MEdical TReatment Optimization in cardiac rehabilitation (METRO study) : a French multicenter study.

BACKGROUND: Cardiac rehabilitation (CR) is the right place to optimize the medical treatment in coronary artery disease (CAD) patients. AIMS: To report the medical management in CAD patients during CR and evaluate the consequences. METHODS: CAD patients who attended a CR program within less than three months of an acute coronary syndrome (ACS), a percutaneous coronary intervention (PCI), or a coronary artery bypass graft (CABG) were included in a prospective multicenter study. Medical treatments were analyzed at the beginning and at discharge of the CR stay. Results of exercise tests were compared between 4 groups. G1: unchanged medication, n=443, G2: beta-blockers or bradycardic agents adaptation n=199, G3: renin-angiotensin system (RAS) inhibitors adaptation, n=194, G4: both medications adaptation, n=164. RESULTS: One thousand consecutive patients were included in 23 French CR centers (85.3% males; mean age 59.9 ± 11 years). The index event was ACS (68.5%), PCI (62.6%) and CABG (36.3%). During CR, we noted an adaptation for beta-blockers in 32.1%, in other bradycardic agents (ivabradine, verapamil, diltiazem, amiodarone) in 9.5%, and in RAS inhibitors in 36.3%. Patients of group 1 had an initial resting heart rate lower than in group 2 and 4, but at the final exercise testing, the range of the decrease was more important in group 2 and 4. The combination of physical training and therapeutic modifications resulted in similar exercise capacities in the four groups, from 5.2, 5.3, 5.4 and 5.2 MET (p=0.68), to 6.3, 6.5, 6.5 and 6.1 MET (p=0.44), respectively. CONCLUSION: The METRO study showed that significant alteration in medical treatment during cardiac rehabilitation programs could take part in improving physical capacity.

Cardiovascular events in perimembranous ventricular septal defect with left ventricular volume overload: a French prospective cohort study (FRANCISCO).

The long-term prospective multi-centre nationwide (French) observational study FRANCISCO will provide new information on perimembranous ventricular septal defect with left ventricular overload but no pulmonary hypertension in children older than 1 year. Outcomes will be compared according to treatment strategy (watchful waiting, surgical closure, or percutaneous closure) and anatomic features of the defect. The results are expected to provide additional guidance about the optimal treatment of this specific population, which is unclear at present. BACKGROUND: The management of paediatric isolated perimembranous ventricular septal defect (pmVSD) with left ventricle (LV) volume overload but no pulmonary arterial hypertension (PAH) remains controversial. Three therapeutic approaches are considered: watchful waiting, surgical closure, and percutaneous closure. We aim to investigate the long-term outcomes of these patients according to anatomic pmVSD characteristics and treatment strategy. METHODS: The Filiale de Cardiologie Pediatrique et Congénitale (FCPC) designed the FRANCISCO registry, a long-term prospective nationwide multi-centre observational cohort study sponsored by the French Society of Cardiology, which enrolled, over 2 years (2018­2020), patients older than 1 year who had isolated pmVSD with LV volume overload. Prevalent complications related to pmVSD at baseline were exclusion criteria. Clinical, echocardiographic, and functional data will be collected at inclusion then after 1, 5, and 10 years. A core lab will analyse all baseline echocardiographic data to depict anatomical pmVSD features. The primary outcome is the 5-year incidence of cardiovascular events (infective endocarditis, sub-aortic stenosis, aortic regurgitation, right ventricular outflow tract stenosis, tricuspid regurgitation, PAH, arrhythmia, stroke, haemolysis, heart failure, or death from a cardiovascular event). We plan to enrol 200 patients, given the 10% estimated 5-year incidence of cardiovascular events with a 95% confidence interval of ±5%. Associations linking anatomical pmVSD features and treatment strategy to the incidence of complications will be assessed. CONCLUSIONS: The FRANSCICO study will provide the long-term incidence of complications in patients older than 1 year with pmVSD and LV volume overload. The results are expected to improve guidance for treatment decisions.

Acute Heart Failure in Multisystem Inflammatory Syndrome in Children in the Context of Global SARS-CoV-2 Pandemic.

BACKGROUND: Cardiac injury and myocarditis have been described in adults with coronavirus disease 2019 (COVID-19). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children is typically minimally symptomatic. We report a series of febrile pediatric patients with acute heart failure potentially associated with SARS-CoV-2 infection and the multisystem inflammatory syndrome in children as defined by the US Centers for Disease Control and Prevention. METHODS: Over a 2-month period, contemporary with the SARS-CoV-2 pandemic in France and Switzerland, we retrospectively collected clinical, biological, therapeutic, and early outcomes data in children who were admitted to pediatric intensive care units in 14 centers for cardiogenic shock, left ventricular dysfunction, and severe inflammatory state. RESULTS: Thirty-five children were identified and included in the study. Median age at admission was 10 years (range, 2-16 years). Comorbidities were present in 28%, including asthma and overweight. Gastrointestinal symptoms were prominent. Left ventricular ejection fraction was <30% in one-third; 80% required inotropic support with 28% treated with extracorporeal membrane oxygenation. Inflammation markers were suggestive of cytokine storm (interleukin-6 median, 135 pg/mL) and macrophage activation (D-dimer median, 5284 ng/mL). Mean BNP (B-type natriuretic peptide) was elevated (5743 pg/mL). Thirty-one of 35 patients (88%) tested positive for SARS-CoV-2 infection by polymerase chain reaction of nasopharyngeal swab or serology. All patients received intravenous immunoglobulin, with adjunctive steroid therapy used in one-third. Left ventricular function was restored in the 25 of 35 of those discharged from the intensive care unit. No patient died, and all patients treated with extracorporeal membrane oxygenation were successfully weaned. CONCLUSIONS: Children may experience an acute cardiac decompensation caused by severe inflammatory state after SARS-CoV-2 infection (multisystem inflammatory syndrome in children). Treatment with immunoglobulin appears to be associated with recovery of left ventricular systolic function.

Physical activity for patients with heart failure: Position paper from the heart failure (GICC) and cardiac rehabilitation (GERS-P) Working Groups of the French Society of Cardiology.

Physical activity is important in heart failure to improve functional capacity, quality of life and prognosis, and is a class IA recommendation in the European Society of Cardiology guidelines (Ponikowski et al., 2016). The benefits of exercise training are widely recognized. Cardiac rehabilitation centres offer tailored exercise training to patients with heart failure, as part of specialized multidisciplinary care, alongside pharmacological treatment optimization and patient education. After cardiac rehabilitation, maintenance of regular physical activity long term is essential, as the benefits of exercise training vanish within a few weeks. Unfortunately, only 10% of patients benefit from a cardiac rehabilitation programme after hospitalization for acute heart failure, and the majority of patients do not pursue long-term physical activity. In this paper, two Working Groups of the French Society of Cardiology (the heart failure group [Groupe Insuffisance Cardiaque et Cardiomyopathies; GICC] and the cardiac rehabilitation group [Groupe Exercice Réadaptation Sport et Prévention; GERS-P]) discuss the obstacles to broader access to cardiac rehabilitation centres, and propose ways to improve the diffusion of cardiac rehabilitation programmes and encourage long-term adherence to physical activity.

Impact of a centre and home-based cardiac rehabilitation program on the quality of life of teenagers and young adults with congenital heart disease: The QUALI-REHAB study rationale, design and methods.

BACKGROUND: Advances in congenital heart disease (CHD) have transferred the mortality from childhood to adulthood. Exercise capacity in young patients with CHD remains lower than in the general population, resulting in deconditioning and impaired quality of life. Evidence based-medicine in cardiac rehabilitation in this age group with CHD remains limited. We present the QUALI-REHAB study rationale, design and methods. METHODS: The QUALI-REHAB trial is a nationwide, multicentre, randomised, controlled study, aiming to assess the impact of a combined centre and home-based cardiac rehabilitation program on the quality of life of adolescents and young adults (13 to 25 years old) with CHD. Patients with a maximum oxygen uptake (VO2max) < 80% and/or a ventilatory anaerobic threshold (VAT) < 55% of predicted VO2max, will be eligible. Patients will be randomised into 2 groups (12-week cardiac rehabilitation program vs. controls). The primary outcome is the change in the PedsQL quality of life score between baseline and 12-month follow-up. A total of 130 patients are required to observe a significant increase of 7 ±â€¯13.5 points in the PedsQL, with a power of 80% and an alpha risk of 5%. The secondary outcomes are: VO2max, VAT, stroke volume, clinical outcomes, physical and psychological status, safety and acceptability. CONCLUSION: After focusing on the survival in CHD, current research is opening on secondary prevention and patient-related outcomes. The QUALI-REHAB trial intends to assess if a combined centre and home-based rehabilitation program, could improve the quality of life and the exercise capacity in youth with CHD. TRIAL REGISTRATION: Clinicaltrials.gov (NCT03690518).

French Society of Cardiology guidelines on exercise tests (part 2): Indications for exercise tests in cardiac diseases.

The exercise test is performed routinely in cardiology; its main indication is the diagnosis of myocardial ischemia, evaluated along with the subject's pretest probability and cardiovascular risk level. Other criteria, such as analysis of repolarization, must be taken into consideration during the interpretation of an exercise test, to improve its predictive value. An exercise test is also indicated for many other cardiac diseases (e.g. rhythm and conduction disorders, severe asymptomatic aortic stenosis, hypertrophic cardiomyopathy, peripheral artery disease, hypertension). Moreover, an exercise test may be indicated for specific populations (women, the elderly, patients with diabetes mellitus, patients in a preoperative context, asymptomatic patients and patients with congenital heart defects). Some cardiac diseases (such as chronic heart failure or arterial pulmonary hypertension) require a cardiopulmonary exercise test. Finally, an exercise test or a cardiopulmonary exercise test is indicated to prescribe a cardiac rehabilitation programme, adapted to the patient.

French Society of Cardiology guidelines on exercise tests (part 1): Methods and interpretation.

The exercise test is still a key examination in cardiology, used for the diagnosis of myocardial ischemia, as well as for the clinical evaluation of other heart diseases. The cardiopulmonary exercise test can further define functional capacity and prognosis for any given cardiac pathology. These new guidelines focus on methods, interpretation and indications for an exercise test or cardiopulmonary exercise test, as summarized below. The safety rules associated with the exercise test must be strictly observed. Interpretation of exercise tests and cardiopulmonary exercise tests must be multivariable. Functional capacity is a strong predictor of all-cause mortality and cardiovascular events. Chest pain, ST-segment changes and an abnormal ST/heart rate index constitute the first findings in favor of myocardial ischemia, mostly related to significant coronary artery disease. Chronotropic incompetence, abnormal heart rate recovery, QRS changes (such as enlargement or axial deviations) and the use of scores (based on the presence of various risk factors) must also be considered in exercise test interpretation for a coronary artery disease diagnosis. Arrhythmias or conduction disorders arising during the exercise test must be considered in the assessment of prognosis, in addition to a decrease or low increase in blood pressure during the exercise phase. When performing a cardiopulmonary exercise test, peak oxygen uptake and the volume of expired gas/carbon dioxide output slope are the two main variables used to evaluate prognosis.

[Sports in children with congenital heart diseases]. / Sport et cardiopathies congénitales chez l'enfant.

The practice of physical activity is one of the essential elements for health in general but also for the well-being and the quality of life. It is highly desirable to encourage physical activities in children with congenital heart diseases, taking into account all the benefits associated with this practice (quality of life, life expectancy) and this especially since these children often have limited capacity (due to their heart disease but also often by relative deconditioning). While there is a transient increase in risk of cardiac complications during intense activity, it would nevertheless be inappropriate to contra-indicate physical activities considering the well-known benefits in the medium and long term. The risks associated with the practice of physical activity must be assessed, on one hand, in terms of the severity of the heart disease, and on the other hand, on the nature and intensity of the activity. The stress test is here an essential tool because it helps to assess the physical capacity and cardiorespiratory adaptations to exercise. The international recommendations for competitive sports generally give an appropriate advice for a specific situation but the practice of moderate activity or leisure sports which are highly desirable should not be neglected and be strongly encouraged.

Outcome of adults with Eisenmenger syndrome treated with drugs specific to pulmonary arterial hypertension: A French multicentre study.

BACKGROUND: The relationship between pulmonary arterial hypertension-specific drug therapy (PAH-SDT) and mortality in Eisenmenger syndrome (ES) is controversial. AIMS: To investigate outcomes in patients with ES, and their relationship with PAH-SDT. METHODS: Retrospective, observational, nationwide, multicentre cohort study. RESULTS: We included 340 patients with ES: genetic syndrome (n=119; 35.3%); pretricuspid defect (n=75; 22.1%). Overall, 276 (81.2%) patients received PAH-SDT: monotherapy (endothelin receptor antagonist [ERA] or phosphodiesterase 5 inhibitor [PDE5I]) 46.7%; dual therapy (ERA+PDE5I) 40.9%; triple therapy (ERA+PDE5I+prostanoid) 9.1%. Median PAH-SDT duration was 5.5 years [3.0-9.1 years]. Events (death, lung or heart-lung transplantation) occurred in 95 (27.9%) patients at a median age of 40.5 years [29.4-47.6]. The cumulative occurrence of events was 16.7% [95% confidence interval 12.8-21.6%] and 46.4% [95% confidence interval 38.2-55.4%] at age 40 and 60 years, respectively. With age at evaluation or time since PAH diagnosis as time scales, cumulative occurrence of events was lower in patients taking one or two PAH-SDTs (P=0.0001 and P=0.004, respectively), with the largest differences in the post-tricuspid defect subgroup (P<0.001 and P<0.02, respectively) versus patients without PAH-SDT. By multivariable Cox analysis, with time since PAH diagnosis as time scale, New York Heart Association/World Health Organization functional class III/IV, lower peripheral arterial oxygen saturation and pretricuspid defect were associated with a higher risk of events (P=0.002, P=0.01 and P=0.04, respectively), and one or two PAH-SDTs with a lower risk of events (P=0.009). CONCLUSIONS: Outcomes are poor in ES, but seem better with PAH-SDT. ES with pretricuspid defects has worse outcomes despite the delayed disease onset.

Vertigo in downhill mountain biking and road cycling.

Vertigo has been described after the practice of mountain bike. This study aimed to investigate the prevalence of vertigo following competitions or training sessions of downhill mountain biking (DMB) or road cycling (RC). One hundred and two DMB riders, 79 road cyclists and 73 control participants filled in a survey intended to evaluate the prevalence of vertigo in daily living activities and following competitions or training sessions. Vertigo causal factors (crashes, head trauma, fatigue, characteristics of the path/road ridden) were recorded. DMB riders and road cyclists did not report more vertigo during daily living activities than controls. But DMB riders older than 30 had more risk to report vertigo than age-matched road cyclists (OR: 5.06, 95% CI: 1.23-20.62). Road cyclists aged between 20 and 29 were 2.59-fold (95% CI: 1.06-6.27) more likely to report vertigo than controls. After competitions and training sessions, DMB riders were 2.33-fold (95% CI: 1.22-4.41) more likely to report vertigo than road cyclists. Vertigo causal factors were crash with head trauma in DMB riders and fatigue in road cyclists. Vertigo during daily living activities may be of concern for cyclists, particularly older DMB riders. The accumulation of impacts (crashes, vibrations) during the career of a DMB rider may generate micro-traumatisms of the central nervous system and/or peripheral vestibular structures, particularly the otolith organs. In RC, the pathophysiological mechanisms generating vertigo might be effort-related disturbance of homeostasis. To avoid injuries, DMB riders should be aware that vertigo may occur at the end of training sessions or competitions.

[Sexual activity and cardiovascular risks]. / Activité sexuelle et risques cardiovasculaires.

Sexual activity is a major aspect of the quality of life in the general population as well as in cardiac patients. It can be compromised by the disease itself (endothelial dysfunction, vascular or cardiac impairment) or by the treatments prescribed. An appropriate treatment should be proposed, including phosphodiesterase inhibitors in men with erectile dysfunction. The risk of cardiovascular complication during sexual activity is low and should not restrain sexual activity in the vast majority of patients. An evaluation of this risk should be made on an individual basis and counseling should be proposed to men and women with cardiovascular diseases regarding their sexual activity. But the most important point, for general practitioners and cardiologists, is to take initiative and talk to the patients about these problems.

[Wine: Good for all cardiovascular diseases?]. / Le vin : bon pour toutes les pathologies cardiovasculaires ?

UNLABELLED: Beneficial effects of wine are mainly due to polyphenol components with a major role for resveratrol. Moderate wine consumption decreases cardiovascular mortality. Very favorable effects in coronary artery disease and cholesterol. Deleterious effects in systemic hypertension and dilated cardiomyopathy. RECOMMENDATION: 1 to 2 drinks (10 to 20g of alcohol) per day.

"Postural first" principle when balance is challenged in elderly people.

Human cognitive processing limits can lead to difficulties in performing two tasks simultaneously. This study aimed to evaluate the effect of cognitive load on both simple and complex postural tasks. Postural control was evaluated in 128 noninstitutionalized elderly people (mean age = 73.6 ± 5.6 years) using a force platform on a firm support in control condition (CC) and mental counting condition (MCC) with eyes open (EO) and eyes closed (EC). Then, the same tests were performed on a foam support. Sway path traveled and area covered by the center of foot pressure were recorded, low values indicating efficient balance. On firm support, sway path was higher in MCC than in CC both in EO and EC conditions (p < 0.001). On foam support, sway path was higher in CC than in MCC in EC condition (p < 0.001), area being higher in CC than in MCC both in EO (p < 0.05) and EC (p < 0.001) conditions. The results indicate that cognitive load alters balance control in a simple postural task (i.e. on firm support), which is highlighted by an increase of energetic expenditure (i.e. increase of the sway path covered) to balance. Awareness may not be increased and the attentional demand may be shared between balance and mental task. Conversely, cognitive load does not perturb the realization of a new complex postural task. This result showed that postural control is prioritized ("postural first" principle) when seriously challenged.

Desensitization of the cough reflex during limb muscle contraction in anesthetized rabbits.

The 'cough network' exhibits plasticity at the sensor and integration levels leading to modulation of the strength or pattern of the cough reflex. Little is known about the interactions between cough and human activities, especially during exercise. The present study was designed to determine whether exercise, mimicked by electrically induced muscle contractions, can modify the incidence and/or strength of cough following mechanical stimulation of the trachea in anesthetized rabbits. Thirteen anesthetized, tracheotomized rabbits were studied by a total of 311 tracheal stimulations: 196 at rest and 115 during exercise. During muscle contractions, the incidence of the cough reflex (CR) decreased and the expiration reflex (ER) increased (p < 0.0001). The sensitivity of the CR and ER both decreased during exercise compared to the sensitivity of the CR at rest (p < 0.02), while the strength of the expulsive response remained unchanged. These results indicate that adjustments occurring during muscle contractions likely downregulate tracheal defensive reflexes in anesthetized rabbits.

Motion sickness in rally car co-drivers.

BACKGROUND: Car sickness is a frequent and potentially disabling problem, commonly related to a theory of sensory conflict, in particular visuo-vestibular, and between actual and anticipated sensory signals. This study aimed to evaluate predictors of motion sickness (MS) in rally car co-drivers exposed to various accelerations. METHODS: The subjects were 85 rally co-drivers (21 women) who filled in a questionnaire investigating MS symptoms in 4 situations: 1) special stages (competition itself); 2) special stages reconnaissance; 3) reading a book in the car; and 4) rear-seat passenger. The main factors related to MS were also investigated. RESULTS: Women reported more MS than men only in the rear-seat passenger situation. MS is reported with increasing frequency in special stages (2.3%), special stages reconnaissance (15.3%), when reading a book in a car (25.9%), and as a rear-seat passenger (25.9%). Stress (63.0%), on-board smells (46.5%), and on-board temperature (43.0%) were the main risk factors for MS. DISCUSSION: In special stages, the lower MS occurrence could be related to the kind of visual input: central vision focuses mainly on accurate pace notes while peripheral vision is restricted by the crash helmet and the head being bent forward. A cognitive process involved in the interpretation of the dynamic environment may lead to anticipation of upcoming accelerations, optimizing integration of vestibular and proprioceptive signals. During reconnaissance, the constant change of gaze between looking at the specifics of the road and the road book for taking notes requires frequent adjustments of the gain of the vestibulo-ocular reflex and the associated head movements could generate Coriolis accelerations.

The epidemiology of vertigo, dizziness, and unsteadiness and its links to co-morbidities.

Vertigo, dizziness, and unsteadiness (VDU) are common symptoms traditionally considered to result from different kinds of vestibular and non-vestibular dysfunctions. The epidemiology of each symptom and how they relate to each other and to migraine, agoraphobia, motion sickness susceptibility (MSS), vaso-vagal episodes (VVE), and anxiety-depression was the object of this population-based study in north-eastern France. A self-administered questionnaire was returned by 2987 adults (age span 18-86 years, 1471 women). The 1-year prevalence for vertigo was 48.3%, for unsteadiness 39.1%, and for dizziness 35.6%. The three symptoms were correlated with each other, occurred mostly (69.4%) in various combinations rather than in isolation, less than once per month, and 90% of episodes lasted ≤2 min. The three symptoms were similar in terms of female predominance, temporary profile of the episodes, and their link to falls and nausea. Symptom episodes of >1 h increase the risk of falls. VDU are much more common than the known prevalence of vestibular disorders. The number of drugs taken increase VDU even when controlling for age. Each VDU symptom was correlated with each co-morbidity in Chi-squared tests. The data suggest that the three symptoms are more likely to represent a spectrum resulting from a range of similar - rather than from different, unrelated - mechanisms or disorders. Logistic regressions controlling for each vestibular symptom showed that vertigo correlated with each co-morbidity but dizziness and unsteadiness did not, suggesting that vertigo is certainly not a more specific symptom than the other two. A logistic regression using a composite score of VDU, controlling for each co-morbidity showed a correlation of VDU to migraine and VVE but not to MSS and not to agoraphobia in men, only in women.

Biological determinants of postural disorders in elderly women.

Postural control impairments and dizziness, which are major health problems with high secondary morbidity and mortality, increase with aging. Elevated homocysteine (Hcy) level is an age-related metabolic disorder, known to be involved in cardiovascular, neurological, and multisensory dysfunctions. Elevated Hcy level might be involved in sensory balance control systems impairment and dizziness occurrence. Dizziness, fitness Instrumental Activity of Daily Living scale (fitness IADL), systolic arterial pressure with ankle-brachial blood pressure index and homocysteinemia were studied in 61 noninstitutionized elderly women. Clinical balance tests (timed "Up and Go", 10-m walking and one-leg balance) and posturography (including sensory conflicting situations [SCS] and cognitive conflicting situations [CCS]) were performed. Clinical balance control was lower in dizzy women who presented particularly poor stability in SCS. Dizziness was related to low fitness IADL scores (odds ratio [OR] 0.452, 95% CI 0.216-0.946) and to elevated Hcy (OR 8.084, 95% CI 1.992-32.810). Elevated Hcy was correlated with balance disorders both in SCS and CCS. Dizziness is associated with a reduced ability in balance control management. Hcy is related both to dizziness and low postural performance. This relation between elevated Hcy levels and balance impairments, resulting in dizziness, may be explained by its angiotoxicity and neurotoxicity.

Exercise and dehydration: A possible role of inner ear in balance control disorder.

To study the effect of exercise and dehydration on the postural sensory-motor strategies, 10 sportsmen performed a 45 min-exercise on a cycle ergometer at intensity just below the ventilatory threshold without fluid intake. They performed, before, immediately and 20 min after exercise, a sensory organization test to evaluate balance control in six different sensory situations, that combine three visual conditions (eyes open, eyes closed and sway-referenced visual surround motion) with two platform conditions (stable platform, sway-referenced platform motion). Blood samples were collected before and after exercise. Exercise induced a mild dehydration, characterized by body mass loss and increase in proteinemia. Postural performances decreased immediately after exercise, mainly in the standard situation (eyes open, stable visual surround and platform) and when only the vestibular cue was reliable (eyes closed and sway-referenced platform). Moreover, the decreased use of vestibular input was correlated with the dehydration level. Finally, postural performances normalized 20 min after exercise. Even though muscular fatigue could explain the decrease in postural performances, vestibular fluid modifications may also be involved by its influence on the intralabyrinthine homeostasis, lowering thus the contribution of vestibular information on balance control.

Reconstruction from free-breathing cardiac MRI data using reproducing kernel Hilbert spaces.

This paper describes a rigorous framework for reconstructing MR images of the heart, acquired continuously over the cardiac and respiratory cycle. The framework generalizes existing techniques, commonly referred to as retrospective gating, and is based on the properties of reproducing kernel Hilbert spaces. The reconstruction problem is formulated as a moment problem in a multidimensional reproducing kernel Hilbert spaces (a two-dimensional space for cardiac and respiratory resolved imaging). Several reproducing kernel Hilbert spaces were tested and compared, including those corresponding to commonly used interpolation techniques (sinc-based and splines kernels) and a more specific kernel allowed by the framework (based on a first-order Sobolev RKHS). The Sobolev reproducing kernel Hilbert spaces was shown to allow improved reconstructions in both simulated and real data from healthy volunteers, acquired in free breathing.