Association Between Midwall Late Gadolinium Enhancement and Sudden Cardiac Death in Patients With Dilated Cardiomyopathy and Mild and Moderate Left Ventricular Systolic Dysfunction

Management of nonischemic-dilated cardiomyopathies in clinical practice: a position paper of the working group on myocardial and pericardial diseases of Italian Society of Cardiology

: Nonischemic-dilated cardiomyopathy (NIDCM) is an entity that gathers extremely heterogeneous diseases. This awareness, although leading to continuous improvement in survival, has increased the complexity of NIDCM patients' management. Even though the endorsed 'red-flags' approach helps clinicians in pursuing an accurate etiological definition in clinical practice, it is not clear when and how peripheral centers should interact with referral centers with specific expertise in challenging scenarios (e.g. postmyocarditis and genetically determined dilated cardiomyopathy) and with easier access to second-line diagnostic tools and therapies. This position paper will summarize each step in NIDCM management, highlighting the multiple interactions between peripheral and referral centers, from first-line diagnostic workup and therapy to advanced heart failure management and long-term follow-up.

Updating the Risk Stratification for Sudden Cardiac Death in Cardiomyopathies: The Evolving Role of Cardiac Magnetic Resonance Imaging. An Approach for the Electrophysiologist

The prevention of sudden cardiac death (SCD) in cardiomyopathies (CM) remains a challenge. The current guidelines still favor the implantation of devices for the primary prevention of SCD only in patients with severely reduced left ventricular ejection fraction (LVEF) and heart failure (HF) symptoms. The implantation of an implantable cardioverter-defibrillator (ICD) is a protective barrier against arrhythmic events in CMs, but the benefit does not outweigh the cost in low risk patients. The identification of high risk patients is the key to an individualized prevention strategy. Cardiac magnetic resonance (CMR) provides reliable and reproducible information about biventricular function and tissue characterization. Furthermore, late gadolinium enhancement (LGE) quantification and pattern of distribution, as well as abnormal T1 mapping and extracellular volume (ECV), representing indices of diffuse fibrosis, can enhance our ability to detect high risk patients. CMR can also complement electro-anatomical mapping (EAM), a technique already applied in the risk evaluation and in the ventricular arrhythmias ablation therapy of CM patients, providing a more accurate assessment of fibrosis and arrhythmic corridors. As a result, CMR provides a new insight into the pathological substrate of CM. CMR may help identify high risk CM patients and, combined with EAM, can provide an integrated evaluation of scar and arrhythmic corridors in the ablative therapy of ventricular arrhythmias.

Association Between Atrial Fibrillation and Sudden Cardiac Death

Emerging evidence suggests that atrial fibrillation (AF) may be associated with an increased risk of sudden cardiac death (SCD). However, AF shares risk factors with numerous cardiac conditions, including coronary heart disease and heart failure—the 2 most common substrates for SCD—making the AF-SCD relationship particularly challenging to address. A careful consideration of confounding factors is essential, since interventions for AF will be effective in reducing SCD only if there is a causal association between these 2 conditions. In this translational review, we detail the plausible underlying pathophysiological mechanisms through which AF may promote or lead to SCD, as well as the existing epidemiological evidence supporting an association between AF and SCD. While the role of AF in predicting SCD in the general population appears limited and not established, AF might be integrated to improve risk stratification in some specific phenotypes. Optimal AF management, including that of its associated conditions, appears to be of interest to prevent AF-related SCD, especially because the AF-SCD relationship is in part driven by heart failure.

Left ventricular midwall fibrosis as a predictor of sudden cardiac death in non-ischaemic dilated cardiomyopathy: a meta-analysis

Identification of patients with non‐ischaemic dilated cardiomyopathy (NICM) who are at risk of sudden cardiac death (SCD) and could benefit from an implantable cardioverter defibrillator (ICD) is challenging. The study aims to systematically assess the prognostic value of left ventricular (LV) midwall late gadolinium enhancement (LGE) pattern in patients with NICM and further explore its value on predicting SCD events. The study was prospectively registered in PROPSERO (CRD42019138468). We systematically searched PubMed, Ovid Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov to identify studies that evaluated the association between LV midwall LGE and clinical outcomes (all‐cause mortality, cardiovascular mortality, and SCD or aborted SCD endpoint) in NICM patients. A meta‐analysis was performed to determine pooled odds ratio (OR) for these adverse events. Seven studies including 1827 NICM patients over a mean follow‐up duration of 36.1 ± 19.3 months were included. The presence of LV midwall LGE pattern was observed in 562 (30.8%) patients. The pooled OR was 3.37 [95% confidence intervals (CIs): 1.35–8.42] for all‐cause mortality, 5.56 (95% CI: 1.23–25.22) for cardiovascular mortality, and 2.25 (95% CI: 1.16–3.16) for SCD or aborted SCD. In a subgroup analysis with mean ejection fraction cut‐off point of 35%, the pooled OR for SCD or aborted SCD was 2.06 (95% CI: 1.32–3.22) for LV ejection fraction (LVEF) > 35% and 2.49 (95% CI: 1.48–4.20) for LVEF ≤ 35%. In addition, our study indicated that LV midwall LGE showed an excellent negative predictive value in identifying high‐risk NICM patients and that the number needed to treat with ICD implantation in NICM patients with midwall LGE is 7. The presence of LV midwall on LGE is a significant prognosticator of adverse events in NICM patients. Additionally, patients with LV midwall LGE may be considered for ICD therapy irrespective of LVEF.

Cardiovascular magnetic resonance in myocardial infarction with non-obstructive coronary arteries patients: A review

The diagnosis of myocardial infarction with non-obstructive coronary arteries (MINOCA) necessitates documentation of an acute myocardial infarction (AMI), non-obstructive coronary arteries, using invasive coronary angiography or coronary computed tomography angiography and no clinically overt cause for AMI. Historically patients with MINOCA represent a clinical dilemma with subsequent uncertain clinical management. Differential diagnosis is crucial to choose the best therapeutic option for ischemic and non-ischemic MINOCA patients. Cardiovascular magnetic resonance (CMR) is able to analyze cardiac structure and function simultaneously and provides tissue characterization. Moreover, CMR could identify the cause of MINOCA in nearly two-third of patients providing valuable information for clinical decision making. Finally, it allows stratification of patients with worse outcomes which resulted in therapeutic changes in almost half of the patients. In this review we discuss the features of CMR in MINOCA; from exam protocols to imaging findings.

Left Ventricular Geometry and Replacement Fibrosis Detected by cMRI Are Associated with Major Adverse Cardiovascular Events in Nonischemic Dilated Cardiomyopathy

To investigate the relationship between left ventricular (LV) long-axis strain (LAS) and LV sphericity index (LVSI) and outcomes in patients with nonischemic dilated cardiomyopathy (NIDCM) and myocardial replacement fibrosis confirmed by late gadolinium enhancement (LGE) using cardiac magnetic resonance imaging (cMRI), we conducted a prospective study on 178 patients (48 ± 14.4 years; 25.2% women) with first NIDCM diagnosis. The evaluation protocol included ECG monitoring, echocardiography and cMRI. LAS and LVSI were cMRI-determined. Major adverse cardiovascular events (MACEs) were defined as a composite outcome including heart failure (HF), ventricular arrhythmias (VAs) and sudden cardiac death (SCD). After a median follow-up of 17 months, patients with LGE+ had increased risk of MACEs. Kaplan-Meier curves showed significantly higher rate of MACEs in patients with LGE+ (p < 0.001), increased LVSI (p < 0.01) and decreased LAS (p < 0.001). In Cox analysis, LAS (HR = 1.32, 95%CI (1.54–9.14), p = 0.001), LVSI [HR = 1.17, 95%CI (1.45–7.19), p < 0.01] and LGE+ (HR = 1.77, 95%CI (2.79–12.51), p < 0.0001) were independent predictors for MACEs. In a 4-point risk scoring system based on LV ejection fraction (LVEF) < 30%, LGE+, LAS > −7.8% and LVSI > 0.48%, patients with 3 and 4 points had a significantly higher risk for MACEs. LAS and LVSI are independent predictors of MACEs and provide incremental value beyond LVEF and LGE+ in patients with NIDCM and myocardial fibrosis.

Arrhythmic risk stratification by cardiac magnetic resonance tissue characterization: disclosing the arrhythmic substrate within the heart muscle

Sudden cardiac death (SCD) is a pivotal health problem worldwide. The identification of subjects at increased risk of SCD is crucial for the accurate selection of candidates for implantable cardioverter defibrillator (ICD) therapy. Current strategies for arrhythmic stratification largely rely on left ventricular (LV) ejection fraction (EF), mostly measured by echocardiography, and New York Heart Association functional status for heart failure with reduced EF. For specific diseases, such as hypertrophic and arrhythmogenic cardiomyopathy, some risk scores have been proposed; however, these scores take into account some parameters that are a partial reflection of the global arrhythmic risk and show a suboptimal accuracy. Thanks to a more comprehensive evaluation, cardiac magnetic resonance (CMR) provides insights into the heart muscle (the so-called tissue characterization) identifying cardiac fibrosis as an arrhythmic substrate. Combining sequences before and after administration of contrast media and mapping techniques, CMR is able to characterize the myocardial tissue composition, shedding light on both intracellular and extracellular alterations. Over time, late gadolinium enhancement (LGE) emerged as solid prognostic marker, strongly associated with major arrhythmic events regardless of LVEF, adding incremental value over current strategy in ischemic heart disease and non-ischemic cardiomyopathies. The evidence on a potential prognostic role of mapping imaging is promising. However, mapping techniques require further investigation and standardization. Disclosing the arrhythmic substrate within the myocardium, CMR should be considered as part of a multiparametric approach to personalized arrhythmic stratification.

Ventricular arrhythmias and ARNI: is it time to reappraise their management in the light of new evidence?

The remarkable scientific progress in the treatment of patients with heart failure (HF) and reduced ejection fraction (HFrEF) has more than halved the risk of sudden cardiac death (SCD) in this setting. However, SCD remains one of the major causes of death in this patient population. Beyond the acknowledged role of beta blockers and inhibitors of the renin-angiotensin-aldosterone system (RAAS), a new class of drugs, the angiotensin receptor neprilysin inhibitors (ARNI), proved to reduce the overall cardiovascular mortality and, more specifically, the risk of SCD in HFrEF patients. The mechanism by which ARNI may reduce the mortality connected with harmful ventricular arrhythmias is not utterly clear. A variety of direct and indirect mechanisms have been suggested, but a favorable left ventricular reverse remodeling seems to play a key role in this setting. Furthermore, the well-known protective effect of implantable cardioverter-defibrillator (ICD) has been debated in HFrEF patients with non-ischemic cardiomyopathy (NICM) arguing against the role of primary prevention ICD in this setting, particularly when ARNI therapy is considered. The purpose of this review was to provide insights into the SCD mechanisms involved in HFrEF patients together with the current role of electrical therapies and new drug agents in this setting. Graphical abstract.

Analysis of the incidence and baseline predictors of the left ventricular ejection fraction returning to normal after dilated cardiomyopathy in postmenopausal women: a retrospective, observational study

Objective

To analyse the incidence and baseline predictors of the left ventricular ejection fraction (LVEF) returning to normal after dilated cardiomyopathy (DCM) following intervention with standard anti-heart failure (HF) medication in postmenopausal women.

Methods

Data from consecutive postmenopausal women who were first diagnosed with DCM and received anti-HF treatment during 2011 to 2018 were prospectively retrieved. The study population was divided into the LVEF recovery (LVR) group and the LVEF unrecovered (LVU) group according to whether LVEF was > 50%. The primary endpoint was baseline predictors of LVEF returning to normal.

Results

LVEF returned to normal in 49.3% (210/426) of patients with DCM. LVEF was significantly higher in the LVR group than in the LVU group (57.4% ± 6.9% vs 44.2% ± 5.3%; hazard ratio 1.312, 95% confidence interval 1.015–1.726) at the final follow-up. High systolic pressure, a short history of HF, a short QRS interval, a small left ventricular end-diastolic diameter (LVEDd), and high LVEF at admission were independent predictors of LVEF returning to normal.

Conclusions

LVEF returning to normal in postmenopausal women with DCM who receive standard anti-HF treatment is associated with systolic pressure, a history of HF, QRS interval, LVEDd, LVEF at admission, and favourable outcome.

Ventricular arrhythmias and risk stratification of cardiac sudden death in athletes

Sudden cardiac death (SCD) of young athletes is an unexpected and tragic event that could occur during sport activities and is frequently related to ventricular arrhythmias. Identifying athletes at risk of SCD remains a major challenge. While specific characteristics of premature ventricular contractions are considered common and benign, other "uncommon" features should require more accurate investigations, in order to determine eligibility for competitive sports. The most common type of idiopathic premature ventricular contractions originates from ventricular outflow tract and is characterized by an ECG pattern with left bundle branch block and inferior QRS axis (infundibular pattern). Another pattern associated with a good prognosis is the "fascicular" morphology, characterized by a typical right bundle branch block, superior QRS axis morphology and QRS duration <130 ms. Conversely, other morphological features (such as left bundle branch block /intermediate or superior axis or right bundle branch block/intermediate or superior axis and wide QRS) correlate to an underlying substrate. In risk stratification setting, cardiac magnetic resonance plays a key role allowing an accurate identification of myocardial tissue abnormalities, which could affect athletes' prognosis. This review focuses on characteristics of premature ventricular contractions characteristics in terms of morphology, distribution, complexity and response to exercise and describes the possible underlying myocardial substrates. This review also critically analyzes the evaluation process of athletes with premature ventricular contractions necessary for an accurate risk stratification.

Myocardial Fibrosis as a Pathway of Prediction of Ventricular Arrhythmias and Sudden Cardiac Death in Patients With Nonischemic Dilated Cardiomyopathy

The mechanism of sudden cardiac death (SCD) in patients with nonischemic dilated cardiomyopathy (NIDCM) is mostly due to sustained ventricular tachycardia and ventricular fibrillation. The clinical guidelines for the therapeutic management of this set of patients are mostly based on left ventricular ejection fraction value which has a low specificity to differentiate the risk of SCD from the risk of mortality associated with heart failure or other comorbidities. Moreover, since SCD can occur in patients with normal or mildly depressed ejection fraction, it is necessary to identify new markers to improve the prognostic stratification of SCD. Several studies that analyzed the ventricular arrhythmia substrate found that myocardial fibrosis plays an important role in the genesis of ventricular arrhythmias in patients with NIDCM. The surrounding zone of the area of fibrosis is a heterogeneous medium, where tissue with different levels of fibrosis coexists, resulting in both viable and nonviable myocardium. This myocardial fibrosis may constitute a substrate for ventricular arrhythmias, where slow and heterogeneous conduction may favor the genesis of reentry mechanism increasing the chance to develop sustained ventricular tachycardia or ventricular fibrillation. Therefore, the evaluation of ventricular fibrosis by late gadolinium enhancement (LGE) cardiac magnetic resonance imaging has been suggested as an indicator for SCD risk stratification. Indeed, LGE in patients with NIDCM is associated with increased risk of all-cause mortality, heart failure hospitalization, and SCD. Detection of myocardial fibrosis as LGE by cardiac magnetic resonance imaging can be considered as a useful pathway of prediction of malignant ventricular arrhythmias since it has excellent prognostic characteristics and may help guide risk stratification and management in patients with NIDCM.

Sudden death in heart failure with preserved ejection fraction and beyond: an elusive target

Heart failure (HF) with preserved ejection fraction (HFpEF) represents half of HF patients, who are more likely older, women, and hypertensive. Mortality rates in HFpEF are higher compared with age- and comorbidity-matched non-HF controls and lower than in HF with reduced ejection fraction (HFrEF); the majority (50-70%) are cardiovascular (CV) deaths. Among CV deaths, sudden death (SD) (~ 35%) and HF-death (~ 20%) are the leading cardiac modes of death; however, proportionally, CV deaths, SD, and HF-deaths are lower in HFpEF, while non-CV deaths constitute a higher proportion of deaths in HFpEF (30-40%) than in HFrEF (~ 15%). Importantly, the underlying mechanism of SD has not been clearly elucidated and non-arrhythmic SD may be more prominent in HFpEF than in HFrEF. Furthermore, there is no specific strategy for identifying high-risk patients, probably due to wide heterogeneity in presentation and pathophysiology of HFpEF and a plethora of comorbidities in this population. Thus, the management of HFpEF remains problematic due to paucity of data on the clinical benefits of current therapies, which focus on symptom relief and reduction of HF-hospitalization by controlling fluid retention and managing risk-factors and comorbidities. Matching a specific pathophysiology or mode of death with available and novel therapies may improve outcomes in HFpEF. However, this still remains an elusive target, as we need more information on determinants of SD. Implantable cardioverter-defibrillators (ICDs) have changed the landscape of SD prevention in HFrEF; if ICDs are to be applied to HFpEF, there must be a coordinated effort to identify and select high-risk patients.

Clinical Importance of Myocardial T2 Mapping and Texture Analysis

Late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) is valuable for diagnosis and assessment of the severity of various myocardial diseases owing to its potential to visualize myocardial scars. T₁ mapping is complementary to LGE because it can quantify the degree of myocardial fibrosis or edema. As such, T₁-weighted imaging techniques, including LGE using an inversion recovery sequence, contribute to cardiac MRI. T₂-weighted imaging is widely used to characterize the tissue of many organs. T₂-weighted imaging is used in cardiac MRI to identify myocardial edema related to chest pain, acute myocardial diseases, or severe myocardial injuries. However, it is difficult to determine the presence and extent of myocardial edema because of the low contrast between normal and diseased myocardium and image artifacts of T₂-weighted images and the lack of an established method to quantify the images. T₂ mapping quantifies myocardial T₂ values and help identify myocardial edema. The T₂ values are significantly related to the clinical symptoms or severity of nonischemic cardiomyopathy. Texture analysis is a postprocessing method to quantify tissue alterations that are reflected in the T₂-weighted images. Texture analysis provides a variety of parameters, such as skewness, entropy, and grey-scale non-uniformity, without the need for additional sequences. The abnormal signal intensity on T₂-weighted images or T₂ values may correspond to not only myocardial edema but also other tissue alterations. In this review, the techniques of cardiac T₂ mapping and texture analysis and their clinical relevance are described.

Risk stratification in patients with nonischemic cardiomyopathy and ventricular arrhythmias based on quantification of intramural delayed enhancement on cardiac magnetic resonance imaging

INTRODUCTION

Intramural scarring is a risk factor for sudden cardiac death. The objective of this study was to determine the value of scar quantification for risk stratification in patients with nonischemic cardiomyopathy (NICM) undergoing ablation procedures for ventricular arrhythmias (VA).

METHODS AND RESULTS

Cardiac late gadolinium-enhanced magnetic resonance imaging was performed in patients with NICM referred for ablation of premature ventricular complexes or ventricular tachycardia (VT). Only patients with intramural delayed enhancement were included. Scar volume was measured and correlated with immediate and long-term outcomes. Receiver operator curves, Wilcoxon signed-rank testing, and logistic regression were used to compare patient characteristics. The study consisted of 99 patients (74 males, mean age: 59.6 [54.0-68.1] years, ejection fraction [EF]: 46.0 [35.0-60.0]%). Patients without clinical VT or inducible VT had smaller total and core scar size compared to patients with a history of VT or inducible VT (total scar 1.12 [0.74-1.79] cm³ vs 7.45 [4.16-12.21] cm³ , P < .001). A total scar volume of greater than or equal to 2.78 cm³ was associated with inducibility of VT (AUC 0.94, 95% CI [0.89-0.98], sensitivity 85%, specificity 90%). Scar volume was associated with VT inducibility independent of a prior history of VT or the preprocedure EF (adjusted OR 1.67 [1.24-2.24]/cm³ , P < .01).

CONCLUSION

Quantification of scar size in patients with intramural scarring is useful for risk stratification in patients with NICM and VA independent of the EF or a prior history of VT. Scar characteristics of patients without a history of VT who have inducible VT are similar to patients with a history of VT.

IL-11 in cardiac and renal fibrosis: Late to the party but a central player

Fibrosis is a pathophysiological hallmark of cardiorenal disease. In the heart, fibrosis leads to contractile dysfunction and arrhythmias; in the kidney, it is the final common pathway for many diseases and predicts end-stage renal failure. Despite this, there are currently no specific anti-fibrotic treatments available for cardiac or renal disease. Recently and unexpectedly, IL-11 was found to be of major importance for cardiorenal fibroblast activation and fibrosis. In mouse models, IL-11 overexpression caused fibrosis of the heart and kidney while genetic deletion of Il11ra1 protected against fibrosis and preserved organ function. Neutralizing antibodies against IL-11 or IL-11RA have been developed that have anti-fibrotic activity in human fibroblasts and protect against fibrosis in murine models of disease. While IL-11 biology has been little studied and, we suggest, largely misunderstood, its autocrine activity in myofibroblasts appears non-redundant for fibrosis, which offers new opportunities to better understand and potentially target cardiorenal fibrosis.

Non-ischemic compared to ischemic cardiomyopathy is associated with increasing recurrent ventricular tachyarrhythmias and ICD-related therapies

OBJECTIVE

The study sought to assess the impact of ischemic (ICMP) compared to non-ischemic cardiomyopathy (NICMP) on recurrences of ventricular tachyarrhythmias in implantable cardioverter defibrillator (ICD) recipients.

BACKGROUND

Data comparing recurrences of ventricular tachyarrhythmias in ICD recipients with ischemic or non-ischemic cardiomyopathy is limited.

METHODS

A large retrospective registry was used including all consecutive ICD recipients with first episodes of ventricular tachycardia (VT) or fibrillation (VF) from 2002 to 2016. Patients with ICMP were compared to patients with NICMP. The primary prognostic endpoint was first recurrences of ventricular tachyarrhythmias at one year. Secondary endpoints comprised ICD-related therapies, rehospitalization and all-cause mortality at one year. Statistics Kaplan-Meier survival and multivariable Cox regression analyses.

RESULTS

A total of 387 consecutive ICD recipients were included retrospectively (ICMP: 82%, NICMP: 18%). At one year of follow-up, freedom from first recurrences of ventricular tachyarrhythmias was lower in NICMP (81% vs. 71%, log-rank p = 0.063; HR = 1.760; 95% CI 0.985-3.002; p = 0.080), mainly attributed to higher rates of sustained VT (20% versus 12%, p = 0.054). Accordingly, freedom from first appropriate device therapies was lower in NICMP (74% vs. 85%, log rank p = 0.004; HR = 1.951; 95% CI 1.121-3.397; p = 0.028), especially in patients with sustained VT or VF at index. Both groups revealed comparable rates of rehospitalization and all-cause mortality at one year.

CONCLUSION

NICMP was associated with higher rates of recurrent ventricular tachyarrhythmias and appropriate ICD therapies compared to ICMP at one year of follow-up, whereas rates of rehospitalization and all-cause mortality were comparable.

CONDENSED ABSTRACT

This study retrospectively compared the impact of cardiomyopathy types (ICMP versus NICMP) on recurrences of ventricular tachyarrhythmias in 387 ICD recipients. Freedom from first episodes of ventricular tachyarrhythmias and first appropriate device therapies were lower in patients with NICMP compared to ICMP.

Non-ischemic dilated cardiomyopathy and cardiac fibrosis

Cardiac fibrosis is associated with non-ischemic dilated cardiomyopathy, increasing its morbidity and mortality. Cardiac fibroblast is the keystone of fibrogenesis, being activated by numerous cellular and humoral factors. Macrophages, CD4+ and CD8+ T cells, mast cells, and endothelial cells stimulate fibrogenesis directly by activating cardiac fibroblasts and indirectly by synthetizing various profibrotic molecules. The synthesis of type 1 and type 3 collagen, fibronectin, and α-smooth muscle actin is rendered by various mechanisms like transforming growth factor-beta/small mothers against decapentaplegic pathway, renin angiotensin system, and estrogens, which in turn alter the extracellular matrix. Investigating the underlying mechanisms will allow the development of diagnostic and prognostic tools and discover novel specific therapies. Serum biomarkers aid in the diagnosis and tracking of cardiac fibrosis progression. The diagnostic gold standard is cardiac magnetic resonance with gadolinium administration that allows quantification of cardiac fibrosis either by late gadolinium enhancement assessment or by T1 mapping. Therefore, the goal is to stop and even reverse cardiac fibrosis by developing specific therapies that directly target fibrogenesis, in addition to the drugs used to treat heart failure. Cardiac resynchronization therapy had shown to revert myocardial remodeling and to reduce cardiac fibrosis. The purpose of this review is to provide an overview of currently available data.

Myocardial fibrosis and the effect of primary prophylactic defibrillator implantation in patients with non-ischemic systolic heart failure-DANISH-MRI

AIMS

Patients with non-ischemic systolic heart failure have an increased risk of sudden cardiac death (SCD). Myocardial fibrosis, detected as late gadolinium enhancement (LGE) with cardiac magnetic resonance (CMR), has been shown to predict all-cause mortality. We hypothesized that LGE can identify patients with non-ischemic heart failure who will benefit from ICD implantation.

METHODS AND RESULTS

In this prospective observational sub-study of the Danish Study to Assess the Efficacy of ICDs in Patients with Nonischemic Systolic Heart Failure on Mortality (DANISH), 252 patients underwent CMR. LGE was quantified by the full width/half maximum method. The primary endpoint was all-cause mortality. LGE could be adequately assessed in 236 patients, median age was 61 years and median duration of heart failure was 14 months; there were 108 patients (46%) randomized to ICD. Median follow-up time was 5.3 years. Median left ventricular ejection fraction on CMR was 35%. In all, 50 patients died. LGE was present in 113 patients (48%). The presence of LGE was an independent predictor of all-cause mortality (HR 1.82; 95% CI 1.002-3.29; P = .049) after adjusting for known cardiovascular risk factors. ICD implantation did not impact all-cause mortality, for either patients with LGE (HR 1.18; 95% CI 0.59-2.38; P = .63), or for patients without LGE (HR 1.00; 95% CI 0.39-2.53; P = .99), (P for interaction =0.79).

CONCLUSION

In patients with non-ischemic systolic heart failure, LGE predicted all-cause mortality. However, in this cohort, LGE did not identify a group of patients who survived longer by receiving an ICD.

Correlation between septal midwall late gadolinium enhancement on CMR and conduction delay on ECG in patients with nonischemic dilated cardiomyopathy

Background

Septal midwall late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) is a characteristic finding in nonischemic dilated cardiomyopathy (DCM) and is associated with adverse cardiac events. QRS-prolongation in DCM is also frequently present and a predictor of arrhythmic events and mortality. Since the His-Purkinje fibres are located in the interventricular septum, QRS-prolongation may directly result from septal fibrosis, visualized by LGE. Our aim was to study the correlation of the presence and extent of septal midwall LGE and QRS-duration.

Methods

DCM-patients with left ventricular (LV) dysfunction (LVEF < 50%) were included. LV volumes, systolic function and nonischemic septal midwall LGE, defined as patchy or stripe-like LGE in the septal segments, were quantified. QRS-duration on standard 12-lead ECG was measured.

Results

165 DCM-patients were included (62% male, mean age 59 ± 15 years) with a median LVEF of 36% [24–44]. Fifty-one patients (31%) demonstrated septal midwall LGE with a median extent of 8.1 gram [4.3–16.8]. Patients with midwall LGE had increased LV end-diastolic volumes (EDV) 248 mL [193–301] vs. 193 mL [160–239], p < 0.001) and lower LVEF (26% [18–35] vs. 40% [32–45], p < 0.001). Median QRS-duration was 110 ms [95–146] without a correlation to the presence nor extent of midwall LGE. QRS-duration was moderately correlated with LV-dilation and mass (respectively r = 0.35, p < 0.001 and r = 0.30, p < 0.001).

Conclusion

In DCM-patients, QRS-prolongation and septal midwall LGE are frequently present and often co-exist. However, they are not correlated. This suggests that the assessment of LGE-CMR has complementary value to ECG evaluation in the clinical assessment and risk stratification of DCM-patients.

Investigation of myocardial extracellular volume fraction in heart failure patients using iodine map with rapid-kV switching dual-energy CT: Segmental comparison with MRI T1 mapping

PURPOSE

To measure myocardial extracellular volume fraction (ECV) for each region or segment using iodine density image (IDI) with single-source dual-energy computed tomography (DECT) and compare the results with an MRI T1 mapping approach.

MATERIALS AND METHODS

For this prospective study, 79 consecutive heart failure patients referred for MRI were included and 23 patients (14 men, 63 ± 14 years) who underwent both MRI and late contrast enhancement DECT following coronary CT angiography were evaluated. CT-ECV was computed from IDI using late acquisition projection data. MR-ECV was computed from native and post-contrast T1 maps using non-rigid image registration for segments with evaluable image quality from 3.0-T MRI. Regional CT-ECV and MR-ECV were measured based on 16-segment models. CT-ECV and MR-ECV were compared using Pearson correlations. Agreement among methods was assessed using Bland-Altman comparisons.

RESULTS

In the 368 segments, although all segments were evaluable on IDI, 37 segments were rated as non-evaluable on T1 maps. Overall, 331 segments were analyzed. Mean CT-ECV and MR-ECV were 31.6 ± 9.1 and 33.2 ± 9.1, respectively. Strong correlations were seen between CT-ECV and MR-ECV for each region, as follows: all segments, r = 0.837; septal, r = 0.871; mid-septal, r = 0.895; anterior, r = 0.869; inferior, r = 0.793; and lateral, 0.864 (all p < 0.001). Differences between CT-ECV and MR-ECV were as follows: all segments, 1.13 ± 4.98; septal, -1.51 ± 4.37; mid-septal, -1.85 ± 4.22; anterior, 2.54 ± 4.89; inferior, 1.2 ± 5.78; and lateral, 2.65 ± 3.98.

CONCLUSION

ECV using DECT and from cardiac MRI showed a strong correlation on regional and segmental evaluations. DECT is useful for characterizing myocardial ECV changes as well as MRI.

Myocardial characterization in pre-dialysis chronic kidney disease: a study of prevalence, patterns and outcomes

Background

Late gadolinium enhancement (LGE) using cardiac magnetic resonance (CMR) characterizes myocardial disease and predicts an adverse cardiovascular (CV) prognosis. Myocardial abnormalities, are present in early chronic kidney disease (CKD). To date there are no data defining prevalence, pattern and clinical implications of LGE-CMR in CKD.

Methods

Patients with pre-dialysis CKD (stage 2–5) attending specialist renal clinics at University Hospital Birmingham (UK) who underwent gadolinium enhanced CMR (1.5 T) between 2005 and 2017 were included. The patterns and presence (LGEpos) / absence (LGEneg) of LGE were assessed by two blinded observers. Association between LGE and CV outcomes were assessed.

Results

In total, 159 patients received gadolinium (male 61%, mean age 55 years, mean left ventricular ejection fraction 69%, left ventricular hypertrophy 5%) with a median follow up period of 3.8 years [1.04–11.59]. LGEpos was present in 55 (34%) subjects; the patterns were: right ventricular insertion point n = 28 (51%), mid wall n = 18 (33%), sub-endocardial n = 5 (9%) and sub-epicardial n = 4 (7%). There were no differences in left ventricular structural or functional parameters with LGEpos. There were 12 adverse CV outcomes over follow up; 7 of 55 with LGEpos and 5 of 104 LGEneg. LGEpos was not predicted by age, gender, glomerular filtration rate or electrocardiographic abnormalities.

Conclusions

In a selected cohort of subjects with moderate CKD but low CV risk, LGE was present in approximately a third of patients. LGE was not associated with adverse CV outcomes. Further studies in high risk CKD cohorts are required to assess the role of LGE with multiplicative risk factors.

Magnetic resonance imaging of dilated cardiomyopathy: prognostic benefit of identifying late gadolinium enhancement in Asian patients

INTRODUCTION

Risk stratification in dilated cardiomyopathy (DCM) is imprecise, relying largely on echocardiographic left ventricular ejection fraction (LVEF) and severity of heart failure symptoms. Adverse cardiovascular events are increased by the presence of myocardial scarring. Late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) imaging is the gold standard for identifying myocardial scars. We examined the association between LGE on CMR imaging and adverse clinical outcomes during long-term follow-up of Asian patients with DCM.

METHODS

Consecutive patients with DCM undergoing CMR imaging at a single Asian academic medical centre between 2005 and 2015 were recruited. Clinical outcomes were tracked using comprehensive electronic medical records and mortality was determined by cross-linkages with national registries. Presence and distribution of LGE on CMR imaging were determined by investigators blinded to patient outcomes. Primary endpoint was a composite of heart failure hospitalisations, appropriate implantable cardioverter-defibrillator shocks and cardiovascular mortality.

RESULTS

Of 86 patients, 64.0% had LGE (80.2% male; mean LVEF 30.1% ± 12.7%). Mid-wall fibrosis (71.7%) was the most common pattern of LGE distribution. Over a mean follow-up period of 4.9 ± 3.2 years, 19 (34.5%) patients with LGE reached the composite endpoint compared to 4 (12.9%) patients without LGE (p = 0.01). Presence of LGE, but not echocardiographic LVEF, independently predicted the primary endpoint (hazard ratio 4.15 [95% confidence interval 1.28-13.50]; p = 0.02).

CONCLUSION

LGE presence independently predicted adverse clinical events in Asian patients with DCM. Routine use of CMR imaging to characterise the myocardial substrate is recommended for enhanced risk stratification and should strongly influence clinical management.

Risk Stratification for Sudden Cardiac Death in Non-Ischaemic Dilated Cardiomyopathy

Purpose of Review

Non-ischaemic dilated cardiomyopathy (DCM) occurs in 1 in 2500 individuals in the general population and is associated with considerable morbidity and mortality. Studies involving large numbers of unselected DCM patients have led to consensus guidelines recommending implantable cardioverter-defibrillator (ICD) implantation for protection against sudden cardiac death (SCD) in those with LVEF ≤35%. The purpose of this article is to review the literature for other potential markers including serological, electrocardiographic, echocardiographic, cardiac magnetic resonance, ambulatory ECG and genetic data, to highlight other potential markers that may optimise risk stratification for SCD in this cohort and thereby allow a more personalized approach to ICD-implantation.

Recent Findings

Recent studies including the Danish study to assess the efficacy of ICDs in patients with non-ischemic systolic heart failure on mortality (DANISH) trial have questioned the benefits of ICD implantation in this group of patients with no changes in all-cause mortality. Recent pooled cohorts of patients with genetic DCM and in particular in those with Lamin A/C (LMNA) mutations have identified patients at increased risk of SCD and allowed the creation of algorithms to prognosticate SCD risk in mutation carriers. Furthermore, genetic testing has identified other DCM-causing genes including filamin C (FLNC) and RBM20 which may be associated with higher rates of ventricular arrhythmia.

Summary

To date, risk-stratification for SCD has been hampered by the utilisation of heterogenous subsets of idiopathic DCM patients and by use of static risk models where predictions are based on a single time point with a lack of consideration of disease progression. The current focus of personalised risk-stratification for SCD is shifting towards better characterisation of underlying DCM aetiology and the development of multi-parametric risk-stratification models that incorporate time-dependent disease characteristics and novel biomarkers.

Primary prevention implantable cardioverter-defibrillator and opportunities for sudden cardiac death risk assessment in non-ischaemic cardiomyopathy

Sudden cardiac death (SCD) accounts for approximately one-third of all deaths among patients with non-ischaemic cardiomyopathy (NICM). Implantable cardioverter-defibrillator (ICD) therapy has been the primary intervention for managing individuals at high risk for SCD. However, individual ICD trials in the NICM population have failed to demonstrate a mortality benefit with prophylactic ICD implantation. Current guidelines recommend ICD implantation in NICM patients with symptomatic heart failure and a left ventricular ≤35% and are based on meta-analyses of multiple trials that span three decades and include the recent Danish Study to Assess the Efficacy of ICDs in Patients with Non-ischaemic Heart Failure on Mortality (DANISH) trial. These pooled analyses report a significant reduction in all-cause mortality with ICD implantation compared with medical therapy alone. In addition, each of these trials has demonstrated consistently a reduction in the risk of SCD compared with medical therapy alone. As a result, a refined approach of risk stratification that selects patients at the highest risk for SCD may lead to a significant improvement in ICD efficacy. In this clinical review, we first discuss the evolution of clinical trials that have evaluated ICDs in the NICM population. We then highlight some key markers of arrhythmia risk that hold promise in personalizing risk stratification for SCD.

Cardiac Magnetic Resonance in Primary Prevention of Sudden Cardiac Death

Sudden death accounts for 400,000 deaths annually in the United States. Most sudden deaths are cardiac and are related to arrhythmias secondary to structural heart disease or primary electrical abnormalities of the heart. Implantable cardioverter defibrillator significantly improves survival in patients at increased risk of life-threatening arrhythmias, but better selection of eligible patients is required to avoid unnecessary implantation and identify those patients who may benefit most from this therapy. Left ventricular (LV) ejection fraction (EF) measured by echocardiography has been considered the most reliable parameter for long-term outcome in many cardiac diseases. However, LVEF is an inaccurate parameter for arrhythmic risk assessment as patients with normal or mildly reduced LV systolic function could experience sudden cardiac death (SCD). Among other tools for arrhythmic stratification, magnetic resonance (CMR) provides the most comprehensive cardiac evaluation including in vivo tissue characterization and significantly aids in the identification of patients at higher SCD risk. Most of the evidence are related to late gadolinium enhancement (LGE), which was proven to detect cardiac fibrosis. LGE has been reported to add incremental value for prognostic stratification and SCD prediction across a wide range of cardiac diseases, including both ischemic and nonischemic cardiomyopathies. In addition, T1, T2 mapping and extracellular volume assessment were reported to add incremental value for arrhythmic assessment despite suffering from several technical limitations. CMR should be part of a multiparametric approach for patients' evaluation, and it will play a pivotal role in prognostic stratification according to the current evidence.

Myocardial fibrosis in arrhythmogenic cardiomyopathy: a genotype–phenotype correlation study

Aims

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a life-threatening entity with a highly heterogeneous genetic background. Cardiac magnetic resonance (CMR) imaging can identify fibrofatty scar by late gadolinium enhancement (LGE). Our aim is to investigate genotype–phenotype correlation in ARVC/D mutation carriers, focusing on CMR-LGE and myocardial fibrosis patterns.

Methods and results

A cohort of 44 genotyped patients, 33 with definite and 11 with borderline ARVC/D diagnosis, was characterized using CMR and divided into groups according to their genetic condition (desmosomal, non-desmosomal mutation, or negative). We collected information on cardiac volumes and function, as well as LGE pattern and extension. In addition, available ventricular myocardium samples from patients with pathogenic gene mutations were histopathologically analysed. Half of the patients were women, with a mean age of 41.6 ± 17.5 years. Next-generation sequencing identified a potential pathogenic mutation in 71.4% of the probands. The phenotype varied according to genetic status, with non-desmosomal male patients showing lower left ventricular (LV) systolic function. LV fibrosis was similar between groups, but distribution in non-desmosomal patients was frequently located at the posterolateral LV wall; a characteristic LV subepicardial circumferential LGE pattern was significantly associated with ARVC/D caused by desmin mutation. Histological analysis showed increased fibrillar connective tissue and intercellular space in all the samples.

Conclusion

Desmosomal and non-desmosomal mutation carriers showed different morphofunctional features but similar LV LGE presence. DES mutation carriers can be identified by a specific and extensive LV subepicardial circumferential LGE pattern. Further studies should investigate the specificity of LGE in ARVC/D.

Therapies to limit myocardial injury in animal models of myocarditis: a systematic review and meta-analysis

Current myocarditis guidelines do not advocate treatment to prevent myocardial injury and scar deposition in patients with myocarditis and normal left ventricular ejection fraction. We aimed to ascertain the utility of beta blockers, calcium channel blockers and antagonists of the renin–angiotensin system in ameliorating myocardial injury, scar formation and calcification in animal in vivo models of myocarditis. The project was prospectively registered with the PROSPERO database of systematic reviews (CRD42018089336). Primary outcomes (necrosis, fibrosis and calcification) were meta-analysed with random-effects modelling. 52 studies were systematically reviewed. Meta-analysis was performed compared with untreated controls. In each study, we identified all independent comparisons of treatment versus control groups. The pooled weighted mean difference (WMD) indicated treatment reduced necrosis by 16.9% (71 controlled analyses, 95% CI 13.2–20.7%; P < 0.001), however there was less evidence of an effect after accounting for publication bias. Treatment led to a 12.8% reduction in fibrosis (73 controlled analyses, 95% CI 7.6–18.0%; P < 0.001). After accounting for publication bias this was attenuated to 7.8% but remained significant. Treatment reduced calcification by 4.1% (28 controlled analyses, 95% CI 0.2–8.0%; P < 0.0395). We observed significant heterogeneity in effect size in all primary endpoints, which was predominantly driven by differences between drug categories. Beta blockers and angiotensin-converting enzyme (ACE) inhibitors were the only agents that were effective for both necrosis and fibrosis, while only ACE inhibitors had a significant effect on calcification. This study provides evidence for a role for ACE inhibitors and beta blockers to prevent myocardial injury and scar deposition in in vivo models of myocarditis. There is a need for further well-designed studies to assess the translational application of these treatments.

Circulating miRNAs and Risk of Sudden Death in Patients With Coronary Heart Disease

OBJECTIVES

This study evaluated whether plasma miRNAs were specifically associated with sudden cardiac and/or arrhythmic death (SCD) in a cohort of patients with coronary heart disease (CHD), most of whom were without primary prevention implantable cardioverter-defibrillators.

BACKGROUND

Novel biomarkers for sudden death risk stratification are needed in patients with CHD to more precisely target preventive therapies, such as implantable cardioverter-defibrillators. miRNAs have been implicated in regulating inflammation and cardiac fibrosis in cells, and plasma miRNAs have been shown to predict cardiovascular death in patients with CHD.

METHODS

We performed a nested case control study within a multicenter cohort of 5,956 patients with CHD followed prospectively for SCD. Plasma levels of 18 candidate miRNAs previously associated with cardiac remodeling were measured in 129 SCD cases and 258 control subjects matched on age, sex, race, and left ventricular ejection fraction.

RESULTS

miR-150-5p, miR-29a-3p, and miR-30a-5p were associated with increased SCD risk (odds ratios and 95% confidence intervals: 2.03 [1.12 to 3.67]; p = 0.02; 1.93 [1.07 to 3.50]; p = 0.02; 0.55 [0.31 to 0.97]; p = 0.04, respectively, for third vs. first tertile miRNA level). Unfavorable levels of all 3 miRNAs was associated with a 4.8-fold increased SCD risk (1.59 to 14.51; p = 0.006). A bioinformatics-based approach predicted miR-150-5p, miR-29a-3p, and miR-30a-5p to be involved in apoptosis, fibrosis, and inflammation.

CONCLUSIONS

These findings suggest that plasma miRNAs may regulate pathways important for remodeling and may be useful in identifying patients with CHD at increased risk of SCD.

Multimodality Imaging for the Assessment of Severe Aortic Stenosis

Aortic stenosis is the most common type of valvular heart disease. Aortic stenosis is characterized both by progressive valve narrowing and the left ventricular remodeling response that ensues. In aortic stenosis, therapeutic decision essentially depends on symptomatic status, stenosis severity, and status of left ventricular systolic function. Imaging is fundamental for the initial diagnostic work-up, follow-up, and selection of the optimal timing and type of intervention. Noninvasive imaging has played a pivotal role in enhancing our understanding of the complex pathophysiology underlying aortic stenosis, as well as disease progression in both the valve and myocardium. The present review provides the application of multimodality imaging in aortic stenosis.

Agreement between gadolinium-enhanced cardiac magnetic resonance and electro-anatomical maps in patients with non-ischaemic dilated cardiomyopathy and ventricular arrhythmias

AIMS

We sought to investigate the overlap between late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR) and electro-anatomical maps (EAM) of patients with non-ischaemic dilated cardiomyopathy (NIDCM) and how it relates with the outcomes after catheter ablation of ventricular arrhythmias (VA).

METHODS AND RESULTS

We identified 50 patients with NIDCM who received CMR and ablation for VA. Late gadolinium enhancement was detected in 16 (32%) patients, mostly in those presenting with sustained ventricular tachycardia (VT): 15 patients. Low-voltage areas (<1.5 mV) were observed in 23 (46%) cases; in 7 (14%) cases without evidence of LGE. Using a threshold of 1.5 mV, a good and partially good agreement between the bipolar EAM and LGE-CMR was observed in only 4 (8%) and 9 (18%) patients, respectively. With further adjustments of EAM to match the LGE, we defined new cut-off limits of median 1.5 and 5 mV for bipolar and unipolar maps, respectively. Most VT exits (12 out of 16 patients) were found in areas with LGE. VT exits were found in segments without LGE in two patients with VT recurrence as well as in two patients without recurrence, P = 0.77. In patients with VT recurrence, the LGE volume was significantly larger than in those without recurrence: 12% ± 5.8% vs. 6.9% ± 3.4%; P = 0.049.

CONCLUSIONS

In NIDCM, the agreement between LGE and bipolar EAM was fairly poor but can be improved with adjustment of the thresholds for EAM according to the amount of LGE. The outcomes were related to the volume of LGE.

Devices in Heart Failure Patients-Who Benefits From ICD and CRT?

Despite advances in heart failure treatment, this condition remains a relevant medical issue and is associated with a high morbidity and mortality. The cause of death in patients suffering from heart failure is not only a result of hemodynamic failure, but can also be due to ventricular arrhythmias. Implantable cardioverter defibrillators (ICDs) are these days the only tool to significantly reduce arrhythmic sudden death; but not all patients benefit to the same extend. In addition, cardiac resynchronization therapy (CRT) is another tool which is used in patients suffering from heart fialure. Even though both devices have been investigated in large randomized trials, both ICD and CRT remain underutilized in many countries. This brief review focuses on various aspects in this regard including a short overview on upcoming device novelties in the near future.

Mortality and Sudden Cardiac Death Risk Stratification Using the Noninvasive Combination of Wide QRS Duration and Late Gadolinium Enhancement in Idiopathic Dilated Cardiomyopathy

BACKGROUND

The aim of this study was to investigate whether the combination of QRS duration ≥120 ms (wide QRS duration [wQRS]) and late gadolinium enhancement (LGE) is a precise prognostic indicator for dilated cardiomyopathy.

METHODS AND RESULTS

We investigated the association between the combination of LGE plus wQRS and the primary end point (all-cause death) and a composite of sudden cardiac death (SCD) or aborted SCD in 531 patients with dilated cardiomyopathy. We also analyzed the association between the combination of LGE and wQRS and these end points among patients with a class I indication for implantable cardioverter defibrillator implantation. We divided study patients into 3 groups according to LGE status and QRS duration: 2 negative indices (LGE negative and narrow QRS), 1 positive index (LGE positive or wQRS), or 2 positive indices (LGE positive and wQRS), and followed them for 3.8 years. Multivariable Cox regression analysis identified 2 positive indices as a significant predictor of all-cause death (hazard ratio, 4.29 [1.19-15.47]; P=0.026). Among 317 patients with a class I indication for implantable cardioverter defibrillator, the 5-year event rate of SCD or aborted SCD was the lowest in the 2 negative indices group (1.4%). With propensity score-matching cohorts, the 2 negative indices group had a significantly lower event rate of SCD or aborted SCD than the other 2 groups (hazard ratio, 0.12 [0.01-0.97]; P=0.046).

CONCLUSIONS

The combination of LGE and wQRS provides additional prognostic stratification compared with LGE status alone and might improve the appropriate use of implantable cardioverter defibrillator therapy in patients with dilated cardiomyopathy.

Microvascular Dysfunction in Dilated Cardiomyopathy: A Quantitative Stress Perfusion Cardiovascular Magnetic Resonance Study

OBJECTIVES

This study sought to quantify myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) in dilated cardiomyopathy (DCM) and examine the relationship between myocardial perfusion and adverse left ventricular (LV) remodeling.

BACKGROUND

Although regarded as a nonischemic condition, DCM has been associated with microvascular dysfunction, which is postulated to play a role in its pathogenesis. However, the relationship of the resulting perfusion abnormalities to myocardial fibrosis and the degree of LV remodeling is unclear.

METHODS

A total of 65 patients and 35 healthy control subjects underwent adenosine (140 μg/kg/min) stress perfusion cardiovascular magnetic resonance with late gadolinium enhancement imaging. Stress and rest MBF and MPR were derived using a modified Fermi-constrained deconvolution algorithm.

RESULTS

Patients had significantly higher global rest MBF compared with control subjects (1.73 ± 0.42 ml/g/min vs. 1.14 ± 0.42 ml/g/min; p < 0.001). In contrast, global stress MBF was significantly lower versus control subjects (3.07 ± 1.02 ml/g/min vs. 3.53 ± 0.79 ml/g/min; p = 0.02), resulting in impaired MPR in the DCM group (1.83 ± 0.58 vs. 3.50 ± 1.45; p < 0.001). Global stress MBF (2.70 ± 0.89 ml/g/min vs. 3.44 ± 1.03 ml/g/min; p = 0.017) and global MPR (1.67 ± 0.61 vs. 1.99 ± 0.50; p = 0.047) were significantly reduced in patients with DCM with LV ejection fraction ≤35% compared with those with LV ejection fraction >35%. Segments with fibrosis had lower rest MBF (mean difference: -0.12 ml/g/min; 95% confidence interval: -0.23 to -0.01 ml/g/min; p = 0.035) and lower stress MBF (mean difference: -0.15 ml/g/min; 95% confidence interval: -0.28 to -0.03 ml/g/min; p = 0.013).

CONCLUSIONS

Patients with DCM exhibit microvascular dysfunction, the severity of which is associated with the degree of LV impairment. However, rest MBF is elevated rather than reduced in DCM. If microvascular dysfunction contributes to the pathogenesis of DCM, then the underlying mechanism is more likely to involve stress-induced repetitive stunning rather than chronic myocardial hypoperfusion.

Comparing CMR Mapping Methods and Myocardial Patterns Toward Heart Failure Outcomes in Nonischemic Dilated Cardiomyopathy

OBJECTIVES

In patients with nonischemic dilated cardiomyopathy (NIDCM), native T1, partition coefficient (λGd), and extracellular volume fraction (ECV) mapping may offer prognostic values beyond late gadolinium enhancement (LGE), by scaling the range of myocardial changes.

BACKGROUND

In patients with NIDCM, LGE is seen in 30% of patients and it indicates adverse prognosis.

METHODS

The study mapped 6 anatomical locations using all 4 cardiac magnetic resonance (CMR) tissue-characterizing methods and associated with outcome. The authors performed T1 mapping of the myocardium and the blood pool, before and serially after contrast injection, using a Look-Locker cine gradient-echo technique to obtain T1 and the corresponding reciprocal R1 values. λGd values were derived from the slopes of the least-squares regression lines for myocardial versus blood R1, then adjusted to serum hematocrit to yield ECV.

RESULTS

Consecutive 240 NIDCM patients (49 ± 16 years of age; 38% women) underwent CMR for cardiac function, LGE, native T1, λGd, and ECV. After a median of 3.8 years, 36 (15%) experienced major adverse cardiac events (MACE), including 22 heart failure hospitalizations and 14 deaths. Nonischemic LGE was detected in 34%, whereas ECV was elevated (≥1 location) in 58%. Comparing the 4 methods, mean ECV and λGd both demonstrated strong association with MACE (both p < 0.001). In contrast to native T1 and LGE, ECV values from all 6 locations were associated with MACE and death, with the anteroseptum being the most significant (p < 0.0001). The number of abnormal ECV locations correlated linearly with annual MACE rates (p = 0.0003). Mean ECV was the only predictor to enter a prognostic model that contained age, sex, New York Heart Association functional class, and left ventricular ejection fraction. For every 10% increase, mean ECV portended to a 2.8-fold adjusted increase risk to MACE (p < 0.001).

CONCLUSIONS

In this study of patients with NIDCM, mapping the myocardial extent of abnormality using ECV offers prognostication toward heart failure outcomes incremental to LGE or native T1 mapping.

Natural History of Myocardial Injury and Chamber Remodeling in Acute Myocarditis

Background:

Cardiovascular magnetic resonance (CMR) imaging is commonly used to diagnose acute myocarditis. However, the natural history of CMR-based tissue markers and their association with left ventricular recovery is poorly explored. We prospectively investigated the natural history of CMR-based myocardial injury and chamber remodeling over 12 months in patients with suspected acute myocarditis.

Methods:

One hundred patients with suspected acute myocarditis were enrolled. All underwent CMR evaluations at baseline and 12 months, inclusive of T2 and late gadolinium enhancement. Blinded quantitative analyses compared left ventricular chamber volumes, function, myocardial edema, and necrosis at each time point using predefined criteria. The predefined primary outcomes were improvement in left ventricular ejection fraction ≥10% and improvement in the indexed left ventricular end diastolic volume ≥10% at 12 months.

Results:

The mean age was 39.9±14.5 years (82 male) with baseline left ventricular ejection fraction of 57.1±11.2%. A total of 72 patients (72%) showed late gadolinium enhancement at baseline with 57 (57%) having any T2 signal elevation. Left ventricular volumes and EF improved significantly at 12 months. Global late gadolinium enhancement extent dropped from 8.5±9.2% of left ventricular mass to 3.0±5.2% ( P =0.0001) with prevalence of any late gadolinium enhancement dropping to 48%. Reductions in global T2 signal ratio occurred at 12 months (1.85±0.3 to 1.56±0.2; P =0.0001) with prevalence of T2 ratio ≥2.0 dropping to 7%. Neither marker provided associations with the primary outcomes.

Conclusions:

In clinically suspected acute myocarditis, significant reductions in tissue injury markers occur during the first 12 months of convalescence. Neither the presence nor extent of the investigated CMR-based tissue injury markers were predictive of our pre-defined function or remodeling outcomes at 12 months in this referral population.

The Role of Cardiac MRI in the Management of Ventricular Arrhythmias in Ischaemic and Non-ischaemic Dilated Cardiomyopathy

Ventricular tachycardia (VT) and VF account for the majority of sudden cardiac deaths worldwide. Treatments for VT/VF include anti-arrhythmic drugs, ICDs and catheter ablation, but these treatments vary in effectiveness and carry substantial risks and/or expense. Current methods of selecting patients for ICD implantation are imprecise and fail to identify some at-risk patients, while leading to others being overtreated. In this article, the authors discuss the current role and future direction of cardiac MRI (CMRI) in refining diagnosis and personalising ventricular arrhythmia management. The capability of CMRI with gadolinium contrast delayed-enhancement patterns and, more recently, T1 mapping to determine the aetiology of patients presenting with heart failure is well established. Although CMRI imaging in patients with ICDs can be challenging, recent technical developments have started to overcome this. CMRI can contribute to risk stratification, with precise and reproducible assessment of ejection fraction, quantification of scar and 'border zone' volumes, and other indices. Detailed tissue characterisation has begun to enable creation of personalised computer models to predict an individual patient's arrhythmia risk. When patients require VT ablation, a substrate-based approach is frequently employed as haemodynamic instability may limit electrophysiological activation mapping. Beyond accurate localisation of substrate, CMRI could be used to predict the location of re-entrant circuits within the scar to guide ablation.