Delayed Enhancement Cardiac MRI Research Articles

Detection of occult thrombosis in individuals with Fontan circulation by cardiac MRI.

Identifying thrombus formation in Fontan circulation has been highly variable, with reports between 17 and 33%. Initially, thrombus detection was mainly done through echocardiograms. Delayed-enhancement cardiac MRI is emerging as a more effective imaging technique for thrombus identification. This study aims to determine the prevalence of occult cardiac thrombosis in patients undergoing clinically indicated cardiac MRI. A retrospective chart review of children and adults in the Duke University Hospital Fontan registry who underwent delayed-enhancement cardiac MRI. Individuals were excluded if they never received a delayed-enhancement cardiac MRI or had insufficient data. Demographic characteristics, native heart anatomy, cardiac MRI measurements, and thromboembolic events were collected for all patients. In total, 119 unique individuals met inclusion criteria with a total of 171 scans. The median age at Fontan procedure was 3 (interquartile range 1, 4) years. The majority of patients had dominant systemic right ventricle. Cardiac function was relatively unchanged from the first cardiac MRI to the third cardiac MRI. While 36.4% had a thrombotic event by history, only 0.5% (1 patient) had an intracardiac thrombus detected by delayed-enhancement cardiac MRI. Despite previous echocardiographic reports of high prevalence of occult thrombosis in patients with Fontan circulation, we found very low prevalence using delayed-enhancement cardiac MRI. As more individuals are reaching adulthood after requiring early Fontan procedures in childhood, further work is needed to develop thrombus-screening protocols as a part of anticoagulation management.

A deep learning algorithm for noise reduction in a novel respiratory-triggered single-shot phase sensitive inversion recovery myocardial delayed enhancement cardiac MRI pulse sequence

Abstract Funding Acknowledgements Type of funding sources: None. Background Phase-sensitive inversion recovery improves tissue contrast by correcting for imperfect choice of inversion recovery time, however it is challenging to combine with a free-breathing acquisition. Deep learning (DL) algorithms have growing applications in cardiac MRI to improve image quality during image reconstruction. Purpose Here, we introduce a single-shot phase-sensitive myocardial delayed enhancement sequence with respiratory triggering (SShPSMDE-RT) (Figure 1). This novel sequence allows faster free-breathing acquisition of late gadolinium enhancement (LGE) images with reduced motion artifact (Figure 2.a). We combined this with a DL noise reduction algorithm to further improve image quality as compared to a standard segmented breath-hold (BH) PSMDE sequence. Methods 61 subjects (29 male, age 51±15) underwent cardiac MRI with the SShPSMDE-RT sequence and a standard BH sequence. The DL algorithm was applied at increasing levels (DL25, DL50, DL75, DL100) (Figure 2.b). Qualitative metrics were image quality, artifact severity, and diagnostic confidence, graded on a 5-point Likert scale. Quantitative metrics were sharpness of the left ventricle septum border and the LGE region (distance in mm for signal intensity to drop from 80% to 20%), blood-myocardium contrast-to-noise ratio (CNR), LGE-myocardium CNR, LGE signal-to-noise ratio (SNR), and LGE burden. 324 slices were included in the analysis. The sequences were compared via paired T-test. Results 27 subjects had positive LGE as determined by CMR experts. The average time to acquire a slice for SShPSMDE-RT is 4–7 seconds versus ∼30–40 seconds for the BH scan. The single-shot sequence had significantly better image quality (SShPSMDE-RT 2.1±0.8 vs. BH 1.5±0.6, p<0.001), less artifact (1.2±0.5 vs. 2.6±1.1, p<0.001), and better diagnostic confidence (3.4±0.7 vs. 2.6±0.8, p<0.001). Septum sharpness was slightly worse in SShPSMDE-RT images (4.1±1.7 mm vs. 3.8±1.6 mm, p = 0.008), but the DL algorithm improved sharpness of SShPSMDE-RT images such that there was no significant difference compared to BH images (p>0.5). There was no significant difference in LGE sharpness between the sequences. The SShPSMDE-RT images had superior blood-myocardium CNR (17.2±6.9 vs. 16.4±6.0, p = 0.040), LGE-myocardium CNR (12.1±7.2 vs. 10.4±6.6, p = 0.054), and LGE SNR (59.8±26.8 vs. 31.2±24.1, p<0.001); these metrics all improved with application of the DL algorithm. There was no significant difference in measured LGE burden (p = 0.12). Conclusions Our novel SShPSMDE-RT sequence significantly reduces scan time and motion artifact. This free-breathing sequence combined with a DL noise reduction algorithm provides better or similar image quality on both qualitative and quantitative metrics as compared to a standard BH PSMDE sequence. This technique can be used to obtain LGE imaging in patients who are unable to breath-hold or tolerate longer scan times.

Automatic classification of patients with myocardial infarction or myocarditis based only on clinical data: A quick response.

In acute cardiovascular disease management, the delay between the admission in a hospital emergency department and the assessment of the disease from a Delayed Enhancement cardiac MRI (DE-MRI) scan is one of the barriers for an immediate management of patients with suspected myocardial infarction or myocarditis. This work targets patients who arrive at the hospital with chest pain and are suspected of having a myocardial infarction or a myocarditis. The main objective is to classify these patients based solely on clinical data in order to provide an early accurate diagnosis. Machine learning (ML) and ensemble approaches have been used to construct a framework to automatically classify the patients according to their clinical conditions. 10-fold cross-validation is used during the model's training to avoid overfitting. Approaches such as Stratified, Over-sampling, Under-sampling, NearMiss, and SMOTE were tested in order to address the imbalance of the data (i.e. proportion of cases per pathology). The ground truth is provided by a DE-MRI exam (normal exam, myocarditis or myocardial infarction). The stacked generalization technique with Over-sampling seems to be the best one providing more than 97% of accuracy corresponding to 11 wrong classifications among 537 cases. Generally speaking, ensemble classifiers such as Stacking provided the best prediction. The five most important features are troponin, age, tobacco, sex and FEVG calculated from echocardiography. Our study provides a reliable approach to classify the patients in emergency department between myocarditis, myocardial infarction or other patient condition from only clinical information, considering DE-MRI as ground-truth. Among the different machine learning and ensemble techniques tested, the stacked generalization technique is the best one providing an accuracy of 97.4%. This automatic classification could provide a quick answer before imaging exam such as cardiovascular MRI depending on the patient's condition.

Utility of Delayed Enhancement Cardiac MRI in Evaluation of Restrictive Cardiomyopathy

Utility of Delayed Enhancement Cardiac MRI in Evaluation of Restrictive Cardiomyopathy

Assessment of Papillary Muscle Infarction with Dark-Blood Delayed Enhancement Cardiac MRI in Canines and Humans.

Background The relationship between papillary muscle infarction (papMI) and the culprit coronary lesion has not been fully investigated. Delayed enhancement cardiac MRI may detect papMI, yet its accuracy is unknown. Flow-independent dark-blood delayed enhancement (FIDDLE) cardiac MRI has been shown to improve the detection of myocardial infarction adjacent to blood pool. Purpose To assess the diagnostic performance of delayed enhancement and FIDDLE cardiac MRI for the detection of papMI, and to investigate the prevalence of papMI and its relationship to the location of the culprit coronary lesion. Materials and Methods A prospective canine study was used to determine the accuracy of conventional delayed enhancement imaging and FIDDLE imaging for detection of papMI, with pathology-based findings as the reference standard. Participants with first-time myocardial infarction with a clear culprit lesion at coronary angiography were prospectively enrolled at a single hospital from 2015 to 2018 and compared against control participants with low Framingham risk scores. In canines, diagnostic accuracy was calculated for delayed enhancement and FIDDLE imaging. Results In canines (n = 27), FIDDLE imaging was more sensitive (100% [23 of 23] vs 57% [13 of 23], P < .001) and accurate (100% [54 of 54] vs 80% [43 of 54], P = .01) than delayed enhancement imaging for detection of papMI. In 43 participants with myocardial infarction (mean age, 56 years ± 16 [SD]; 28 men), the infarct-related artery was the left anterior descending coronary artery (LAD), left circumflex coronary artery (LCX), and right coronary artery in 47% (20 of 43), 26% (11 of 43), and 28% (12 of 43), respectively. The prevalence of anterior papMI was lower than posterior papMI (37% [16 of 43 participants] vs 44% [19 of 43 participants]) despite more LAD culprit lesions. Culprits leading to papMI were restricted to a smaller "at-risk" portion of the coronary tree for anterior papMI (subtended first diagonal branch of the LAD or first marginal branch of the LCX) compared with posterior (subtended posterior descending artery or third obtuse marginal branch of the LCX). Culprits within these at-risk portions were predictive of papMI at a similar rate (anterior, 83% [15 of 18 participants] vs posterior, 86% [18 of 21 participants]). Conclusion Flow-independent dark-blood delayed enhancement cardiac MRI, unlike conventional delayed enhancement cardiac MRI, was highly accurate in the detection of papillary muscle infarction (papMI). Anterior papMI was less prevalent than posterior papMI, most likely due to culprit lesions being restricted to a smaller portion of the coronary tree rather than because of redundant, dual vascular supply. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Kawel-Boehm and Bremerich in this issue.

Automatic deep learning-based myocardial infarction segmentation from delayed enhancement MRI.

Delayed Enhancement cardiac MRI (DE-MRI) has become indispensable for the diagnosis of myocardial diseases. However, to quantify the disease severity, doctors need time to manually annotate the scar and myocardium. To address this issue, in this paper we propose an automatic myocardial infarction segmentation approach on the left ventricle from short-axis DE-MRI based on Convolutional Neural Networks (CNN). The objective is to segment myocardial infarction on short-axis DE-MRI images of the left ventricle acquired 10min after the injection of a gadolinium-based contrast agent. The segmentation of the infarction area is realized in two stages: a first CNN model finds the contour of myocardium and a second CNN model segments the infarction. Compared to the manual intra-observer and inter-observer variations for the segmentation of myocardial infarction, and to the automatic segmentation with Gaussian Mixture Model, our proposal achieves satisfying segmentation results on our dataset of 904 DE-MRI slices.

Associations between the size and location of myocardial infarction and cerebral infarction

BackgroundMyocardial infarction (MI) is a known cause of cerebral infarction. We assessed whether the size and location of MI is associated with the risk of cerebral infarction. Methods and resultsWe performed a cross-sectional study of adults who underwent both brain MRI and delayed-enhancement cardiac MRI (DE-CMR) within 365 days of each other at Weill Cornell Medicine between 2014 and 2017 and had evidence of MI on DE-CMR. We used multiple logistic regression to evaluate associations between MI size and any cerebral infarction, apical MI location and any cerebral infarction, and MI size/location and cortical versus subcortical cerebral infarction. Models were adjusted for demographics, and the total number of vascular risk factors. Among 234 patients who underwent both DE-CMR and brain MRI within 365 days, 76 had evidence for MI on DE-CMR. Among these 76 patients, 51 (67.1%) had evidence of cerebral infarction. The size of MI (global MI burden) was not associated with any cerebral infarction (OR per 5% increase in MI size, 1.12; 95% CI, 0.85–1.47), but was associated with cortical cerebral infarction (OR per 5% increase in MI size, 1.30; 95% CI, 1.00.-1.68). Similarly, apical MI location was not associated with any cerebral infarction (OR 2.63, 95% CI, 0.78–8.87), but was associated with cortical cerebral infarction (OR, 3.67; 95% CI, 1.19–11.33). ConclusionAmong patients with MI on cardiac MRI, both size and apical location of MI were associated with cortical cerebral infarction. Our results may help stratify cardioembolic risk and inform antithrombotic treatment algorithms among patients with MI.

Abstract WP232: Association Between Myocardial Infarction Size and Location and Cerebral Infarction

Introduction: Myocardial infarction (MI) is associated with cerebral infarction. We assessed whether MI size and location is related to the risk of cerebral infarction. Methods: We performed a cross-sectional study of patients evaluated between 2014-2017 at New York-Presbyterian Hospital/Weill Cornell Medicine. We included all adults who underwent both brain MRI and delayed-enhancement cardiac MRI (DE-CMR) within 365 days of each other and had evidence of MI on DE-CMR. We evaluated associations between MI size and any cerebral infarction, apical MI and any cerebral infarction, and between MI size/location and cortical versus subcortical cerebral infarction. We used multiple logistic regression models adjusted for age, sex, race, and the total number of vascular risk factors. Results: We identified 234 patients who underwent DE-CMR and brain MRI within 365 days, among whom 76 had evidence of MI on DE-CMR. Of these 76 patients, 51 (67.1%) had evidence of cerebral infarction. There was no association between the size of MI (global MI burden) and any cerebral infarction (OR per 1% increase in MI size, 1.02; 95% CI, 1.0-1.1; P = 0.43), but there was an association between MI size and cortical cerebral infarction (OR per 1% increase in MI size, 1.05; 95% CI, 1.0-1.1; P = 0.047). We found no association between apical MI location and any cerebral infarction (OR 3.2, 95% CI, 0.9-12.2, P = 0.08), but there was an association between apical MI location and cortical cerebral infarction (OR, 3.7; 95% CI, 1.2-11.3; P = 0.02). Conclusion: Among patients with MI on cardiac imaging, MI size and apical MI location were associated with cortical cerebral infarction. Our results may help stratify cardioembolic risk and lead to improved antithrombotic treatment algorithms among patients with MI.

Comprehensive Assessment of Endomyocardial Fibrosis with Cardiac MRI: Morphology, Function, and Tissue Characterization.

Endomyocardial fibrosis (EMF) affects approximately 12 million persons worldwide and is an important cause of restrictive cardiomyopathy in the developing world, with the highest prevalence reported in sub-Saharan Africa, South Asia, and South America. EMF is characterized by apical filling with fibrotic tissue of one or both ventricles, often associated with thrombus, calcification, and atrioventricular valve regurgitation, leading to typical symptoms of restrictive heart failure. Transthoracic echocardiography (TTE) is the first-line modality for assessment of EMF, basically owing to its widespread availability. However, in recent years cardiac MRI has emerged as a powerful tool for assessment of cardiac morphology and function, with higher accuracy than TTE, along with the unique advantage of being able to provide comprehensive noninvasive tissue characterization. Delayed enhancement (DE) imaging is the cornerstone of cardiac MRI tissue characterization and allows accurate identification of myocardial fibrosis, conveying valuable additional diagnostic and prognostic information. The typical DE pattern in EMF, described as the "double V" sign, consists of a three-layered pattern of normal myocardium, thickened enhanced endomyocardium, and overlying thrombus at the apex of the affected ventricle; it has excellent correlation with histopathologic findings and plays an important role in differentiating EMF from other cardiomyopathies. Conversely, fibrous tissue deposition quantified using DE imaging, when indexed to body surface area, has been shown to be a strong independent predictor of mortality. The aim of this review is to summarize state-of-the-art applications of cardiac MRI for diagnostic and prognostic assessment of patients with suspected or confirmed EMF. Online supplemental material is available for this article. ©RSNA, 2020.

Abstract 13819: Delayed Enhancement Cardiac Magnetic Resonance Imaging Predicts Response to Cardiac Resynchronization Therapy

Introduction: Primary predictors of cardiac resynchronization therapy (CRT) are based on conduction system characteristics, such as QRS duration and morphology. The ability of MRI to predict CRT response is less understood. Methods: We studied 83 patients who received cardiac MRI with gadolinium delayed enhancement (DE) prior to CRT. Patients had preCRT EF ≤ 40%, preCRT QRS ≥ 120ms, and paired ~1 year postCRT echocardiograms. MRIs were read without knowledge of patient characteristics or CRT outcomes and echocardiograms were read in a core-lab blinded to MRI results. Results: Patients were classified as having no DE (n=27), only septal midwall DE (n=20), or scar / DE (transmural, subendocardial, or subepicardial) (n=36). Prior to CRT, those with septal midwall DE (25 ± 7) had lower EFs than those with scar / DE (31 ± 6, p=0&lt;0.01), but not statistically different from those without DE (29 ± 6). Those without DE had better (p&lt;0.001) EF (14.2 ± 10 units) and LVESV improvements (-42 ± 21%) following CRT than those with midwall DE (EF: 2.1 ± 9 units; LVESV: -3 ± 35%) or those with scar / DE (EF: 1.4 ± 8 units; LVESV: -5 ± 25%). There was no difference in CRT response between non-ischemics with septal midwall DE and patients with scar / DE. In univariate regression models LBBB tended (p=0.12) to predict a beneficial EF response to CRT while presence of midwall DE was highly significant (p&lt;0.001) for predicting a lack of response in the 47 patients without scar. In a multivariate model including many baseline characteristics, septal midwall DE provided predictive value (p&lt;0.001) for EF response whereas the common predictors of gender (p=0.693) and LBBB (p=0.913) did not. Conclusions: DE cardiac MRI is a good predictor of response to CRT. The absence of any DE predicts a significant improvement in EF and LV volumes. In the idiopathic non-ischemic population the presence of septal midwall DE was a better negative predictor of response than more traditional characteristics of LBBB and gender. In addition, the presence of transmural, subendocardial, or subepicardial scar also predicted lack of improvement in LV function and volumes with CRT. The information obtained from DE MRI could help determine which patients would be best helped by CRT.

E.452 - Artefacts and reliability in 3D atrial fibrosis segmentation of delayed-enhancement cardiac MRI

E.452 - Artefacts and reliability in 3D atrial fibrosis segmentation of delayed-enhancement cardiac MRI

Abstract O.55: Utility of Adenosine Cardiac Stress MRI to Evaluate Ischemia in Patients with Kawasaki Disease

Background: Patients with Kawasaki Disease (KD) and a history of coronary artery disease (CAD) are at risk of myocardial ischemia/infarction. Adenosine stress cardiac MRI (CMR) has been increasingly used in adults to evaluate for atherosclerotic CAD. This modality has not been widely used in the evaluation of CAD in children and young adults, but may be useful in those with a history of KD. Methods: Patients with a history of Kawasaki disease and a clinical indication for a stress cardiac MRI were prospectively enrolled in the study. SSFP cine and delayed enhancement CMR (DE-CMR) were performed in a standard manner. Adenosine stress perfusion was performed with administration of adenosine (140 ug/kg/min) for 2-4 minutes and gadolinium (0.1 mmol/kg) using a standard adult protocol. Results: A total of 13 procedures were performed between 2010 and 2014 on 8 patients with a history of KD (ages 8 to 22, 3F/5M). Seven of eight patients presented with chest pain. Seven of eight patients had documented moderate to giant aneurysms and one had a previous coronary bypass operation. Scans were performed 3-16 years after initial episodes of KD. Three of 16 (19%) scans demonstrated inducible regional ischemia in the distribution of coronary abnormalities. Of these, all underwent cardiac catheterization and 1 patient subsequently underwent coronary bypass surgery. All patients with negative scans were followed clinically with no evidence of further symptoms. Conclusion: As a non-invasive imaging modality, adenosine cardiac stress MRI is feasible in patients with KD and coronary abnormalities and may obviate the need for invasive studies in order to rule out significant CAD. Further studies are needed to evaluate this imaging modality as a more definitive test in the evaluation of KD and chest pain.

Cardiac MRI in the treatment of arrhythmias

Catheter-based ablation techniques are extensively used for the treatment of atrial and ventricular arrhythmias. Preprocedural cardiac MRI is valuable for the management of these patients due to its ability to provide high-resolution anatomic mapping and tissue characterization in the absence of ionizing radiation. Delayed enhancement imaging can be used to localize the arrhythmia substrate within the chamber of interest prior to the procedure. There is growing evidence that delayed enhancement cardiac MRI may be useful in patients with atrial fibrillation in terms of treatment decisions and assessment of ablation efficacy.

050 Automated analysis of atrial delayed enhancement cardiac MRI correlates with voltage, AF recurrence post-ablation, and high stroke risk

IntroductionVisualisation of atrial scar using delayed-enhanced MRI (DE-MRI) may reveal causes for atrial fibrillation recurrence following ablation. To develop an objective method for delineating ablation-scar we compared DE-MRI before and...

Circulation: Cardiovascular Imaging Editors' Picks

<i>Circulation: Cardiovascular Imaging</i> Editors' Picks

Cost-effectiveness of substituting dual-energy CT for SPECT in the assessment of myocardial perfusion for the workup of coronary artery disease

PurposeWe compared cost-effectiveness and potential lifetime benefits of using dual-energy computed tomography (DECT) for myocardial perfusion assessment instead of single photon emission computed tomography (SPECT) for the workup of coronary artery disease (CAD). Materials and methodsA decision and simulation model was developed to estimate cost and health effects of using DECT myocardial perfusion imaging instead of SPECT for identifying patients in need of invasive imaging and possible revascularization. The model was based on the performance indices of stress/rest DECT compared with stress/rest SPECT for detecting myocardial perfusion deficits in 50 patients (mean age 61±10 years) with CAD. Stress/rest perfusion and delayed enhancement cardiac MRI served as reference standard. For DECT a reimbursement of US$1700 was assumed but costs of cardiac MRI were not included in the model. All other actual healthcare costs in these patients were derived from MUSC's hospital billing system. ResultsCompared with cardiac MRI, DECT (versus SPECT) had 90% (85%) sensitivity and 71% (58%) specificity for identifying patients with obstructive CAD. Compared with the no imaging and no treatment strategy, routine SPECT gained 13.49 quality-adjusted life-years (QALYs) with an incremental cost-effectiveness ratio (ICER) of US$3557 (in 2010) per QALY. In comparison, DECT ICER was lower (US$3.191 per QALY, p=0.0002) and an additional 0.64 QALYs was obtained (total of 14.13 QALYs) if compared with the SPECT strategy as well as the no imaging and no treatment strategy. ConclusionUsing DECT as the first-line imaging test for myocardial perfusion for the workup of patients with CAD has the potential to provide gains in QALYs, while lowering costs if compared to routine myocardial perfusion SPECT.

Isolated Right Ventricular Infarct Presenting as Ventricular Fibrillation Arrest and Confirmed by Delayed-Enhancement Cardiac MRI

Malignant ventricular arrhythmias resulting from isolated right ventricular myocardial infarction (RVMI) without left ventricular myocardial ischaemia or infarction occur rarely. We present a case of a 61 year-old male with acute onset of chest pain and ventricular fibrillation cardiac arrest requiring prompt defibrillation. Subsequent 15-lead EKG, showed ST-segment elevation in the anterior and right precordial leads without ST-segment elevation in the inferior leads. Angiography documented occlusion of a large RV marginal branch. Delayed enhancement cardiac magnetic resonance imaging (DE-CMR) with gadolinium performed two days post-infarct showed isolated RVMI. Patient remained symptom free and haemodynamically stable throughout his hospital stay. The clinical presentation of isolated RV infarct can be misleading and diagnosis difficult. EKG findings can resemble acute anterior wall myocardial infarction, while its course can be accompanied by life-threatening ventricular arrhythmias. This case uniquely combines this rare clinical sequence with DE-CMR images using gadolinium to confirm isolated RVMI. A brief review of RVMI presentation and associated EKG patterns is also discussed.

Delayed-enhancement cardiac MRI in the evaluation of cardiomyopathies

Cardiomyopathies are a diverse group of disorders with etiologies ranging from ischemic to infiltrative. Clinical differentiation may be complex, but diagnosis is essential as complications include congestive heart failure and sudden death. Recent developments in cardiac MRI, particularly the implementation of delayed-enhancement imaging has introduced a novel approach to noninvasive tissue characterization that can more accurately differentiate the spectrum of cardiomyopathies. This article summarizes the comprehensive diagnostic abilities of cardiac MRI in defining cardiac anatomy and physiology and, more importantly, identifying pathologic tissues and differentiating those with substrates amenable to therapy. The value of delayed-enhancement imaging in prognostics will also be presented.

Cardioprotective Effects of Ischemic Postconditioning in Patients Treated With Primary Percutaneous Coronary Intervention, Evaluated by Magnetic Resonance

Postconditioning has been suggested to reduce myocardial damage during primary percutaneous coronary intervention (PPCI) in patients with ST-segment-elevation myocardial infarction. However, because clinical experience is limited, we examined the cardioprotective effects of postconditioning, using cardiac MRI in patients treated with PPCI. One hundred eighteen patients with ST-segment-elevation myocardial infarction referred for PPCI were randomly assigned to have either conventional PPCI or PPCI with postconditioning. Postconditioning was performed immediately after obtained reperfusion with 4 balloon occlusions, each lasting 30 seconds, followed by 30 seconds of reperfusion. The primary end point was myocardial salvage after 3 months as judged by delayed enhancement cardiac MRI. We found a 19% relative reduction of infarct size in the postconditioning group (51+/-16% of total area at risk versus 63+/-17%, P<0.01), corresponding to a 31% increase in salvage ratio. The number of patients developing heart failure was significantly fewer in the postconditioning group (27% versus 46%, P=0.048). No significant evidence of interaction between the impact of postconditioning and the location of the culprit lesion or size of the myocardium at risk was detected (P=0.21 and P=0.71). Mechanical postconditioning reduces infarct size in patients with ST-segment-elevation myocardial infarction treated with PPCI. The impact of mechanical postconditioning seems to be independent of the size of myocardium at risk. http://www.clinicaltrials.gov. Unique Identifier: NCT00507156.

Unrecognised myocardial infarction in subjects at high vascular risk: prevalence and determinants

Objective:To investigate the prevalence and determinants of unrecognised myocardial infarction (UMI).Design, setting, patients:In this cross-sectional study in a tertiary centre, a delayed enhancement cardiac MRI (DE-CMR), which identifies both Q-wave...