Delayed Enhancement Cardiac Magnetic Resonance Research Articles

Determination of viable myocardium through delayed enhancement cardiac magnetic resonance imaging combined with 18F-FDG PET myocardial perfusion/metabolic imaging before CABG.

Study aims to investigate the consistency of delayed enhancement cardiac magnetic resonance imaging (DE-CMR) and 18F-FDG PET myocardial imaging in evaluating myocardial viability before CABG. The study analyzed data from 100 patients who were examined with DE-CMR, PET imaging, and echocardiography before and after CABG. All subjects were followed up for 6-12 month post- CABG. DE-CMR and PET imaging have high consistency (90.1%; Kappa value = 0.71, p < 0.01) in determining myocardial viability. The degree of delayed enhancement was negatively correlated with the improvement in myocardial contractile function in this segment after revascularization (P < 0.001). The ratio of scarred myocardial segments and total DE score was significantly lower in the improvement group than non-improvement group. Multivariate regression identified that hibernating myocardium (OR = 1.229, 95%CI: 1.053-1.433, p = 0.009) was influencing factor of LVEF improvement after CABG. Both imaging techniques are consistent in evaluating myocardial viability. Detecting the number of hibernating myocardium by PET is also important to predict the left heart function improvement after CABG.

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.

MP-453092-11 LONG TERM FOLLOW-UP OF HIGH-RISK PATIENTS WITH NEGATIVE PROGRAMMED VENTRICULAR STIMULATION TESTING AND THE IMPACT OF DELAYED-ENHANCEMENT CARDIAC MAGNETIC RESONANCE IMAGING

Programed ventricular stimulation (PVS) to induce monomorphic ventricular tachycardia (VT) is a risk stratification tool in patients with a variety of established or suspected cardiac conditions. Patients who are non-inducible for VT may yet be at risk for adverse arrhythmia related events, particularly in the presence of cardiac scar. To investigate the long-term outcomes of real-world patients with negative PVS and examine the role of cardiac scaring on long-term risks of arrhythmia recurrence. Consecutive patients with negative PVS testing and who underwent delayed enhancement cardiac magnetic resonance imaging (DE-CMR) for risk stratification were included. All patients underwent placement of implantable cardiac monitors (ICM) and were followed. Survival analysis was performed to investigate the impact of DE-CMR findings on survival free from adverse arrhythmic events. Ninety-one patients were included (age 60.3±14.8 years, women n=44(48.4%), ejection fraction 58.2±9.2%, cardiomyopathy n=27(29.7%), positive DE-CMR scar n= 54(59%)). Indications included non-sustained VT/premature ventricular contractions (PVC) (n=67), syncope (n=36), mitral valve prolapse (n=10), or muscular dystrophy (n=2). Patients were followed for 1.4±1.5 years during which 18 patients (20%) experienced clinically significant VT (n=12), syncope due to bradycardia (n=5), or death due to pulseless electrical activity (n=1). Baseline characteristics between those with and without adverse events were similar (P>0.05); however, the presence of cardiac scar on DE-CMR was associated with an increased risk of adverse events (HR 4.0 95%CI [1.2-14.3], P<0.03, log rank P =0.019). In a real-world cohort with long-term follow up, adverse arrhythmic outcomes occurred in 20% of patients with high-risk features despite non-inducibility for VT on PVS, and this risk was significantly greater in patients with positive DE-CMR scar. Long term-monitoring, including the use of ICM, may be appropriate in these patients.

1151 MYOCARDIAL VIABILITY IN PATIENTS WITH ISCHEMIC LEFT VENTRICULAR DYSFUNCTION: A CARDIAC MAGNETIC RESONANCE SINGLE-CENTRE EXPERIENCE

Abstract Background Whether assessment of myocardial viability (MV) by delayed enhancement cardiac magnetic resonance (DE-CMR) can help identify patient with severe ischemic left ventricular (LV) disfunction who might benefit from coronary revascularization has not been yet clearly established. Moreover, although improvement in LV function is one of the heart failure treatment goal, its prognostic implication remains controversial. Methods We retrospectively evaluated all consecutive patients with a LV ejection fraction (EF) of 35% or less and extensive coronary artery disease undergoing DE-CMR for assessment of MV in our Department from November 2013 to December 2020. DE-CMR was routinely prescribed before any heart team indication, either coronary intervention (surgical or percutaneous) plus optimal medical therapy (OMT) or OMT only. Quantification of DE was determined visually by comparing the ratio of the thickness of infarcted myocardium to that of total wall thickness within a given segment. A dysfunctional segment (hypokinetic/akinetic) was considered viable when DE transmurality was ≤50%. Accordingly, a patient was considered to have MV when ≥4 dysfunctional but viable segments were present. The primary end point was death from any cause. Secondary end point was improvement in LVEF during follow-up, defined as an increase in LVEF class compared to baseline. Results Of the 70 patients (64 males, median age 67 years [62-75], median LVEF 27% [21-30]) enrolled, 46 (66%) underwent coronary revascularization, of which 16 with surgery and 30 with percutaneous intervention. Only 16 procedures were considered complete, fully revascularizing all diseased vessels and dysfunctional segments. The baseline clinical characteristics (including age, diabetes, eGFR, peripheral vascular disease, LVEF, LV end diastolic volume, and Syntax score) of revascularized patients did not differ significantly to those receiving OMT only, except for number of viable segments, which were significantly higher in patients undergoing revascularization (p=0.017). Over a median follow-up of 31 months (18-45), 15 patients (21%) died. Revascularization plus OMT was associated with a lower incidence of death from any cause than OMT only group (hazard ratio, 0.26; 95% CI 0.09-0.74; p=0.01). However, no significant interaction was observed between the presence/absence of MV and the beneficial effect of revascularization (p=0.39). Improvement in LVEF was observed only among patients with MV, irrespective of treatment assignment (p=0.02). However, survival did not differ significantly between patients who had improvement in LVEF from those who did not have such improvement (logRank p=0.81) Conclusion Among patients with severe ischemic LV systolic dysfunction, coronary revascularization plus OMT was beneficial in prolonging survival, compared to OMT only. However, this beneficial effect was not driven by MV. Furthermore, although increase in LVEF was more likely to occur among patients with MV, such improvement was not related to long-term survival.

Prognostic implications of unrecognized myocardial infarction before elective percutaneous coronary intervention

Unrecognized myocardial infarction (UMI) is associated with adverse outcomes. This prospective, single-center study elucidated the prevalence and prognostic significance of UMI before elective percutaneous coronary intervention (PCI) using delayed-enhancement cardiac magnetic resonance (DE-CMR). We enrolled 236 patients with stable coronary artery disease who underwent DE-CMR before elective PCI. The prevalence of UMI and the association of clinical and CMR-derived variables with major adverse cardiac events (MACE), defined as cardiovascular death, nonfatal MI, hospitalization for congestive heart failure, and unplanned late revascularization, were assessed. Final analysis revealed that 63/213 (29.6%) patients had UMI. Target territory UMI was observed in 38 patients (17.8% of the total cohort, 60.3% of patients with UMI). UMI was significantly associated with sex, diabetes mellitus, left ventricular ejection fraction, SYNTAX score, and fractional flow reserve in the target vessels. During follow-up (median, 23 months), MACE occurred in 17 (27.0%) patients with UMI and 17 (11.3%) without UMI (P = 0.001). Multivariable modeling revealed that UMI (hazard ratio: 2.18, 95%CI, 1.10–4.33, P = 0.001) was an independent predictor of MACE. Kaplan–Meier analysis indicated that the presence of UMI was significantly associated with a higher incidence of MACE. UMI was independently associated with a greater risk of MACE after successful PCI.

Prognostic implications of unrecognized myocardial infarction before elective percutaneous coronary intervention

Abstract Background A non-negligible proportion of myocardial infarction (MI) is not clinically recognized and unrecognized myocardial infarction (UMI) is associated with adverse outcomes. Purpose To determine the prevalence and prognostic significance of UMI by delayed-enhancement cardiac magnetic resonance (DE-CMR) before elective percutaneous coronary intervention (PCI). Methods In this prospective, single-center study, 236 patients with stable coronary artery disease undergoing elective and uncomplicated PCI were studied. All patients underwent DE-CMR before PCI. The prevalence of UMI was evaluated and the association of clinical and CMR-derived variables with primary MACE, defined as cardiovascular death, nonfatal MI, hospitalization for heart failure, unplanned late revascularization, and ischemic stroke was investigated. Results In the final analysis of 213 patients, 63 patients (29.6%) showed UMI. Target territory UMI was observed in 38 (17.8% of total, 60.3% of patients with UMI). UMI was significantly associated with sex, diabetes mellitus, left ventricular ejection fraction, SYNTAX score and fractional flow reserve in target vessels. During follow-up periods (median, 23 months), MACE was observed in 17 (27.0%) of patients with UMI, and 17 (11.3%) without (P=0.001). In a multivariable model, UMI (hazard ratio [HR] 2.18, 95% confidential interval, 1.10–4.33, P=0.001) remained as an independent predictor of MACE. Kaplan–Meier analysis indicated that the presence of UMI was significantly associated with higher incidence of MACE. Conclusions The prevalence of UMI in patients undergoing elective PCI was 29.6%. UMI was independently associated with an increased risk of MACE after successful PCI. Given the non-negligible prevalence and potential clinical significance of UMI, clinical studies comparing PCI and guideline directed medical therapy (GDMT) versus GDMT only strategy might have to take the presence of UMI into consideration. Funding Acknowledgement Type of funding sources: None.

Role of Late Gadolinium Enhancement in the Assessment of Myocardial Viability.

Background: Prior to any revascularization procedure for coronary artery disease, it is essential to identify viable myocardium which will likely benefit from it. In such a situation, delayed enhanced cardiac MRI is beneficial.Methods: Our study consisted of 50 patients with at least a one-month prior history of myocardial infarction (MI), abnormal findings on electrocardiography (ECG), and 2D-echocardiography (2D-ECHO), who were subjected to cardiac MRI performed on a 3T MRI machine. The MRI scans were evaluated for anatomical and especially functional characteristics of the heart, such as wall motion. On late gadolinium enhancement (LGE), the diseased segments were classified into two categories: < 50% LGE (viable) and > 50% LGE (non-viable).Results: Of the 378 diseased segments detected on LGE, 137 (36.2%) segments showed < 50% LGE and 241 (63.8%) segments showed > 50% LGE. The segments showing < 50% LGE showed normokinesia or hypokinesia, with none of the segments showing akinesia or dyskinesia, whereas the segments showing > 50% LGE showed akinesia or dyskinesia predominantly. This was found to be statistically highly significant (p-value < 0.001). Conclusion: Delayed enhanced-cardiac magnetic resonance (DE-CMR) imaging in patients with ischemic heart disease (IHD) helps evaluate the severity of the infarcted myocardium by classifying the diseased myocardium into viable and non-viable, as viable myocardium is more likely to regain functional recovery than non-viable myocardium. It also predicts the functional recovery of the myocardium after revascularization therapy.

Usefulness of longitudinal systolic strain and delayed enhancement cardiac magnetic resonance in depicting risk of supraventricular arrythmias in patients with acute myocarditis and preserved left ventricular function.

Myocarditis have variable clinical presentation, evolution and prognosis. Aim of our study was to evaluate the value of speckle tracking echocardiography and cardiac magnetic resonance (CMR) in the short-term prediction of supraventricular arrhythmias (SVA) in patients with acute myocarditis. Seventy patients (mean age 31±14 years old) with acute myocarditis and preserved left ventricular ejection fraction (LVEF) were enrolled. Longitudinal systolic strain (LS) of the left ventricle (LV), mechanical dispersion (MD) and CMR with quantitative measurement of delayed enhancement (DE) were performed in a subset of 43 patients. Logistic regression and ROC analysis were used to identify predictors of SVA RESULTS: Only LS measured at sup-epicardial, mid-wall and sub-endocardial level of the apical 4-chamber view was significantly lower in patients with SVA, while MD was marginally prolonged in this setting. A value of LS>- 16.1% measured at LV mid-wall in the apical 4-chamber view (ROC-AUC .75, Sensitivity 63%, Specificity 85%) was the most accurate measure to identify patients with SVA. DE mass was also helpful with a ROC-AUC .76; a DE-Mass>18.9 gr. had a Sensitivity 63% and a Specificity 77%, to identify patients at risk of SVA. Both DE mass and LS were associated with higher risk of SVA in patients with acute myocarditis and preserved LVEF. However, LS measured at the mid-wall level and limited to LV segments included in the apical 4-chamber view was the most accurate measure and did not show interaction with DE mass.

The Relationship between Epicardial Fat and Atrial Fibrillation Cannot Be Fully Explained by Left Atrial Fibrosis.

ResumoFundamento O tecido adiposo epicárdico (TAE) tem sido associado à fibrilação atrial (FA), mas seus mecanismos fisiopatológicos permanecem obscuros.Objetivos Medir a correlação entre TAE e fibrose do átrio esquerdo (AE), e avaliar sua capacidade de prever recidiva após o isolamento da veia pulmonar (IVP).Métodos Pacientes com FA inscritos para um primeiro procedimento de IVP foram submetidos à tomografia computadorizada (TC) cardíaca e ressonância magnética cardíaca (RMC) em menos de 48 horas. Quantificou-se o TAECE em imagens de TC realçadas com contraste no nível do tronco da coronária esquerda. Quantificou-se a fibrose do AE em RMC tridimensional com realce tardio isotrópico de 1,5 mm. Após o isolamento da veia pulmonar (IVP), os pacientes foram submetidos a seguimento para checar a recidiva da FA. A significância estatística foi definida com p<0,05.Resultados A maioria dos 68 pacientes (46 homens, idade 61±12 anos) tinha FA paroxística (71%, n=48). Os pacientes apresentavam volume TAECE mediano de 2,4 cm3/m2 (intervalo interquartil [IIQ] 1,6–3,2 cm3/m2) e um volume médio de fibrose do AE de 8,9 g (IIQ 5–15 g). A correlação entre TAECE e fibrose do AE foi estatisticamente significativa, mas fraca (coeficiente de correlação de postos de Spearman = 0,40, p=0,001). Durante um seguimento médio de 22 meses (IIQ 12–31), 31 pacientes (46%) tiveram recidiva da FA. A análise multivariada produziu dois preditores independentes de recidiva da FA: TAECE (FC 2,05, IC de 95% 1,51–2,79, p<0,001) e FA não paroxística (FC 2,36, IC de 95% 1,08–5,16, p=0,031).Conclusão A correlação fraca entre TAE e AE sugere que a fibrose do AE não é o principal mecanismo que liga o TAE e a FA. O TAE mostrou-se mais fortemente associado à recidiva da FA do que à fibrose do AE, corroborando a existência de outros mediadores mais importantes do TAE e da FA.

Validity of resting strain/strain rate in prediction of myocardial viability.

To evaluate the validity of the resting strain/strain rate measurements in predicting myocardial viability taking delayed enhancement cardiac magnetic resonance imaging as the gold standard. A cohort of 60 patients at three months followed up after acute myocardial infarction were recruited for this study. Resting echocardiography with offline analysis of deformation indices and gadolinium contrast enhanced cardiac magnetic resonance imaging were applied for all patients. For the final assessment, 268 segments with significant resting wall motion abnormalities were presented. Resting longitudinal strain was significantly (p < 0.05) higher in viable, compared with non-viable segments in all the studied individual myocardial segments (apical inferior, mid antro-lateral, mid-inferolateral, mid inferoseptum, and all other segments). Likewise, resting longitudinal strain rate was significantly (p < 0.05) higher in viable, compared with non-viable segments in almost all studied individual myocardial segments apart from apical inferior, mid inferolateral and basal antro-septum (p = 0.245, p = 0.098, p = 0.097 respectively). Resting Strain and Resting Strain rate could be used as accurate predictors of myocardia viability following acute myocardial infarction.

B-PO03-126 DELAYED ENHANCEMENT CARDIAC MAGNETIC RESONANCE IMAGING IDENTIFIES PRIOR ABLATION LESIONS AFTER POSTINFARCTION VENTRICULAR TACHYCARDIA ABLATION PROCEDURES: IMPLICATIONS FOR VT RECURRENCE

Ventricular tachycardia (VT) frequently recurs after radiofrequency catheter ablation for post-infarction VT. Delayed enhancement cardiac magnetic resonance (DE-CMR) imaging delineates between native postinfarction scarring and radiofrequency ablation lesions related scar and may be used to study the relationship between VT circuits and prior ablation lesions.

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.

Epicardial Surface Area of Infarction: A Stable Surrogate of Microvascular Obstruction in Acute Myocardial Infarction.

Microvascular obstruction (MO) is a pathophysiologic complication of acute myocardial infarction that portends poor prognosis; however, it is transient and disappears with infarct healing. Much remains unknown regarding its pathophysiology and whether there are predictors of MO that could function as stable surrogates. We tested for clinical and cardiovascular magnetic resonance predictors of MO to gain insight into its pathophysiology and to find a stable surrogate. Three hundred two consecutive patients from 2 centers underwent cardiovascular magnetic resonance within 2 weeks of first acute myocardial infarction. Three measures of infarct morphology: infarct size, transmurality, and a new index-the epicardial surface area (EpiSA) of full-thickness infarction-were quantified on delayed-enhancement cardiovascular magnetic resonance. Considering all clinical characteristics, only measures of infarct morphology were independent predictors of MO. EpiSA was the strongest predictor of MO and provided incremental predictive value beyond that of infarct size and transmurality (P<0.0001). In patients with 3-month follow-up cardiovascular magnetic resonance (n=81), EpiSA extent remained stable while MO disappeared, and EpiSA was a predictor of adverse ventricular remodeling. After 20 months of follow-up, 11 died and 1 had heart transplantation. Patients with an EpiSA larger than the median value (≥6%) had worse outcome than those with less than the median value (adverse events: 6.4% versus 1.9%, P=0.045). The EpiSA of infarction is a novel index of infarct morphology which accurately predicts MO during the first 2 weeks of MI, but unlike MO, does not disappear with infarct healing. This index has potential as a stable surrogate of the presence of acute MO and may be useful as a predictor of adverse remodeling and outcome which is less dependent on the time window of patient assessment.

The value of cardiac magnetic resonance imaging and programmed ventricular stimulation in patients with ventricular noncompaction and ventricular arrhythmias.

Left ventricular noncompaction (LVNC) is associated with ventricular arrhythmias (VA) including premature ventricular complexes, and ventricular tachycardia (VT). The value of imaging with delayed enhancement cardiac magnetic resonance (DE-CMR) and programmed ventricular stimulation (PVS) for risk stratification in patients with VA and LVNC is unknown. The purpose of this study was to determine whether DE-CMR and PVS are beneficial for risk stratification and whether CMR helps to identify VA target sites. Consecutive patients with LVNC undergoing ablation for VAs were included, all patients had preprocedure DE-CMR. A total of 23 patients (7 women, 46 ± 14 years, ejection fraction 35 ± 14) were included and followed for 2.9 ± 2.2 years. DE-CMR scar was present in 12/23 patients (52%). PVS was performed in 20/23 patients, 8/10 patients (80%) with scar were inducible for VT compared to 0/10 (0%) patients without scar (p < .001). VA target sites in patients with scarring were located adjacent to areas of scarring in all but 1 patient and ablation was successful in 15/23 patients (65%). Patients with scar had worse survival free of VT than those without scar (log rank p = .01) and patients with inducible VT had worse survival free of VT than those who were noninducible (log rank p < .001). The presence of CMR defined scar in patients with LVNC was associated with inducible VT and worse outcomes. Inducibility for VT was associated with VT recurrence. Furthermore, CMR is beneficial in localizing the arrhythmogenic substrate in LVNC and therefore can aid in procedural planning.

Factors predictive for delayed enhancement in cardiac resonance imaging in patients undergoing catheter ablation of premature ventricular complexes.

BackgroundPatients undergoing ablation of premature ventricular complexes (PVCs) can have cardiac scar. Risk factors for the presence of scar are not well defined.ObjectivesTo determine the prevalence of scarring detected by delayed enhancement cardiac magnetic resonance imaging (DE-CMR) in patients undergoing ablation of PVCs, to create a risk score predictive of scar, and to explore correlations between the scoring system and long-term outcomes.MethodsDE-CMR imaging was performed in consecutive patients with frequent PVCs referred for ablation. The full sample was used to develop a prediction model for cardiac scar based on demographic and clinical characteristics, and internal validation of the prediction model was done using bootstrap samples.ResultsThe study consisted of 333 patients (52% male, aged 53.2 ± 14.5 years, preablation ejection fraction 50.9% ± 12.2%, PVC burden 20.7 ± 13.14), of whom 112 (34%) had DE-CMR scarring. Multiple logistic regression analysis showed age (odds ratio [OR] 1.02 [1.01–1.04]/year, P = .019) and preablation ejection fraction (OR 0.92 [0.89–0.94]/%, P < .001) to be predictive of scar. A weighted risk score incorporating age and ejection fraction was used to stratify patients into low-, medium-, and high-risk groups. Scar prevalence was around 86% in the high-risk group and 12% in the low-risk group; high-risk patients had worse survival free of arrhythmia.ConclusionsCardiac scar was present in one-third of patients referred for PVC ablation. A weighted risk score based simply on patient age and preprocedural ejection fraction can help discriminate between patients at high and low risk for the presence of cardiac scar and worse arrhythmia outcomes.

Relationship between epicardial fat and left atrium fibrosis in patients with atrial fibrillation

Abstract Background Epicardial adipose tissue (EAT) has recently been shown to be associated with the presence, severity, and recurrence of atrial fibrillation (AF). Although the pathophysiological mechanisms underlying this association remain to be established, several hypotheses have been put forward, including direct adipocyte infiltration, oxidative stress, and the secretion of adipokines causing inflammation and fibrosis of atrial tissue. We hypothesized that the volume of EAT and the amount of left atrium (LA) fibrosis assessed by non-invasive imaging would be significantly correlated in patients with AF, and that both would predict time to relapse after pulmonary vein isolation (PVI). Methods Sixty-eight patients with AF being studied for a first PVI procedure underwent both cardiac computerized tomography (CT) and cardiac magnetic resonance (CMR) within less than 48h. EAT was quantified on contrast-enhanced CT images. LA fibrosis was quantified on isotropic 1.5mm 3D delayed enhancement CMR for image intensity ratio values &amp;gt;1.20. Radiofrequency PVI was performed using an irrigated contact force-sensing ablation catheter, guided by electroanatomical mapping. After PVI, patients were followed for AF recurrence, defined as symptomatic or documented AF after a 3-month blanking period. Pearson's correlation coefficient was used for gauging the correlation between EATLM volume and LA fibrosis. The relationship between these two variables and time to AF recurrence was assessed by Cox regression. Results Most of the 68 patients (46 men, mean age 61±12 years) had paroxysmal AF (71%, n=48). The mean body mass index (BMI) was 28.0±4.0 kg/m2. Patients had a median EATLM volume of 2.4 cm3/m2 [interquartile range (IQR) 1.6–3.2 cm3/m2], and a median estimated amount of LA fibrosis of 8.9 g (IQR 5–15 g), corresponding to 8% (IQR 5–11%) of the total LA wall mass. The correlation between EATLM and LA fibrosis was statistically significant but weak (Pearson's R = 0.38, P=0.001) – Figure 1. During a median follow-up of 22 months (IQR 12–31), 31 patients (46%) suffered AF recurrence. Four predictors of relapse were identified in univariate Cox regression: EATLM (HR 2.19, 95% CI 1.65–2.91, P&amp;lt;0.001), LA fibrosis (HR 1.05, 95% CI 1.01–1.09, P=0.033), non-paroxysmal AF (HR 3.36, 95% CI 1.64–6.87, P=0.001), and LA volume (HR 1.03, 95% CI 1.01–1.06, P=0.006). Multivariate analysis yielded two independent predictors of time to AF relapse: EATLM (HR 2.05, 95% CI 1.51–2.79, P&amp;lt;0.001), and non-paroxysmal AF (HR 2.36, 95% CI 1.08–5.16, P=0.031). Conclusion The weak correlation between EAT and LA suggests that LA fibrosis is not the main mechanism by which EAT and AF are linked. EAT was more strongly associated with AF recurrence than LA fibrosis, which supports the existence of other, more important mediators between EAT and this arrhythmia. Correlation between EAT and LA Funding Acknowledgement Type of funding source: None

Magnetic resonance-guided re-ablation for atrial fibrillation is associated with a lower recurrence rate: a case-control study.

Our aim was to analyse whether using delayed enhancement cardiac magnetic resonance imaging (DE-CMR) to localize veno-atrial gaps in atrial fibrillation (AF) redo ablation procedures improves outcomes during follow-up. We conducted a case-control study with 35 consecutive patients undergoing a DE-CMR-guided Repeat-pulmonary vein isolation (Re-PVI) procedure. Those with more extensive ablations (e.g. roof lines, box) were excluded. Patients were matched for age, sex, AF pattern, and left atrial dimension with 35 patients who had undergone a conventional Re-PVI procedure guided with a three dimensional (3D)-navigation system. Procedural characteristics were recorded, and patients were followed for 24 months in a specialized outpatient clinic. The primary endpoint was freedom from recurrent AF, atrial tachycardia, or flutter. The duration of CMR-guided procedures was shorter compared to the conventional group (161 ± 52 vs. 195 ± 72 min, respectively, P = 0.049), with no significant differences in fluoroscopy or total radiofrequency time. At the 2-year follow-up, more patients in the DE-CMR-guided group remained free from recurrences compared with the conventional group (70% vs. 39%, respectively, P = 0.007). In univariate Cox-regression analyses, AF pattern [persistent AF, hazard ratio (HR) 2.66 (1.27-5.46), P = 0.006] and the use of DE-CMR [HR 0.36 (0.17-0.79), P = 0.009] predicted recurrences during follow-up; both factors remained independent predictors in multivariate analyses. The substrate characterization provided by DE-CMR facilitates the identification of anatomical veno-atrial gaps and associates with shorter procedures and better clinical outcomes in repeated AF ablation procedures.