Left ventricular fibro-fatty replacement in arrhythmogenic right ventricular dysplasia/cardiomyopathy: prevalence, patterns, and association with arrhythmias

Multimodality imaging in arrhythmogenic cardiomyopathy - From diagnosis to management

Arrhythmogenic Cardiomyopathy (AC), an inherited cardiac disorder characterized by myocardial fibrofatty replacement, carries a significant risk of sudden cardiac death (SCD) due to ventricular arrhythmias. A comprehensive multimodality imaging approach, including echocardiography, cardiac magnetic resonance imaging (CMR), and cardiac computed tomography (CCT), allows for accurate diagnosis, effective risk stratification, vigilant monitoring, and appropriate intervention, leading to improved patient outcomes and the prevention of SCD. Echocardiography is primary tool ventricular morphology and function assessment, CMR provides detailed visualization, CCT is essential in early stages for excluding congenital anomalies and coronary artery disease. Echocardiography is preferred for follow-up, with CMR capturing changes over time. The strategic use of these imaging methods aids in confirming AC, differentiating it from other conditions, tracking its progression, managing complications, and addressing end-stage scenarios.

Imaging Features of Arrhythmogenic Cardiomyopathies

Arrhythmogenic cardiomyopathy (ACM) is a genetic disease characterized by replacement of ventricular myocardium with fibrofatty tissue, predisposing the patient to ventricular arrhythmias and/or sudden cardiac death. Most cases of ACM are associated with pathogenic variants in genes that encode desmosomal proteins, an important cell-to-cell adhesion complex present in both the heart and skin tissue. Although ACM was first described as a disease predominantly of the right ventricle, it is now acknowledged that it can also primarily involve the left ventricle or both ventricles. The original right-dominant phenotype is traditionally diagnosed using the 2010 task force criteria, a multifactorial algorithm divided into major and minor criteria consisting of structural criteria based on two-dimensional echocardiographic, cardiac MRI, or right ventricular angiographic findings; tissue characterization based on endomyocardial biopsy results; repolarization and depolarization abnormalities based on electrocardiographic findings; arrhythmic features; and family history. Shortfalls in the task force criteria due to the modern understanding of the disease have led to development of the Padua criteria, which include updated criteria for diagnosis of the right-dominant phenotype and new criteria for diagnosis of the left-predominant and biventricular phenotypes. In addition to incorporating cardiac MRI findings of ventricular dilatation, systolic dysfunction, and regional wall motion abnormalities, the new Padua criteria emphasize late gadolinium enhancement at cardiac MRI as a key feature in diagnosis and imaging-based tissue characterization. Conditions to consider in the differential diagnosis of the right-dominant phenotype include various other causes of right ventricular dilatation such as left-to-right shunts and variants of normal right ventricular anatomy that can be misinterpreted as abnormalities. The left-dominant phenotype can mimic myocarditis at imaging and clinical examination. Additional considerations for the differential diagnosis of ACM, particularly for the left-dominant phenotype, include sarcoidosis and dilated cardiomyopathy. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

3D Fractal Dimension Analysis: Prognostic Value of Right Ventricular Trabecular Complexity in Participants with Arrhythmogenic Cardiomyopathy

BACKGROUND

Arrhythmogenic cardiomyopathy (ACM) is characterized by progressive myocardial fibro-fatty infiltration accompanied by trabecular disarray. Traditionally, two-dimensional (2D) instead of 3D fractal dimension (FD) analysis has been used to evaluate trabecular disarray. However, the prognostic value of trabecular disorder assessed by 3D FD measurement remains unclear.

PURPOSE

To investigate the prognostic value of right ventricular trabecular complexity in ACM patients using 3D FD analysis based on cardiac MR cine images.

STUDY TYPE

Retrospective.

POPULATION

85 ACM patients (mean age: 45 ± 17 years, 52 male).

FIELD STRENGTH/SEQUENCE

3.0T/cine imaging, T2-short tau inversion recovery (T2-STIR), and late gadolinium enhancement (LGE).

ASSESSMENT

Using cine images, RV (right ventricular) volumetric and functional parameters were obtained. RV trabecular complexity was measured with 3D fractal analysis by box-counting method to calculate 3D-FD. Cox and logistic regression models were established to evaluate the prognostic value of 3D-FD for major adverse cardiac events (MACE).

STATISTICAL TESTS

Cox regression and logistic regression to explore the prognostic value of 3D-FD. C-index, time-dependent receiver operating characteristic (ROC) curves and area under the ROC curve (AUC) to evaluate the incremental value of 3D-FD. Intraclass correlation coefficient for interobserver variability. P < 0.05 indicated statistical significance.

RESULTS

26 MACE were recorded during the 60 month follow-up (interquartile range: 48-67 months). RV 3D-FD significantly differed between ACM patients with MACE (2.67, interquartile range: 2.51 ~ 2.81) and without (2.52, interquartile range: 2.40 ~ 2.67) and was a significant independent risk factor for MACE (hazard ratio, 1.02; 95% confidence interval: 1.01, 1.04). In addition, prognostic model fitness was significantly improved after adding 3D-FD to RV global longitudinal strain, LV involvement, and 5-year risk score separately.

DATA CONCLUSION

The myocardial trabecular complexity assessed through 3D FD analysis was found associated with MACE and provided incremental prognostic value beyond conventional ACM risk factors.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 1.

Proposed diagnostic criteria for arrhythmogenic cardiomyopathy: European Task Force consensus report

Arrhythmogenic cardiomyopathy (ACM) is a heart muscle disease characterized by prominent "non-ischemic" myocardial scarring predisposing to ventricular electrical instability. Diagnostic criteria for the original phenotype, arrhythmogenic right ventricular cardiomyopathy (ARVC), were first proposed in 1994 and revised in 2010 by an international Task Force (TF). A 2019 International Expert report appraised these previous criteria, finding good accuracy for diagnosis of ARVC but a lack of sensitivity for identification of the expanding phenotypic disease spectrum, which includes left-sided variants, i.e., biventricular (ABVC) and arrhythmogenic left ventricular cardiomyopathy (ALVC). The ARVC phenotype together with these left-sided variants are now more appropriately named ACM. The lack of diagnostic criteria for the left ventricular (LV) phenotype has resulted in clinical under-recognition of ACM patients over the 4 decades since the disease discovery. In 2020, the "Padua criteria" were proposed for both right- and left-sided ACM phenotypes. The presently proposed criteria represent a refinement of the 2020 Padua criteria and have been developed by an expert European TF to improve the diagnosis of ACM with upgraded and internationally recognized criteria. The growing recognition of the diagnostic role of CMR has led to the incorporation of myocardial tissue characterization findings for detection of myocardial scar using the late‑gadolinium enhancement (LGE) technique to more fully characterize right, biventricular and left disease variants, whether genetic or acquired (phenocopies), and to exclude other "non-scarring" myocardial disease. The "ring-like' pattern of myocardial LGE/scar is now a recognized diagnostic hallmark of ALVC. Additional diagnostic criteria regarding LV depolarization and repolarization ECG abnormalities and ventricular arrhythmias of LV origin are also provided. These proposed upgrading of diagnostic criteria represents a working framework to improve management of ACM patients.

Arrhythmogenic Cardiomyopathy: Definition, Classification and Arrhythmic Risk Stratification

Arrhythmogenic cardiomyopathy (ACM) is a heart disease characterized by a fibrotic replacement of myocardial tissue and a consequent predisposition to ventricular arrhythmic events, especially in the young. Post-mortem studies and the subsequent diffusion of cardiac MRI have shown that left ventricular involvement in arrhythmogenic cardiomyopathy is common and often develops early. Regarding the arrhythmic risk stratification, the current scores underestimate the arrhythmic risk of patients with arrhythmogenic cardiomyopathy with left involvement. Indeed, the data on arrhythmic risk stratification in this group of patients are contradictory and not exhaustive, with the consequence of not correctly identifying patients at a high arrhythmic risk who deserve protection from arrhythmic death. We propose a literature review on arrhythmic risk stratification in patients with ACM and left involvement to identify the main features associated with an increased arrhythmic risk in this group of patients.

Prognostic value of right ventricular trabecular complexity in patients with arrhythmogenic cardiomyopathy

OBJECTIVES

The present study aimed to investigate the incremental prognostic value of the right ventricular fractal dimension (FD), a novel marker of myocardial trabecular complexity by cardiac magnetic resonance (CMR) in patients with arrhythmogenic cardiomyopathy (ACM).

METHODS

Consecutive patients with ACM undergoing CMR were followed up for major cardiac events, including sudden cardiac death, aborted cardiac arrest, and appropriate implantable cardioverter defibrillator intervention. Prognosis prediction was compared by Cox regression analysis. We established a multivariable model supplemented with RV FD and evaluated its discrimination by Harrell's C-statistic. We compared the category-free, continuous net reclassification improvement (cNRI) and integrated discrimination index (IDI) before and after the addition of FD.

RESULTS

A total of 105 patients were prospectively included from three centers and followed up for a median of 60 (48, 66) months; experienced 36 major cardiac events were recorded. Trabecular FD displayed a strong unadjusted association with major cardiac events (p < 0.05). In the multivariable Cox regression analysis, RV maximal apical FD maintained an independent association with major cardiac events (hazard ratio, 1.31 (1.11-1.55), p < 0.002). The Hosmer-Lemeshow goodness of fit test displayed good fit (X2 = 0.68, p = 0.99). Diagnostic performance was significantly improved after the addition of RV maximal apical FD to the multivariable baseline model, and the continuous net reclassification improvement increased 21% (p = 0.001), and the integrated discrimination index improved 16% (p = 0.045).

CONCLUSIONS

In patients with ACM, CMR-assessed myocardial trabecular complexity was independently correlated with adverse cardiovascular events and provided incremental prognostic value.

CLINICAL RELEVANCE STATEMENT

The application of FD values for assessing RV myocardial trabeculae may become an accessible and promising parameter in monitoring and early diagnosis of risk factors for adverse cardiovascular events in patients with ACM.

KEY POINTS

• Ventricular trabecular morphology, a novel quantitative marker by CMR, has been explored for the first time to determine the severity of ACM. • Patients with higher maximal apical fractal dimension of RV displayed significantly higher cumulative incidence of major cardiac events. • RV maximal apical FD was independently associated with major cardiac events and provided incremental prognostic value in patients with ACM.

Epidemiology of arrhythmogenic ventricular cardiomyopathy in China

BACKGROUND

Arrhythmogenic ventricular cardiomyopathy (AVC) is a common cause of ventricular arrhythmias and mortality, but limited data are available from large Asian cohorts. Our aim was to explore the current status of AVC and second, we examined the prevalence of ventricular tachycardia (VT), heart failure (HF) and mortality in patients with AVC in the Chinese population.

HYPOTHESIS

At present, some studies have reported that the incidence of AVC is on the rise, which may be due to the increasing number of diagnostic methods for AVC. However, there is no epidemiological data on AVC in the Chinese population, so we speculate that the incidence of AVC in the Chinese population is increasing.

METHODS AND RESULTS

We studied 15 888 adults from the Beijing Municipal Health Commission Information Center (BMHCIC) registry database in China from January 2010 to December 2020, and calculated the average annual percentage change (AAPC). Second, we determined the incidence of VT, HF and mortality in patients with AVC. Of the 10 318 men and 5570 women who were screened by cardiac magnetic resonance or examined by myocardial biopsy, there were a total of 256 newly diagnosed AVC patients (mean [SD]: 37.54[17.10]; 39.45% female). The incidence of AVC increased from 7.60 (3.12-12.06) in 2010 to 19.62 (11.51-27.75) per 1000 person-years in 2020. Males had higher incidence of AVC than females. The AAPC for the rising incidence of AVC was 8.9 %. Males had similar VT prevalence (70.32% vs. 62.38%, p = 0.19) and mortality (1.94% vs. 1.98%, p = 0.98) but lower HF prevalence (42.58% vs. 60.40%, p = 0.006), when compared to females. Radiofrequency ablation (RFA) was more likely to be performed in males (p = 0.006).

CONCLUSIONS

The rising trend in AVC incidence was evident, with two-fold increase by 2020. Males with AVC had similar VT prevalence and mortality rate, but HF prevalence were lower than females, perhaps impacted by RFA use.

The Diagnostic Value of the 12-Lead ECG in Arrhythmogenic Left Ventricular Cardiomyopathy: Novel ECG Signs

BACKGROUND

Electrocardiographic (ECG) findings in arrhythmogenic left ventricular cardiomyopathy (ALVC) are limited to small case series.

OBJECTIVES

This study aimed to analyze the ECG characteristics of ALVC patients and to correlate ECG with cardiac magnetic resonance and genotype data.

METHODS

We reviewed data of 54 consecutive ALVC patients (32 men, age 39 ± 15 years) and compared them with 84 healthy controls with normal cardiac magnetic resonance.

RESULTS

T-wave inversion was often noted (57.4%), particularly in the inferior and lateral leads. Low QRS voltages in limb leads were observed in 22.2% of patients. The following novel ECG findings were identified: left posterior fascicular block (LPFB) (20.4%), pathological Q waves (33.3%), and a prominent R-wave in V1 with a R/S ratio ≥0.5 (24.1%). The QRS voltages were lower in ALVC compared with controls, particularly in lead I and II. At receiver-operating characteristic analysis, the sum of the R-wave in I to II ≤8 mm (AUC: 0.909; P < 0.0001) and S-wave in V1 plus R-wave in V6 ≤12 mm (AUC: 0.784; P < 0.0001) effectively discriminated ALVC patients from controls. It is noteworthy that 4 of the 8 patients with an apparently normal ECG were recognized by these new signs. Transmural late gadolinium enhancement was associated to LPFB, a R/S ratio ≥0.5 in V1, and inferolateral T-wave inversion, and a ringlike pattern correlated to fragmented QRS, SV1+RV6 ≤12 mm, low QRS voltage, and desmoplakin alterations.

CONCLUSIONS

Pathological Q waves, LPFB, and a prominent R-wave in V1 were common ECG signs in ALVC. An R-wave sum in I to II ≤8 mm and SV1+RV6 ≤12 mm were specific findings for ALVC phenotypes compared with controls.

Ringlike late gadolinium enhancement provides incremental prognostic value in non-classical arrhythmogenic cardiomyopathy

BACKGROUND

The 2019 arrhythmogenic right ventricular cardiomyopathy (ARVC) risk model has proved insufficient in the capability of predicting ventricular arrhythmia (VA) risk in non-classical arrhythmogenic cardiomyopathy (ACM). Furthermore, the prognostic value of ringlike late gadolinium enhancement (LGE) of the left ventricle in non-classical ACM remains unknown. We aimed to assess the incremental value of ringlike LGE over the 2019 ARVC risk model in predicting sustained VA in patients with non-classical ACM.

METHODS

In this retrospective study, consecutive patients with non-classical ACM who underwent CMR from January 2011 to January 2022 were included. The pattern of LGE was categorized as no, non-ringlike, and ringlike LGE. The primary outcome was defined as the occurrence of sustained VA. Univariable and multivariable Cox regression analysis was used to evaluate the impact of LGE patterns on sustained VA and area under curve (AUC) was calculated for the incremental value of ringlike LGE.

RESULTS

A total of 73 patients were collected in the final cohort (mean age, 39.3 ± 14.4 years, 51 male), of whom 10 (13.7%) had no LGE, 33 (45.2%) had non-ringlike LGE, and 30 (41.1%) had ringlike LGE. There was no statistically significant difference in the 5-year risk score among the three groups (P = 0.190). During a median follow-up of 34 (13-56) months, 34 (46.6%) patients experienced sustained VA, including 1 (10.0%), 13 (39.4%) and 20 (66.7%) of patients with no, non-ringlike and ringlike LGE, respectively. After multivariable adjustment, ringlike LGE remained independently associated with the presence of sustained VA (adjusted hazard ratio: 6.91, 95% confidence intervals: 1.89-54.60; P = 0.036). Adding ringlike LGE to the 2019 ARVC risk model showed significantly incremental prognostic value for sustained VA (AUC: 0.80 vs. 0.67; P = 0.024).

CONCLUSION

Ringlike LGE provides independent and incremental prognostic value over the 2019 ARVC risk model in patients with non-classical ACM.

Tools to differentiate between Filamin C and Titin truncating variant carriers: value of MRI

Whereas truncating variants of the giant protein Titin (TTNtv) are the main cause of familial dilated cardiomyopathy (DCM), recently Filamin C truncating variants (FLNCtv) were identified as a cause of arrhythmogenic cardiomyopathy (ACM). Our aim was to characterize and compare clinical and MRI features of TTNtv and FLNCtv in the Belgian population. In index patients referred for genetic testing of ACM/DCM, FLNCtv and TTNtv were found in 17 (3.6%) and 33 (12.3%) subjects, respectively. Further family cascade screening yielded 24 and 19 additional truncating variant carriers in FLNC and TTN, respectively. The main phenotype was ACM in FLNCtv carriers whereas TTNtv carriers showed either an ACM or DCM phenotype. Non-sustained Ventricular Tachycardia was frequent in both populations. MRI data, available in 28/40 FLNCtv and 32/52 TTNtv patients, showed lower Left Ventricular (LV) ejection fraction and lower LV strain in TTNtv patients (p < 0.01). Conversely, both the frequency (68% vs 22%) and extent of non-ischemic myocardial late gadolinium enhancement (LGE) was significantly higher in FLNCtv patients (p < 0.01). Hereby, ring-like LGE was found in 16/19 (84%) FLNCtv versus 1/7 (14%) of TTNtv patients (p < 0.01). In conclusion, a large number of FLNCtv and TTNtv patients present with an ACM phenotype but can be separated by cardiac MRI. Whereas FLNCtv patients often have extensive myocardial fibrosis, typically following a ring-like pattern, LV dysfunction without or limited replacement fibrosis is the common TTNtv phenotype.

Value of cardiac magnetic resonance on the risk stratification of cardiomyopathies

Cardiomyopathies represent a diverse group of heart muscle diseases with varying etiologies, presenting a diagnostic challenge due to their heterogeneous manifestations. Regular evaluation using cardiac imaging techniques is imperative as symptoms can evolve over time. These imaging approaches are pivotal for accurate diagnosis, treatment planning, and optimizing prognostic outcomes. Among these, cardiovascular magnetic resonance (CMR) stands out for its ability to provide precise anatomical and functional assessments. This manuscript explores the significant contributions of CMR in the diagnosis and management of patients with cardiomyopathies, with special attention to risk stratification. CMR's high spatial resolution and tissue characterization capabilities enable early detection and differentiation of various cardiomyopathy subtypes. Additionally, it offers valuable insights into myocardial fibrosis, tissue viability, and left ventricular function, crucial parameters for risk stratification and predicting adverse cardiac events. By integrating CMR into clinical practice, clinicians can tailor patient-specific treatment plans, implement timely interventions, and optimize long-term prognosis. The non-invasive nature of CMR reduces the need for invasive procedures, minimizing patient discomfort. This review highlights the vital role of CMR in monitoring disease progression, guiding treatment decisions, and identifying potential complications in patients with cardiomyopathies. The utilization of CMR has significantly advanced our understanding and management of these complex cardiac conditions, leading to improved patient outcomes and a more personalized approach to care.

Recognizing a "Hot Phase" of An Arrhythmogenic Left Ventricular Cardiomyopathy: A Case Report

A 35-year-old male, with a medical history of acute myocarditis, presented with palpitations. Further investigation revealed non-sustained ventricular tachycardia and a slightly reduced left ventricular systolic function. Cardiac magnetic resonance showed extended late gadolinium enhancement of the left ventricle and fat infiltration. Genetic testing was positive for a pathogenic desmoplakin mutation, fulfilling the criteria of arrhythmogenic left ventricular cardiomyopathy. In conclusion, the authors described a case of a mimicked acute myocarditis at a young age in a patient with an arrhythmogenic left ventricular cardiomyopathy. Therefore, the genetic study is essential for both diagnosis and management.

The arrhythmogenic cardiomyopathy phenotype associated with PKP2 c.1211dup variant

BACKGROUND

The arrhythmogenic cardiomyopathy (ACM) phenotype, with life-threatening ventricular arrhythmias and heart failure, varies according to genetic aetiology. We aimed to characterise the phenotype associated with the variant c.1211dup (p.Val406Serfs*4) in the plakophilin‑2 gene (PKP2) and compare it with previously reported Dutch PKP2 founder variants.

METHODS

Clinical data were collected retrospectively from medical records of 106 PKP2 c.1211dup heterozygous carriers. Using data from the Netherlands ACM Registry, c.1211dup was compared with 3 other truncating PKP2 variants (c.235C > T (p.Arg79*), c.397C > T (p.Gln133*) and c.2489+1G > A (p.?)).

RESULTS

Of the 106 carriers, 47 (44%) were diagnosed with ACM, at a mean age of 41 years. By the end of follow-up, 29 (27%) had experienced sustained ventricular arrhythmias and 12 (11%) had developed heart failure, with male carriers showing significantly higher risks than females on these endpoints (p < 0.05). Based on available cardiac magnetic resonance imaging and echocardiographic data, 46% of the carriers showed either right ventricular dilatation and/or dysfunction, whereas a substantial minority (37%) had some form of left ventricular involvement. Both geographical distribution of carriers and haplotype analysis suggested PKP2 c.1211dup to be a founder variant originating from the South-Western coast of the Netherlands. Finally, a Cox proportional hazards model suggested significant differences in ventricular arrhythmia-free survival between 4 PKP2 founder variants, including c.1211dup.

CONCLUSIONS

The PKP2 c.1211dup variant is a Dutch founder variant associated with a typical right-dominant ACM phenotype, but also left ventricular involvement, and a possibly more severe phenotype than other Dutch PKP2 founder variants.

Multimodality Imaging in Arrhythmogenic Left Ventricular Cardiomyopathy

The term arrhythmogenic cardiomyopathy (ACM) describes a large spectrum of myocardial diseases characterized by progressive fibrotic or fibrofatty replacement, which gives the substrate for the occurrence of ventricular tachyarrhythmias and the development of ventricular dysfunction. This condition may exclusively affect the left ventricle, leading to the introduction of the term arrhythmogenic left ventricular cardiomyopathy (ALVC). The clinical features of ALVC are progressive fibrotic replacement with the absence or mild dilation of the LV and the occurrence of ventricular arrhythmias within the left ventricle. In 2019, the diagnostic criteria for the diagnosis of ALVC, based on family history and clinical, electrocardiographic, and imaging features, have been proposed. However, since the significant clinical and imaging overlap with other cardiac diseases, genetic testing with the demonstration of a pathogenic variant in an ACM-related gene is required for diagnostic confirmation. In ALVC, the multimodality imaging approach comprises different imaging techniques, such as echocardiography, cardiac magnetic resonance, and cardiac nuclear imaging. It provides essential information for the diagnosis, differential diagnosis, sudden cardiac death risk stratification, and management purposes. This review aims to elucidate the current role of the different multimodality imaging techniques in patients with ALVC.

Characterisation of patients referred to a tertiary-level inherited cardiac condition clinic with suspected arrhythmogenic right ventricular cardiomyopathy (ARVC)

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy (ARVC) or arrhythmogenic cardiomyopathy is a rare inherited disease with incomplete penetrance and an environmental component. Although a rare disease, ARVC is a common cause of sudden cardiac death in young adults. Data on the different stages of ARVC remains scarce. The purpose of this study is to describe the initial presentation and cardiac phenotype of definite and non-definite ARVC for patients seen at a tertiary service.

METHODS

This is a single centre, observational cohort study of patients with definite and non-definite ARVC seen at the Inherited Cardiac Conditions services at University Hospital Birmingham (UHB) in the period 2010-2021. Patients were identified by interrogation of digital health records, medical history, imaging and by examining 12-lead electrocardiograms (ECG).

RESULT

The records of 1451 patients were reviewed; of those, 165 patients were at risk of ARVC (mean age 41 ± 17 years, 56% male). 60 patients fulfilled task force criteria for definite ARVC diagnosis (n = 40, 67% males), and 38 (72%) of them carried a known pathogenic variant. The remaining 105 patients (50% males) were non-definite, and of these 45 (62%) carried a known pathogenic variant. Patients in the definite group were more symptomatic, with palpitations (57% vs. 17%), syncope (35% vs. 6%) and shortness of breath (28% vs. 5%, p < 0.001). T-wave inversion in V1-V3 and epsilon waves were observed only in the definite group. Both PR interval and QRS duration were longer in the definite (170 ± 34 ms and 100 ± 19 ms, p < 0.001) compared to (149 ± 25 and 91 ± 14 ms, p = 0.005). Patients with definite ARVC had significantly larger RV end diastolic areas and significantly reduced biventricular function (RVEDA = 27 ± 10 cm², RVFAC = 37 ± 11% and EF = 56 ± 12%) compared to the non-definite group (RVEDA = 18 ± 4 cm², RVFAC 49 ± 6% and LVEF 64 ± 7%, p < 0.001). Sustained ventricular tachycardia (VT) occurred more frequently in the definite group compared to the non-definite group (27% vs. 2%, p < 0.001). Ventricular fibrillation was observed in the definite group only (8 of 60 patients, 13%).

CONCLUSION

Our study showed differences between definite and non-definite ARVC patients in terms of clinical, electrophysiological and imaging features. Major adverse cardiac events occurred more commonly in the definite group, but also were observed in non-definite ARVC. This single centre observational cohort study forms a basis for further prospective multicentre interventional studies.

2021-2022 state of our JCMR

In 2021, there were 136 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR), including 122 original research papers, six reviews, four technical notes, one Society for Cardiovascular Magnetic Resonance (SCMR) guideline, one SCMR position paper, one study protocol, and one obituary (Nathaniel Reichek). The volume was up 53% from 2020 (n = 89) with a corresponding 21% decrease in manuscript submissions from 435 to 345. This led to an increase in the acceptance rate from 24 to 32%. The quality of the submissions continues to be high. The 2021 JCMR Impact Factor (which is released in June 2022) markedly increased from 5.41 to 6.90 placing us in the top quartile of Society and cardiac imaging journals. Our 5 year impact factor similarly increased from 6.52 to 7.25. Fifteen years ago, the JCMR was at the forefront of medical and medical society journal migration to the Open-Access format. The Open-Access system has dramatically increased the availability and JCMR citation. Full-text article requests in 2021 approached 1.5 M!. As I have mentioned, it takes a village to run a journal. JCMR is very fortunate to have a group of very dedicated Associate Editors, Guest Editors, Journal Club Editors, and Reviewers. I thank each of them for their efforts to ensure that the review process occurs in a timely and responsible manner. These efforts have allowed the JCMR to continue as the premier journal of our field. My role, and the entire editorial process would not be possible without the ongoing high dedication and efforts of our managing editor, Jennifer Rodriguez. Her premier organizational skills have allowed for streamlining of the review process and marked improvement in our time-to-decision (see later). As I conclude my 6th and final year as your editor-in-chief, I thank you for entrusting me with the JCMR editorship and appreciate the time I have had at the helm. I am very confident that our Journal will reach new heights under the stewardship of Dr. Tim Leiner, currently at the Mayo Clinic with a seamless transition occurring as I write this in late November. I hope that you will continue to send your very best, high quality CMR manuscripts to JCMR, and that our readers will continue to look to JCMR for the very best/state-of-the-art CMR publications.

Desmoplakin cardiomyopathy—an inherited cardiomyopathy presenting with recurrent episodes of acute myocardial injury

We present two female patients with recurrent episodes of myocardial injury, consisting of acute chest pain and elevated cardiac markers without coronary artery disease. Cardiovascular magnetic resonance imaging identified extensive late gadolinium enhancement suggestive of an inherited cardiomyopathy. Genetic testing showed heterozygous pathogenic variants in the desmoplakin (DSP) gene, the gene coding for the desmoplakin protein, a structural protein found in the cardiac desmosome. Pathogenic variants in the DSP gene are associated with dilated and arrhythmogenic cardiomyopathy. DSP cardiomyopathies may cause recurring myocardial injury mimicking an acute coronary syndrome or myocarditis. Cardiac magnetic resonance imaging is key in its diagnosis due to its specifying imaging features. Genetic testing is essential for the evaluation and confirmation of the diagnosis.

Cardiac magnetic resonance imaging of arrhythmogenic cardiomyopathy: evolving diagnostic perspectives

Arrhythmogenic cardiomyopathy (ACM) is a genetically determined heart muscle disease characterized by fibro-fatty myocardial replacement, clinically associated with malignant ventricular arrhythmias and sudden cardiac death. Originally described a disease with a prevalent right ventricular (RV) involvement, subsequently two other phenotypes have been recognized, such as the left dominant and the biventricular phenotypes, for which a recent International Expert consensus document provided upgrade diagnostic criteria (the 2020 "Padua Criteria"). In this novel workup for the diagnosis of the entire spectrum of phenotypic variants of ACM, including left ventricular (LV) variants, cardiac magnetic resonance (CMR) has emerged as the cardiac imaging technique of choice, due to its capability of detailed morpho-functional and tissue characterization evaluation of both RV and LV. In this review, the key role of CMR in the diagnosis of ACM is outlined, including the supplemental value for the characterization of the disease variants. An ACM-specific CMR study protocol, as well as strengths and weaknesses of each imaging technique, is also provided. KEY POINTS: • Arrhythmogenic cardiomyopathy includes three different phenotypes: dominant right, biventricular, and dominant left. • In 2020, diagnostic criteria have been updated and cardiac magnetic resonance has emerged as the cardiac imaging technique of choice. • This aim of this review is to provide an update of the current state of art regarding the use of CMR in ACM, with a particular focus on novel diagnostic criteria, CMR protocols, and prognostic significance of CMR findings in ACM.

Prognostic Cardiac Magnetic Resonance Markers of Left Ventricular Involvement in Arrhythmogenic Cardiomyopathy for Predicting Heart Failure Outcomes

Background

Left ventricular (LV) involvement is frequently observed in arrhythmogenic cardiomyopathy (ACM). We investigated the association of LV myocardial assessment using cardiac magnetic resonance (CMR) with clinical outcomes including heart failure (HF)‐related events in ACM.

Methods and Results

We retrospectively analyzed 60 patients with ACM between 2005 and 2020 according to the 2010 Task Force Criteria and assessed HF‐related events (HF hospitalization, heart transplantation, and cardiac death) and ventricular tachycardia events. We analyzed CMR findings including late gadolinium enhancement (LGE) in all subjects and obtained mapping values (native T1, extracellular volume, and T2) on 30 (50%) patients out of them. Among the study population (mean age 49 years, 77% male), 41 (68%) patients had LV LGE. During a median follow‐up of 34 months, there were 13 (22%) HF‐related events, and 20 (30%) ventricular tachycardia events. Kaplan‐Meier survival analysis revealed that HF‐related events occurred only in patients with LV LGE (+) (versus LV LGE (‐), log‐rank P=0.006), and the events were not significantly different regarding right ventricular LGE (log‐rank P>0.999). When categorized by median value for each mapping parameter, HF‐related events occurred more in patients with higher native T1 (versus lower native T1, log‐rank P=0.002), and higher T2 (versus lower T2, log‐rank P=0.002), higher extracellular volume (versus lower extracellular volume, log‐rank P=0.002). However, regarding ventricular tachycardia events, there were no significant differences according to these CMR markers.

Conclusions

LV myocardial assessment using CMR with LGE imaging and native T1, T2, and extracellular volume markers were significantly associated with HF‐related event risk in patients with ACM.

Insights Into Genetics and Pathophysiology of Arrhythmogenic Cardiomyopathy

Purpose of Review

Arrhythmogenic cardiomyopathy (ACM) is a genetic disease characterized by life-threatening ventricular arrhythmias and sudden cardiac death (SCD) in apparently healthy young adults. Mutations in genes encoding for cellular junctions can be found in about half of the patients. However, disease onset and severity, risk of arrhythmias, and outcome are highly variable and drug-targeted treatment is currently unavailable.

Recent Findings

This review focuses on advances in clinical risk stratification, genetic etiology, and pathophysiological concepts. The desmosome is the central part of the disease, but other intercalated disc and associated structural proteins not only broaden the genetic spectrum but also provide novel molecular and cellular insights into the pathogenesis of ACM. Signaling pathways and the role of inflammation will be discussed and targets for novel therapeutic approaches outlined.

Summary

Genetic discoveries and experimental-driven preclinical research contributed significantly to the understanding of ACM towards mutation- and pathway-specific personalized medicine.