Late gadolinium enhancement among survivors of sudden cardiac arrest

Implantable Cardioverter-Defibrillators Among Older Survivors of Out-of-Hospital Cardiac Arrest

BACKGROUND

Although current guidelines recommend implantable cardioverter-defibrillator (ICD) placement in survivors of out-of-hospital cardiac arrest, contemporary data on secondary-prevention ICDs in survivors of out-of-hospital cardiac arrest remain limited.

METHODS AND RESULTS

Using 2013 to 2019 CARES (Cardiac Arrest Registry to Enhance Survival) linked to Medicare, we identified 3226 patients aged ≥65 years with an initial shockable rhythm who survived to discharge without severe neurological disability. Multivariable hierarchical regression models were used to examine the association between patient variables and ICD placement and quantify hospital variation in ICD implantation. The mean age was 72.2 years, 23.5% were women, 10% were Black individuals, and 4% were Hispanic individuals. Overall, 997 (30.9%) patients received an ICD before discharge, 1266 (39.2%) at 90 days, and 1287 (39.9%) within 6 months. Older age (≥85 years), female sex, history of diabetes, calendar year, and presentation with acute myocardial infarction were associated with lower odds of ICD implantation, but race or ethnicity was not associated with ICD implantation. Among 297 hospitals, the median proportion of survivors receiving ICD at discharge was 28.6% (interquartile range, 20%-50%). The relative odds of ICD implantation varied by 62% across hospitals (median odds ratio, 1.62 [95% CI, 1.38-1.82]) after adjusting for case mix.

CONCLUSIONS

Fewer than 1 in 3 survivors of out-of-hospital cardiac arrest due to a shockable rhythm received a secondary-prevention ICD before discharge. Although patient variables were associated with ICD implantation, there was no difference by race or ethnicity. Even after adjusting for patient case mix, ICD implantation varied markedly across hospitals.

Management of cardiac sarcoidosis

Cardiac sarcoidosis (CS) is a form of inflammatory cardiomyopathy associated with significant clinical complications such as high-degree atrioventricular block, ventricular tachycardia, and heart failure as well as sudden cardiac death. It is therefore important to provide an expert consensus statement summarizing the role of different available diagnostic tools and emphasizing the importance of a multidisciplinary approach. By integrating clinical information and the results of diagnostic tests, an accurate, validated, and timely diagnosis can be made, while alternative diagnoses can be reasonably excluded. This clinical expert consensus statement reviews the evidence on the management of different CS manifestations and provides advice to practicing clinicians in the field on the role of immunosuppression and the treatment of cardiac complications based on limited published data and the experience of international CS experts. The monitoring and risk stratification of patients with CS is also covered, while controversies and future research needs are explored.

Early identification of severe immune checkpoint inhibitor associated myocarditis: From an electrocardiographic perspective

OBJECTIVES

Immune checkpoint inhibitor (ICI)-associated myocarditis, particularly severe ICI-associated myocarditis, has a high mortality rate. However, the predictive value of electrocardiogram (ECG) remains unclear. The present study aimed to evaluate the predictive value of clinical and electrocardiographic parameters for severe myocarditis.

METHODS

Clinical and electrocardiographic data of 73 cancer patients with ICI-associated myocarditis were retrospectively collected. The severity of ICI-associated myocarditis was graded using the NCCN guidelines for managing immunotherapy-related toxicities. Myocarditis grades 1-2 and grades 3-4 were classified as mild and severe myocarditis, respectively. Logistic regression analysis was performed to analyze the predictive value of each parameter in predicting severe myocarditis.

RESULTS

Among the 73 patients with myocarditis, 20 (27.4%) patients had severe myocarditis. Compared with mild myocarditis group, sinus tachycardia (p = 0.001), QRS duration ≥110 ms (p = 0.001), prolonged QTc interval (p < 0.001), and bundle branch block (p = 0.007) at the time of myocarditis were more common in the severe myocarditis group. Logistic regression analysis revealed that sinus tachycardia (p = 0.028) and QTc interval prolongation (p = 0.007) were predictors of severe myocarditis. Whereas the predictive value of other electrocardiographic parameters was weak. Concurrent targeted therapy didn't increase the risk of severe myocarditis. A high NT-proBNP level was associated with severe myocarditis.

CONCLUSIONS

ECG at the onset of myocarditis manifested as sinus tachycardia and prolonged QTc interval predicted a high risk of severe myocarditis. Early detection of ECG abnormalities may faciliate early detection of severe ICI-associated myocarditis.

Idiopathic Ventricular Fibrillation - Just How Much Idiopathic is it?

Idiopathic ventricular fibrillation is diagnosed in survivors of sudden cardiac death that has been caused by ventricular fibrillation without known structural or electrical abnormalities, even after extensive investigation. It is a common cause of sudden death in young adults. Although idiopathic ventricular fibrillation is a diagnosis of exclusion, in many cases only a partial investigation algorithm is performed. The aim of this review is to present a comprehensive diagnostic evaluation algorithm with a focus on diagnostic assessment of inherited arrhythmic syndromes and genetic background.

Feasibility of the Threshold-Based Quantification of Myocardial Fibrosis on Cardiac CT as a Prognostic Marker in Nonischemic Dilated Cardiomyopathy

OBJECTIVE

This study investigated the feasibility and prognostic relevance of threshold-based quantification of myocardial delayed enhancement (MDE) on CT in patients with nonischemic dilated cardiomyopathy (NIDCM).

MATERIALS AND METHODS

Forty-three patients with NIDCM (59.3 ± 17.1 years; 21 male) were included in the study and underwent cardiac CT and MRI. MDE was quantified manually and with a threshold-based quantification method using cutoffs of 2, 3, and 4 standard deviations (SDs) on three sets of CT images (100 kVp, 120 kVp, and 70 keV). Interobserver agreement in MDE quantification was assessed using the intraclass correlation coefficient (ICC). Agreement between CT and MRI was evaluated using the Bland-Altman method and the concordance correlation coefficient (CCC). Patients were followed up for the subsequent occurrence of the primary composite outcome, including cardiac death, heart transplantation, heart failure hospitalization, or appropriate use of an implantable cardioverter-defibrillator. The Kaplan-Meier method was used to estimate event-free survival according to MDE levels.

RESULTS

Late gadolinium enhancement (LGE) was observed in 29 patients (67%, 29/43), and the mean LGE found with the 5-SD threshold was 4.1% ± 3.6%. The 4-SD threshold on 70-keV CT showed excellent interobserver agreement (ICC = 0.810) and the highest concordance with MRI (CCC = 0.803). This method also yielded the smallest bias with the narrowest range of 95% limits of agreement compared to MRI (bias, -0.119%; 95% limits of agreement, -4.216% to 3.978%). During a median follow-up of 1625 days (interquartile range, 712-1430 days), 10 patients (23%, 10/43) experienced the primary composite outcome. Event-free survival significantly differed between risk subgroups divided by the optimal MDE cutoff of 4.3% (log-rank P = 0.005).

CONCLUSION

The 4-SD threshold on 70-keV monochromatic CT yielded results comparable to those of MRI for quantifying MDE as a marker of myocardial fibrosis, which showed prognostic value in patients with NIDCM.

Mitral annular disjunction in out-of-hospital cardiac arrest patients-a retrospective cardiac MRI study

BACKGROUND

Mitral annular disjunction (MAD), defined as defective attachment of the mitral annulus to the ventricular myocardium, has recently been linked to malignant arrhythmias. However, its role and prognostic significance in patients requiring cardiopulmonary resuscitation (CPR) remain unknown. This retrospective analysis aimed to describe the prevalence and significance of MAD by cardiac magnetic resonance (CMR) imaging in out-of-hospital cardiac arrest (OHCA) patients.

METHODS

Eighty-six patients with OHCA and a CMR scan 5 days after CPR (interquartile range (IQR): 49 days before - 9 days after) were included. MAD was defined as disjunction-extent ≥ 1 mm in CMR long-axis cine-images. Medical records were screened for laboratory parameters, comorbidities, and a history of arrhythmia.

RESULTS

In 34 patients (40%), no underlying cause for OHCA was found during hospitalization despite profound diagnostics. Unknown-cause OHCA patients showed a higher prevalence of MAD compared to definite-cause patients (56% vs. 10%, p < 0.001) and had a MAD-extent of 6.3 mm (IQR: 4.4-10.3); moreover, these patients were significantly younger (43 years vs. 61 years, p < 0.001), more often female (74% vs. 21%, p < 0.001) and had fewer comorbidities (hypertension, hypercholesterolemia, coronary artery disease, all p < 0.005). By logistic regression analysis, the presence of MAD remained significantly associated with OHCA of unknown cause (odds ratio: 8.49, 95% confidence interval: 2.37-30.41, p = 0.001) after adjustment for age, presence of hypertension, and hypercholesterolemia.

CONCLUSIONS

MAD is rather common in OHCA patients without definitive aetiology undergoing CMR. The presence of MAD was independently associated to OHCA without an identifiable trigger. Further research is needed to understand the exact role of MAD in OHCA patients.

Cardiac MRI after Sudden Cardiac Arrest: A Systematic Review

Purpose To perform a systematic review to assess the diagnostic and prognostic value of cardiac MRI after sudden cardiac arrest (SCA). Materials and Methods PubMed and Cochrane Library databases were systematically searched for studies investigating cardiac MRI after SCA in adult patients (≥18 years of age). The time frame of the encompassed studies spans from January 2012 to January 2023. The study protocol was preregistered in OSF Registries (www.osf.io/nxaev), and the systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of the included studies was evaluated using the Newcastle-Ottawa quality assessment scale. Results Fourteen studies involving 1367 individuals, 1257 (91.9%) of whom underwent cardiac MRI, were included. Inconsistent findings were reported on the diagnostic value of cardiac MRI-specific findings. The included studies demonstrated the following main findings: (a) cardiac MRI led to a new or alternative diagnosis in patients with SCA; (b) cardiac MRI identified pathologic or arrhythmogenic substrates; (c) cardiac MRI helped detect myocardial edema (potentially reversible); (d) cardiac MRI provided evidence for the occurrence of adverse events; and (e) functional markers or ventricular dimensions were considered prognostically relevant in a few studies. Relevant challenges in this systematic review were the lack of comparators and reference standards relative to cardiac MRI as the index test and patient selection bias. Conclusion Cardiac MRI following SCA can contribute to the diagnostic process and offer supplementary information essential for treatment planning. Limitations of the review include studies with insufficient comparators and potential bias in patient selection. Systematic review registration link: osf.io/nxaev Keywords: Cardiac MRI, Cardiovascular Disease, Cardiomyopathy, Ischemia, Myocardial Edema, Sudden Cardiac Arrest © RSNA, 2024.

Review and critical appraisal of the indications for cardiac magnetic resonance imaging in the ESC guidelines

Cardiac MRI has made significant advances in the past decade, becoming an important technique for the evaluation of various cardiac pathologies. The aim of this document is to review the current indications for performing cardiac MRI based on the current ESC guidelines for STEMI, NSTEMI, chronic coronary artery disease, heart failure, arrhythmias, sudden cardiac death, valvular heart disease, pericardial disease and congenital heart disease. The review discusses the diagnostic and prognostic value of cMR for numerous cardiac diseases, and its important value in assessing structural heart disease and predicting arrhythmia risk. Additionally, it reflects upon the appropriateness of the guidelines and points out areas where the indications should be revised in future editions, based on the author's personal opinion. It is suggested that guideline criteria for the use of cMR should be more explicit to promote its use and lead to more specific reimbursements. However, further studies are needed to even better document the value of cMR in the future.

Diagnostic Impact and Prognostic Value of Cardiac Magnetic Resonance in Patients With Ventricular Arrhythmias

BACKGROUND

Cardiac magnetic resonance (CMR) characterizes myocardial substrate relevant to sudden cardiac death (SCD). However, its clinical value in patients presenting with ventricular arrhythmias is still being defined.

OBJECTIVES

The authors sought to examine the diagnostic and prognostic value of multiparametric CMR in a cohort of consecutive patients referred for assessment of ventricular arrhythmias.

METHODS

Consecutive patients undergoing CMR for nonsustained ventricular tachycardia (NSVT) (n = 345) or sustained ventricular tachycardia (VT)/aborted SCD (n = 297) were followed over a median of 4.4 years. Major adverse cardiac events included death, recurrent VT/ventricular fibrillation requiring therapy, and hospitalization for congestive heart failure.

RESULTS

Of the 642 patients, 256 were women (40%), mean age was 54 ± 15 years, and median left ventricular ejection fraction was 58% (IQR: 49%-63%). A structurally abnormal heart by CMR assessment was detected in 40% of patients with NSVT and 66% in those with VT/SCD (P < 0.001). CMR assessment yielded a diagnostic change in 27% of NSVT patients vs 41% of those with VT/SCD (P < 0.001). During follow-up, 51 patients (15%) with NSVT and 104 patients (35%) with VT/SCD experienced major adverse cardiac events (MACE). An abnormal CMR was associated with a higher annual rate for MACE for both NSVT (0.7% vs 7.7%; P < 0.001) and VT/SCD (3.8% vs 13.3%; P < 0.001) patients. In a multivariate model including left ventricular ejection fraction, an abnormal CMR remained strongly associated with MACE in NSVT (HR: 5.23 [95% CI: 2.28-12.0]; P < 0.001) and VT/SCD (HR: 1.88 [95% CI: 1.07-3.30]; P = 0.03). Adding CMR assessment to the multivariable model for MACE yielded a significant improvement in the integrated discrimination improvement and an improvement in the C-statistic in the NSVT cohort.

CONCLUSIONS

In patients presenting with ventricular arrhythmias, multiparametric CMR assessment provides diagnostic clarification and effective risk stratification beyond current standard of care.

Explaining the Unexplained: A Practical Approach to Investigating the Cardiac Arrest Survivor

Sudden cardiac arrest (SCA) is a common cause of death. The majority of SCA is caused by ventricular arrhythmia due to underlying CHD. Aborted SCA with no apparent diagnosis after initial assessment with ECG, echocardiography and coronary assessment is referred to as unexplained cardiac arrest (UCA). Systematic evaluation of such patients may reveal a specific diagnosis in up to half of patients before a diagnosis of idiopathic VF is assigned. Specific diagnoses include inherited cardiac conditions, such as latent cardiomyopathies or inherited primary electrical disease. Identifying the cause of UCA is therefore not only critical for appropriate management of the SCA survivors to prevent recurrence, but also for their family members who may be at risk of the same condition. This review provides a tiered, systematic approach for the investigation of UCA.

Myocardial scarring and recurrence of ventricular arrhythmia in patients surviving an out-of-hospital cardiac arrest

INTRODUCTION

Prediction of recurrent ventricular arrhythmia (VA) in survivors of an out-of-hospital cardiac arrest (OHCA) is important, but currently difficult. Risk of recurrence may be related to presence of myocardial scarring assessed with late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Our study aims to characterize myocardial scarring as defined by LGE-CMR in survivors of a VA-OHCA and investigate its potential role in the risk of new VA events.

METHODS

Between 2015 and 2022, a total of 230 VA-OHCA patients without ST-segment elevation myocardial infarction had CMR before implantable cardioverter-defibrillator implantation for secondary prevention at Copenhagen University Hospital, Rigshospitalet, and Hospital Clínic, University of Barcelona, of which n = 170 patients had a conventional (no LGE protocol) CMR and n = 60 patients had LGE-CMR (including LGE protocol). Scar tissue including core, border zone (BZ) and BZ channels were automatically detected by specialized investigational software in patients with LGE-CMR. The primary endpoint was recurrent VA.

RESULTS

After exclusion, n = 52 VA-OHCA patients with LGE-CMR and a mean left ventricular ejection fraction of 49 ± 16% were included, of which 18 (32%) patients reached the primary endpoint of VA. Patients with recurrent VA in exhibited greater scar mass, core mass, BZ mass, and presence of BZ channels compared with patients without recurrent VA. The presence of BZ channels identified patients with recurrent VA with 67% sensitivity and 85% specificity (area under the ROC curve (AUC) 0.76; 95% CI: 0.63-0.89; p < .001) and was the strongest predictor of the primary endpoint.

CONCLUSIONS

The presence of BZ channels was the strongest predictor of recurrent VA in patients with an out of-hospital cardiac arrest and LGE-CMR.

Cardiac Magnetic Resonance as an Etiological Diagnosis Tool in Recovered Sudden Cardiac Death or Unstable Ventricular Arrhythmia Patients

BACKGROUND

Cardiac magnetic resonance (CMR) has an increasing diagnostic relevance in survivors of sudden cardiac death (SCD) or unstable ventricular arrhythmia (UVA) in developed countries.

OBJECTIVE

To evaluate retrospectively the additional role of CMR in a developing country where few resources are available, and should be used more effectively.

METHODS

The study included SCD or UVA survivors admitted between 2009 and 2019 at a tertiary academic institution referred to CMR. Demographic, clinical, and laboratory data were collected from the medical records. CMR images and reports were reviewed and their impact on the final etiological diagnosis was determined. A descriptive analysis was performed and p<0.05 established as significant.

RESULTS

Sixty-four patients, 54.9±15.4 years old, and 42 (71.9%) males. Most events (81.3%) were out of the hospital and ventricular tachycardia was the most common rhythm. Cardiovascular medications were previously used by 55 patients, and beta-blockers were the most used medications (37.5%). Electrocardiogram had electrical inactive areas in 21.9% and all of them had fibrosis at CMR. Mean left ventricular ejection fraction (LVEF) was 44±14%, with 60.9% ≤50% and only 29.7% ≤35%. Late gadolinium enhancement was identified in 71.9%, with a transmural pattern in 43.8%. Chagas cardiomyopathy was the most common etiology (28.1%), followed by ischemic cardiomyopathy (17.2%). Among 26 without a previously identified etiology, CMR could define it (15 patients - 57%).

CONCLUSION

In accordance with previous studies in developed countries, CMR was capable of increasing etiological diagnosis and identifying the arrhythmogenic substrate, allowing better care in half of the underdiagnosed patients.

Early evaluation of severe immune checkpoint inhibitor-associated myocarditis: a real-world clinical practice

PURPOSE

Immune checkpoint inhibitor (ICI)-associated myocarditis is a rare but severe complication for patients treated with immunotherapy. This study aims to explore the predictive significance of patients' clinical features and examination results for the severity of ICI-associated myocarditis.

METHODS

Data from a real-world cohort of 81 cancer patients who developed ICI-associated myocarditis after immunotherapy were retrospectively analyzed. The development of myocarditis of Common Terminology Criteria for Adverse Events (CTCAE) grades 3-5 and/or the major adverse cardiovascular event (MACE) was set as endpoints. Logistic regression was used to evaluate the predictive value of each factor.

RESULTS

CTCAE grades 3-5 and MACE developed in 43/81 (53.1%) and 28/81 (34.6%) cases, respectively. The likelihood of CTCAE grades 3-5 and MACE increased with the accumulation of organs affected by the ICI-associated adverse events and initial clinical symptoms. Concurrent systematic therapies during ICI treatment did not raise the risk of myocarditis severity, while prior chemotherapy did. Besides classical serum cardiac markers, a higher neutrophil ratio was also related to poorer cardiac outcomes, whereas higher lymphocyte and monocyte ratios were predictors of favorable cardiac outcomes. The CD4+ T cell ratio and CD4/CD8 ratio were negatively related to CTCAE grades 3-5. Several cardiovascular magnetic resonance parameters were associated with myocarditis severity, whereas the predictive value of echocardiography and electrocardiogram was weak.

CONCLUSION

This study comprehensively evaluated the prognostic value of patients' clinical characteristics and examination results and identified several predictors of severe ICI-associated myocarditis, which will facilitate early detection of severe ICI-associated myocarditis in patients receiving immunotherapy.

Arrhythmogenic Mitral Valve Prolapse and Sudden Cardiac Death: An Update and Current Perspectives

Mitral valve prolapse (MVP) affects about 2% to 3% of the general population, mostly women, and is the most common cause of primary chronic mitral regurgitation (MR) in western countries. The natural history is heterogeneous and widely determined by the severity of MR. Although most patients remain asymptomatic with a near-normal life expectancy, approximately 5% to 10 % progress to severe MR. As largely recognized, left ventricular (LV) dysfunction due to chronic volume overload per se identifies a subgroup at risk of cardiac death. However, there is rising evidence of a link between MVP and life threating ventricular arrhythmias (VAs)/sudden cardiac death (SCD) in a small subset of middle-aged patients without significant MR, heart failure and remodeled hearts. The present review focuses on the underlying mechanism of electric instability and unexpected cardiac death in this subset of young patients, from the myocardial scarring of the LV infero-lateral wall due to mechanical stretch exerted by the prolapsing leaflets and mitral annular disjunction, to the inflammation's impact on fibrosis pathways along with a constitutional hyperadrenergic state. The heterogeneity of clinical course reveals a necessity of risk stratification, preferably through noninvasive multimodality imaging, that will help to identify and prevent adverse scenarios in young MVP patients.

Sudden Cardiac Death in Young Individuals: A Current Review of Evaluation, Screening and Prevention

Sudden cardiac death (SCD) can affect all age groups, including young persons. While less common in the age < 35 population, the occurrence of SCD in the young raises concern, with multiple possible etiologies and often unanswered questions. While coronary artery disease is the leading cause in those > 35 years of age, the younger population faces a different subset of pathologies associated with SCD, including arrhythmias and cardiomyopathies. The tragic nature of SCD in the young entails that we explore and implement available screening methods for this population, and perform the necessary investigations such as electrocardiography (ECG) and echocardiography. In this review, we not only explore the vast etiology associated with SCD in those age < 35, but emphasize evaluation methods, who is at risk, and delve into screening of SCD in potential victims and their family members, in an attempt to prevent this traumatic event. Future research must work towards establishing preventative measures in order to reduce SCD, particularly unexplained SCD in the young.

The prognostic value of global myocardium strain by CMR-feature tracking in immune checkpoint inhibitor-associated myocarditis

OBJECTIVES

Immune checkpoint inhibitor (ICI)-associated myocarditis is a potentially fatal complication. Sparse published researches evaluated the prognostic value of cardiovascular magnetic resonance feature tracking (CMR-FT) for ICI-associated myocarditis.

METHODS

In the single-center retrospective study, 52 patients with ICI-associated myocarditis and CMR were included from August 2018 to July 2021. The ICI-associated myocarditis was diagnosed by using the clinical criteria of the European Society of Cardiology guidelines. Major adverse cardiovascular events (MACE) were comprised of cardiovascular death, cardiogenic shock, cardiac arrest, and complete heart block.

RESULTS

During a median follow-up of 171 days, 14 (27%) patients developed MACE. For patients with MACE, the global circumferential strain (GCS), global radial strain (GRS), global longitudinal strain (GLS), and left ventricular ejection fraction (LVEF) were significantly worse and native T1 values and late gadolinium enhancement (LGE) extent were significantly increased, compared with patients without MACE (p < 0.05). The GLS remained the independent factor associated with a higher risk of MACE (hazard ratio (HR): 2.115; 95% confidence interval (CI): 1.379-3.246; p = 0.001) when adjusting for LVEF, LGE extent, age, sex, body mass index, steroid treatment, and prior cardiotoxic chemotherapy or radiation. After adjustment for LVEF, the GLS remained the independent risk factor associated with a higher rate of MACE among patients with a preserved LVEF (HR: 1.358; 95% CI: 1.007-1.830; p = 0.045).

CONCLUSIONS

GLS could provide independent prognostic value over GCS, GRS, traditional CMR features, and clinical features in patients with ICI-associated myocarditis.

KEY POINTS

• The global circumferential strain (GCS), global radial strain (GRS), and global longitudinal strain (GLS) by cardiovascular magnetic resonance feature tracking were significantly impaired in patients with an immune checkpoint inhibitor (ICI)-associated myocarditis. • GLS was still significantly impaired in patients with preserved left ventricular ejection fraction. • The worse GLS was an independent risk factor over GCS, GRS, traditional CMR features, and clinical features for predicting major adverse cardiovascular events in patients with ICI-associated myocarditis.

The role of multimodality imaging in the selection for implantable cardioverter-defibrillators in heart failure: A narrative review

Advanced pharmacologic and interventional therapies have improved survival in heart failure. Implantable cardioverter-defibrillators (ICD) have been shown to reduce mortality in patients with heart failure, but the benefit appears to be uneven in this population. We reviewed the evidence showing the benefit of ICD therapy in heart failure patients, the main issues arising from these studies, and the possible answers for a better risk stratification. In addition, we showed that multimodality imaging could improve patient selection for the implantation of ICDs, in both primary and secondary prevention, beyond the selection using only the left ventricular ejection fraction, by concentrating on arrhythmic substrate.

Cardiac Magnetic Resonance in the Evaluation of Patients With Frequent Premature Ventricular Complexes

BACKGROUND

The role of cardiac magnetic resonance (CMR) in the evaluation and management of patients with frequent premature ventricular complexes (PVCs) of unknown etiology remains unclear.

OBJECTIVES

This study evaluated the prevalence and prognostic significance of myocardial abnormalities detected with CMR among patients with frequent PVCs and no known structural heart disease.

METHODS

This prospective cohort study included consecutive patients with frequent PVCs and a negative initial diagnostic work-up who underwent CMR with late gadolinium enhancement imaging. The clinical outcome was a composite of mortality, ventricular fibrillation, sustained ventricular tachycardia, or reduction in left ventricular ejection fraction of ≥10%.

RESULTS

A total of 255 patients were included, of whom 35 (13.7%) had evidence of myocardial abnormality on CMR. Age ≥60 years (odds ratio [OR]: 6.96; 95% CI: 1.30-37.18), multifocal PVCs (OR: 10.90; 95% CI: 3.21-36.97), and non-outflow tract left ventricular PVC origin (OR: 3.00; 95% CI: 1.00-8.95) were independently associated with the presence of a myocardial abnormality on CMR. After a median follow-up of 36 months, the composite outcome occurred in 15 (5.9%) patients. The presence of a myocardial abnormality on CMR was independently associated with the composite outcome (HR: 4.35; 95% CI: 1.34-14.15; P = 0.014).

CONCLUSIONS

One in 7 patients with frequent PVCs with no known structural heart disease had myocardial abnormality detected on CMR, and these abnormalities were associated with adverse clinical outcomes. These findings highlight the important role of CMR in the evaluation of patients with frequent PVCs.

State-of-the-Art Multimodality Imaging in Sudden Cardiac Arrest with Focus on Idiopathic Ventricular Fibrillation: A Review

Idiopathic ventricular fibrillation is a rare cause of sudden cardiac arrest and a diagnosis by exclusion. Unraveling the mechanism of ventricular fibrillation is important for targeted management, and potentially for initiating family screening. Sudden cardiac arrest survivors undergo extensive clinical testing, with a growing role for multimodality imaging, before diagnosing "idiopathic" ventricular fibrillation. Multimodality imaging, considered as using multiple imaging modalities as diagnostics, is important for revealing structural myocardial abnormalities in patients with cardiac arrest. This review focuses on combining imaging modalities (echocardiography, cardiac magnetic resonance and computed tomography) and the electrocardiographic characterization of sudden cardiac arrest survivors and discusses the surplus value of multimodality imaging in the diagnostic routing of these patients. We focus on novel insights obtained through electrostructural and/or electromechanical imaging in apparently idiopathic ventricular fibrillation patients, with special attention to non-invasive electrocardiographic imaging.

Entropy as a Measure of Myocardial Tissue Heterogeneity in Patients With Ventricular Arrhythmias

OBJECTIVES

The authors investigated the incremental prognostic value of entropy, a novel measure of myocardial tissue heterogeneity by cardiac magnetic resonance (CMR) imaging in patients presenting with ventricular arrhythmias (VAs).

BACKGROUND

CMR can characterize myocardial areas serving as arrhythmogenic substrate.

METHODS

Consecutive patients undergoing CMR imaging for VAs were followed for major adverse cardiac events (MACEs) defined by all-cause death, incident VAs requiring therapy, or heart failure hospitalization. Entropy was derived from the probability distribution of pixel signal intensities of the left ventricular (LV) myocardium.

RESULTS

A total of 583 patients (age 54 ± 15 years, female 39%, left ventricular ejection fraction [LVEF] 54 ± 13%) were followed for a median of 4.4 years and experienced 141 MACEs. Entropy showed strong unadjusted association with MACE (HR: 1.88; 95% CI: 1.63-2.17; P < 0.001). In a multivariable model including LVEF, QRS duration, late gadolinium enhancement, and presenting arrhythmia, entropy maintained independent association with MACE (HR: 1.61; 95% CI: 1.32-1.96; P < 0.001). Entropy was further significantly associated with MACE in patients without myocardial scar (HR: 2.43; 95% CI: 1.55-3.82; P < 0.001) and in those presenting with nonsustained VAs (HR: 2.16; 95% CI: 1.43-3.25; P < 0.001). Addition of LV entropy to the baseline multivariable model significantly improved model performance (C-statistic improvement: 0.725 to 0.754; P = 0.003) and risk reclassification.

CONCLUSIONS

In patients with VAs, CMR-assessed LV entropy was independently associated with MACE and provided incremental prognostic value, on top of LVEF and late gadolinium enhancement. LV entropy assessment may help risk stratification in patients with absence of myocardial scar or with nonsustained VAs.

Malignant Mitral Valve Prolapse: Risk and Prevention of Sudden Cardiac Death

Purpose of review

The purpose of this review is to explore the prevalence and risk factors for a malignant phenotype in mitral valve prolapse (MVP) characterized by life-threatening ventricular arrhythmias and sudden cardiac arrest and death (SCD), including mechanistic and pathophysiologic findings and mechanism-based potential therapies.

Recent findings

A malignant phenotype in MVP characterized by life-threatening arrhythmias has long been recognized, although MVP is often benign. Efforts to identify this malignant phenotype have revealed potential risk factors for SCD that include elongated, myxomatous leaflets, ECG changes and complex ventricular ectopy. More recently, malignant MVP has been associated with myocardial fibrosis in the papillary muscles and inferobasal left ventricular wall. This localization suggests a central role of prolapse-induced mechanical forces on the myocardium in creating an arrhythmogenic substrate and triggering life-threatening arrhythmias. This mechanism for fibrosis is also consistent with imaging evidence of prolapse-induced mechanical changes in the papillary muscles and inferobasal left ventricular wall. Currently, no therapy to prevent SCD in malignant MVP has been established and limited clinical data are available. Mechanistic information and prospective study have the potential to identify patients at risk of SCD and preventive strategies.

Summary

Malignant MVP relates to unique properties and mechanical abnormalities in the mitral valve apparatus and adjacent myocardium. Increased understanding of disease mechanisms and determinants of arrhythmias is needed to establish effective therapies.

Role of Cardiac Magnetic Resonance Imaging in the Evaluation of Athletes with Premature Ventricular Beats

Premature ventricular beats (PVBs) in athletes are not rare. The risk of PVBs depends on the presence of an underlying pathological myocardial substrate predisposing the subject to sudden cardiac death. The standard diagnostic work-up of athletes with PVBs includes an examination of family and personal history, resting electrocardiogram (ECG), 24 h ambulatory ECG (possibly with a 12-lead configuration and including a training session), maximal exercise testing and echocardiography. Despite its fundamental role in the diagnostic assessment of athletes with PVBs, echocardiography has very limited sensitivity in detecting the presence of non-ischemic left ventricular scars, which can be revealed only through more in-depth studies, particularly with the use of contrast-enhanced cardiac magnetic resonance (CMR) imaging. The morphology, complexity and exercise inducibility of PVBs can help estimate the probability of an underlying heart disease. Based on these features, CMR imaging may be indicated even when echocardiography is normal. This review focuses on interpreting PVBs, and on the indication and role of CMR imaging in the diagnostic evaluation of athletes, with a special focus on non-ischemic left ventricular scars that are an emerging substrate of cardiac arrest during sport.

Supraventricular Tachycardia Without Preexcitation as a Cause of Sudden Cardiac Arrest in Pediatric Patients

Sudden cardiac arrest in pediatric patients is a rare occurrence. Supraventricular tachycardia without the presence of ventricular preexcitation in pediatric patients with a structurally normal heart is generally considered benign. Previous literature in adults reported a subset of patients in whom SVT was suspected to be the primary trigger of sudden cardiac arrest. We performed a single-center, retrospective cohort study of pediatric patients without known heart disease, 1-21 years of age, presenting with aborted SCA between 2009 and 2019. We collected diagnostic studies in all patients to identify the etiology of the aborted SCA. Thirty patients met the inclusion criteria. The median age at the time of SCA was 15.2 years. The etiology of SCA was identified in 23 (77%) patients. Of the seven patients with unknown diagnosis after initial diagnostic studies, three patients subsequently developed fast SVT that was presumed to be the etiology of the initial SCA. These three patients had varying diagnoses of atrioventricular nodal reentry tachycardia, ectopic atrial tachycardia, and a concealed accessory pathway with atrioventricular reentrant tachycardia. After ablation or medical treatment of the SVT substrate, no further tachyarrhythmias were observed. Pediatric patients presenting with an aborted SCA of unknown etiology ought to be considered for electrophysiology testing to elicit occult SVT substrates that may lead to a malignant ventricular tachyarrhythmia.

Layer-Specific Global Longitudinal Strain Predicts Arrhythmic Risk in Arrhythmogenic Cardiomyopathy

Background: Arrhythmogenic cardiomyopathy (AC) is a life-threatening disease which predispose to malignant arrhythmias and sudden cardiac death (SCD) in the early stages of the disease. Risk stratification relies on the electrical, genetic, and imaging data. Our study aimed to investigate how myocardial deformation parameters may identify the subjects at risk of known predictors of major ventricular arrhythmias.

Methods: A cohort of 45 subjects with definite or borderline diagnosis of AC was characterized using the advanced transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) and divided into the groups according to the potential arrhythmic risk markers, such as non-sustained ventricular tachycardia (NSVT), late gadolinium enhancement (LGE), and genetic status. Layer-specific global longitudinal strain (GLS) by TTE 2D speckle tracking was compared in patients with and without these arrhythmic risk markers.

Results: In this study, 23 (51.1%) patients were men with mean age of 43 ± 16 years. Next-generation sequencing identified a potential pathogenic mutation in 39 (86.7%) patients. Thirty-nine patients presented LGE (73.3%), mostly located at the subepicardial-to-mesocardial layers. A layer-specific-GLS analysis showed worse GLS values at the epicardial and mesocardial layers in the subjects with NSVT and LGE. The epicardial GLS values of −15.4 and −16.1% were the best cut-off values for identifying the individuals with NSVT and LGE, respectively, regardless of left ventricular ejection fraction (LVEF).

Conclusions: The layer-specific GLS assessment identified the subjects with high-risk arrhythmic features in AC, such as NSVT and LGE. An epicardial GLS may emerge as a potential instrument for detecting the subjects at risk of SCD in AC.

Usefulness of cardiac magnetic resonance images for prediction of sudden cardiac arrest in patients with mitral valve prolapse: a multicenter retrospective cohort study

Background

An association has been identified between mitral valve prolapse (MVP) and sudden cardiac arrest (SCA), and ventricular arrhythmias (VA). This study aimed to elucidate predictive factors for SCA or VA in MVP patients.

Methods

MVP patients who underwent cardiac magnetic resonance (CMR) were retrospectively included. Patients with other structural heart disease or causes of aborted SCA were excluded. Clinical characteristics (sex, age, body mass index, histories of diabetes, hypertension, and dyslipidemia) and electrocardiographic (PR interval, QRS duration, corrected QT interval, inverted T wave in the inferior leads, bundle branch block, and atrial fibrillation), echocardiographic [mitral regurgitation grade, prolapsing mitral leaflet, and right ventricular systolic pressure (RVSP)], and CMR [left atrial volume index, both ventricular ejection fractions, both ventricular end-diastolic and systolic volume indexes, prolapse distance, mitral annular disjunction, systolic curling motion, presence of late gadolinium enhancement (LGE), LGE volume and proportion] parameters were analyzed.

Results

Of the 85 patients [age, 54.0 (41.0–65.0) years; 46 men], seven experienced SCA or VA. Younger age and wide QRS complex were observed more often in the SCA/VA group than in the no-SCA/VA group. The SCA/VA group exhibited lower RVSP, more systolic curling motion and LGE, greater LGE volume, and higher LGE proportion. The presence of LGE [hazard ratio (HR), 19.8; 95% confidence interval (CI) 2.65–148.15; P = 0.004], LGE volume (HR 1.08; 95% CI 1.02–1.14; P = 0.006) and LGE proportion (HR 1.32; 95% CI 1.08–1.60; P = 0.006) were independently associated with higher risk of SCA or VA in MVP patients together with systolic curling motion in each model.

Conclusions

The presence of systolic curling motion, high LGE volume and proportion, and the presence of LGE on CMR were independent predictive factors for SCA or VA in MVP patients.

Prognostic Role of Myocardial Edema as Evidenced by Early Cardiac Magnetic Resonance in Survivors of Out-of-Hospital Cardiac Arrest: A Multicenter Study

Background Sudden cardiac arrest (SCA) may be caused by an acute and reversible myocardial injury, a chronic and irreversible myocardial damage, or a primary ventricular arrhythmia. Cardiac magnetic resonance imaging may identify myocardial edema (ME), which denotes acute and reversible myocardial damage. We evaluated the arrhythmic outcome of SCA survivors during follow-up and tested the prognostic role of ME. Methods and Results We included a consecutive series of 101 (71% men, median age 47 years) SCA survivors from 9 collaborative centers who underwent early (<1 month) cardiac magnetic resonance imaging and received an implantable cardioverter-defibrillator (ICD). On T2-weighted sequences, ME was found in 18 of 101 (18%) patients. According to cardiac magnetic resonance imaging findings, the arrhythmic SCA was ascribed to acute myocardial injury (either ischemic [n=10] or inflammatory [n=8]), to chronic structural heart diseases (ischemic heart disease [n=11], cardiomyopathy [n=20], or other [n=23]), or to primarily arrhythmic syndrome (n=29). During a follow-up of 47 months (28 to 67 months), 24 of 101 (24%) patients received an appropriate ICD intervention. ME was associated with a significantly higher survival free from both any ICD interventions (log-rank=0.04) and ICD shocks (log-rank=0.03) and remained an independent predictor of better arrhythmic outcome after adjustment for left ventricular ejection fraction and late gadolinium enhancement. The risk of appropriate ICD intervention was unrelated to the type of underlying heart disease. Conclusions ME on early cardiac magnetic resonance imaging, which denotes an acute and transient arrhythmogenic substrate, predicted a favorable long-term arrhythmic outcome of SCA survivors. These findings may have a substantial impact on future guidelines on the management of SCA survivors.

Long-term outcome of myocardial scarring and deformation with cardiovascular magnetic resonance in out of hospital cardiac arrest survivors

AIMS

Cardiovascular magnetic resonance (CMR) is increasingly recognized as a diagnostic and prognostic tool in out of hospital cardiac arrest (OHCA) survivors. After assessing CMR findings early after ventricular fibrillation (VF) OHCA, we sought to explore the long-term outcome of myocardial scarring and deformation.

METHODS AND RESULTS

We included 121 consecutive VF OHCA survivors (82% male, median 62 years) undergoing CMR within 2 weeks from cardiac arrest. Late gadolinium-enhancement (LGE) was quantified using the full width at half maximum method and tissue tracking analysis software was used to assess myocardial deformation. LGE was found in 71% of patients (median LGE mass 6.2% of the left ventricle, LV), mainly with an ischaemic pattern. Myocardial deformation was overall impaired and showed a significant correlation with LGE presence and extent (P < 0.001). A composite end-point of all-cause mortality and appropriate ICD discharge/anti-tachycardia pacing was met in 24% of patients. Patients meeting the end-point had significantly greater LGE extent (8.6% of LV myocardium vs. 4.1%, P = 0.02), while there was no difference with regards to myocardial deformation. Survival rate was significantly lower in patients with LGE (P = 0.05) and LGE mass >4.4% of the LV identified a group of patients at higher risk of adverse events (P = 0.005).

CONCLUSIONS

We found a high prevalence of LGE, early after OHCA, and an overall impaired myocardial deformation. On long-term follow-up both LGE presence and extent showed a significant association with recurrent adverse events, while LV ejection fraction and myocardial deformation did not identify patients with an unfavourable outcome.

Predictors of subclinical systemic sclerosis primary heart involvement characterised by microvasculopathy and myocardial fibrosis

OBJECTIVES

SSc primary heart involvement (SSc-pHI) is a significant cause of mortality. We aimed to characterize and identify predictors of subclinical SSc-pHI using cardiovascular MRI.

METHODS

A total of 83 SSc patients with no history of cardiovascular disease or pulmonary arterial hypertension and 44 healthy controls (HCs) underwent 3 Tesla contrast-enhanced cardiovascular MRI, including T1 mapping and quantitative stress perfusion. High-sensitivity troponin I and N-terminal pro-brain natriuretic peptide were also measured.

RESULTS

Cardiovascular MRI revealed a lower myocardial perfusion reserve in the SSc patients compared with HCs {median (interquartile range (IQR)] 1.9 (1.6-2.4) vs 3 (2-3.6), P < 0.001}. Late gadolinium enhancement, indicating focal fibrosis, was observed in 17/83 patients but in none of the HCs, with significantly higher extracellular volume (ECV), suggestive of diffuse fibrosis, in SSc vs HC [mean (s.d.) 31 (4) vs 25 (2), P < 0.001]. Presence of late gadolinium enhancement and higher ECV was associated with skin score [odds ratio (OR) = 1.115, P = 0.048; R2 = 0.353, P = 0.004], and ECV and myocardial perfusion reserve was associated with the presence of digital ulcers at multivariate analysis (R2 = 0.353, P < 0.001; R2 = 0.238, P = 0.011). High-sensitivity troponin I was significantly higher in patients with late gadolinium enhancement, and N-terminal pro-brain natriuretic peptide was associated with ECV (P < 0.05).

CONCLUSION

Subclinical SSc-pHI is characterized by myocardial microvasculopathy, diffuse and focal myocardial fibrosis but preserved myocardial contractile function. This subclinical phenotype of SSc-pHI was associated with high-sensitivity troponin I, N-terminal pro-brain natriuretic peptide, SSc disease severity and complicated peripheral vasculopathy. These data provide information regarding the underlying pathophysiological processes and provide a basis for identifying individuals at risk of SSc-pHI.

CMR-Based Risk Stratification of Sudden Cardiac Death and Use of Implantable Cardioverter-Defibrillator in Non-Ischemic Cardiomyopathy

Non-ischemic cardiomyopathy (NICM) is one of the most important entities for arrhythmias and sudden cardiac death (SCD). Previous studies suggest a lower benefit of implantable cardioverter–defibrillator (ICD) therapy in patients with NICM as compared to ischemic cardiomyopathy (ICM). Nevertheless, current guidelines do not differentiate between the two subgroups in recommending ICD implantation. Hence, risk stratification is required to determine the subgroup of patients with NICM who will likely benefit from ICD therapy. Various predictors have been proposed, among others genetic mutations, left-ventricular ejection fraction (LVEF), left-ventricular end-diastolic volume (LVEDD), and T-wave alternans (TWA). In addition to these parameters, cardiovascular magnetic resonance imaging (CMR) has the potential to further improve risk stratification. CMR allows the comprehensive analysis of cardiac function and myocardial tissue composition. A range of CMR parameters have been associated with SCD. Applicable examples include late gadolinium enhancement (LGE), T1 relaxation times, and myocardial strain. This review evaluates the epidemiological aspects of SCD in NICM, the role of CMR for risk stratification, and resulting indications for ICD implantation.

Electrocardiographic features of immune checkpoint inhibitor associated myocarditis

BACKGROUND

Myocarditis is a highly morbid complication of immune checkpoint inhibitor (ICI) use that remains inadequately characterized. The QRS duration and the QTc interval are standardized electrocardiographic measures that are prolonged in other cardiac conditions; however, there are no data on their utility in ICI myocarditis.

METHODS

From an international registry, ECG parameters were compared between 140 myocarditis cases and 179 controls across multiple time points (pre-ICI, on ICI prior to myocarditis, and at the time of myocarditis). The association between ECG values and major adverse cardiac events (MACE) was also tested.

RESULTS

Both the QRS duration and QTc interval were similar between cases and controls prior to myocarditis. When compared with controls on an ICI (93±19 ms) or to baseline prior to myocarditis (97±19 ms), the QRS duration prolonged with myocarditis (110±22 ms, p<0.001 and p=0.009, respectively). In contrast, the QTc interval at the time of myocarditis (435±39 ms) was not increased compared with pre-myocarditis baseline (422±27 ms, p=0.42). A prolonged QRS duration conferred an increased risk of subsequent MACE (HR 3.28, 95% CI 1.98 to 5.62, p<0.001). After adjustment, each 10 ms increase in the QRS duration conferred a 1.3-fold increase in the odds of MACE (95% CI 1.07 to 1.61, p=0.011). Conversely, there was no association between the QTc interval and MACE among men (HR 1.33, 95% CI 0.70 to 2.53, p=0.38) or women (HR 1.48, 95% CI 0.61 to 3.58, p=0.39).

CONCLUSIONS

The QRS duration is increased in ICI myocarditis and is associated with increased MACE risk. Use of this widely available ECG parameter may aid in ICI myocarditis diagnosis and risk-stratification.

Myocardial T1 and T2 Mapping by Magnetic Resonance in Patients With Immune Checkpoint Inhibitor-Associated Myocarditis

BACKGROUND

Myocarditis is a potentially fatal complication of immune checkpoint inhibitor (ICI) therapy. Data on the utility of cardiovascular magnetic resonance (CMR) T1 and T2 mapping in ICI myocarditis are limited.

OBJECTIVES

This study sought to assess the value of CMR T1 and T2 mapping in patients with ICI myocarditis.

METHODS

In this retrospective study from an international registry of patients with ICI myocarditis, clinical and CMR findings (including T1 and T2 maps) were collected. Abnormal T1 and T2 were defined as 2 SD above site (vendor/field strength specific) reference values and a z-score was calculated for each patient. Major adverse cardiovascular events (MACE) were a composite of cardiovascular death, cardiogenic shock, cardiac arrest, and complete heart block.

RESULTS

Of 136 patients with ICI myocarditis with a CMR, 86 (63%) had T1 maps and 79 (58%) also had T2 maps. Among the 86 patients (66.3 ± 13.1 years of age), 36 (41.9%) had a left ventricular ejection fraction <55%. Across all patients, mean z-scores for T1 and T2 values were 2.9 ± 1.9 (p < 0.001) and 2.2 ± 2.1 (p < 0.001), respectively. On Siemens 1.5-T scanner (n = 67), native T1 (1,079.0 ± 55.5 ms vs. 1,000.3 ± 22.1 ms; p < 0.001) and T2 (56.2 ± 4.9 ms vs. 49.8 ± 2.2 ms; p < 0.001) values were elevated compared with reference values. Abnormal T1 and T2 values were seen in 78% and 43% of the patients, respectively. Applying the modified Lake Louise Criteria, 95% met the nonischemic myocardial injury criteria and 53% met the myocardial edema criteria. Native T1 values had excellent discriminatory value for subsequent MACE, with an area under the curve of 0.91 (95% confidence interval: 0.84 to 0.98). Native T1 values (for every 1-unit increase in z-score, hazard ratio: 1.44; 95% confidence interval: 1.12 to 1.84; p = 0.004) but not T2 values were independently associated with subsequent MACE.

CONCLUSIONS

The use of T1 mapping and application of the modified Lake Louise Criteria provides important diagnostic value, and T1 mapping provides prognostic value in patients with ICI myocarditis.

Cardiac Magnetic Resonance Imaging for Nonischemic Cardiac Disease in Out-of-Hospital Cardiac Arrest Survivors Treated with Targeted Temperature Management: A Multicenter Retrospective Analysis

(1) Background: Cardiac magnetic resonance (CMR) imaging is an emerging tool for investigating nonischemic cardiomyopathies and cardiac systemic disease. However, data on the cardiac arrest population are limited. This study aimed to evaluate the usefulness of CMR imaging in out-of-hospital cardiac arrest (OHCA) survivors treated with targeted temperature management (TTM). (2) Methods: We conducted the retrospective observational study using a multicenter registry of adult non-traumatic comatose OHCA survivors who underwent TTM between January 2010 and December 2019. Of the 949 patients, 389 with OHCA of non-cardiac cause, 145 with significant lesions in the coronary artery, 151 who died during TTM, 81 without further evaluation due to anticipated poor neurological outcome, and 51 whose etiology is underlying disease were excluded. In 36 of the 132 remaining patients, the etiologies included variant angina, long QT syndrome, and complete atrioventricular block in ancillary studies. Fifty-six patients were diagnosed idiopathic ventricular fibrillation without CMR. (3) Results: CMR imaging was performed in the remaining 40 patients with cardiac arrest of unknown cause. The median time from cardiac arrest to CMR imaging was 10.1 days. The CMR finding was normal in 23 patients, non-diagnostic in 12, and abnormal in 5, which suggested non-ischemic cardiomyopathy but did not support the final diagnosis. (4) Conclusions: CMR imaging may not be useful for identifying unknown causes of cardiac arrest in OHCA survivors treated with targeted temperature management without definitive diagnosis even after coronary angiography, echocardiography, and electrophysiology studies. However, further large-scale studies will be needed to confirm these findings.

Secondary Prevention of Potentially Life-Threatening Arrhythmia Using Implantable Cardioverter Defibrillators in Patients with Biopsy-Proven Viral Myocarditis and Preserved Ejection Fraction

BACKGROUND

Arrhythmia and sudden cardiac death (SCD) are known complications of acute viral myocarditis, regardless of ejection fraction (EF) at presentation. Whether such complications confer long-term risk is unknown, especially in those who present with preserved left ventricular (LV) function. No guidelines exist to the long-term reduction of arrhythmic death in such patients.

METHOD

In this retrospective study, we analyzed the long-term results of implantable cardioverter defibrillator (ICD) treatment in patients after an acute phase of myocarditis with life-threatening arrhythmia.

RESULTS

We identified 51 patients who had ICDs implanted following life-threatening arrhythmia presentation of confirmed acute viral myocarditis, despite preserved LVEF. Overall, 72.5% of patients had a clinical history of chest pain and viral infection with fever. Viral myocarditis was confirmed by cardiac magnetic resonance imaging (all had late enhancement) plus endomyocardial biopsies (most frequent were Epstein-Barr virus 29.4%, adenovirus 17.6%, and Coxsackie 17.6%), and 88.2% were discharged on anti-arrhythmic drugs. Overall, 12 patients (23.5%) required ICD intervention within the first 3 months, a further 7 patients (37.3% overall) between 3 and 12 months, and a further 12 patients (60.8% overall) until 58 months. During the follow-up, 3 of 51 patients (5.9%) died-deaths were due to cardiac events (n = 1), fatal infection (n = 1), and car accidents (n = 1). Of the 31 patients who had ventricular tachycardias after the acute phase of myocarditis, 11 needed radiofrequency ablation due to a high number of events or electrical storm. No baseline variables were identified that would serve as a basis for risk stratification.

CONCLUSION

Malignant arrhythmic events due to viral myocarditis are potential predictors of future SCD in patients not only with a reduced but also with a preserved EF.

Prognostic Value of Nonischemic Ringlike Left Ventricular Scar in Patients With Apparently Idiopathic Nonsustained Ventricular Arrhythmias

BACKGROUND

Left ventricular (LV) scar on late gadolinium enhancement (LGE) cardiac magnetic resonance has been correlated with life-threatening arrhythmic events in patients with apparently idiopathic ventricular arrhythmias (VAs). We investigated the prognostic significance of a specific LV-LGE phenotype characterized by a ringlike pattern of fibrosis.

METHODS

A total of 686 patients with apparently idiopathic nonsustained VA underwent contrast-enhanced cardiac magnetic resonance. A ringlike pattern of LV scar was defined as LV subepicardial/midmyocardial LGE involving at least 3 contiguous segments in the same short-axis slice. The end point of the study was time to the composite outcome of all-cause death, resuscitated cardiac arrest because of ventricular fibrillation or hemodynamically unstable ventricular tachycardia and appropriate implantable cardioverter defibrillator therapy.

RESULTS

A total of 28 patients (4%) had a ringlike pattern of scar (group A), 78 (11%) had a non-ringlike pattern (group B), and 580 (85%) had normal cardiac magnetic resonance with no LGE (group C). Group A patients were younger compared with groups B and C (median age, 40 vs 52 vs 45 years; P<0.01), more frequently men (96% vs 82% vs 55%; P<0.01), with a higher prevalence of family history of sudden cardiac death or cardiomyopathy (39% vs 14% vs 6%; P<0.01) and more frequent history of unexplained syncope (18% vs 9% vs 3%; P<0.01). All patients in group A showed VA with a right bundle-branch block morphology versus 69% in group B and 21% in group C (P<0.01). Multifocal VAs were observed in 46% of group A patients compared with 26% of group B and 4% of group C (P<0.01). After a median follow-up of 61 months (range, 34-84 months), the composite outcome occurred in 14 patients (50.0%) in group A versus 15 (19.0%) in group B and 2 (0.3%) in group C (P<0.01). After multivariable adjustment, the presence of LGE with ringlike pattern remained independently associated with increased risk of the composite end point (hazard ratio, 68.98 [95% CI, 14.67-324.39], P<0.01).

CONCLUSIONS

In patients with apparently idiopathic nonsustained VA, nonischemic LV scar with a ringlike pattern is associated with malignant arrhythmic events.

The Extent of Late Gadolinium Enhancement Can Predict Adverse Cardiac Outcomes in Patients with Non-Ischemic Cardiomyopathy with Reduced Left Ventricular Ejection Fraction: A Prospective Observational Study

OBJECTIVE

The clinical course of an individual patient with heart failure is unpredictable with left ventricle ejection fraction (LVEF) only. We aimed to evaluate the prognostic value of cardiac magnetic resonance (CMR)-derived myocardial fibrosis extent and to determine the cutoff value for event-free survival in patients with non-ischemic cardiomyopathy (NICM) who had severely reduced LVEF.

MATERIALS AND METHODS

Our prospective cohort study included 78 NICM patients with significantly reduced LV systolic function (LVEF < 35%). CMR images were analyzed for the presence and extent of late gadolinium enhancement (LGE). The primary outcome was major adverse cardiac events (MACEs), defined as a composite of cardiac death, heart transplantation, implantable cardioverter-defibrillator discharge for major arrhythmia, and hospitalization for congestive heart failure within 5 years after enrollment.

RESULTS

A total of 80.8% (n = 63) of enrolled patients had LGE, with the median LVEF of 25.4% (19.8-32.4%). The extent of myocardial scarring was significantly higher in patients who experienced MACE than in those without any cardiac events (22.0 [5.5-46.1] %LV vs. 6.7 [0-17.1] %LV, respectively, p = 0.008). During follow-up, 51.4% of patients with LGE ≥ 12.0 %LV experienced MACE, along with 20.9% of those with LGE ≤ 12.0 %LV (log-rank p = 0.001). According to multivariate analysis, LGE extent more than 12.0 %LV was independently associated with MACE (adjusted hazard ratio, 6.71; 95% confidence interval, 2.54-17.74; p < 0.001).

CONCLUSION

In NICM patients with significantly reduced LV systolic function, the extent of LGE is a strong predictor for long-term adverse cardiac outcomes. Event-free survival was well discriminated with an LGE cutoff value of 12.0 %LV in these patients.

Secondary prevention of sudden cardiac death

The prevention and treatment of sudden cardiac death (SCD) remains a significant public health challenge. For patients with a history of sudden death attributable to ventricular arrhythmia, implantable cardioverter-defibrillator (ICD) therapy is a mainstay of treatment, although these patients remain at high risk for recurrent ventricular arrhythmia and defibrillator therapies. In this review, we summarize landmark clinical trials evaluating the efficacy of ICD therapy in secondary prevention patients, review clinical outcomes including mode of death in survivors of SCD, and highlight the role for systematic diagnostic evaluation. We additionally discuss the invasive electrophysiological management of these patients, including ICD selection and programming as well as the role and timing of antiarrhythmic drug therapy and catheter ablation. Finally, we frame future challenges and needs to advance the care for secondary prevention patients.

Idiopathic Ventricular Fibrillation: Role of Purkinje System and Microstructural Myocardial Abnormalities

Idiopathic ventricular fibrillation is diagnosed in patients who survived a ventricular fibrillation episode without any identifiable structural or electrical cause after extensive investigations. It is a common cause of sudden death in young adults. The study reviews the diagnostic value of systematic investigations and the new insights provided by detailed electrophysiological mapping. Recent studies have shown the high incidence of microstructural cardiomyopathic areas, which act as the substrate of ventricular fibrillation re-entries. These subclinical alterations require high-density endo- and epicardial mapping to be identified using electrogram criteria. Small areas are involved and located individually in various sites (mostly epicardial). Their characteristics suggest a variety of genetic or acquired pathological processes affecting cellular connectivity or tissue structure, such as cardiomyopathies, myocarditis, or fatty infiltration. Purkinje abnormalities manifesting as triggering ectopy or providing a substrate for re-entry represent a second important cause. The documentation of ephemeral Purkinje ectopy requires continuous electrocardiography monitoring for diagnosis. A variety of diseases affecting Purkinje cell function or conduction are potentially at play in their pathogenesis. Comprehensive investigations can therefore allow the great majority of idiopathic ventricular fibrillation to ultimately receive diagnoses of a cardiac disease, likely underlain by a mosaic of pathologies. Precise phenotypic characterization has significant implications for interpretation of genetic variants, the risk assessment, and individual therapy. Future improvements in imaging or electrophysiological methods may hopefully allow the identification of the subjects at risk and the development of primary prevention strategies.

68Ga-DOTA chelate, a novel imaging agent for assessment of myocardial perfusion and infarction detection in a rodent model

BACKGROUND

Magnetic resonance imaging (MRI) with Gadolinium 1,4,7,10-tetraazacyclododecane-N',N″,N''',N″″-tetraacetic acid (Gd-DOTA) enables assessment of myocardial perfusion during first-pass of the contrast agent, while increased retention can signify areas of myocardial infarction (MI). We studied whether Gallium-68-labeled analog, 68Ga-DOTA, can be used to assess myocardial perfusion on positron emission tomography/computed tomography (PET/CT) in rats, comparing it with 11C-acetate.

METHODS

Rats were studied with 11C-acetate and 68Ga-DOTA at 24 hours after permanent ligation of the left coronary artery or sham operation. One-tissue compartmental models were used to estimate myocardial perfusion in normal and infarcted myocardium. After the PET scan, hearts were sectioned for autoradiographic detection of 68Ga-DOTA distribution.

RESULTS

11C-acetate PET showed perfusion defects and histology showed myocardial necrosis in all animals after coronary ligation. Kinetic modeling of 68Ga-DOTA showed significantly higher k1 values in normal myocardium than in infarcted areas. There was a significant correlation (r = 0.82, P = 0.001) between k1 values obtained with 68Ga-DOTA and 11C-acetate. After 10 minutes of tracer distribution, the 68Ga-DOTA concentration was significantly higher in the infarcted than normal myocardium on PET imaging and autoradiography.

CONCLUSIONS

Our results indicate that acute MI can be detected as reduced perfusion, as well as increased late retention of 68Ga-DOTA.

Concealed structural heart disease discovered at cardiac magnetic resonance in patients with ventricular extrasystoles from ventricular outflow tract and apparently normal hearts

BACKGROUND

Outflow tract (OT) premature ventricular contractions (PVCs) are commonly found in clinical practice; in most cases, PVCs are benign and observed in structurally normal hearts, not requiring any therapeutic intervention. In this study, we therefore sought to evaluate with cardiac magnetic resonance (CMR) patients with PVC and apparently normal heart at echocardiographic examination, in order to identify possible substrates linked with higher prevalence of arrhythmias or structural heart disease.

METHODS

Thirty-three consecutive patients with frequent PVCs originating from the ventricular OT (right and left) were enrolled in the study and assessed by echocardiography and CMR. All patients had normal baseline electrocardiogram.

RESULTS

CMR showed structural changes in 5 patients out of 33; in 3 cases, areas of fibrosis limited in one case to the middle basal segments of the interventricular septum and in two patients to the middle basal segments of the inferior-lateral wall were found. In 2 other cases, however, late gadolinium enhancement showed significant anomalies characterized in one patient by extensive areas of subepicardial fibrosis of the left ventricle, suitable with arrhythmogenic left dominant dysplasia; in another patient, a marked trabeculation of left ventricular medium apical segments suitable with non-compaction myocardium was present.

CONCLUSIONS

CMR may identify cases of structural heart disease in subjects with OT PVCs and apparently normal electrocardiogram and echocardiogram examinations. A preliminary screening with CMR may be considered before any further invasive electrophysiology assessment and therapeutic planning.

Cardiovascular magnetic resonance in immune checkpoint inhibitor-associated myocarditis

AIMS

Myocarditis is a potentially fatal complication of immune checkpoint inhibitors (ICI). Sparse data exist on the use of cardiovascular magnetic resonance (CMR) in ICI-associated myocarditis. In this study, the CMR characteristics and the association between CMR features and cardiovascular events among patients with ICI-associated myocarditis are presented.

METHODS AND RESULTS

From an international registry of patients with ICI-associated myocarditis, clinical, CMR, and histopathological findings were collected. Major adverse cardiovascular events (MACE) were a composite of cardiovascular death, cardiogenic shock, cardiac arrest, and complete heart block. In 103 patients diagnosed with ICI-associated myocarditis who had a CMR, the mean left ventricular ejection fraction (LVEF) was 50%, and 61% of patients had an LVEF ≥50%. Late gadolinium enhancement (LGE) was present in 48% overall, 55% of the reduced EF, and 43% of the preserved EF cohort. Elevated T2-weighted short tau inversion recovery (STIR) was present in 28% overall, 30% of the reduced EF, and 26% of the preserved EF cohort. The presence of LGE increased from 21.6%, when CMR was performed within 4 days of admission to 72.0% when CMR was performed on Day 4 of admission or later. Fifty-six patients had cardiac pathology. Late gadolinium enhancement was present in 35% of patients with pathological fibrosis and elevated T2-weighted STIR signal was present in 26% with a lymphocytic infiltration. Forty-one patients (40%) had MACE over a follow-up time of 5 months. The presence of LGE, LGE pattern, or elevated T2-weighted STIR were not associated with MACE.

CONCLUSION

These data suggest caution in reliance on LGE or a qualitative T2-STIR-only approach for the exclusion of ICI-associated myocarditis.

Heart Failure among People with HIV: Evolving Risks, Mechanisms, and Preventive Considerations

PURPOSE

People with HIV (PHIV) with access to modern antiretroviral therapy (ART) face a two-fold increased risk of heart failure as compared with non-HIV-infected individuals. The purpose of this review is to consider evolving risks, mechanisms, and preventive considerations pertaining to heart failure among PHIV.

RECENT FINDINGS

While unchecked HIV/AIDS has been documented to precipitate heart failure characterized by overtly reduced cardiac contractile function, ART-treated HIV may be associated with either heart failure with reduced ejection fraction (HFrEF) or with heart failure with preserved ejection fraction (HFpEF). In HFpEF, a "stiff" left ventricle cannot adequately relax in diastole-a condition known as diastolic dysfunction. Diastolic dysfunction, in turn, may result from processes including myocardial fibrosis (triggered by hypertension and/or immune activation/inflammation) and/or myocardial steatosis (triggered by metabolic dysregulation). Notably, hypertension, systemic immune activation, and metabolic dysregulation are all common conditions among even those PHIV who are well-treated with ART. Of clinical consequence, HFpEF is uniquely intransigent to conventional medical therapies and portends high morbidity and mortality. However, diastolic dysfunction is reversible-as are contributing processes of myocardial fibrosis and myocardial steatosis. Our challenges in preserving myocardial health among PHIV are two-fold. First, we must continue working to realize UNAIDS 90-90-90 goals. This achievement will reduce AIDS-related mortality, including cardiovascular deaths from AIDS-associated heart failure. Second, we must work to elucidate the detailed mechanisms continuing to predispose ART-treated PHIV to heart failure and particularly HFpEF. Such efforts will enable the development and implementation of targeted preventive strategies.

Estimating Myocardial Infarction Size With a Simple Electrocardiographic Marker Score

Background

Myocardial infarction (MI) size is a key predictor of prognosis in post‐MI patients. Cardiovascular magnetic resonance (CMR) is the gold standard test for MI quantification, but the ECG is less expensive and more widely available. We sought to quantify the relationship between ECG markers and cardiovascular magnetic resonance infarct size.

Methods and Results

Patients with prior MI enrolled in the DETERMINE (Defibrillators to Reduce Risk by Magnetic Resonance Imaging Evaluation) and PRE‐DETERMINE Trial and Registry were included. ECG leads were analyzed for markers of MI: Q waves, fragmented QRS, and T wave inversion. DETERMINE Score=number of leads with [Q waves×2]+[fragmented QRS]+[T wave inversion]. Left ventricular ejection fraction (LVEF) and infarct size as a percentage of left ventricular mass (MI%) were quantified by cardiovascular magnetic resonance. The Modified Selvester Score estimates MI size from 37 ECG criteria. In 551 patients (aged 62.1±10.9 years, 79% men, and LVEF=40.3±11.0%), MI% increased as the number of ECG markers increased (P<0.001). By univariable linear regression, the DETERMINE Score (range 0–26) estimated MI% (R²=0.18, P<0.001) with an accuracy approaching that of LVEF (R²=0.22, P<0.001) and higher than the Modified Selvester Score (R²=0.09, P<0.001). By multivariable linear regression, addition of the DETERMINE Score improved estimation of MI% over LVEF alone (P<0.001) and over Modified Selvester Score alone (P<0.001).

Conclusions

In patients with prior MI, a simple ECG score estimates infarct size and improves infarct size estimation over LVEF alone. Because infarct size is a powerful prognostic indicator, the DETERMINE Score holds promise as a simple and inexpensive risk assessment tool.

Diagnostic and prognostic role of electrocardiogram in acute myocarditis: A comprehensive review

Background

Acute myocarditis represents a challenging diagnosis as there is no pathognomonic clinical presentation. In patients with myocarditis, electrocardiogram (ECG) can display a variety of non‐specific abnormalities. Nevertheless, ECG is widely used as an initial screening tool for myocarditis.

Methods

We researched all possible ECG alterations during acute myocarditis evaluating prevalence, physiopathology, correlation with clinical presentation patterns, role in differential diagnosis, and prognostic yield.

Results

The most common ECG abnormality in myocarditis is sinus tachycardia associated with nonspecific ST/T‐wave changes. The presence of PR segment depression both in precordial and limb leads, a PR segment depression in leads with ST segment elevation, a PR segment elevation in aVR lead or a ST elevation with pericarditis pattern favor generally diagnosis of perimyocarditis rather than myocardial infarction. In patients with acute myocarditis, features associated with a poorer prognosis are: pathological Q wave, wide QRS complex, QRS/T angle ≥ 100°, prolonged QT interval, high‐degree atrioventricular block and malignant ventricular tachyarrhythmia. On the contrary, ST elevation with a typical early repolarization pattern is associated with a better prognosis.

Conclusions

ECG alterations in acute myocarditis could be very useful in clinical practice for a patient‐tailored approach in order to decide appropriate therapy, length of hospitalization, and frequency of followup.

Incidence, Predictors, and Outcomes of Implantable Cardioverter-Defibrillator Discharge Among People Living With HIV

Background

People living with HIV (PHIV) are at an increased risk for sudden cardiac death, and implantable cardioverter‐defibrillators (ICDs) prevent SCD. There are no data on the incidence, predictors, and effects of ICD therapies among PHIV.

Methods and Results

We compared ICD discharge rates between 59 PHIV and 267 uninfected controls. For PHIV, we tested the association of traditional cardiovascular risk factors and HIV‐specific parameters with an ICD discharge and then tested whether an ICD discharge among PHIV was associated with cardiovascular mortality or an admission for heart failure. The indication for ICD insertion was similar among groups. Compared with controls, PHIV with an ICD were more likely to have coronary artery disease and to use cocaine. In follow‐up, PHIV had a higher ICD discharge rate (39% versus 20%; P=0.001; median follow‐up period, 19 months). Among PHIV, cocaine use, coronary artery disease, QRS duration, and higher New York Heart Association class were associated with an ICD discharge. An ICD discharge had a prognostic effect, with a subsequent 1.7‐fold increase in heart failure admission and a 2‐fold increase in cardiovascular mortality, an effect consistent across racial/ethnic and sex categories.

Conclusions

ICD discharge rates are higher among PHIV compared with uninfected controls. Among PHIV, cocaine use and New York Heart Association class are associated with increased ICD discharge, and an ICD discharge is associated with a subsequent increase in admission for heart failure and cardiovascular mortality.

Sleep Apnea and Heart Failure With a Reduced Ejection Fraction Among Persons Living With Human Immunodeficiency Virus

Background

Sleep apnea (SA) is common and has prognostic significance among broad groups of patients with heart failure (HF). There are no data characterizing the presence, associations, and prognostic significance of SA among persons living with human immunodeficiency virus (PLHIV) with HF.

Methods

We conducted a single-center study of PLHIV with HF with reduced ejection fraction (HFrEF; left ventricular ejection fraction [LVEF] <50%) and analyzed the relationship of SA with 30-day HF hospital readmission rate.

Results

Our cohort included 1124 individuals admitted with HFrEF; 15% were PLHIV, and 92% were on antiretroviral therapy. SA was noted in 28% of PLHIV and 26% of uninfected controls. Compared to uninfected controls with HFrEF and SA, PLHIV with HFrEF and SA had a lower body mass index, lower LVEF, a higher pulmonary artery systolic pressure (PASP), were more likely to have obstructive rather than central SA (P < .05 for all). In a multivariable model, PASP, low CD4 count, high viral load (VL), and SA parameters (apnea-hypopnea index, CPAP use and duration) were predictors of 30-day HF readmission rate. Each 1-hour increase in CPAP use was associated with a 14% decreased risk of 30-day HF readmission among PLHIV.

Conclusions

Compared to uninfected controls, PLHIV were more likely to have obstructive SA than central SA. Apnea severity, low CD4 count, high VL, and cocaine use were positively associated with 30-day HF hospital readmission rate, whereas CPAP use and increased duration of CPAP use conferred protection.

Detection of concealed structural heart disease by imaging in patients with apparently idiopathic premature ventricular complexes: A review of current literature

Background

Premature ventricular complexes (PVCs) are the most common form of ventricular arrhythmia in the general population. While in most cases PVCs represent a primitive phenomenon with benign behavior, in a non‐negligible proportion of subjects frequent PVCs may be epiphenomenon of underlying occult heart diseases, requiring special medical attention since they have been resulted linked to increased total and cardiac mortality. Nevertheless, PVCs themselves, when incessantly frequent, may be responsible for left ventricular dysfunction in otherwise normal heart. Aim of this narrative review is to update current knowledge on the general approach to patients with frequent PVCs on the basis of available data, with a special focus on the value of imaging.

Hypothesis

Routine diagnostic work‐up not infrequently miss subtle concealed arrhythmic substrate, leading to erroneously refer to such arrhythmias as to “idiopathic”.

Methods

Literature search of PVCs articles was conducted in PubMed and Scopus electronic database.

Results

Conflicting data arise from literature about the true clinical significance of idiopathic PVCs. There is growing body of data providing evidence that more advanced non‐invasive imaging modalities, such as cardiac magnetic resonance, have an incremental diagnostic and prognostic value. On the other hand, in some cases the prognostic significance of isolated subtle myocardial structural abnormalities in patients with PVCs, still remains area of uncertainty.

Conclusion

In selected subjects with PVCs and high‐risk features for concealed arrhythmic substrate, traditional assessment to rule out the presence of heart disease, including surface ECG and transthoracic echocardiography, should be implemented with more advanced cardiovascular imaging modalities.