MRI examination to June 2020; the minimum and maximum follow-up intervals were 6 months and 156 months, respectively. Patients were excluded if at least one of the following conditions was present: cardiomyopathy, LV ejection fraction less than 40%, ischemic heart disease, congenital heart disease, inflammatory heart disease, moderate or worse mitral regurgitation, participation in competitive sport, or electrocardiogram suggestive of channelopathies. In the remainder, cardiac MRI studies were reanalyzed, and patients were included if they were aged 18 years or older, MVP was diagnosed at cardiac MRI, and clinical information and electrocardiogram monitoring were available within 3 months from cardiac MRI examination. The end point was a composite of adverse outcomes: sustained ventricular tachycardia (VT), sudden cardiac death (SCD), or unexplained syncope. Multivariable Cox regression analysis was performed. Results A total of 474 patients (mean age, 47 years ± 16 [SD]; 244 women) were included. Over a median follow-up of 3.3 years, 18 patients (4%) reached the study end point. LGE presence (hazard ratio, 4.2 [95% CI: 1.5, 11.9]; P = .006) and extent (hazard ratio, 1.2 per 1% increase [95% CI: 1.1, 1.4]; P = .006), but not MAD presence (P = .89), were associated with clinical outcome. LGE presence had incremental prognostic value over MVP severity and sustained VT and aborted SCD at baseline (area under the receiver operating characteristic curve, 0.70 vs 0.62; P = .03). Conclusion In contrast to mitral annulus disjunction, myocardial fibrosis determined according to late gadolinium enhancement at cardiac MRI was associated with adverse outcome in patients with mitral valve prolapse without moderate-to-severe mitral regurgitation or left ventricular dysfunction. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Gerber in this issue.

AI Cardiac MRI Scar Analysis Aids Prediction of Major Arrhythmic Events in the Multicenter DERIVATE Registry.

Background Scar burden with late gadolinium enhancement (LGE) cardiac MRI (CMR) predicts arrhythmic events in patients with postinfarction in single-center studies. However, LGE analysis requires experienced human observers, is time consuming, and introduces variability. Purpose To test whether postinfarct scar with LGE CMR can be quantified fully automatically by machines and to compare the ability of LGE CMR scar analyzed by humans and machines to predict arrhythmic events. Materials and Methods This study is a retrospective analysis of the multicenter, multivendor CarDiac MagnEtic Resonance for Primary Prevention Implantable CardioVerter DebrillAtor ThErapy (DERIVATE) registry. Patients with chronic heart failure, echocardiographic left ventricular ejection fraction (LVEF) of less than 50%, and LGE CMR were recruited (from January 2015 through December 2020). In the current study, only patients with ischemic cardiomyopathy were included. Quantification of total, dense, and nondense scars was carried out by two experienced readers or a Ternaus network, trained and tested with LGE images of 515 and 246 patients, respectively. Univariable and multivariable Cox analyses were used to assess patient and cardiac characteristics associated with a major adverse cardiac event (MACE). Area under the receiver operating characteristic curve (AUC) was used to compare model performances. Results In 761 patients (mean age, 65 years ± 11, 671 men), 83 MACEs occurred. With use of the testing group, univariable Cox-analysis found New York Heart Association class, left ventricle volume and/or function parameters (by echocardiography or CMR), guideline criterion (LVEF of ≤35% and New York Heart Association class II or III), and LGE scar analyzed by humans or the machine-learning algorithm as predictors of MACE. Machine-based dense or total scar conferred incremental value over the guideline criterion for the association with MACE (AUC: 0.68 vs 0.63, P = .02 and AUC: 0.67 vs 0.63, P = .01, respectively). Modeling with competing risks yielded for dense and total scar (AUC: 0.67 vs 0.61, P = .01 and AUC: 0.66 vs 0.61, P = .005, respectively). Conclusion In this analysis of the multicenter CarDiac MagnEtic Resonance for Primary Prevention Implantable CardioVerter DebrillAtor ThErapy (DERIVATE) registry, fully automatic machine learning-based late gadolinium enhancement analysis reliably quantifies myocardial scar mass and improves the current prediction model that uses guideline-based risk criteria for implantable cardioverter defibrillator implantation. ClinicalTrials.gov registration no.: NCT03352648 Published under a CC BY 4.0 license. Supplemental material is available for this article.

Feasibility of adenosine stress cardiovascular magnetic resonance perfusion imaging in patients with MR-conditional transvenous permanent pacemakers and defibrillators.

BACKGROUND: The use of stress perfusion-cardiovascular magnetic resonance (CMR) imaging remains limited in patients with implantable devices. The primary goal of the study was to assess the safety, image quality, and the diagnostic value of stress perfusion-CMR in patients with MR-conditional transvenous permanent pacemakers (PPM) or implantable cardioverter-defibrillators (ICD). METHODS: Consecutive patients with a transvenous PPM or ICD referred for adenosine stress-CMR were enrolled in this single-center longitudinal study. The CMR protocol was performed using a 1.5 T system according to current guidelines while all devices were put in MR-mode. Quality of cine, late-gadolinium-enhancement (LGE), and stress perfusion sequences were assessed. An ischemia burden of ≥ 1.5 segments was considered significant. We assessed the safety, image quality and the occurrence of interference of the magnetic field with the implantable device. In case of ischemia, we also assessed the correlation with the presence of significant coronary lesions on coronary angiography. RESULTS: Among 3743 perfusion-CMR examinations, 66 patients had implantable devices (1.7%). Image quality proved diagnostic in 98% of cases. No device damage or malfunction was reported immediately and at 1 year. Fifty patients were continuously paced during CMR. Heart rate and systolic blood pressure remained unchanged during adenosine stress, while diastolic blood pressure decreased (p = 0.007). Six patients (9%) had an ischemia-positive stress CMR and significant coronary stenoses were confirmed by coronary angiography in all cases. CONCLUSION: Stress perfusion-CMR is safe, allows reliable ischemia detection, and provides good diagnostic value.

Evidence-based cardiovascular magnetic resonance cost-effectiveness calculator for the detection of significant coronary artery disease.

BACKGROUND: Although prior reports have evaluated the clinical and cost impacts of cardiovascular magnetic resonance (CMR) for low-to-intermediate-risk patients with suspected significant coronary artery disease (CAD), the cost-effectiveness of CMR compared to relevant comparators remains poorly understood. We aimed to summarize the cost-effectiveness literature on CMR for CAD and create a cost-effectiveness calculator, useable worldwide, to approximate the cost-per-quality-adjusted-life-year (QALY) of CMR and relevant comparators with context-specific patient-level and system-level inputs. METHODS: We searched the Tufts Cost-Effectiveness Analysis Registry and PubMed for cost-per-QALY or cost-per-life-year-saved studies of CMR to detect significant CAD. We also developed a linear regression meta-model (CMR Cost-Effectiveness Calculator) based on a larger CMR cost-effectiveness simulation model that can approximate CMR lifetime discount cost, QALY, and cost effectiveness compared to relevant comparators [such as single-photon emission computed tomography (SPECT), coronary computed tomography angiography (CCTA)] or invasive coronary angiography. RESULTS: CMR was cost-effective for evaluation of significant CAD (either health-improving and cost saving or having a cost-per-QALY or cost-per-life-year result lower than the cost-effectiveness threshold) versus its relevant comparator in 10 out of 15 studies, with 3 studies reporting uncertain cost effectiveness, and 2 studies showing CCTA was optimal. Our cost-effectiveness calculator showed that CCTA was not cost-effective in the US compared to CMR when the most recent publications on imaging performance were included in the model. CONCLUSIONS: Based on current world-wide evidence in the literature, CMR usually represents a cost-effective option compared to relevant comparators to assess for significant CAD.

[Cardiology]. / Cardiologie.

Significant advances have been made in 2021 in the areas of interventional cardiology, heart failure, cardiac imaging, electrophysiology and congenital heart disease. In addition to improving the screening, diagnosis and management of many heart diseases, these advances will change our daily practice. Moreover, the European Society of Cardiology has updated its guidelines on heart failure, valve disease, cardiac pacing and cardiovascular disease prevention. As in previous years, members of the Cardiology division of Lausanne University Hospital (CHUV) came together to select and present to you the papers that they considered to be the most important of the past year.

De nombreux progrès ont été réalisés en 2021 dans les domaines de la cardiologie interventionnelle, de l'insuffisance cardiaque, de l'imagerie cardiaque, de l'électrophysiologie et des cardiopathies congénitales. En plus d'améliorer le dépistage, le diagnostic et la prise en charge de nombreuses cardiopathies, ces avancées vont faire évoluer notre pratique quotidienne. Par ailleurs, la Société européenne de cardiologie a mis à jour ses recommandations portant sur l'insuffisance cardiaque, les valvulopathies, la stimulation cardiaque et la prévention des maladies cardiovasculaires. Comme les années précédentes, les membres du Service de cardiologie du CHUV se sont réunis pour sélectionner et vous présenter les travaux qui leur ont semblé être les plus importants de l'année écoulée.

Impact of manual thrombectomy on microvascular obstruction in STEMI patients.

OBJECTIVE: To assess the effect of manual thrombectomy (MT) on microvascular obstruction (MVO) using cardiac magnetic resonance (CMR) in ST-segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PCI). METHODS AND RESULTS: Three hundred and eighty-three patients admitted for STEMI and undergoing CMR fulfilled the inclusion criteria and were categorized into two groups (did or did not undergo MT). The two primary endpoints were the occurrence and extent of MVO, analyzed as a categorical variable and as a semicontinuous variable. Among the 383 patients, 49.1% exhibited MVO. Both the incidence of MVO and the median number of segments presenting with MVO were significantly higher in the MT group than in the no-MT group, (59.5 vs. 38.9%, p < .001) and (1.5 [0;4] vs. 0 [0;2], p < .001). Analysis stratified on coronary thrombus grade showed similar results, only in patients with a high thrombus burden (60.7 vs. 43.5%, p = .004, and 2 [0;4] vs. 0 [0;3], p = .001. When adjusting for baseline differences, MT remained a determinant of MVO occurrence and extent (odds ratio, OR 1.802 [95% confidence interval, CI 1.080-3.009], p = .024) and ß = .137, p = .024) in patients with a high thrombus grade. CONCLUSION: In STEMI patients, MT was associated with the occurrence and extent of MVO, on CMR, especially in patients with a high thrombus burden.

Head-to-head comparison of multiple cardiovascular magnetic resonance techniques for the detection and quantification of intramyocardial haemorrhage in patients with ST-elevation myocardial infarction.

OBJECTIVES: T2*-weighted (T2*w) is deemed as a reference standard for post-infarction intramyocardial haemorrhage (IMH). However, high proportion of T2* images is affected by off-resonance artefacts hampering image interpretation. Diagnostic accuracy and precision of alternative techniques for IMH diagnosis and quantification have been seldomly investigated. METHODS AND RESULTS: Between April 2016 and May 2017, 50 ST-segment elevation myocardial infarction patients (66% male, 57 ± 17 years) and 15 healthy controls (60% male, 58 ± 13) were consecutively enrolled. Subjects underwent head-to-head comparison of single mid-infarct slice acquired on black-blood T2-weighted short-TI-inversion recovery (T2w-STIR), bright-blood T2prep-steady-state-free precession (T2prep-SSFP), and T2/T1 maps for IMH diagnosis and quantification against T2*w. All images were graded for quality (grade 1: very poor; grade 4: excellent) and diagnostic confidence (Likert scale, 1: very unsure and 5: highly confident). Reduced relaxation time/hypointense region (hypocore) embedded in infarct-related oedema on T2 map, T1 map, and T2w-STIR had the best overall diagnostic accuracy (per-subject: 91%, 86%, and 86%, respectively; per segment: 95%, 93%, and 93%, respectively). By mixed-effects analysis, image quality, and diagnostic confidence were higher for T2 map and T1 maps than T2*w (p < 0.05 for both scores). For IMH quantification, hypocore on T2 map and T1 map strongly correlated (Spearman's r > 0.7, p < 0.001 for both) with IMH extent on T2*w and presented an overall excellent agreement on Bland-Altman analysis. By linear mixed model analysis, absolute hypocore size did not differ among T1-, T2 map, and T2*w. T2/T1 maps had the best intra- and inter-observer reproducibility among CMR techniques. CONCLUSION: Hypocore on T2/T1 map is the best alternative technique to T2*w for diagnosing and quantifying IMH in post-STEMI patients. KEY POINT: • Mapping techniques are the best alternatives for diagnosing post-infarction intramyocardial haemorrhage. • Mapping techniques are valuable tools for imaging intramyocardial haemorrhage.

Motion compensated whole-heart coronary cardiovascular magnetic resonance angiography using focused navigation (fNAV).

BACKGROUND: Radial self-navigated (RSN) whole-heart coronary cardiovascular magnetic resonance angiography (CCMRA) is a free-breathing technique that estimates and corrects for respiratory motion. However, RSN has been limited to a 1D rigid correction which is often insufficient for patients with complex respiratory patterns. The goal of this work is therefore to improve the robustness and quality of 3D radial CCMRA by incorporating both 3D motion information and nonrigid intra-acquisition correction of the data into a framework called focused navigation (fNAV). METHODS: We applied fNAV to 500 data sets from a numerical simulation, 22 healthy subjects, and 549 cardiac patients. In each of these cohorts we compared fNAV to RSN and respiratory resolved extradimensional golden-angle radial sparse parallel (XD-GRASP) reconstructions of the same data. Reconstruction times for each method were recorded. Motion estimate accuracy was measured as the correlation between fNAV and ground truth for simulations, and fNAV and image registration for in vivo data. Percent vessel sharpness was measured in all simulated data sets and healthy subjects, and a subset of patients. Finally, subjective image quality analysis was performed by a blinded expert reviewer who chose the best image for each in vivo data set and scored on a Likert scale 0-4 in a subset of patients by two reviewers in consensus. RESULTS: The reconstruction time for fNAV images was significantly higher than RSN (6.1 ± 2.1 min vs 1.4 ± 0.3, min, p < 0.025) but significantly lower than XD-GRASP (25.6 ± 7.1, min, p < 0.025). Overall, there is high correlation between the fNAV and reference displacement estimates across all data sets (0.73 ± 0.29). For simulated data, healthy subjects, and patients, fNAV lead to significantly sharper coronary arteries than all other reconstruction methods (p < 0.01). Finally, in a blinded evaluation by an expert reviewer fNAV was chosen as the best image in 444 out of 571 data sets (78%; p < 0.001) and consensus grades of fNAV images (2.6 ± 0.6) were significantly higher (p < 0.05) than uncorrected (1.7 ± 0.7), RSN (1.9 ± 0.6), and XD-GRASP (1.8 ± 0.8). CONCLUSION: fNAV is a promising technique for improving the quality of RSN free-breathing 3D whole-heart CCMRA. This novel approach to respiratory self-navigation can derive 3D nonrigid motion estimations from an acquired 1D signal yielding statistically significant improvement in image sharpness relative to 1D translational correction as well as XD-GRASP reconstructions. Further study of the diagnostic impact of this technique is therefore warranted to evaluate its full clinical utility.

Myocardial extracellular volume by T1 mapping: a new marker of arrhythmia in mitral valve prolapse.

OBJECTIVES: We aimed to evaluate the relationship between mitral annular disjunction (MAD) severity and myocardial interstitial fibrosis at the left ventricular (LV) base in patients with mitral valve prolapse (MVP), and to assess the association between severity of interstitial fibrosis and the occurrence of ventricular arrhythmic events. BACKGROUND: In MVP, MAD has been associated with myocardial replacement fibrosis and arrhythmia, but the importance of interstitial fibrosis remains unknown. METHODS: In this retrospective study, 30 patients with MVP and MAD (MVP-MAD) underwent cardiovascular magnetic resonance (CMR) with assessment of MAD length, late gadolinium enhancement (LGE), and basal segments myocardial extracellular volume (ECVsyn). The control group included 14 patients with mitral regurgitation (MR) but no MAD (MR-NoMAD) and 10 patients with normal CMR (NoMR-NoMAD). Fifteen MVP-MAD patients underwent 24 h-Holter monitoring. RESULTS: LGE was observed in 47% of MVP-MAD patients and was absent in all controls. ECVsyn was higher in MVP-MAD (30 ± 3% vs 24 ± 3% MR-NoMAD, p < 0.001 and vs 24 ± 2% NoMR-NoMAD, p < 0.001), even in MVP-MAD patients without LGE (29 ± 3% vs 24 ± 3%, p < 0.001 and vs 24 ± 2%, p < 0.001, respectively). MAD length correlated with ECVsyn (rho = 0.61, p < 0.001), but not with LGE extent. Four patients had history of out-of-hospital cardiac arrest; LGE and ECVsyn were equally performant to identify those high-risk patients, area under the receiver operating characteristic (ROC) curve 0.81 vs 0.83, p = 0.84). Among patients with Holter, 87% had complex ventricular arrhythmia. ECVsyn was above the cut-off value in all while only 53% had LGE. CONCLUSION: Increase in ECVsyn, a marker of interstitial fibrosis, occurs in MVP-MAD even in the absence of LGE, and was correlated with MAD length and increased risk of out-of-hospital cardiac arrest. ECV should be includedin the CMR examination of MVP patients in an effort to better assess fibrous remodelling as it may provide additional value beyond the assessment of LGE in the arrhythmic risk stratification.

[Cardiology]. / Cardiologie.

In 2020, new guidelines have been published by the European Society of Cardiology including those on non-ST-segment elevation acute coronary syndromes, atrial fibrillation and adult congenital heart disease. Regarding interventional cardiology, POPular TAVI opens the possibility of anti-platelet monotherapy after transcutaneous aortic valve replacement. EMPEROR-Reduced confirms the importance of SGLT2 inhibitors in the treatment of heart failure with reduced ejection fraction. Within the field of imaging, stress MRI has now become the first-line technique for the screening of coronary artery disease, demonstrating an excellent cost-benefit ratio. Finally, renin-angiotensin-aldosterone inhibitors do not appear to increase the risk of an infection by COVID-19.

L'année 2020 a été marquée par la publication de nouvelles guidelines de la Société européenne de cardiologie dont le syndrome coronarien aigu sans élévation du segment ST, la fibrillation auriculaire et les cardiopathies congénitales à l'âge adulte. En interventionnel, POPular TAVI permet d'envisager la monothérapie antithrombotique après remplacement de la valve aortique par voie transcutanée. EMPEROR-Reduced confirme l'importance des inhibiteurs du cotransporteur sodium-glucose de type 2 dans le traitement de l'insuffisance cardiaque à fraction d'éjection réduite. En imagerie, l'IRM de stress s'impose comme examen de choix pour le dépistage de la maladie coronarienne avec un rapport coût-bénéfice favorable. Enfin, les inhibiteurs du système rénine-angiotensine-aldostérone ne semblent pas augmenter le risque d'une infection au Covid-19.

Detection of myocardial medium-chain fatty acid oxidation and tricarboxylic acid cycle activity with hyperpolarized [1-13 C]octanoate.

Under normal conditions, the heart mainly relies on fatty acid oxidation to meet its energy needs. Changes in myocardial fuel preference are noted in the diseased and failing heart. The magnetic resonance signal enhancement provided by spin hyperpolarization allows the metabolism of substrates labeled with carbon-13 to be followed in real time in vivo. Although the low water solubility of long-chain fatty acids abrogates their hyperpolarization by dissolution dynamic nuclear polarization, medium-chain fatty acids have sufficient solubility to be efficiently polarized and dissolved. In this study, we investigated the applicability of hyperpolarized [1-13 C]octanoate to measure myocardial medium-chain fatty acid metabolism in vivo. Scanning rats infused with a bolus of hyperpolarized [1-13 C]octanoate, the primary metabolite observed in the heart was identified as [1-13 C]acetylcarnitine. Additionally, [5-13 C]glutamate and [5-13 C]citrate could be respectively resolved in seven and five of 31 experiments, demonstrating the incorporation of oxidation products of octanoate into the tricarboxylic acid cycle. A variable drop in blood pressure was observed immediately following the bolus injection, and this drop correlated with a decrease in normalized acetylcarnitine signal (acetylcarnitine/octanoate). Increasing the delay before infusion moderated the decrease in blood pressure, which was attributed to the presence of residual gas bubbles in the octanoate solution. No significant difference in normalized acetylcarnitine signal was apparent between fed and 12-hour fasted rats. Compared with a solution in buffer, the longitudinal relaxation of [1-13 C]octanoate was accelerated ~3-fold in blood and by the addition of serum albumin. These results demonstrate the potential of hyperpolarized [1-13 C]octanoate to probe myocardial medium-chain fatty acid metabolism as well as some of the limitations that may accompany its use.

[Cardiology]. / Cardiologie.

In 2019, the guidelines on the new entity « chronic coronary syndrome ¼ have been published. They influence importantly the work-up and treatment of patients with stable coronary artery disease. We will also report on publications showing the benefit of percutaneous aortic valve implantation (TAVI) in patients with aortic stenosis and low risk surgical risk. With regard to infectious endocarditis, we elucidate the importance of the vegetation's size for predicting mortality and the prognostic value of the positron emission tomography in predicting septic embolism. We highlight the spectacular results of the DAPA-HF study in patients with heart failure and review publications showing the important role of the detection of myocardial fibrosis and scar by cardiac MRI for risk stratification of sudden cardiac death.

L'année 2019 a été marquée par la publication de recommandations sur une nouvelle entité, appelée « syndrome coronarien chronique ¼, qui modifient de manière importante la prise en charge et le traitement des patients avec une maladie coronarienne stable. On relève plusieurs publications démontrant, chez les patients ayant une sténose aortique, et étant à bas risque chirurgical, le bénéfice d'un traitement percutané par rapport à un traitement chirurgical. La prise en charge de l'endocardite a été challengée par deux publications montrant que la taille de la végétation est un facteur de risque de mortalité et la valeur pronostique de la tomographie par émission de positons dans la survenue d'emboles septiques. Nous discutons les résultats spectaculaires de l'étude DAPA-HF dans le domaine d'insuffisance cardiaque et plusieurs études montrant l'intérêt de la recherche de cicatrice myocardique à l'IRM cardiaque dans la stratification du risque de mort subite.

Probing the intravascular and interstitial compartments of remodeled myocardium in heart failure patients with preserved and reduced ejection fraction: a CMR study.

BACKGROUND: Recent autopsy studies found microvascular rarefaction in remodeled myocardium of patients who died of heart failure with preserved ejection-fraction (HFpEF). This condition has not been investigated so far by non-invasive methods in patients with HFpEF. The aim was to quantify the intravascular volume (IVV) compartment by CMR in HFpEF patients. METHODS: In two separate CMR examinations, HFpEF patients (n = 6; 12 examinations) and post-myocardial infarction patients (post-MI; n = 6; 12 examinations) were studied with T1-mapping (MOLLI-sequence) before and after IV bolus of 0.03 mmol/Kg of the intravascular contrast-medium (CM) Gadofosveset and 0.2 mmol/Kg of the extravascular CM Gadobutrol yielding IVV and extracellular volume (ECV), respectively. Healthy controls (n = 10 with Gadofosveset only, n = 10 with Gadobutrol only) were also studied with the same protocol. IVV and ECV were measured in the basal septum (without ischemic scar in post-MI patients). In post-MI patients, ECV and IVV were also measured in the ischemic scar. Left ventricular (LV) volumes, mass, and ejection-fraction were measured by standard protocol. LV global longitudinal strain (GLS) was calculated by feature tracking on long-axis cine acquisitions. RESULTS: LV mass to end-diastolic volume ratio and GLS in HFpEF were higher and lower, respectively, than in healthy controls and post-MI patients, whereas the post-MI patients showed lower LV ejection-fraction. Compared to healthy myocardium of controls, IVV in scar was reduced (0.135 ± 0.018 vs 0.109 ± 0.008, respectively, p = 0.005), while ECV was increased (0.244 ± 0.037 vs 0.698 ± 0.106, respectively, p < 0.001). However, IVV did not differ among HFpEF, post-MI, and healthy controls (0.155 ± 0.033, 0.146 ± 0.038, and 0.135 ± 0.018, respectively, p = 0.413), whereas ECV was higher in HFpEF than in post-MI and healthy controls (0.304 ± 0.159, 0.270 ± 0.017, and 0.244 ± 0.037, respectively, p = 0.003). CONCLUSIONS: The T1-mapping technique combined with an intravascular CM shows potential to measure IVV. In infarct scar with substantially increased ECV, IVV was significantly reduced. Unlike in infarct scar, in remodeled myocardium of HFpEF patients, increased ECV was not accompanied by a reduction of IVV.

[Management of refractory ventricular tachycardia using stereotactic body radiotherapy]. / Prise en charge des tachycardies ventriculaires réfractaires par radiothérapie stéréotaxique.

Stereotactic body radiotherapy (SBRT) is routinely used in oncology to treat non-invasively solid tumors with high precision and efficacy. Recently, this technology has been evaluated in the treatment of ventricular tachycardia (VT). This article presents the basic underlying principles, proofs of concept and main results of clinical studies that used SBRT for the treatment of VT.

La radiothérapie stéréotaxique (SBRT) est une technologie couramment utilisée en oncologie pour traiter de façon non invasive les tumeurs solides avec précision et efficacité. Récemment, cette technologie a été évaluée dans le traitement des tachycardies ventriculaires (TV). Cet article présente les principes de base sous-jacents, le concept ainsi que les résultats des premières études cliniques ayant traité avec succès des patients souffrant de TV avec la SBRT.

Probing cardiac metabolism by hyperpolarized 13C MR using an exclusively endogenous substrate mixture and photo-induced nonpersistent radicals.

PURPOSE: To probe the cardiac metabolism of carbohydrates and short chain fatty acids simultaneously in vivo following the injection of a hyperpolarized 13 C-labeled substrate mixture prepared using photo-induced nonpersistent radicals. METHODS: Droplets of mixed [1-13 C]pyruvic and [1-13 C]butyric acids were frozen into glassy beads in liquid nitrogen. Ethanol addition was investigated as a means to increase the polarization level. The beads were irradiated with ultraviolet light and the radical concentration was measured by ESR spectroscopy. Following dynamic nuclear polarization in a 7T polarizer, the beads were dissolved, and the radical-free hyperpolarized solution was rapidly transferred into an injection pump located inside a 9.4T scanner. The hyperpolarized solution was injected in healthy rats to measure cardiac metabolism in vivo. RESULTS: Ultraviolet irradiation created nonpersistent radicals in a mixture containing 13 C-labeled pyruvic and butyric acids, and enabled the hyperpolarization of both substrates by dynamic nuclear polarization. Ethanol addition increased the radical concentration from 16 to 26 mM. Liquid-state 13 C polarization was 3% inside the pump at the time of injection, and increased to 5% by addition of ethanol to the substrate mixture prior to ultraviolet irradiation. In the rat heart, the in vivo 13 C signals from lactate, alanine, bicarbonate, and acetylcarnitine were detected following the metabolism of the injected substrate mixture. CONCLUSION: Copolarization of two different 13 C-labeled substrates and the detection of their myocardial metabolism in vivo was achieved without using persistent radicals. The absence of radicals in the solution containing the hyperpolarized 13 C-substrates may simplify the translation to clinical use, as no radical filtration is required prior to injection.

Relationship between CMR-derived parameters of ischemia/reperfusion injury and the timing of CMR after reperfused ST-segment elevation myocardial infarction.

BACKGROUND: To investigate the influence of cardiovascular magnetic resonance (CMR) timing after reperfusion on CMR-derived parameters of ischemia/reperfusion (I/R) injury in patients with ST-segment elevation myocardial infarction (STEMI). METHODS: The study included 163 reperfused STEMI patients undergoing CMR during the index hospitalization. Patients were divided according to the time between revascularization and CMR (Trevasc-CMR: Tertile-1 ≤ 43; 43 < Tertile-2 ≤ 93; Tertile-3 > 93 h). T2-mapping derived area-at-risk (AAR) and intramyocardial-hemorrhage (IMH), and late gadolinium enhancement (LGE)-derived infarct size (IS) and microvascular obstruction (MVO) were quantified. T1-mapping was performed before and > 15 min after Gd-based contrast-agent administration yielding extracellular volume (ECV) of infarct. RESULTS: Main factors influencing I/R injury were homogenously balanced across Trevasc-CMR tertiles. T2 values of infarct and remote regions increased with increasing Trevasc-CMR tertiles (infarct: 60.0 ± 4.9 vs 63.5 ± 5.6 vs 64.8 ± 7.5 ms; P < 0.001; remote: 44.3 ± 2.8 vs 46.1 ± 2.8 vs ± 46.1 ± 3.0; P = 0.001). However, T2 value of infarct largely and significantly exceeded that of remote myocardium in each tertile yielding comparable T2-mapping-derived AAR extent throughout Trevasc-CMR tertiles (17 ± 9% vs 19 ± 9% vs 18 ± 8% of LV, respectively, P = 0.385). Similarly, T2-mapping-based IMH detection and quantification were independent of Trevasc-CMR. LGE-derived IS and MVO were not influenced by Trevasc-CMR (IS: 12 ± 9% vs 12 ± 9% vs 14 ± 9% of LV, respectively, P = 0.646). In 68 patients without MVO, T1-mapping based ECV of infarct region was comparable across Trevasc-CMR tertiles (P = 0.470). CONCLUSION: In STEMI patients, T2 values of infarct and remote myocardium increase with increasing CMR time after revascularization. However, these changes do not give rise to substantial variation of T2-mapping-derived AAR size nor of other CMR-based parameters of I/R. TRIAL REGISTRATION: ISRCTN03522116 . Registered 30.4.2018 (retrospectively registered).

[Myocardial fibrosis detected by cardiac MR : A substrate for ventricular arrhythmias and sudden cardiac death]. / Fibrose myocardique détectée à l'IRM cardiaque : un substrat aux arythmies ventriculaires et à la mort subite.

Myocardial fibrosis often develops in the setting of hypertrophic and dilated cardiomyopathies (CMP), but is also a common sequela after inflammatory CMP or following an acute myocardial infarction in patients with coronary artery disease. Cardiac magnetic resonance (CMR) provides a precise quantification of mass and spatial distribution of myocardial fibrosis by the so-called « late-gadolinium-enhancement ¼ (LGE) technique and current evidence is provided in this article linking fibrosis mass to outcome in these specific patient populations. The position of CMR fibrosis imaging in the current guidelines is discussed and suggestions are given how to integrate CMR fibrosis imaging in the work-up and risk stratification of these patient populations. Finally, a short outlook is given on anticipated developments on CMR fibrosis imaging and its integration into patient management.

La fibrose myocardique se développe fréquemment dans le contexte des cardiomyopathies hypertrophiques ou dilatatives, mais elle représente également une séquelle fréquente des cardiopathies inflammatoires ou de l'infarctus myocardique. L'IRM cardiaque permet la quantification précise de la masse fibrotique et de sa distribution spatiale par le « rehaussement tardif ¼. Cet article présente les données soutenant la relation entre la fibrose myocardique et le pronostic dans ces populations spécifiques. La place de l'imagerie de la fibrose par IRM dans les guidelines actuelles est discutée, de même que des suggestions d'intégration de la détection de fibrose par IRM cardiaque dans le bilan de ces patients. Enfin, les développements en cours dans le domaine de la fibrose en IRM sont brièvement évoqués, de même que leur potentielle intégration dans la prise en charge du patient.

[Cardiology update 2017]. / Cardiologie.

As usual, numerous papers published in 2017 contributed to optimize the management of patients in all clinical cardiologic fields. It is of course impossible to summarize them all in such an article. Subjects and papers were thus selected if they were thought to be particularly important for non-cardiologist physicians, especially general practitioners. The authors would also like to take the opportunity of this article to honor the memory of Pr Daniel Wagner who unfortunately passed away after less than six months at the head of our Cardiology Department. He was well recognized for his generosity as well as his clinical and scientific competence. This article is dedicated to him.

Comme à l'accoutumée, l'année 2017 a été marquée par la publication de nombreux travaux permettant d'optimaliser la prise en charge de nos patients dans tous les domaines de la cardiologie et il est évidemment impossible de les synthétiser ici de façon exhaustive. Nous avons donc sélectionné les sujets et les travaux qui nous ont paru les plus saillants et surtout les plus utiles pour nos collègues non cardiologues et particulièrement pour nos collègues médecins de premier recours. Cette revue de l'année 2017 ne serait toutefois pas complète sans un hommage au Pr Daniel Wagner qui a débuté son activité de chef du service de cardiologie du CHUV au 1er janvier et nous a quittés après seulement quelques mois passés parmi nous. Daniel fut un chef de service apprécié tant pour ses qualités humaines que pour ses compétences scientifiques et cliniques. Cet article lui est donc dédié.

Four-dimensional respiratory motion-resolved whole heart coronary MR angiography.

PURPOSE: Free-breathing whole-heart coronary MR angiography (MRA) commonly uses navigators to gate respiratory motion, resulting in lengthy and unpredictable acquisition times. Conversely, self-navigation has 100% scan efficiency, but requires motion correction over a broad range of respiratory displacements, which may introduce image artifacts. We propose replacing navigators and self-navigation with a respiratory motion-resolved reconstruction approach. METHODS: Using a respiratory signal extracted directly from the imaging data, individual signal-readouts are binned according to their respiratory states. The resultant series of undersampled images are reconstructed using an extradimensional golden-angle radial sparse parallel imaging (XD-GRASP) algorithm, which exploits sparsity along the respiratory dimension. Whole-heart coronary MRA was performed in 11 volunteers and four patients with the proposed methodology. Image quality was compared with that obtained with one-dimensional respiratory self-navigation. RESULTS: Respiratory-resolved reconstruction effectively suppressed respiratory motion artifacts. The quality score for XD-GRASP reconstructions was greater than or equal to self-navigation in 80/88 coronary segments, reaching diagnostic quality in 61/88 segments versus 41/88. Coronary sharpness and length were always superior for the respiratory-resolved datasets, reaching statistical significance (P < 0.05) in most cases. CONCLUSION: XD-GRASP represents an attractive alternative for handling respiratory motion in free-breathing whole heart MRI and provides an effective alternative to self-navigation. Magn Reson Med 77:1473-1484, 2017. © 2016 International Society for Magnetic Resonance in Medicine.