Delayed-enhancement Cardiac Magnetic Resonance Imaging Research Articles

Meta-analysis of cardiac imaging modalities for the diagnosis of left ventricular thrombus following acute myocardial infarction

Abstract Background The formation of left ventricular thrombus (LVT) in post-acute myocardial infarction (AMI) patient carries significant risk of systemic embolism. Hence, there is a need to adopt strategies aimed at accurate and early diagnosis of LVT in order to mitigate the risk of embolic events with anti-thrombotic therapy. We aimed to conduct a systematic review and meta-analysis to appraise the current literature on the various diagnostic modalities used in post-AMI LVT detection. Methods We conducted a comprehensive search in Medline, EMBASE, and Scopus using an appropriate keyword/MeSH term search strategy up to 31 December 2021. All studies reporting a comparison between at least two imaging modalities in the diagnosis of LVT in post-AMI patients were included. Results A total of 2039 patient from 11 studies published between 2006 and 2021 were studied. Across all study populations, a majority of patients were male (82.3%) and the overall incidence of LVT was 15.2%. Using delayed-enhancement cardiac magnetic resonance imaging (DE-CMR) as the gold standard reference, transthoracic echocardiogram (TTE) with ultrasound enhancing agent (UEA) had the highest sensitivity (0.886, 95% CI 0.667-0.967) and specificity (0.980, 95% CI 0.900-0.996), while cine-CMR had the best diagnostic performance in terms of positive likelihood ratio (LR+ 437, 95% CI 37.2-1890), negative likelihood ratio (LR- 0.246, 95% CI 0.118-0.423) and diagnostic odds ratio (DOR 2050, 95% CI 134-9590). The summary receiver operating characteristic curves (SROCs) of the three studied imaging modalities were plotted and the AUC values were 0.920, 0.974 and 0.989 for TTE without and with UEA, and cine-CMR. Conclusions The diagnostic modalities used for LVT detection examined in this study had good specificity but poor sensitivity when compared to DE-CMR. Post-AMI patients at higher risk of LVT formation may benefit from further imaging studies with DE-CMR if initial TTE were negative.

Discussion to: Delayed-enhancement cardiac magnetic resonance imaging detects disease progression in patients with mitral valve disease and atrial fibrillation

Discussion to: Delayed-enhancement cardiac magnetic resonance imaging detects disease progression in patients with mitral valve disease and atrial fibrillation

Delayed-enhancement cardiac magnetic resonance imaging detects disease progression in patients with mitral valve disease and atrial fibrillation

ObjectivesThe mechanism by which mitral valve (MV) disease leads to atrial fibrillation (AF) remains poorly understood. Delayed-enhancement cardiac magnetic resonance imaging (DE-MRI) has been used to assess left atrial (LA) fibrosis in patients with lone AF before catheter ablation; however, few studies have used DE-MRI to assess MV-induced LA fibrosis in patients with or without AF undergoing MV surgery. MethodsBetween March 2018 and September 2022, 38 subjects were enrolled; 15 age-matched controls, 14 patients with lone mitral regurgitation (MR), and 9 patients with MR and AF (MR + AF). Indexed LA volume, total LA wall, and regional LA posterior wall (LAPW) enhancement were defined by the DE-MRI. One-way analysis of variance was performed. ResultsLA volume and LA enhancement were associated (r = 0.451, P = .004). LA volume differed significantly between controls (37.1 ± 10.6 mL) and patients with lone MR (71.0 ± 35.9, P = .020 and controls and patients with MR + AF (99.3 ± 47.4, P < .001). The difference in LA enhancement was significant between MR + AF (16.7 ± 9.6%) versus controls (8.3 ± 3.9%, P = .006) and MR + AF versus lone MR (8.0 ± 4.8%, P = .004). Similarly, the was significantly more LAPW enhancement in the MR + AF (17.5 ± 8.7%) versus control (9.2 ± 5.1%, P = .011) and MR + AF versus lone MR (9.8 ± 6.0%, P = .020) ConclusionsPatients with MR + AF had significantly more total and LAPW fibrosis compared with both controls and lone MR. Volume and delayed enhancement were associated, but there was no difference between MR and MR + AF.

Value of genotyping and scar-phenotyping for VT ablation procedures in patients with nonischemic left ventricular cardiomyopathies.

Variants of cardiomyopathy genes in patients with nonischemic cardiomyopathy (NICM) generate various phenotypes of cardiac scar and delayed enhancement cardiac magnetic resonance (DE-CMR) imaging which may impact ventricular tachycardia (VT) management. The objective was to compare the findings of cardiomyopathy genetic testing on DE-CMR imaging and long-term outcomes among patients with NICM undergoing VT ablation procedures. Image phenotyping and genotyping were performed in a consecutive series of patients referred for VT ablation and correlated to survival free of VT. Scar depth index (SDI) (% of scar at 0-3 mm, 3-5 mm and >5 mm projected on the closest endocardial surface) was determined. Forty-three patients were included (11 women, 55 ± 14 years, ejection fraction (EF) 45 ± 16%) and were followed for 3.4 ± 2.9 years. Pathogenic variants (PV) were identified in 16 patients (37%) in the following genes: LMNA (n = 5), TTN (n = 5), DSP (n = 2), AMLS1 (n = 1), MYBPC3 (n = 1), PLN (n = 1), and SCN5A (n = 1). A ring-like septal scar (RLSS) pattern was more often seen in patients with pathogenic variants (66% vs 15%, p = .001). RLSS was associated with deeper seated scars (SDI >5 mm 30.6 ± 22.6% vs 12.4 ± 16.2%, p = .005), and increased VT recurrence (HR 5.7 95% CI[1.8-18.4], p = .003). After adjustment for age, sex, EF, and total scar burden, the presence of a PV remained independently associated with worse outcomes (HR 4.7 95% CI[1.22-18.0], p = .02). Preprocedural genotyping and scar phenotyping is beneficial to identify patients with a favorable procedural outcome. Some PVs are associated with an intramural, deeper seated scar phenotype and have an increase of VT recurrence after ablation.

Automatic Left Ventricle Segmentation from Short-Axis Cardiac MRI Images Based on Fully Convolutional Neural Network.

Background: Left ventricle (LV) segmentation using a cardiac magnetic resonance imaging (MRI) dataset is critical for evaluating global and regional cardiac functions and diagnosing cardiovascular diseases. LV clinical metrics such as LV volume, LV mass and ejection fraction (EF) are frequently extracted based on the LV segmentation from short-axis MRI images. Manual segmentation to assess such functions is tedious and time-consuming for medical experts to diagnose cardiac pathologies. Therefore, a fully automated LV segmentation technique is required to assist medical experts in working more efficiently. Method: This paper proposes a fully convolutional network (FCN) architecture for automatic LV segmentation from short-axis MRI images. Several experiments were conducted in the training phase to compare the performance of the network and the U-Net model with various hyper-parameters, including optimization algorithms, epochs, learning rate, and mini-batch size. In addition, a class weighting method was introduced to avoid having a high imbalance of pixels in the classes of image’s labels since the number of background pixels was significantly higher than the number of LV and myocardium pixels. Furthermore, effective image conversion with pixel normalization was applied to obtain exact features representing target organs (LV and myocardium). The segmentation models were trained and tested on a public dataset, namely the evaluation of myocardial infarction from the delayed-enhancement cardiac MRI (EMIDEC) dataset. Results: The dice metric, Jaccard index, sensitivity, and specificity were used to evaluate the network’s performance, with values of 0.93, 0.87, 0.98, and 0.94, respectively. Based on the experimental results, the proposed network outperforms the standard U-Net model and is an advanced fully automated method in terms of segmentation performance. Conclusion: This proposed method is applicable in clinical practice for doctors to diagnose cardiac diseases from short-axis MRI images.

Insights on the left ventricular thrombus in patients with ischemic dilated cardiomyopathy

BackgroundLeft ventricular thrombus (LVT) formation represents a common complication of dilated cardiomyopathy (DCM). LVT is usually underestimated with transthoracic echocardiography (TTE) while cardiac magnetic resonance imaging (CMRI) is promising as an alternative imaging modality for cardiac thrombus detection. The study aims to compare TTE and CMRI in their ability to detect LVT, also, to assess the clinical and imaging parameters to determine variables that may predispose for thrombus formation. The study population includes seventy-six patients with ischemic DCM. They were divided into 2 groups based on the presence of LVT as detected by delayed-enhancement CMRI (DE-CMRI) [Group A included 20 patients with a LVT and Group B included 56 patients without].ResultsAll of the current study population had ischemic DCM with left ventricular ejection fraction (LVEF) < 50%. DE-CMR detected thrombus in 20 cases of the studied population that represented group A. From group A, conventional TTE detected LVT only in 8 and cine-CMR detected 13 cases out of the out of 20 cases. The ejection fraction of the left ventricle as measured by functional CMRI was significantly lower in group A (P = 0.045). Interestingly, the myocardial scarring in group A was seen significantly more extensive than in group B (the P value is < 0.00001), paralleling the increased prevalence of thrombus.ConclusionsDE-CMRI provides superiority for the detection of LVT compared with standard TTE or cine-CMRI and the amount of myocardial scarring detected by DE-CMRI can be considered an independent marker for thrombus presence.

57884 Fast strain-encoded cardiac magnetic resonance detects immune checkpoint inhibitor associated cardiotoxicity

ABSTRACT IMPACT: Advanced cardiac magnetic resonance imaging techniques can help to protect cancer patients from cardiotoxicity from immunotherapy with a more sensitive assessment of cardiac function with strain imaging for detection of abnormal cardiac function in the setting of normal left ventricular ejection fraction. OBJECTIVES/GOALS: Immune checkpoint inhibitors (ICI) are associated with fatal cardiotoxicity. Cardiac magnetic resonance (CMR) imaging can assess ICI-associated cardiotoxicity, but the utility of CMR strain imaging is unknown. We present a study of patients with ICI-associated cardiotoxicity evaluated with fast strain-encoded (fast-SENC) CMR. METHODS/STUDY POPULATION: This prospective study was approved by the institutional IRB and informed consent was obtained from 15 patients (5 patients with ICI-associated cardiotoxicity, 10 controls patients) between August 2018 and January 2020. All patients with ICI-associated cardiotoxicity had abnormal troponin values and evidence of cardiotoxicity on T2-weighted and/or delayed enhancement CMR images. All patients underwent standard CMR assessment with steady state free precession cine images, T2-weighted imaging, and delayed gadolinium enhancement imaging. Additionally, free-breathing SENC images were obtained and then processed by a team of blinded cardiovascular imaging specialists using Myostrain software (Morrisville, USA). RESULTS/ANTICIPATED RESULTS: Left ventricular ejection fraction (LVEF) was normal in both groups (ï,³53%). Global longitudinal LV strain was significantly depressed in the ICI cardiotoxicity group versus controls (-12.8 ±3.2% vs. -16.6 ±1.9%, p=0.028). The average global circumferential LV strain was mildly abnormal (defined as strain &gt; -17) in the ICI cardiotoxicity group and trended towards a higher value compared with controls (-16.0 ±2.6% vs -17.8 ±1.7%, p=0.103). The average number of dysfunctional segments (defined as strain &gt; -10) was significantly higher in the ICI cardiotoxicity group (6.8 ±4.2 vs. 1.0 ±1.7, p=0.017). The proportion of abnormal myocardium was higher in the ICI cardiotoxicity group (66 ±21% vs. 45 ±18%, p=0.050), as well as the proportion of myocardium found to be dysfunctional (26 ±22% vs. 3.0 ±6.0%, p=0.041). DISCUSSION/SIGNIFICANCE OF FINDINGS: Despite having preserved LVEF, patients who met criteria for ICI-associated cardiotoxicity had both global and regional abnormal LV strain. Fast-SENC imaging may provide a sensitive tool for detection of early cardiotoxicity in this population. This study is limited by its small cohort and a larger prospective study would be of value.

Ventricular arrhythmia risk is associated with myocardial scar but not with response to cardiac resynchronization therapy.

Sudden cardiac death (SCD) risk estimation in patients referred for cardiac resynchronization therapy (CRT) remains a challenge. By CRT-mediated improvement of left ventricular ejection fraction (LVEF), many patients loose indication for primary prevention implantable cardioverter-defibrillator (ICD). Increasing evidence shows the importance of myocardial scar for risk prediction. The aim of this study was to investigate the prognostic impact of myocardial scar depending on the echocardiographic response in patients undergoing CRT. Patients with indication for CRT were prospectively enrolled. Decision about ICD or pacemaker implantation was based on clinical criteria. All patients underwent delayed-enhancement cardiac magnetic resonance imaging. Median follow-up duration was 45 (24-75) months. Primary outcome was a composite of sustained ventricular arrhythmia, appropriate ICD therapy, or SCD. A total of 218 patients with LVEF 25.5 ± 6.6% were analysed [158 (73%) male, 64.9 ± 10.7 years]. Myocardial scar was observed in 73 patients with ischaemic cardiomyopathy (ICM) (95% of ICM patients); in 62 with non-ischaemic cardiomyopathy (45% of these patients); and in all but 1 of 36 (17%) patients who reached the primary outcome. Myocardial scar was the only significant predictor of primary outcome [odds ratio 27.7 (3.8-202.7)], independent of echocardiographic CRT response. A total of 55 (25%) patients died from any cause or received heart transplant. For overall survival, only a combination of the absence of myocardial scar with CRT response was associated with favourable outcome. Malignant arrhythmic events and SCD depend on the presence of myocardial scar but not on CRT response. All-cause mortality improved only with the combined absence of myocardial scar and CRT response.

The Role of Atrial Fibrosis Detected by Delayed - Enhancement MRI in Atrial Fibrillation Ablation.

Atrial Fibrillation (AF) is associated with remodeling of the atrial tissue, which leads to fibrosis that can contribute to the initiation and maintenance of AF. Delayed- Enhanced Cardiac Magnetic Resonance (DE-CMR) imaging for atrial wall fibrosis detection was used in several studies to guide AF ablation. The aim of present study was to systematically review the literature on the role of atrial fibrosis detected by DE-CMR imaging on AF ablation outcome. Eight bibliographic electronic databases were searched to identify all published relevant studies until 21st of March, 2016. Search of the scientific literature was performed for studies describing DE-CMR imaging on atrial fibrosis in AF patients underwent Pulmonary Vein Isolation (PVI). Of the 763 citations reviewed for eligibility, 5 articles (enrolling a total of 1040 patients) were included into the final analysis. The overall recurrence of AF ranged from 24.4 - 40.9% with median follow-up of 324 to 540 days after PVI. With less than 5-10% fibrosis in the atrial wall there was a maximum of 10% recurrence of AF after ablation. With more than 35% fibrosis in the atrial wall there was 86% recurrence of AF after ablation. Our analysis suggests that more extensive left atrial wall fibrosis prior ablation predicts the higher arrhythmia recurrence rate after PVI. The DE-CMR imaging modality seems to be a useful method for identifying the ideal candidate for catheter ablation. Our findings encourage wider usage of DE-CMR in distinct AF patients in a pre-ablation setting.

P872 A case of transient atrioventricular block: the role of cardiac magnetic resonance imaging

Abstract A 42-year old man with no relevant past medical history presented to the emergency department for recurrent transient loss of consciousness in the last 12 hours. 3 weeks earlier he had flu-like symptoms which spontaneously resolved. Physical examination revealed altered mental state, heart rate 30 beats per minute, respiratory rate 30 cycles per minute, blood pressure 70/40mmHg and basal lung rales on pulmonary auscultation. Blood gas analysis revealed hyperlactacidemia with hypocapnia. Electrocardiogram showed third-degree atrioventricular block. Atropine was administrated (total dose 3mg) with no rate response. Transcutaneous pacing was initiated followed by a temporary transvenous pacemaker, removed after 72 hours. Transthoracic echocardiogram revealed compromised left ventricular systolic function (ejection fraction by Simpson’s method 45%) due to septal dyskinesia and reduced global longitudinal strain (-11%). Blood analysis revealed erythrocyte sedimentation rate 20mm/hr, C-reactive protein 2.43mg/dL and negative high-sensitivity troponin T (9.44ng/L). Rheumatologic screening was negative. Coronary computed tomography angiography revealed normal epicardial coronaries. Cardiac magnetic resonance imaging (CMRI) performed 7 days after admission revealed preserved left ventricular systolic function (ejection fraction 51%). Late gadolinium enhancement showed scared myocardium in the medium and basal segments of the interventricular septum, compatible with subacute myocarditis. Due to the history of recurrent syncope, a permanent pacemaker was inserted. The patient was discharged the day after. No further syncope occurred. In last pacemaker follow-up, 9 months after presentation, patient had 0% auricular and ventricular pacing and 100% sensing over the previous 6 months. Discussion Transient atrioventricular block is a well-known complication of myocarditis when there is involvement of the conduction system by the inflammatory reaction. However, in rare cases it can persist or recur. CMRI plays an important role in these cases. Gadolinium-enhanced CMRI can be used to access the extent of inflammation and cellular edema and delayed-enhanced CMRI can also be used to quantify scarring which has important prognostic value. CMRI can also play a crucial role in excluding infiltrative disorders with conduction system involvement. Also, in these patients, the transient aspect of atrioventricular block poses a challenge when deciding about permanent pacemaker insertion. Abstract P872 Figure. Magnetic Ressonance IVS

Cryoballoon vs. radiofrequency lesions as detected by late-enhancement cardiac magnetic resonance after ablation of paroxysmal atrial fibrillation: a case-control study.

Cryoballoon (CB) ablation has emerged as a reliable modality to isolate pulmonary veins (PVs) in atrial fibrillation. Ablation lesions and the long-term effects of energy delivery can be assessed by delayed-enhancement cardiac magnetic resonance (DE-CMR). The aim of the study was to compare the number, extension, and localization of gaps in CB and radiofrequency (RF) techniques in pulmonary vein isolation (PVI). Consecutive patients submitted to PVI with CB in whom DE-CMR images were available (n = 30) were matched (1:1) to patients who underwent PVI with RF (n = 30), considering age, sex, hypertension, and diabetes. Delayed-enhancement cardiac magnetic resonance was obtained at 3 months post-procedure, and images were processed to assess the mean number of gaps around PV ostia, their localization, and the normalized gap length (NGL), calculated as the difference between total gap length and total PV perimeter. Patients were followed up for 12 months. The CB and RF procedures did not differ in the mean number of gaps per patient (4.40 vs. 5.13 gaps, respectively; P = 0.21) nor NGL (0.35 vs. 0.32, P = 0.59). For both techniques, a higher mean number of gaps were detected in right vs. left PVs (3.18 vs. 1.58, respectively; P = 0.01). The incidence of recurrences did not differ between techniques (odds ratio 1.87, 95% confidence interval 0.66-4.97; P = 0.29). Location and extension of ablation gaps in PVI did not differ between CB and RF groups in DE-CMR image analysis.

Risk stratification in patients with frequent premature ventricular complexes in the absence of known heart disease

Frequent premature ventricular complexes (PVCs) can be an indicator of structural heart disease. The purpose of this study was to determine the prevalence of scarring detected by delayed enhancement cardiac magnetic resonance (DE-CMR) imaging in patients with frequent PVCs without apparent structural heart disease and to determine the value of programmed ventricular stimulation (PVS) for risk stratification in patients with frequent PVCs and myocardial scarring. DE-CMR imaging was performed in patients without apparent heart disease who had frequent PVCs and were referred for ablation. In the presence of scarring, scar volume was measured and correlated with outcome variables. All patients underwent PVS and were monitored for the occurrence of ventricular arrhythmias. Logistic regression was used to compare imaging and procedural findings with long-term outcomes, with adjustment for postablation ejection fraction (EF). The study consisted of 272 patients (135 men; mean age 52 ± 15 years; EF 52% ± 12%). DE-CMR scar was found in 67 patients (25%), and 7 (3%) were found to have inducible ventricular tachycardia (VT). The presence and amount of DE-CMR were related to the risk of long-term VT independent of EF (hazard ratio 18.8 [95% confidence interval] [2.0-176.6], P = .01; and hazard ratio 1.4 [1.1-1.7] per cm3 scar, P <.001, respectively). The positive predictive value and negative predictive value of PVS for VT during long-term follow-up were 71% and 100%, respectively. Preprocedural cardiac DE-CMR and PVS can be used to identify patients with frequent PVCs without apparent heart disease who are at risk for VT.

Effect of Erythropoietin Administration on Myocardial Viability and Coronary Microvascular Dysfunction in Anterior Acute Myocardial Infarction: Randomized Controlled Trial in the Japanese Population.

IntroductionCardioprotective effects of erythropoietin (EPO) on infarcted myocardium in acute myocardial infarction (AMI) patients have been inconclusive. This study aimed to assess the effect of EPO administration on coronary microvascular dysfunction (CMD) and myocardial viability in anterior AMI. We also evaluated the serial changes in CMD and cardiac remodeling in these patients.MethodsPatients with a successful percutaneous coronary intervention (PCI) for the first anterior AMI were randomly assigned to two groups (EPO and control groups), and given single-dose intravenous administration of recombinant human EPO (12,000 IU) or saline after PCI. Delayed-enhanced cardiac magnetic resonance imaging was performed at 1 week after AMI to assess the average of transmural extent of infarction and infarct size. Coronary flow velocity reserve (CFVR) of the left anterior descending coronary artery was measured by Doppler echocardiography at 1 week, 1 month, and 8 months after AMI. All patients underwent clinical follow-up for the assessment of cardiac remodeling.ResultsSixty-one patients (EPO 32, control 29) were eligible for analysis. EPO group (2.4 ± 1.2) had a tendency of smaller transmural extent of infarction than that of control group (2.9 ± 1.1; p = 0.063). CFVR-8 months improved significantly in EPO group (2.9 ± 0.6) compared to control group (2.6 ± 0.5; p = 0.04). Left atrial (LA) volume − 8 months was significantly lower in EPO group (47 ± 11) than those of control group (65 ± 20; p = 0.004).ConclusionsA single medium dose of EPO could have a favorable effect on CMD and LA remodeling in the chronic phase of anterior AMI.Trial RegistrationThe institutional ethics committee of Wakayama Medical University, identifier, 1125.Electronic supplementary materialThe online version of this article (10.1007/s40119-018-0122-1) contains supplementary material, which is available to authorized users.

Abstract TP191: Association Between Myocardial Infarction and Brain Infarction on Magnetic Resonance Imaging

Introduction: The relationship between myocardial infarction and brain infarction remains incompletely understood. Magnetic resonance imaging (MRI) offers excellent characterization of infarction in both the heart and brain. Methods: We performed a retrospective cross-sectional study at our hospital to evaluate the association between myocardial infarction and brain infarction as detected on MRI. We identified all adult patients who underwent both cardiac MRI and brain MRI within 6 months of each other during the period 2014-2017. Myocardial infarction was identified by the presence of myocardial scar on delayed enhancement cardiac MRI. A neuroradiologist investigator reviewed all brain MRI studies to characterize acute and chronic infarcts. In secondary analyses, we evaluated the association between myocardial infarction and cortical versus subcortical brain infarction. The chi-square test was use to compare categorical variables. Results: We identified 211 adults who underwent cardiac MRI and brain MRI within 6 months of each other. Myocardial infarction was present in 66 (31.3%) of cardiac MRIs. Brain infarction was present in 112 (53.1%) of brain MRIs, 61 (28.9%) of which were cortical infarcts, 33 (15.6%) subcortical, and 18 (8.5%) posterior fossa. Myocardial infarction was more common in patients with brain infarction (41.1%; 95% confidence interval [CI], 31.9-50.8%) than in patients without brain infarction (20.2%; 95% CI, 12.8-29.5%) ( P = 0.001). In secondary analyses, myocardial infarction was most common in patients with cortical brain infarcts (50.8%; 95% CI, 37.7-63.9%), less common in patients with only subcortical infarcts (27.3%; 95% CI, 13.3-45.5%), and least common in those with no brain infarcts ( P value for comparison among groups, &lt; 0.001). Conclusions: We found an association between myocardial infarction and brain infarction on MRI. The association was strongest between myocardial infarcts and cortical brain infarcts.

A novel approach for left ventricular lead placement in cardiac resynchronization therapy: Intraprocedural integration of coronary venous electroanatomic mapping with delayed enhancement cardiac magnetic resonance imaging

Placing the left ventricular (LV) lead at a site of late electrical activation remote from scar is desired to improve cardiac resynchronization therapy (CRT) response. The purpose of this study was to integrate coronary venous electroanatomic mapping (EAM) with delayed enhancement cardiac magnetic resonance (DE-CMR) enabling LV lead guidance to the latest activated vein remote from scar. Eighteen CRT candidates with focal scar on DE-CMR were prospectively included. DE-CMR images were semi-automatically analyzed. Coronary venous EAM was performed intraprocedurally and integrated with DE-CMR to guide LV lead placement in real time. Image integration accuracy and electrogram parameters were evaluated offline. Integration of EAM and DE-CMR was achieved using 8.9 ± 2.8 anatomic landmarks and with accuracy of 4.7 ± 1.1 mm (mean ± SD). Maximal electrical delay ranged between 72 and 197ms (57%-113% of QRS duration) and was heterogeneously located among individuals. In 12 patients, the latest activated vein was located outside scar, and placing the LV lead in the latest activated vein remote from scar was accomplished in 10 patients and prohibited in 2 patients. In the other 6 patients, the latest activated vein was located in scar, and targeting alternative veins was considered. Unipolar voltages were on average lower in scar compared to nonscar (6.71 ± 3.45 mV vs 8.18 ± 4.02 mV [median ± interquartile range), P <.001) but correlated weakly with DE-CMR scar extent (R -0.161, P <.001) and varied widely among individual patients. Integration of coronary venous EAM with DE-CMR can be used during CRT implantation to guide LV lead placement to the latest activated vein remote from scar, possibly improving CRT.

Contact force threshold for permanent lesion formation in atrial fibrillation ablation: A cardiac magnetic resonance–based study to detect ablation gaps

Catheter contact force (CF) has a strong correlation with lesion formation during radiofrequency ablation. Delayed-enhancement cardiac magnetic resonance (DE-CMR) provides lesion information in patients with prior atrial fibrillation (AF) ablation. The aim of this study was to determine the CF threshold to create permanent lesions detected by DE-CMR. A total of 36 patients referred for AF ablation were included. A CF catheter was used during the ablation procedure, and DE-CMR was performed 3 months after the ablation procedure. Eighteen pulmonary vein (PV) segments were defined, and 3-dimensional (3D) reconstructions of the left atrium (LA) derived from the DE-CMR images were obtained. One observer evaluated the presence of any discontinuity of previous ablation lesions (gap) in the 3D reconstructions of the LA, and another observer (blinded to the gap findings) determined the minimum CF value in each PV segment. The PV segments where a gap was observed had a lower maximal CF value than did the segments without gap in the 3D LA reconstructions (6.7 ± 4.4 g vs 12.2 ± 4.7 g; P < .001). In receiver operating characteristic analysis, a CF threshold of >8 g provided 73% sensitivity and 81% specificity in the prediction of a complete PV lesion (positive predictive value [PPV] 84%). A CF threshold of >12 g had a specificity of 94% and increased the PPV to 91% in creating a complete lesion in the LA wall (area under the curve 0.834). A CF threshold of >12 g H5H20 predicts a complete lesion with high specificity and PPV when a dragging ablation strategy is used in AF ablation.

The utility of cardiac magnetic resonance imaging in Kounis syndrome.

IntroductionCurrent diagnostic measurements used to assess myocardial involvement in Kounis syndrome, such as electrocardiography (ECG), cardiac enzymes, and troponin levels, are relatively insensitive to small but potentially significant functional change. According to our review of the literature, there has been no study using magnetic resonance imaging (MRI) on Kounis syndrome except for one case report.AimTo identify the findings of dynamic contrast-enhanced magnetic resonance imaging (CE-MRI) in patients with Kounis syndrome (KS) type 1.Material and methodsWe studied 26 patients (35 ±11.5 years, 53.8% male) with known or suspected KS type 1. The patients underwent precontrast, first-pass, and delayed enhancement cardiac MRI (DE-MRI). Contrast enhancement patterns, edema, hypokinesia, and localization for myocardial lesions were evaluated in all KS type 1 patients.ResultsContrast-enhanced magnetic resonance imaging demonstrated an early-phase subendocardial contrast defect, and T2-weighted images showed high-signal intensity consistent with edema in lesion areas. None of the lesion areas was found upon contrast enhancement on DE-MRI. The area of early-phase subendocardial contrast defect was reported as follows: the interventricular septum in 14 (53.8%) patients, the left ventricular lateral wall in 8 (30.7%), and the left ventricular apex in 4 (15.4%).ConclusionsDynamic cardiac MR imaging is a reliable tool for assessing cardiac involvement in Kounis syndrome. Delayed contrast-enhanced images show normal washout in the subendocardial lesion area in patients with Kounis syndrome type 1.

Imaging techniques in electrophysiology and implantable device procedures: results of the European Heart Rhythm Association survey

The purpose of this European Heart Rhythm Association (EHRA) survey is to assess the implementation and use of imaging techniques in cardiac electrophysiology (EP) and device procedures across European cardiovascular centres. Forty European centres, all members of the EHRA EP research network, responded to this survey. Thirty-one centres (88%) use transthoracic echocardiography (TTE) to evaluate left atrial size and/or volume before atrial fibrillation (AF) ablation. Sixteen centres (46%) perform delayed-enhancement cardiac magnetic resonance imaging (MRI) to guide ventricular tachycardia ablation. Electroanatomical mapping (EAM) systems are available in >65% of responding centres and the use of robotic catheter and remote magnetic navigation systems is limited to <10%. Fusion of EAM data with cardiac computed tomography (CT) and/or MRI is performed in up to 43% of AF ablation procedures. Seventeen out of 35 (49%) responding centres also perform TTE to predict a favourable response to cardiac resynchronization therapy (CRT). Imaging of the cardiac venous system with CT and identification of myocardial scar using CT or MRI, is not routinely performed in the majority of centres [32 (91%) and 26 (75%) centres, respectively) prior to CRT. This EHRA survey shows that several imaging techniques are used to guide catheter ablation and CRT procedures in European centres. Echocardiographic imaging, EAM techniques, and cardiac CT/MRI are commonly used.

Atrial Fibrillation Through the Years

Information about a real patient is presented in stages (boldface type) to an expert clinician (Dr Valentin Fuster), who responds to the information, sharing his reasoning with the reader (regular type). A discussion by the authors follows. A 61-year-old man presents with 2 weeks of exertional dyspnea. Pertinent medical history includes hypertension, nephrolithiasis, and internal hemorrhoids. He takes no medications and has no known drug allergies. His father died after a myocardial infarction at 57 years of age. He formerly smoked 1 pack of cigarettes daily for 15 years but ceased tobacco use 10 years before presentation. He ingests 2 glasses of alcohol weekly and denies illicit drug use. His caffeine intake is limited. He is an architect and is married, with healthy children. On physical examination, his temperature is 98.0°F, blood pressure is 130/85 mm Hg bilaterally, pulse is irregular at 130 beats per minute, and respiratory rate is 18 breaths per minute with an oxygen saturation of 97% while breathing room air. He is a slender white man in no distress. His jugular venous pressure is elevated at 14 cm H 2 O. There is no thyromegaly, and the carotid upstrokes are brisk, without bruits. Cardiovascular examination reveals a rapid and irregular heart rhythm with variation in the intensity of the first heart sound. The point of maximal impulse is not displaced. The remainder of the chest and abdominal examination is within normal limits. The extremities are warm and show mild pitting edema. Laboratory testing is significant for normal renal function and electrolytes, but a hemogram reveals a mild thrombocytopenia of 90 000 platelets/μL. ECG demonstrates atrial fibrillation (AF) with an average ventricular rate of 123 bpm ( Figure 1 ). Figure 1. The 12-lead ECG showing atrial fibrillation with a rapid ventricular rate. Dr Valentin Fuster : This is a …

PET imaging with FDG to guide revascularization in patients with systolic heart failure

Abstract The assessment of myocardial viability is important in the management of patients with coronary artery disease and left ventricular systolic dysfunction. There are several different imaging modalities currently available for the identification of viable myocardium: dobutamine stress echocardiography, single photon emission computed tomography, delayed-enhancement cardiac magnetic resonance imaging, and F-18 fluorodeoxyglucose positron emission tomography. The goal of viability imaging is to determine the likelihood of recovery of systolic function after revascularization. Positron emission tomography with F-18 fluorodeoxyglucose (FDG-PET) provides information about perfusion as well as myocardial metabolism, requires meticulous patient preparation, and is currently the gold standard imaging modality for the assessment of myocardial viability. Viability imaging for the purposes of predicting which patients will have improvement in left ventricular systolic function is supported under current guidelines, but the results of the recent STICH-viability substudy have created uncertainty about the incremental benefit. This review article will provide a summary of the currently available imaging modalities with an emphasis on FDG-PET and discuss the clinical relevance of viability imaging in light of the STICH-viability substudy.