Hypertrophic cardiomyopathy in a dog: a systematic diagnostic approach

A seven-year-old female neutered Parson Russel Terrier was referred for syncopal episodes. An electrocardiogram revealed paroxysmal atrial flutter followed by periods of sinus arrest, suggesting sick sinus syndrome. Echocardiography showed severe biventricular wall thickening (hypertrophic cardiomyopathy (HCM) phenotype) with no signs of fixed or dynamic left ventricular outflow tract obstruction. Blood pressure, abdominal ultrasound, serum total thyroxin and thyroid-stimulating hormone, and insulin-like growth factor-1 were all within normal limits. Cardiac troponin I was elevated (1.7 ng/mL, ref<0.07). Serological tests for common infectious diseases were negative. A 24-h Holter confirmed that the syncopal episodes were associated with asystolic pauses (sinus arrest after runs of atrial flutter) ranging between 8.5 and 9.6 s. Right ventricular endomyocardial biopsies (EMB) were performed at the time of pacemaker implantation to assess for storage or infiltrative diseases that mimic HCM in people. Histological analysis of the EMB revealed plurifocal inflammatory infiltrates with macrophages and lymphocytes (CD3+ > 7/mm2) associated with myocyte necrosis, but no evidence of myocyte vacuolisation or infiltrative myocardial disorders. These findings were compatible with myocardial ischaemic injury or acute lymphocytic myocarditis. Molecular analysis of canine cardiotropic viruses were negative. The dog developed refractory congestive heart failure and was euthanised 16 months later. Cardiac post-mortem examination revealed cardiomyocyte hypertrophy and disarray with diffuse interstitial and patchy replacement fibrosis, and small vessel disease, confirming HCM. We described a systemic diagnostic approach to an HCM phenotype in a dog, where a diagnosis of HCM was reached by excluding HCM phenocopies.

Myocarditis and inflammatory bowel diseases: A single-center experience and a systematic literature review

BACKGROUND

Myocarditis and inflammatory bowel diseases (IBD) are rare conditions, but may coexist. Myocarditis in IBD may be infective, immune-mediated, or due to mesalamine toxicity. A gap of knowledge exists on the clinical features of patients that present myocarditis in association with IBD, especially for endomyocardial biopsy-proven cases. Our aims are: 1) to describe the clinical characteristics of patients with an associated diagnosis of myocarditis and IBD in a single-center hospital, 2) to perform a systematic review of the literature of analogous cases.

METHODS

We retrospectively analyzed data of patients followed up at the outpatient Cardio-immunology and Gastroenterology Clinic of Padua University Hospital, to identify those with an associated diagnosis of myocarditis and IBD. In addition, a systematic review of the literature was conducted. We performed a qualitative analysis of the overall study population.

RESULTS

The study included 104 patients (21 from our single center cohort, 83 from the literature review). Myocarditis in IBD more frequently affects young (median age 31 years) males (72%), predominantly with infarct-like presentation (58%), within an acute phase of the IBD (67%) and with an overall benign clinical course (87%). Nevertheless, a not negligible quote of patients may present giant cell myocarditis, deserve immunosuppression and have a chronic, or even fatal course. Histological evidence of mesalamine hypersensitivity is scarce and its incidence may be overestimated.

CONCLUSIONS

Our study shows that myocarditis in association with IBD, if correctly managed, may have a spontaneous benign course, but predictors of worse prognosis must be promptly recognized.

Acute ischemic stroke on anti-Xa inhibitors: Pharmacokinetics and outcomes

BACKGROUND AND PURPOSE

Direct oral anticoagulant (DOAC) ingestion within 48 h is an exclusion for thrombolysis in acute ischemic stroke (AIS) patients. We aim to shed light on pharmacokinetic correlates and outcomes in patients with AIS excluded from thrombolysis due to DOAC use.

METHODS

This is a single center retrospective study of consecutive patients with AIS within 4.5 h from last known normal and excluded from thrombolytic therapy due to confirmed Xa inhibitor DOAC (DOAC_Xa) intake within the prior 48 h. We used linear regression to test the correlation between time from last DOAC_Xa ingestion and anti-Xa level.

RESULTS

Over a period of 2.5 years, we identified 44 patients who did not receive thrombolysis because of presumed DOAC intake within 48 h. In adjusted linear regression, there was an association between time from last DOAC ingestion and Xa level (beta = -0.69, p < 0.001). Among the 37 patients with known atrial fibrillation not receiving alteplase due to DOAC use, the 90-day mortality was 35.1% (13/37) and 77% (10/13) of deaths were stroke related.

CONCLUSIONS

Patients with AIS on DOAC therapy face a heightened risk of mortality. Studies are needed to investigate the safety and efficacy of thrombolysis in such patients based on time of last DOAC ingestion and/or anti-Xa/drug level.

Impact of gut microbiota and immune contexture on effectiveness of neo-adjuvant chemo-radiotherapy in locally advanced rectal cancer (LARC)

Objective

Among patients affected by Locally Advanced Rectal Cancer (LARC), 15–20% ultimately reveal a complete pathological response to the neo-adjuvant chemo-radiotherapy nCRT), which might render the surgical resection no longer necessary. However, the possibility to adopt alternative management options, such as a “wait and see” strategy, is hampered by the lack of reliable indicators of complete responsiveness to nCRT. Our hypothesis is that the composition of LARC-associated microbiome and immune contexture may predict the responsiveness to nCRT. We therefore proceed to a quantitative and qualitative evaluation of gut microbiome composition and immune contexture in LARC bioptic tissues and we then comparatively evaluated those markers in complete responders (Tumor regression grade, TRG,1) versus others (TRG2-3-4).

Methods

FFPE (Formalin Fixed Paraffin Embedded) LARC tissues from diagnostic biopsies and corresponding resections from patients treated at our hospital from 2012 to December 2019 were collected. Following sample deparaffinization, n. 71 genomic DNA (gDNA) and total cellular RNA were extracted. DNA used for microbiome analysis, upon amplification and sequencing of the hypervariable V3-V4 region of 16S gene. Expression of immune cell genes was evaluated by the Nanostring PanCancer Immune profiling panel on extracted RNA.

Results

Regarding the Microbiome profile we found no difference in terms of biodiversity between complete responders and others. However, we found some species significantly disregulated, in particular an over-expression of Alloprevotella Rava and down-expression of Porphyromonas Asaccharolytica, Turicibacter Sanguinis, Leptotrichia Trevisanii, Fusobacterium Nucleatum. The immune contexture analysis revealead a significant disregulation of 41 genes.

Conclusion

FFPE tissues from diagnostic biopsies proved suitable for the analysis of LARC-associated microbiome and immune contexture.

A specific microbiome signature appears to be associated with responsiveness to neo-adjuvant chemoradiotherapy. Defined immune related genes, in particular those associated with IFN-gamma response, are up-regulated in tumors exhibiting complete response. A possible associations between the bacterial species significantly disregulated and this favorable immune contexture is currently under investigation.

Prognostic role of myocardial inflammation in patients with undefined left ventricular arrhythmogenic cardiomyopathy

Funding Acknowledgements

Type of funding sources: None.

Background

Etiology identification and risk stratification represent major issues for patients presenting with undefined left ventricular arrhythmogenic cardiomyopathy (ULVACM).

Purpose

To investigate the role of genetics and histology for ULVACM classification, management, and risk assessment.

Methods

We retrospectively analyzed a multicenter cohort of patients (screened n=1037) with ULVACM defined by ventricular arrhythmia (VA) onset, nonischemic late gadolinium enhancement (LGE) limited to the LV, and no severe dilated cardiomyopathy (LVEF≥40%). We selected patients undergoing both next generation sequencing (NGS) screening and endomyocardial biopsy (EMB) for etiology definition. When feasible, immunosuppressive therapy (IST) was used to target active myocardial inflammation (AMI). The study endpoint was a composite of cardiac death, heart transplantation and malignant VAs (VT, VF, appropriate ICD treatment).

Results

The study cohort is composed by 135 ULVACM patients (age 43±14 years, 63% males, LVEF 55±7 %). NGS identified pathogenic or likely-pathogenic variants (PVs/LPVs) consistent with ACM in 21 cases (16%), whereas EMB showed AMI in 78 patients (58%), including 13/21 PVs/LPVs+ (62%). After reclassification of 86 patients (64%), only 49 (36%) remained ULVACM. IST was started in 41/78 AMI patients (53%), including 9/13 PVs/LPVs+ (69%). Twenty patients (15%) met the study endpoint by 12 months, and 36 (27%) by the end of the study (60±27 months). Beyond malignant VT onset, AMI was the only predictor of events by 12 months (HR 5.0, 95%CI 1.4-18.1, p=0.007). No prognostic role was found for PVs/LPVs, except for the subgroup (n=77) with nonsustained VT onset. Among AMI patients, those treated by IST had a significantly lower occurrence of events, both by 12-months (1/41 vs. 16/37, p&lt;0.001) and later (HR 0.05, 95%CI 0.01-0.21, p&lt;0.001). Results were independently confirmed in PVs/LPVs+ and PVs/LPVs- cases. Excluding the IST population, the association of multiple factors among VT onset, PVs/LPVs, and AMI, resulted in an improved discrimination of arrhythmic risk profiles.

Conclusion

The combined genetic and histological workup allowed reclassification of up to 64% ULVACM patients, and substantially contributed into prognostic assessment. Furthermore, EMB identified suitable candidates for IST, who showed better outcomes irrespectively of their genotype.

C61 MULTIDISCIPLINARY MANAGEMENT IN A CASE OF EOSINOPHILIC MYOCARDITIS WITH CHURG STRAUSS SYNDROME: FROM ECG TO ENDOMYOCARDIAL BIOPSY

Background

Eosinophilic granulomatosis with polyangiitis (EGPA), previously known as Churg–Strauss, is a rare multisystem disorder characterized by chronic rhinosinusitis, asthma, and prominent peripheral blood eosinophilia (PE). Cardiac involvement may include eosinophilic myocarditis and it is a serious manifestation of EGPA.

Case Presentation

A 67–year–old woman presented to the emergency department with 2–weeks history of dyspnea, orthopnea and asthenia. She had history of asthma, PE, adjuvant radiotherapy after right mastectomy (July 2021). The patient was diagnosed with new onset atrial fibrillation in the previous month. At admission, the patient was hemodynamically stable and with signs of congestion. Complementary exams showed sinus rhythm and T–wave inversion on lateral leads; PE (2010/uL), elevated troponin and BNP values; and severe biventricular systolic dysfunction with diffuse hypokinesia and apical akinesia. The patient was admitted to the ICU and was treated with intravenous diuretics and levosimendan. Optimal HF therapy was introduced. Serial echocardiography revealed partial recovery of LVEF and blood analysis showed a decrease in troponin levels, with persistent eosinophilia (6330/uL). Computed tomography (CT) excluded significant coronary disease, and showed bilateral basal ground–glass opacities, areas of air–space consolidation and bilateral reticular–nodular pattern. Cardiac magnetic resonance revealed increased T2 values/signs of myocardial edema in anterior wall, interventricular septum and apex and no late gadolinium enhancement, compatible with myocarditis. An endomyocardial biopsy (EMB) was performed and confirmed the diagnosis of eosinophilic myocarditis. Oral corticosteroids were started. Paranasal CT scan showed signs of chronic sinusitis, without polyposis, and antineutrophil cytoplasmic antibodies were positive, making the diagnosis of EGPA, according to ACR criteria.

Discussion

In a patient presenting with new onset heart failure and with history of asthma and eosinophilia, it is important to suspect eosinophilic myocarditis, as this is a rare but reversible life–threatening condition. EMB plays an important role in the diagnosis and should be done promptly.

Conclusion

We described a multidisciplinary management of a case of a patient with eosinophilic myocarditis and EGPA, presenting with severe acute biventricular dysfunction.

P430 TUMORAL THROMBOTIC MICROANGIOPATHY: A RARE CAUSE OF ACUTE PULMONARY HYPERTENSION

Introduction

Among the causes of acute pulmonary hypertension, the occlusion of the little pulmonary vessels caused by tumoral microemboli, even from an unknown neoplasm, is an infrequent condition with a very poor prognosis.

Clinical Case

A 55–years old woman with no relevant past medical history presented to the Emergency Department with dyspnea at rest, desaturation, palpitations and a brief episode of chest pain, after several days of fatigue and exertional dyspnea. ECG showed sinus tachycardia and signs of right ventricle pressure overload with inverted T waves in V3–V4 and in the inferior leads (Fig. 1). On laboratory tests there were high D–dimer values and a slightly elevated TnI. Blood gas analysis showed hypoxemic hypocapnic respirstory alkalosis. An Echocardiogram revealed severe dilatation and dysfunction of the right ventricle and signs of high probability of pulmonary hypertension (Fig. 2). Pulmonary CT scan ruled out embolism and showed irregular thickening of the interstitium and mediastinal lymphoadenopathy. Then, a rapid clinical deterioration happened, refractory to inotropes infusion and larger volumes of oxygen. The programmed diagnostic pathway cannot be pursued. On day 4, there was respiratory distress and pulseless electrical activity cardiac arrest during endotracheal intubation. ECMO mechanical support was positioned but on day 7 the patient died. Autopsy, made to discover the cause of pulmonary hypertension, revealed the presence of a colonic invasive adenocarcinoma with micropapillary pattern and thoracic and pelvic lymph–nodal metastases. Microscopic evaluation of the lungs showed a widespread neoplastic vascular invasion with microthromboemboli (Fig. 3).

Discussion

Tumoral thrombotic microangiopathy is a cause of pulmonary hypertension of multifactorial origin and should be suspected in cases of pulmonary hypertension without pulmonary embolism or interstitial lung disease. The rarity of this condition and the absence of an oncological medical history make difficult the diagnostic hypothesis. Besides, the lacking of an effective therapy makes the prognosis poor.

Arrhythmic risk stratification in patients with clinically-suspected left ventricular arrhythmogenic cardiomyopathy

Background

Arrhythmic risk of patients with left ventricular arrhythmogenic cardiomyopathy (LVAC) is unpredictable.

Purpose

To identify risk facors associated with major ventricular tachyarrhythmias (VTA) in clinically-suspected LVAC patients.

Methods

We enrolled 127 consecutive patients (69% males, age 46±13 y, LVEF 54±7%) with clinically-suspected LVAC. All patients presented with either major (VT, VF) or minor VTA (NSVT, frequent VEB), and underwent extensive diagnostic workup to rule-out alternative diagnoses. Medical treatment and ICD implant were clinically-driven. Prospective follow-up was obtained via sequential 24h-Holter ECG (2–4/y) with or without continuous arrhythmia monitoring (ICD or implantable loop recorders, ILR). The primary endpoint was occurrence of major VTA (VT/VF/ICD therapy) by 24-month follow-up.

Results

At presentation, 56 (44%) and 71 patients (56%) had, respectively, major and minor VTA. Variants in desmosomal genes were identified in 7 of the 9 patients with clinically-indicated genetic test. Delayed gadolinium enhancement (DGE, average 23±12% of the LV mass) had anteroseptal distribution in 43 cases (34%). Monitoring strategy included ICD (n=64), ILR (n=33), or sequential Holer ECGs (n=30). By 24-month follow-up, major VTA occurred in 32 patients (25%). At univariable anlysis, major VTA onset (HR 16.8, 95% CI 5.4–52.2, p&lt;0.001) and anteroseptal DGE (HR 3.0, 95% CI 1.3–6.9, p=0.010) were significantly associated with major VTA by 24-month follow-up. Among patients presenting with minor VTA, the only factor significantly associated with the primary endpoint was anteroseptal DGE (3/4 vs. 14/67, p=0.004).

Conclusion

Our preliminary experience suggests that, in patients with clinically-suspected LVAC, major VTA onset and anteroseptal DGE are relevant risk factors for major arrhythmic events by 24-month follow-up.

Funding Acknowledgement

Type of funding sources: None.

Generation and phenotyping of a novel knock-in mouse model of desmoplakin dependent arrhythmogenic cardiomyopathy

Background

Arrhythmogenic Cardiomyopathy (AC) is a genetic cardiac disorder, mainly caused by mutations in genes encoding desmosomal proteins, and accounts for most stress-related arrhythmic sudden cardiac deaths (SCD) in the young and athletes. The AC myocardium is hallmarked by cardiomyocyte (CM) death and fibro-fatty replacement, which generate a pro-arrhythmogenic substrate. Several pathogenetic factors in AC remain obscure and better understanding of the disease mechanisms is required to develop novel efficacious therapies to prevent SCD, which are sorely missing.

The lexical analogy between desmosomes and desmosomal proteins has originally biased AC research towards CMs, the paradigmatic desmosome-bearing cells in heart. However, the myocardium is composed by different cell types, many of which express desmosomal proteins, albeit in the absence of desmosomes, including CMs, sympathetic neurons, vascular cells and fibroblasts. Notably, AC mutations are transmitted at germline, and thus may manifest in all cell types expressing desmosomal proteins. This might explain why the majority of preclinical AC models, using CM specific over-expression or deletion of the disease-causing mutation, failed to fully recapitulate the human disease phenotype.

Hypothesis

On these bases, we aimed to generate a knock-in (KI) AC mouse model for comprehensively studying AC pathogenesis.

Methods

As Desmoplakin (DSP) mutations occur in a large part of the Italian AC population, we used CRISP/Cas9 to generate a KI mouse strain harboring the Serine-to-Alanine substitution of S311, the murine homolog of human S299 [Bauce et al, 2005]. We successfully obtained DSPS311A/WT KI founders, which were viable and fertile and after backcrossing for &gt;10 generations, used to expand the new mouse strain. Mouse cardiac phenotype was characterized, at different stages (1,2,4,6,9 mo.) by functional (i.e. ECHO, telemetry-ECG, chronic exercise) and structural (i.e. EM, standard histology, confocal IF, TUNEL assay) analyses. Molecular/biochemical analyses probed the state of the main pathways involved in AC.

Results

Our analyses showed that, starting from 4 mo., DSP homozygous KI mice display contractile dysfunction, worsening during aging, and fibrotic myocardial remodelling with focal fatty lesions, accompanied by frequent arrhythmic beats, which become sustained ventricular arrhythmias upon Noradrenaline administration. Hearts showed desmosome alterations, particularly at advanced disease stages, and lateralization of cx43, which corresponded to the phenotype of human AC hearts. Heterozygous mice showed similar alterations, which only took longer to appear. Exercise accelerated disease progression and increased the incidence of SCD (DSPS311A: SCD=63%, n=11; ctrls: SCD=8%, n=12).

Conclusion

Our KI mice replicate the clinical and pathological phenotype of DSP-linked biventricular AC and are thus suited for the mechanistic study of the multicellular origin of the disease.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): PRIN Miur 2015

A new inherited syndrome causing sudden cardiac death with specific ECG changes and idiopathic left ventricular hypertrophy

Funding Acknowledgements

Type of funding sources: None.

Introduction

 Sudden cardiac death (SCD) is a serious threat. In individuals under the age of 35 years sudden arrhythmic death is the most frequent cause. In younger persons, genetically determined cardiac diseases (e.g., cardiomyopathies, ion-channel diseases) account for an important proportion of these cases.

Purpose

We discovered a unusual combination of ECG changes and left ventricular hypertrophy that lead to a cumulation of sudden cardiac death in a single family. We therefore did a scientific work-up of this finding.

Methods

We investigated the case of a 23 year-old male with SCD, specific ECG changes and left ventricular hypertrophy (Figure 1). Family history was significant for SCD in the paternal line. A precise analysis was performed by an international multidisciplinary expert panel including autopsy of the index patient’s heart, molecular autopsy, whole exome sequencing, analysis of the pedigree and examination of available family members (Figure 2).

Results 

Three cases of SCD were  reported in paternal relatives. The index patient exhibited specific ECG changes (ST-depression), which were also found in five paternal relatives and the brother of the index Patient (Figure 3). Post-mortem analysis of the heart yielded mild idiopathic concentric hypertrophy without myocardial disarray.

 The genetic analysis of the index patient showed two nucleotide variations in two different genes (ANK2: c.11791G &gt; A , MYO18B: c.3761G &gt; A), which were also expressed in five relatives. Two family members had showed all indicators of the inherited syndrome including specific ECG changes, genetic changes and left ventricular hypertrophy.

Conclusions

We described a distinct inheritable syndrome causing SCD, characterized by specific ECG changes, idiopathic left ventricular hypertrophy and mutations of ANK2 and MYO18. As far as we know this is the first description of this syndrom. We hypothesize that if all features (ECG-changes, described genetic mutations, left ventricular hypertrophy) are positive, the risk for SCD may be considerably increased. Abstract Figure. ECG of index patient and pedigree

Implication of substance use in suicidal or violent behaviours in a first episode psychosis spectrum disorder population : A 45 patients retrospective study

Introduction

In First Episode Psychosis (FEP), Suicidal Behaviours (SB), Violent Behaviours (VB) and substance use are frequent respectively 10% to 30%, 34.5% and 50% (Pompili et al., 2011), (Tournier et al., 2013). The role of substance use in facilitating SB and VB is described (Large et al., 2011).

Objectives

We aim to evaluate the impact of substance use in FEP patients. Our hypothesis is that substance use is associated with more SB or VB before first admission.

Methods

First admission files of 45 patients diagnosed ICD10 F20 to F29 during the 2013-2018 period were retrospectively studied. SB, VB and substance use (Cannabis, alcohol and opiate/cocaine) before admission were collected. Correlation between SB and VB were tested with cannabis, alcohol, opiate/cocaine use with chi2 Pearson independance test.

Results

The frequencies of suicidal behaviours and violent behaviours were 25 % and 22.7 %. The frequencies of cannabis use, alcohol use, opiate/cocaine use were 56.1 %, 10 % and 16.3 %. A strong significant correlation was found between opiate/cocaine use and violent behaviour, p = 0.011 Chi2 was 6.471 DF 1. No other significant correlations were found.

Conclusions

Suicidal behaviours and violent behaviours are known to be more frequent in psychotic patients with addictive comorbidity. Our french rural hospital retrospective study confirms that violent behaviours in first admission psychotic patients are strongly associated with opiate/cocaine substance use comorbidity.

The neuro-cardiac junction defines an extracellular microdomain required for neurotrophic signaling

Background

Sympathetic neurons (SNs) innervate the myocardium with a defined topology that allows physiological modulation of cardiac activity. Neurotrophins released by cardiac cells control SN viability and myocardial distribution, which are impaired in heart diseases with reduced (e.g. heart failure) or heterogenous sympathetic stimulation (e.g. arrhythmias). We previously demonstrated that SNs interact directly with cardiomyocytes (CMs) at neuro-cardiac junctions (NCJ), and such structured contact sites allow neurons to efficiently activate β-adrenoceptors on the myocyte membrane.

Aims

We here asked whether NCJs are functional for retrograde (myocyte to neuron) neurotrophic signaling.

Methods and results

Electron microscopy and immunofluorescence on mouse heart slices and SN/CM co-cultures showed that the NGF receptor, TrkA, is preferentially found in correspondence of the NCJ. Consistently, neurons taking structured contact with CMs showed fast TrkA activation and its retrograde transport to the soma, which was monitored using live confocal imaging in cells expressing TrkA-RFP. In accord with NGF dependent effects, CM-contacted SN showed larger synaptic varicosities and did not require NGF supplementation in the culture medium. In support that NGF locally released at NCJs sustains SN viability, the neurotrophin concentration in the culture medium was 1.61 pg/mL, and did not suffice to maintain neuronal viability, which was also perturbed (66% decrease of neuronal density) by silencing NGF expression in CMs. These results support that the NCJ is essential for intercellular neurotrophin signaling. Consistently, by applying competitive inhibition of TrkA with increasing doses of K252a, we estimated NGF concentration at the contact site to be about 1000-fold higher than that released by CM in the culture medium.

To seek for the structural determinants of the NCJ, we focused on dystrophin, based on the finding that the protein accumulates on the CM membrane portion contacted by SNs, as observed in mouse heart slices, and co-cultured CMs. In support of a role of CM-expressed dystrophin in neurotrophic signaling, hearts from dystrophin-KO (mdx) mice showed 74.36% decrease of innervation, with no significant changes of NGF expression. In line with the purported role of NCJs, in co-cultures between wild type SNs and mdx CMs, TrkA activation (TrkA movements toward SN soma (%): WTCM-WTSN=18±4; MDXCM-WTSN= 12±3; p&lt;0,05) and neuronal survival were reduced.

Conclusions

Taken together, our results suggest that NGF-dependent signaling to SNs requires a direct and specialized interaction with myocytes, and that loss of dystrophin at the CM membrane impairs retrograde signaling to the neurons leading to cardiac sympathetic dys-innervation.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): University of Padova

Muscle ring finger-1 is required to prevent age-related cardiac hypertrophy and interstitial remodelling

Purpose

The Ubiquitin Proteasome System (UPS) is a selective degradation system mediating the removal of intracellular unfolded/misfolded proteins and is essential for cardiomyocyte (CM) health. Substrate specificity and ubiquitination rate are mediated by E3 ubiquitin-ligases, such as Atrogin1 and MuRF1, which are specifically expressed in muscle cells. Perturbation of protein quality control causes aggregation of misfolded proteins, leading to CM proteotoxicity. UPS dysfunction occurs in ageing, a risk factor for cardiac hypertrophy and HF. We recently demonstrated that Atrogin-1 is essential to maintain CM health, during ageing. Whether MuRF1 plays similar roles in heart adaptation to ageing is still unexplored, and different studies have yielded contrasting results.

Methods

To assess the role of MuRF1 in heart homeostasis, we combined echocardiography, histology, IF, TUNEL assay and EM on heart sections from MuRF1 knock-out (KO) mice, and littermate controls, at 3, 10 and 24 mo. RTqPCR and WB assessed markers of UPS and extracellular matrix. Langendorff procedure was used to separate CMs from cardiac fibroblasts. Molecular and IF analyses were performed in heart samples from patients affected by aortic stenosis.

Results

MuRF1 ablation leads to cardiac hypertrophy, progressing during ageing (LV CM areas: 3 mo., KO: 329.14±10.66 vs Ctrl: 296.25±5.43; 10 mo., KO: 399.73±7.64 vs Ctrl: 247.49±3.67; 24 mo., KO: 418.89±11.10 vs. Ctrl: 209.93±4.48, in μm2). The hypertrophic remodeling was accompanied by diastolic dysfunction in the adulthood and, during ageing, also by systolic dysfunction (EF, 24 mo., KO: 29.55±8.82 vs Ctrl: 51.23±6.56, in %). Loss of MuRF1 causes increased interstitial collagen -I and -VI deposition, even before the onset of contractile dysfunction, followed by activation of Matrix MetalloProteinases (MMPs), suggesting that such alterations may be responsible for decreased cardiac performance. Interestingly, collagen established rings enveloping MuRF1 KO CMs and such fibrotic remodeling was not accompanied by increased CM apoptosis, nor myofibroblast activation. Such peculiar remodelling, called peri-endomysial fibrosis, was detected in hearts from patients with aortic stenosis, a condition in which MuRF1 levels decrease. Our data supports that MuRF1 has a role in CM-dependent regulation of the extracellular matrix (ECM) dynamics. Consistently, MuRF1 downregulation in normal cultured CMs demonstrated that such ubiquitin ligase impacts on signaling pathways involved in the control of the ECM homeostasis. In addition, fibroblasts treated with culture medium conditioned by MuRF1 KO CM display increased collagen and MMP expression.

Conclusions

We identifieded a novel role of MuRF1 in the control of CM proteostasis, and unveiled that in addition to cardiac fibroblasts, CM may directly regulate ECM dynamics, indicating that the correct function of MuRF1 is essential for heart adaptation to aging.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): University of Padova

Predictors of death, heart transplantation and relapse in clinically suspected and biopsy-proven myocarditis in the pre-immunosuppression era

Background

Myocarditis is an infectious or autoimmune inflammatory disease of the myocardium; diagnosis relies on the exclusion of an acute coronary syndrome, and is confirmed by endomyocardial biopsy (EMB). Prognosis is highly variable, outcome predictors are not well defined.

Purpose

To identify clinical, imaging and immunological predictors of death, heart transplantation (HTx) and relapse in patients with myocarditis in the pre-immunosuppression era.

Methods

From 1993 to 2012 we consecutively enrolled 466 patients (68% male, mean age 37±17 years), 216 with clinically suspected and 250 with EMB-proven myocarditis. All patients underwent coronary angiogram and transthoracic echocardiogram, 44% of patients underwent cardiac magnetic resonance (CMR). Circulating auto-antibodies were measured in patients' sera by indirect immunofluorescence. All patients were prospectively followed-up at the local Cardio-immunology outpatient clinic.

Results

After a median follow-up of 50 months (IQR 25–75), 366 patients (79%) were alive, while 42 (9%) were dead or underwent HTx; 58 were lost to follow-up. Ten-year survival free from death or HTx was overall 83%, but was lower in patients with EMB-proven myocarditis (76% vs 94% in patients with clinically suspected myocarditis, p&lt;0.001). On univariate analysis, predictors of death and HTx were female gender (p=0.003), previous myocarditis (p=0.03), heart failure on presentation and advanced NYHA class (p&lt;0.001, respectively), histological diagnosis of giant-cell myocarditis (p=0.002), positivity for anti-heart antibodies (AHA, p=0.04), anti-cardiac endothelial cell (AECA, p=0.002) and anti-nucleus antibodies (ANA, p=0.003). On multivariate analysis, female gender (HR 2.69, p=0.02), lower left ventricular ejection fraction on echocardiogram (p&lt;0.001), positivity for high-titre organ-specific AHA (HR 4.1, p=0.02) and for ANA (HR 5.1, p&lt;0.001) were independent predictors of death and HTx. Seventy-seven patients had relapsing myocarditis; on univariate analysis, young age (p&lt;0.001), previous myocarditis (p&lt;0.001), symptoms preceding diagnosis (p=0.004), positivity for anti-intercalated disk autoantibody (AIDA, p=0.02), and presence of diffuse late gadolinium enhancement (LGE) on CMR (p&lt;0.001) were predictors of relapse. On multivariate analysis young age (p=0.02) and previous myocarditis (HR 8.4, p&lt;0.001) were independent predictors of relapse. Predictors of death, HTx and relapse, respectively, did not differ when considering separately patients with EMB-proven myocarditis and those with clinically suspected myocarditis.

Conclusions

In the pre-immunosuppressive era, young age and a previous episode of myocarditis were independent predictors of relapse, female gender, left ventricular dysfunction at presentation and high-titre organ-specific AHA and ANA were independent predictors of death and HTx, suggesting that autoimmune features in myocarditis predict worse prognosis.

Funding Acknowledgement

Type of funding source: None

Late gadolinium enhancement location and transcatheter ablation efficacy in a large cohort of patients affected by myocarditis with arrhythmic manifestation

Introduction

Myocarditis is a complex inflammatory disease, usually secondary to viral infections or immune system dysregulation, with extremely heterogeneous clinical manifestations. Among them, potentially life-threatening ventricular arrhythmias (VA) may present at any stage of the disease as an expression of myocardial electrical instability.

Purpose

Our aim was to evaluate the efficacy of radiofrequency catheter ablation (RFCA) of VA in our large cohort of myocarditis, trying to understand the predictors of RFCA success.

Methods and results

144 patients (61 men; age 43 [29–54] years) with history of myocarditis with arrhythmic presentation (118 biopsy-proven, 82%) composed our population. At presentation, 26% of patients suffered of ventricular tachycardia (VT) while in 17% cardiac arrest occurred: overall 49 patients (35%) were implanted with an ICD. The median left ventricular ejection fraction (LVEF) was 58% (48–61%). An intensive non-invasive and invasive work-up was performed: 104 patients underwent cardiac magnetic resonance (CMR) that showed late gadolinium enhancement (LGE) in 67 of them (63%). In 37 patients LGE was found in the anteroseptal portion of the left ventricle: this pattern showed association with major arrhythmic relapse (VT and ventricular fibrillation) during follow up (Fig. 1; OR 4.0, CI 95% 1.14–14.1, p=0.03). 95 patients underwent endocardial RFCA, using contact electroanatomic mapping. Interestingly, in patients with anteroseptal LGE RCFA didn't affect significantly the arrhythmic relapse (OR 5, CI 95% 0.9–33, p=0.06). Otherwise RFCA prevent arrhythmic relapse in patients that showed LGE in ventricular portion other than the anteroseptal one (OR 0.027, IC 95% 0.002–0.40, p&lt;0.01). During a median follow-up of 735 days (418–2168) 6 deaths occurred: logistic regression on all-cause death showed LVEF and VT at presentation as the only independent predictors for mortality (p=0.01).

Conclusions

In myocarditis patients with VA, LGE pattern predicts arrhythmic relapse during follow-up. RFCA success rate is strictly linked to scar location, being significantly higher in patients with non-anteroseptal LGE.

Figure 1

Funding Acknowledgement

Type of funding source: None

Endomyocardial biopsy: what future in arrhythmogenic right ventricular dysplasia diagnosis?

Background

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a leading cause of sudden cardiac death, but its diagnosis is challenging and the role of endomyocardial biopsy (EMB) is controversial and has been recently questioned.

Purpose

We aimed to 1) analyse the role of EMB in improving the diagnostic performance of 2010 Task Force Criteria (TFC) in the diagnosis of ARVC; 2) assess EMB safety in our population.

Methods

We retrospectively analysed data from 54 consecutive patients admitted to our Hospital with a clinical suspicion of ARVC undergoing endomyocardial biopsy. During hospitalization a complete assessment was performed for every patient (including electrocardiogram, echocardiogram, cardiac MRI, genetic analysis, and electroanatomic-mapping-guided endomyocardial biopsy). ARVC diagnosis was assessed for every patient using both traditional 2010 TFC and a non-invasive modified TFC (2010 TFC criteria excluding biopsy).

Results

Overall, 9/54 (17%) patients showed a left-dominant variant of ARVC and were therefore excluded from the analysis. Non-invasive modified TFC allowed 16/45 (36%) patients to receive a definite diagnosis; when biopsy results were added the number of definite diagnosis increased to 22/45 (49%), increasing the number of patients with a definite diagnosis by 13%. More specifically: 8/11 patients not reaching a possible diagnosis were reclassified as either possible (4/8) or borderline (4/8); 3/9 patients with a possible diagnosis were reclassified as borderline; 6/9 borderline patients received a definite diagnosis of ARVC. Globally, in 6 out of 29 patients with a non-definite diagnosis, EMB confirmed ARVC diagnosis and 17/45 (38%) patients received an upgrade in their diagnostic status with EMB. Notably, EMB also revealed the coexistence of myocarditis and fibro-fatty replacement in 5/45 (9%) patients. No patient experienced complications related to EMB.

Conclusions

Endomyocardial biopsy is a safe, reliable, and useful tool for ARVC diagnosis, allowing to upgrade the diagnostic status of 38% of our patients with a suspect of ARVC diagnosis. It should be performed in experienced centers and it should be guided by electro-anatomic mapping, to maximize its diagnostic power.

Funding Acknowledgement

Type of funding source: None

Myocarditis and arrhythmogenic right ventricular cardiomyopathy: a diagnostic challenge

Background

Current arrhythmogenic right ventricular cardiomyopathy (ARVC) diagnostic criteria are mostly based on ventricle function and dimension. Previous studies have reported a significant overlap between ARVC and chronic myocarditis, at non-invasive assessment.

Purpose

Tto compare biopsy-proven ARVC and myocarditis patients, in order to identify clinical, imaging and invasive electroanatomic voltage mapping (EVM) differences between the two groups.

Methods

Patients with borderline diagnosis of ARVC or suspected myocarditis underwent compete assessment with cardiac magnetic resonance (CMR). All patients underwent endomyocardial biopsy (EMB) with targeted tissue sampling guided by EVM. All patients with an histological diagnosis of myocarditis or ARVC were included.

Results

83 patients were included, divided into 35 (42.2%) ARVC and 48 (57.8%) myocarditis. Among ARVC patients, 25 (71.4%) had right dominant ARVC, 5 (14.3%) left dominant patter and 5 (14.3%) bi-ventricular involvement. Nine patients (23.1%) with suspected clinic diagnosis of ARVC before EMB, received and histological diagnosis of myocarditis. Two (5.7%) patients with suspected myocarditis were proven to have ARVC. When comparing patients with ARVC and patients with myocarditis, univariate analysis showed that age, sex, family history, arrhythmic disorders at presentation and ECG abnormalities were similar between the two groups (P&gt;0.05 for all the variables). There was also no significant difference with regards to bi-ventricular function and dimension at CMR evaluation. More patients with myocarditis resulted positive at late gadolinium enhancement (LGE) evaluation, although non-significantly (P=0.082). Oedema was more frequently present in patients with myocarditis (P=0.01), while adipose tissue infiltration and segmental wall motion abnormalities were more often observed in patients with ARVC (P=0.002 and P&lt;0.001 respectively). At EVM analysis, a significant greater number of patients had a pathological uni- and bi-polar EVM (P&lt;0.05 in all cases) and the scar-area was greater in patients with ARVC: 18.8 vs 11.0 cmq (P=0.041).

Conclusion(s)

A significant number of patients who received a clinical diagnosis of Myocarditis or ARVC according to current guidelines, were subsequently reclassified after histological analysis. Patients with ARVC and myocarditis were not distinguishable on the basis of clinical features and ventricular function and dimensions. Conversely, tissue analysis with CMR demonstrated how patient with ARVC had less oedema, more adipose tissue infiltration and had more extensive scar at EVM evaluation.

Funding Acknowledgement

Type of funding source: None

Diagnostic yield of Electroanatomic voltage mapping in guiding Endomyocardial biopsies; a comparison with an MRI-guided approach

Background

Electroanatomic voltage mapping (EVM) is a promising modality for guiding Endomyocardial biopsies (EMB). Previous experiences on this techniques have reported safety and feasibility of this approach. These reports however, resulted limited by sample size or imperfect designs, preventing reliable comparisons of the effectiveness of this new methods with a conventional or a cardiac magnetic resonance (CMR) imaging guided approach.

Aim

We now report the largest cohort of patients undergoing EVM-guided EMB in order to show its diagnostic yield and comparing it with a cardiac magnetic resonance (CMR) guided approach.

Methods

One-hundred and sixty-two consecutive patients undergoing EMB at our Institution from 2010 to 2019 were included. Pathological areas identified at EVM and CMR underwent EMB. According to EMB results, CMR and EVM sensitivity and specificity regarding the identification of pathological substrates of myocardium were evaluated.

Results

A gadolinium-enhanced CMR had been performed in 143 (88.9%) of the population and yielded pathological findings in 121 (85.8%) of such cases. Late gadolinium enhancement (LGE) was present in 94 (70%) of the patients, while EVM identified areas of low voltages in 61%. Right (73%), left (19%) or both ventricles (8%) underwent sampling. EVM proved to have similar sensitivity to CMR (74% vs. 77%; P=0.479), with non-significantly higher specificity (70% vs. 47% P=0.738). In 12 patients with EMB-proven cardiomyopathy, EVM identified pathological areas, which had been undetected at CMR evaluation (concordance rate 53.8%; k = 0.26). Sensitivity of pooled EVM and CMR was as high as 95%. Five cases (3,8%) of cardiomyopathies were undetected by both CMR and EVM. Complications rate was low (4,9%), mostly vascular access related, with no patients requiring urgent management.

Conclusion

EVM proved to be a promising tool for targeted-EMB due to its sensitivity and specificity in identifying myocardial pathological substrates. EVM demonstrated to have an accuracy similar to CMR. EVM and CMR together conferred EMB a positive predictive value of 89%.

Funding Acknowledgement

Type of funding source: None

Procalcitonin in myocarditis patients: role in aetiology identification and risk stratification

Background

Procalcitonin (PCT) is an established predictor of bacterial infections and sepsis. However, PCT involvement in cardiovascular diseases has been scarcely investigated so far. In particular, no studies at all ever addressed the role of PCT in myocarditis patients.

We aimed at evaluating PCT in myocarditis patients, as a potential biomarker of: a) aetiologic diagnosis; b) prognosis.

Methods

A cohort of 130 consecutive patients with a novel diagnosis of myocarditis confirmed by both endomyocardial biopsy and cardiac magnetic resonance were included in the study. Patients with known bacterial infections or bacterial myocarditis were excluded (n=5). PCT concentration was measured on admission in all patients. Prospective follow-up (FU) was performed every 6 months up to 5 years.

Results

Of 125 patients analyzed (mean age 45±15 years, males 62%, mean LVEF 48±15%), 22 (18%) had fulminant myocarditis (FM). The remaining 103 cases had non-fulminant myocarditis (NFM), including infarct-like presentation and non-malignant arrhythmias. Aetiology was viral or virus-negative in 23 and 102 patients, respectively.

The mean PCT value was 0.44±0.18 mcg/ml, with no significant differences between viral and virus-negative myocarditis (0.43±0.19 vs. 0.44±0.18 mcg/ml, p=0.90).

Baseline PCT concentration was significantly higher in FM patients (0.69±0.21 vs. 0.39±0.16 mcg/ml, p=0.07). Consistently, PCT was higher in patients with LVEF &lt;60% (0.51±0.20 vs. 0.30±0.14 mcg/ml, p=0.03) and in those with elevated (&gt;400 pg/mL) NT-proBNP (0.55±0.19 vs. 0.36±0.17 mcg/ml, p=0.03). As for inflammatory biomarkers, patients with high ESR (&gt;20 mm/h) had also higher PCT values (0.56±0.20 vs. 0.37±0.16 mcg/ml, p=0.03). By converse, no association was found between PCT and CRP abnormal values (p&gt;0.05).

At univariate analysis, high PCT (≥0.20 mcg/ml) was predictive of heart failure recurrence (OR 2.77, 95% CI 1.18–6.48, p=0.02) or arrhythmic cardiac arrest (OR 3.22, 95% CI 1.19–8.71, p=0.02) by discharge, with overall hospitalization prolonged by 10±4 days (p&lt;0.05). Furthermore, patients with high PCT were more prone to myocarditis recurrences (13/80 vs. 4/45, p=0.03) by 5-year FU.

Conclusions

In myocarditis patients, elevated PCT values at presentation are not associated with myocarditis aetiology. Nonetheless, PCT suggests a worse short-term clinical outcome, and also a higher risk of myocarditis recurrences at long-term FU.

Funding Acknowledgement

Type of funding source: None

Filmin-c mutations in arrhythmogenic cardiomyopathy: a peculiar association with left dominat variant and high risk of sudden death

Introduction

Arrhythmogenic cardiomyopathy (AC) is characterized by myocyte necrosis and progressive fibro-fatty substitution. Recently, truncated mutations on Filamin C gene have been correlated with AC and a peculiar phenotype characterized by a prominent left ventricular fibrosis and high risk of sudden death.

Purpose

To evaluate clinical and instrumental features of subjects affected by AC in whom genetic study identified presence of truncating and missense mutations on FLNC gene.

Materials and methods

A population of 192 probands affected by AC according to 2010 Task Force Criteria or McKenna's proposed criteria for left dominant AC were evaluated for FLNC variants. In positive probands and families anamnestic and clinical data (ECG, echocardiographic and cardiac magnetic resonance (CMR), twenty-four-hours ECG monitoring) were evaluated.

Results

A total of 19 subjects (9 probands and 10 family members) were identified as carrier of nine different FLNC mutations (5 truncating and 4 missense). In 3 patients (23%) clinical onset was characterized by major arrhythmic episodes and in one (8%) by sudden death. In 6 (46%) ECG was unremarkable and the most common abnormalities were low QRS voltages in peripheral leads (85%), followed by T wave inversion in lateral (15%) and in inferior leads (16%). Twenty-four-hours ECG monitoring revealed a high arrhythmic burden (PVC &gt;500/die) in 6 cases (46%). CMR was performed in all patients. Four of them (31%) showed a LV dilatation, while in 2 cases (15%) a RV dilatation was present. In 8 (61%) a fatty infiltration was detected mainly affecting the left ventricle (6 cases, 46%). Moreover, late enhancement was present in 8 cases (62%), with a LV distribution.

Conclusions

This is the first studied population in which both truncating and missense variants were evaluated as causative of AC, confirming that FLNC gene mutations are rare (4% of probands without known AC causative mutations) and the prevalent clinical expression is a left dominant phenotype with a high degree of electrical instability and recurrence of sudden familial cardiac death.

Funding Acknowledgement

Type of funding source: None

Predictors of death and heart transplantation in biopsy-proven myocarditis: a machine-learning approach

Background

Risk stratification for death and heart transplantation (HTx) in myocarditis is complex. A random forest (RF) is a tree-based machine learning technique (MLT) which is being increasingly used for clinical data analysis; it allows the detection of complex relationships between the outcome of interest and the covariates, overcoming the limits of traditional statistical analysis (i.e. regression approaches). Purpose To assess the potential role of clinical and diagnostic features at presentation as predictors of death and HTx in biopsy (Bx)-proven myocarditis using RF. Methods From January 1993 to August 2019, we consecutively enrolled 357 patients with Bx-proven myocarditis (65% male, median age 39 years, interquartile range (IQR) 26–51). An RF approach for survival data was used. Variables included in the analysis were: histology type by Bx, NYHA, type of presentation (infarct-like, arrhythmia, heart failure), viral genome detection on Bx, serum antiheart (AHA), antiintercalated disk (AIDA), anticardiac endothelial cells (AECA), antinuclear (ANA) autoantibodies, immunosuppressive therapy, cardiac catheterisation (left ventricular enddiastolic volume (LVEDV), mean capillary wedge pressure, right and left ventricular enddiastolic pressure) and 2-D echocardiographic measures (LVEDV, left ventricular ejection fraction (LVEF) at presentation and at follow-up, right ventricular fractional area change (FAC%), right ventricular diastolic area). Results The median follow-up time was of 1352 days (IQR 423.25–2535.75). At the end of follow-up, 42 patients were dead or transplanted. The 1-year, 5-year, and 10-year survival probabilities were of 0.928, 0.854, and 0.817, respectively. The most relevant predictors of death or HTx identified by the RF algorithm (according to the variable importance measure) were histological type, NYHA, clinical presentation, LVEF, and FAC%. Among the circulating auto-antibodies AECA were found to be the most important. Histological type was the strongest predictor of death/HT (100% relative importance, (RI)), giant cell myocarditis having a lower survival probability compared to other types. The next stronger predictors were advanced (III-IV) NYHA and heart failure presentation with lower survival probabilities (90% and 84% RI respectively). AECA-positive patients had lower survival probability compared to AECA negative ones (20% RI). The RF algorithm revealed an excellent predictive performance in the correct identification of all alive patients, with only 5 dead patients being misclassified (balanced accuracy 94%).

Conclusions

Autoimmune features, i.e Giant cell myocarditis and AECA, as well as severity of heart failure and of left ventricular disfunction at presentation were the strongest predictors of dismal prognosis. Our RF approach provides a new automated powerful tool for accurate risk stratification for death/HTx in Bx-proven myocarditis.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Budget Integrato per la Ricerca dei Dipartimenti (BIRD, year 2019), Padova University, Padova, Italy (project Title: Myocarditis: genetic background, predictors of dismal prognosis and of response to immunosuppressive therapy.)

Cardiac magnetic resonance features of left dominant arrhythmogenic cardiomyopathy: differential diagnosis with myocarditis

Objectives

To identify potential imaging features at cardiac magnetic resonance (CMR) specific for left-dominant arrhythmogenic cardiomyopathy (LDAC) diagnosis.

Materials and methods

Between January 2011 and May 2016, we considered 36 consecutive stable patients with a recent diagnosis of significant VA and ECG morphology consistent with a LV origin, detection of potential LV arrhythmic substrate at CMR, undergoing a clinically-indicated LV endomyocardial biopsy. Exclusion criteria were history of known cardiac disease, contraindications to CMR and impaired CMR image quality. After application of these criteria, in 9 patients endomyocardial biopsy showed tissue abnormalities consistent with the diagnosis of LDAC. From the same CMR-endomyocardial biopsy registry, a second group of 9 consecutive patients with a histological diagnosis of previous myocarditis were identified.

Results

Mid-wall LGE in the interventricular septum was detected in 5 myocarditis, without findings in LDAC group (p=0.03), whereas subepicardial LGE at the level of posterolateral wall of LV was detected in 8 cases of LDAC vs. 2 cases of myocarditis (p=0.02). Fat infiltration, and particularly subepicardial posterolateral fat infiltration, was found in all LDAC patients vs. one myocarditis only (p&lt;0.01). No differences in other CMR findings or in any clinical or echocardiographic parameters were found between patients with a biopsy consistent with LDAC vs. patients in whom biopsy suggested myocarditis.

Conclusions

In patients with significant VA and ECG morphology consistent with a LV origin, identification of morpho-functional involvement of the subepicardial layer of LV posterolateral wall at CMR (LGE, fat infiltration, wall dyskinesis) is consistent with a diagnosis of LDAC.

Funding Acknowledgement

Type of funding source: None

Role of endomyocardial biopsy guided by electroanatomic voltage mapping for the diagnosis of cardiomyopathies in patients with arrhythmic presentation

Background

A myocardial substrate assessment through percutaneous endomyocardial biopsy (EMB) represents an important additional diagnostic test for cardiomyopathies when uncertainties remain after non-invasive evaluation. Yet, extensive application of EMB has been limited by the low sensitivity of biopsies. Electroanatomic voltage mapping (EVM) is a promising modality for guiding Endomyocardial biopsies (EMB).

Aim

The aim of our study is to evaluate the diagnostic yield of EVM-guided EMB and the role of histological analysis in the diagnosis of patients with suspected cardiomyopathies and arrhythmic presentation.

Methods

One-hundred and sixty-two consecutive patients undergoing EMB at our Institution from 2010 to 2019 were included. Demographics, clinical data, CMR data and peri-procedural complications were retrospectively retrieved. All procedures were guided by endo-cavitary EVM. According to non-invasive data collected before proceeding with EMB a suspected clinical diagnosis was expressed and compared to histological diagnosis

Results

One-hundred and sixty-two patients were included in the study. Mean age of the cohort resulted 40.9±14.7 years, with 26.5% of the included patients being females. ECG alterations were present in 51.3% of the population, with the most common abnormality being T wave inversion. Sustained or non-sustained ventricular tachycardia was registered in 51 (31.5%) of the patients, while 44 (27.2%) patients were referred for frequent isolated premature ventricular complex (PVC), and 19 (11.7%) after an episode of an arrhythmogenic syncope or resuscitated cardiac arrest. Suspected ARVC (41.6%) together with acute/chronic myocarditis (28.0%) were the main clinical diagnosis leading to an invasive approach. The sampling site was the right ventricle in 116 (72.5%), the left ventricle in 31 (19.4%), and both ventricles in 13 (8.1%) patients. Biopsy samplings were judged appropriate for histological analysis in 141 (87.0%) patients. Among the analyzed samples, a diagnosis was reached in 120 patients (74.1%). In the remaining 21 cases (25.9%), the analysis yielded nonspecific histologic findings, inconclusive results, or sampling error. The biopsy allowed to confirm the clinical diagnosis in 72 (60.0%) patients, while a different diagnosis was reached in 48 (39.0%) cases (Reclassification are showed Figure 1).In particular of 67 (41.6%) patients suspected for ARVC, only 32 (22.7) reached a confirmation. Conversely, the number of patients with acute/chronic myocarditis augmented from 45 (28.0%) to 47 (33.3%).

Conclusion

EMB guided by EVM reached a diagnostic yield as high as 74.1%. EMB proved to be a useful tool in the clinical management of patients, as it allowed to correctly reclassify a significant number of patients who would have been misdiagnosed based only on non-invasive assessment.

Sankey Diagram

Funding Acknowledgement

Type of funding source: None

Immunosuppression and outcomes of myocarditis patients presenting with ventricular arrhythmias

Background

Effects of immunosuppressive therapy (IST) on ventricular arrhythmias (VA) have not been reported in immune-mediated biopsy-proven myocarditis patients. Furthermore, myocarditis arrhythmic risk is still unpredictable. The aim of our study was to evaluate effectiveness of IST on VA in myocarditis patients, and stratify their arrhythmic risk, using clinical and diagnostic features, including serum organ-specific anti-heart (AHA) and antiintercalated-disk autoantibodies (AIDA).

Methods

From a cohort of 498 consecutive patients, we enrolled 255 cases with biopsy-proven virus-negative myocarditis and evidence of VA (VF, VT, NSVT, and Lown's grade ≥2 PVC) at index hospitalization. Serum AHA and AIDA were detected by a standardised indirect immunofluorescence technique. Whenever accepted and non-contraindicated, IST was started. Controls (IST-) were chosen after 1:1 matching to IST+ cases by age, gender, ethnicity, left ventricular ejection fraction, VA type, and treatment. Prospective follow-up (FU), occurred at defined timepoints.

Results

58 matched patient couples (42±13 y, 67% males, 50% IST+) were analyzed in the main study cohort. Overall, 28 (24%) had VT, and 62 (53%) were discharged with ICD. IST duration was 12±1 months. No patients died and no serious complications from IST occurred. By 24-month FU, major VA occurred in 6 IST+ vs. 10 IST- patients (p=0.420), with no cases of VT following IST termination. As compared to IST- ones, IST+ patients showed a significant reduction in NSVT and PVC burden, as well as an improvement in clinical, laboratory and imaging findings (all p&lt;0.05). Major VA onset and positive AIDA status were independently associated with major VA at FU (HR 14.2, 95% CI 2.9–68.7, and 8.0, 95% CI 2.6–25.2, respectively, both p&lt;0.001). Furthermore, in the whole study population (N=255), IST played as an independent protective factor from major VA (HR 0.3, 95% CI 0.2–0.7, p=0.005) at 38±21 months FU.

Conclusions

In immune-mediated virus-negative myocarditis patients presenting with VA, IST is feasible and effective on NSVT and PVC burden, as well as on structural, laboratory and imaging endpoints. Short-term effects are limited on major VA, which were independently associated with major arrhythmic onset and positive AIDA, in keeping with the proposed etiopathogenetic involvement of autoimmunity in virus-negative myocarditis.

Funding Acknowledgement

Type of funding source: None

P3684Detecting true left dominant arrhythmogenic cardiomyopathy: cardiac magnetic resonance imaging and an invasive diagnostic assessment to go beyond current diagnostic criteria

Background

Left-dominant arrhythmogenic cardiomyopathy (LDACM) represents an underdiagnosed subtype of the classical right-dominant ACM, with a fibro-fatty infiltration of the left ventricle ab disease initio. To date, ACM diagnosing criteria do not include any paradigm for LDACM and no shared consensus or position statement has been issued yet.

Purpose

To analyse the diagnostic work-up needed to reach a definite diagnosis in LDACM patients (pts).

Methods

All pts with a high clinical suspicion of ACM admitted at our institution were evaluated. Disease and familiar history, and both baseline ECG and cardiac ultrasound (US) were retrieved in all pts. Before invasive evaluation, all pts underwent cardiac magnetic resonance imaging (MRI) for morphology assessment and tissue characterization by late gadolinium enhancement (LGE). An invasive evaluation with an electrophysiological study (EPS) and an endo-cavitary electro-anatomical mapping (EAM) was then subsequently performed; EAM-guided endo-myocardial biopsy (EMB) was performed at physician discretion, for direct histological evaluation of myocardial substrate.

Results

30 ACM pts (53±6 y.o.; 66% male) were defined as LDACM; 22 (73%) pts presented unspecific ECG abnormalities, with 8 (27%) pts instead presenting negative t-waves in V4-V6. Cardiac US resulted unremarkable in 27 (90%) pts. Sustained ventricular arrhythmia with right bundle brunch block were experienced in 4 (14%) pts, while frequent premature ventricular beats with the same morphology in 10 (33%).

LDACM diagnosis was mainly suspected upon MRI evaluation: all 30 pts presented a late gadolinium enhancement (LGE) pattern revealing an isolate left ventricle fibro-fatty infiltration, with normal biventricular contractility (LV and RV ejection fraction 57±9% and 53±2%, respectively).

Right ventricular, left ventricular and biventricular endo-cavitary EAM was performed in 10 (33%), 11 (37%) and 9 (30%) pts respectively, revealing pathologically low unipolar voltages in 7 (23%) and both unipolar and bipolar low voltages in 15 (50%) pts. In 18 (60%) pts an EMB was performed, revealing in 15 (83%) a fibro-fatty infiltrate and a fibro-fatty infiltrated with a superimposed viral myocarditis in a single pt. Genetic testing was performed in 16 (53%) pts, of which 10 (33%) showed causative mutation of desmosomal genes.

If strictly adhering to the existing criteria, only 7 (23%) LDACM definite diagnosis would have been reached, even when using EMB and genetic testing.

LDACM EAM with late potentials

Conclusion

LDACM is an underestimated ACM subtype that require MRI evaluation and an invasive work-up for definite diagnosis. Although EMB and genetic testing being the most effective diagnostic tools currently at disposal adhering to existing criteria, a definite diagnosis could be reached only in a fraction of patient population. Existing diagnostic criteria should be revised, mainly to take in consideration EAM specific role and to properly define the LDACM entity.

P3682Myocardial structural abnormalities in nonischemic patients presenting with ventricular arrhythmias

Background

The diagnosis of concealed cardiomyopathies in patients with ventricular arrhythmias (VAs) is one of the major challenging issues faced by physicians.

Purpose

We aimed at reporting the cardiomyopathic substrate in patients with recurrent arrhythmias of ventricular origin.

Methods

Consecutive patients with unexplained VAs underwent a complete diagnostic work-out, including endomyocardial biopsy (EMB).

Results

Ninety-seven patients were enrolled (76.3% male, age 39.7±13.3 yrs). The presenting arrhythmic manifestation was aborted cardiac arrest in 30 (30.9%) patients, sustained ventricular tachycardia (VT) in 9 (9.3%), nonsustained VT in 15 (15.5%) and frequent premature ventricular complexes in 43 (44.3%). Overall, 350 biopsies were collected (3.6/patient). The incidence of procedure-related complications was 5.1% (n=5): 4 major complications (1 rupture of a tricuspid chorda tendinea w/o hemodynamic impairment, 1 dissection of right external iliac artery treated with stent, 1 thrombotic occlusion of left superficial femoral artery which required surgical treatment, 1 TIA) and 1 minor complication (groin hematoma) occurred. The final diagnosis was arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) (n=41; 42.3%), followed by myocarditis (n=20; 20.6%), dilated cardiomyopathy (n=6; 6.2%), cardiac sarcoidosis (n=6; 6.2%), and myocarditis in ARVD/C (n=5; 5.1%). Among the 25 patients whose final diagnosis was consistent with myocarditis, an acute stage of the disease was documented in 7 (7.2%), while a chronic myocarditis in 18 (18.5%). Additionally, according to medical history and diagnostic workout, in 2 of the 6 patients the dilated cardiomyopathy had a likely post-inflammatory etiology. Absence of myocardial abnormalities was documented in 15 (15.5%) patients: this group included 1 case of methadone-induced torsade de pointes. The remaining 4 (4.1%) patients were diagnosed with a cardiac hypertrophy (n=2, 2.1%, secondary to exercise or Fabry disease), a dilated mitochondrial cardiomyopathy (n=1, 1.0%), a dilated cardiomyopathy in Emery-Dreifuss muscular dystrophy (n=1; 1.0%).

Conclusion

In our series, approximately 45% of patients with unexplained VAs had a final diagnosis of ARVD/C.

P5557Cardiac autoantibodies and ventricular arrhythmias in patients with biopsy-proved myocarditis

Background

Cardiac autoandibodies have been associated with dilatative cardiomyopathy in subjects with inflammatory heart disease. However, their association with ventricular arrhythmias (VA) in patients with autoimmune myocardits has never been investigated so far.

Purpose

To evaluate the association between cardiac autoantibodies and both baseline and FU VA in patients with a de novo diagnosis of biopsy-proved autoimmune myocarditis.

Methods

We enrolled 44 consecutive patients (59% males, mean age 44±13y, mean LVEF 50±10%) presenting with symptomatic VA (VF, VT, NSVT, >1ehz746.0501 PVC/24h) and a de novo diagnosis of biopsy-proved autoimmune myocarditis according to the ESC criteria. Serum anti-heart (AHA) and anti-intercalated disk (AIDA) autoantibodies were assessed at a referral center at the time of the index hospitalization. Complete baseline data, including ECG, arrhythmia telemonitoring, echocardiogram, cardiac magnetic resonance (CMR) and blood biomarkers (T-troponin, NT-proBNP) were collected. The endpoint of the study was the occurrence of major VA (VT, VF, appropriate ICD shocks) at 5y FU, as assessed by 2/y Holter ECG monitoring and (when applicable) ICD interrogation.

Results

At baseline evaluation, 24 (55%) and 23 patients (52%) were AHA+ and AIDA+, respectively. Clinical onset with major VA was documented in 24 patients (55%): 9 AHA+ vs. 15 AHA- (p=0.017) and 13 AIDA+ vs. 11 AIDA- (p=0.547). At presentation, no significant differences were found between AHA+ vs. AHA- and AIDA+ vs. AIDA- patients in LVEDV, LVEF, T-troponin and NT-proBNP values (all p=n.s.). Positive (2/3) Lake Louise criteria at CMR were found in 33 patients (75%; p=n.s. among different subgroups). Before discharge, 27 subjects (61%) underwent ICD implant. Optimal medical treatment was started in all of the cases, with no significant differences in betablockers, antiarrhythmic drugs and immunsuppressive therapy, among different subgroups (all p=n.s.). Overall, 10 patients (23%) experienced major VA by 5y FU: 3 AHA+ vs. 7 AHA- (p=0.147) and 9 AIDA+ vs. 1 AIDA- (p=0.013). In particular, 18 events were documented (range 1–3 episodes per patient at 2.2±1.7 y mean FU), including 3 VT episodes and 15 appropriate ICD shocks. Taking together baseline and FU data, multiple (>1) major VA episodes occurred in 8 patients: 3 AHA+ vs. 5 AHA- (p=0.436) and 8 AIDA+ vs. 0 AIDA- (p=0.005). Of note, 3/3 AHA+ patients with multiple major VA espisodes were also AIDA+ (double positivity).

Conclusion

In biopsy-proved autoimmune myocarditis presenting with VA, major VA occurrence by 5y FU, as well as arrhythmias recurrences, are more common among AIDA+ patients. By converse, none of the isolated AHA+ cases experienced multiple episodes of major VA. These findings may suggest distinct pathophysiological mechanisms involving the different molecular targets of cardiac autoimmunity.

Acknowledgement/Funding

None

4252Additional value of stress testing for evaluation of ventricular arrhythmias in athletes undergoing preparticipation screening

Introduction

The optimal protocol of athletes pre-participation screening is a matter of debate. The aim of this study is to test the additional value of exercise testing (ET) for evaluation of ventricular arrhythmias (VA) in athletes with otherwise normal findings.

Methods

The study included 10,975 competitive athletes who underwent preparticipation screening including ECG and stress testing. Athletes with ≥3 isolated premature ventricular beats or ≥1 repetitive VA underwent second-line investigations (echocardiography and 24-hour ambulatory ECG monitoring with a training session) and, in case of frequent, complex or exercise-induced VA or echocardiographic abnormalities, also cardiac magnetic resonance (CMR).

Results

451 (4,1%) athletes were excluded for abnormalities at history, physical examination and baseline ECG. Among the remaining 10524 athletes, 524 (5%)showed VA at ET, 87 of whom underwent CMR.Echocardiography identified major cardiac abnormalities in 5 athletes and regional ventricular systolic dysfunction in 7, which were confirmed by CMR in 6. Other 12 patients with normal echocardiography had a positive CMR. In particular, in 16 subjects the CMR showed left ventricular late gadolinium enhancement suggesting myocardial fibrosis with a non-ischemic distribution. At multivariate analysis, VA observed at high work load at ET, the presence of complex VA at ET and the presence of a morphology other than infundibular or fascicular predicted an underlying pathological myocardial substrate while the presence of frequent (>500/24-hour) premature ventricular beats did not.

Predictors of underlying pathological myocardial substrate Substrate Univariate Multivariable YES (n=23) NO (n=501) OR (95% IC) P OR (95% IC) P Age 17 [13–43] 15 [14–17] 1.03 [0.98 -1.06] 0.18 – Male gender 15 (65%) 184 (37%) 3.2 [1.3–7.7] <0.001 1.6 [0.7–4.8] 0.28 >500 PVBs/24-hour 7 (30%) 98 (20%) 1.8 [0.7–4.5] 0.21 – VA at high work-load 10 (44%) 78 (16%) 4.2 [1.8–9.8] <0.001 1.6 [1.1–4.7] 0.02 Couplets/NSVT at ET 14 (61%) 117 (23%) 6.2 [2.5–15] <0.001 8.5 [2.5–29] 0.01 PVBs other than infundibular/fascicular 17 (74%) 118 (24%) 6.1 [2.4–16] <0.001 3.9 [1.4–11] 0.008

Conclusions

VA at ET may represent the only sign of a pathological myocardial abnormalities, such as the “isolated nonischemic left ventricular scar”, that could be the substrate for life-threatening ventricular arrhythmias. Addition of ET to baseline ECG may increase the sensitivity of PPE of competitive athletes.

P3687Abnormal voltage recordings in patients with ventricular arrhythmias: comparison between right and left cardiomyopathy

Background

Arrhythmogenic Cardio-Myopathy (ACM) is characterized by epi-endocardial fibro-fatty replacement. Depending on the most affected ventricle, right dominant (RDACM) or left dominant (LDACM) phenotypes can be defined. RDACM voltage mapping characteristics have already been described, with late potentials strongly correlating with arrhythmia recurrence risk; LDACM voltage features have not been described yet.

Purpose

To analyze voltage map characteristics in LDACM patients (pts) and compare them with RDACM; to assess if there is any correlation between late potentials and recurrence rate in LDACM as well.

Methods

We retrospectively enrolled all consecutive ACM patients treated c/o our center and diagnosed according to the 2010 Task Force Criteria. Procedural and follow up data were collected. Patient were sorted by ventricular involvement lateralization. Recurrence rates were evaluated and linearly regressed for the presence of late potentials.

Results

89 ACM patients were enrolled (67 RDACM, 22 LDACM; 76% males, 69±4 y.o.) in our study. All patients underwent endocardial voltage mapping; procedurally, 43 (48%) pts underwent catheter ablation, while 46 (52%) were managed conservatively with anti-arrhythmic drugs.

Bipolar pathological potentials were found in 43 (64%) and 13 (59%), unipolar pathological potentials in 45 (67%) and 14 (63%), while late potentials in 19 (31%) and 8 (36%) in the RDACM and LDACM group respectively [p = 0.66, p=0.63, and p=0.33].

The average follow-up was 18 months [14–48]; 15 (22%) in the RDACM and 9 (40%) in LDACM arrhythmic recurrences were respectively encountered; recurrences in both groups were regressed for the presence of late potentials. Results were as follows: the presence of late potentials correlated with recurrences with an 4,3 [1.15–16.1; p=0.03] OR and with an 11 [0.4–85; p=0.022] OR in the RDACM and LDACM group respectively.

Conclusion

Pathologically low unipolar, bipolar and late potentials can be found in comparable % both in RDACM and LDACM; like in RDACM, late potentials represent an important risk factor for arrhythmic recurrence in LDACM as well.

P3828Zebrafish models for arrhythmogenic cardiomyopathy type 8: a starting platform for exercise stress test and drug treatment

Background

Arrhythmogenic Cardiomyopathy (AC) is an inherited heart disease characterized by progressive substitution of the myocardium with fibro-fatty tissue, leading to electrical instability and high risk of sudden death, particularly in young subjects and athletes. In recent years, our laboratory has produced zebrafish (zf) mutant lines modelling AC type 8, an AC form linked to mutations in the junctional protein Desmoplakin (Dsp). Mutations in the DSP gene have been identified in both dominant and recessive AC cases, characterized by left-dominant and biventricular forms of the disease. Sports medicine has highlighted that they are the most dangerous forms, being less easily identifiable by ECG.

Purpose

Taking advantage of our zf Dsp mutant lines, we aim to fully characterize the pathological phenotype, analyze the perturbation of cell communication pathways, evaluate the role of the physical exercise, and test the efficacy of candidate drugs.

Methods

Among our zf lines we have identified double mutant animals, bearing both zf dspa and dspb mutations in heterozygous condition, as the best model able to recapitulate the human AC phenotype. This model underwent physical stress tests in the presence/absence of candidate drug treatment. Phenotyping included heart rhythm measurement, gene expression analysis using Real Time PCR and signaling pathway transgenes, immune-histochemistry, whole-mount in situ hybridization, standard histology and ultrastructural TEM analysis.

Results

Preliminary results from mutant phenotyping indicate alterations in heart rate, sudden cardiac death, structural alterations of the myocardium associated with junctional disorganization and, in parallel, dysregulation of Wnt, Hippo and TGFbeta pathways. Specifically, Dsp mutant animals can range from an 8% decrease to a 14% increase of heart rhythm compared to the physiological range (120–140 beats per minute in zf larvae). At the adult stage, about 1% of the fish mutant population dies suddenly. The histological examination shows a 50% reduction of the myocardial cell mass, in parallel with a 50% decrease of Dsp signal, detected by TEM, associated with the so-called “pale desmosome” phenotype. Signaling dysregulation includes an 80% loss of Wnt/Beta-catenin, a 300% increase of TGFbeta and a 500% increase of Hippo/YAP-TAZ signaling in the cardiac tissue. Physical stress tests and pathway-directed drug treatment have clarified that these factors can modulate the pathological phenotype, as preliminarily evidenced by the rescue of Wnt signal decrease to normal levels through SB216763 treatment of Dsp-deficient individuals at rest.

Conclusion

Preliminary evidences corroborate the zf organism as a suitable model for AC cellular and molecular phenotyping, exploitable for the dissection of the genetic events leading to the onset and progression of the disease, and applicable to the analysis of chemical and mechanical modulators of AC-associated features.

Acknowledgement/Funding

Cariparo 2017 SHoCD; TRANSAC; CPDA133979/13; RP-2014-ehz745.06700394

P4652Magnetic resonance and electroanatomical guided endomyocardial biopsy as a diagnostic tool in the clinician's box: a 5 year experience

Background

Percutaneous endo-myocardial biopsy (EMB) is an invasive diagnostic test used to reach or confirm a diagnosis when structural or substrate anomalies are suspected, such as in cardiomyopathies or myocarditis evaluation. In recent years, cardiac magnetic resonance imaging (MRI) and endo-cavitary electro-anatomical mapping (EAM) have been used to localize the most significant myocardial area to sample, therefore increasing EMB overall effectiveness and reliability.

Purpose

To describe and characterize safety, feasibility and anatomical findings of a large cohort of patients (pts) undergoing diagnostic EMB and to assess its impact on the treatment decision making algorithm.

Methods

A cohort of all pts undergoing a percutaneous EMB at our Institution from January 2014 to January 2019 was analyzed. All EMB procedures were guided by a pre-procedural cardiac MRI radiological alteration analysis and an endo-cavitary EAM. Intra-cardiac echography (ICE) was used in all procedures, to directly visualize the sample area and to evaluate in real time post-EBM complications. Demographics, clinical data, MRI data, pathological EMB features, and peri-procedural data were systematically retrieved.

Results

One-hundred and eleven pts were enrolled (78% male, 47±4 y.o., 33% athletes). EMB indication was abnormal MRI findings in 94 (85%), pathological EMB voltages in 10 (9%) and clinical suspect and patient history in 7 (6%) pts.

EMB sample area was determined by both MRI and EAM pathological area analysis in 92 (83%) pts, while by EAM alone in 19 (17%) pts (n=6 pathological unipolar EAM; n=13 bipolar and unipolar pathological EAM). The sample site was the right ventricle in 89 (80%), the left ventricle in 20 (18%), and both in 3 (2%) pts.

In 103 (93%) pts a concomitant electrophysiological induction study was performed (40% positive for sustained ventricular arrhythmias) and 35 (32%) pts underwent a trans-catheter ablation (TCA) (n=8 epicardial TCA; n=2 endo-epicardial TCA; n=25 endocardial ATC). Only 2 (2%) peri-procedural adverse events were witnessed, specifically femoral pseudo-aneurysms, requiring surgical repair. EMB analysis allowed to confirm 58 (52%) pre-procedural diagnosis and to reach 32 (29%) new diagnosis, while resulting inconclusive or non-specific in the diagnostic process only in 21 (19%) cases [Figure1]. A total of 33 (30%) intra-cardiac devices (ICDs) were implanted contextually in the cohort, of which 9 (8%) solely upon EMB indication; in 4 (4%) other patients, biopsy represented a strong decisional factor in the multi-modality decision process for abstaining from ICD implant.

Dashed lines: diagnosis changed upon EMB

Conclusion

MRI and EAM guided EMBs allowed to finely define a large cohort of patients by representing a disease defining parameter in over 80% of the enrolled pts while and a decision shifting parameter in ICD implant algorithm in a high % of pts.

P5695Catheter ablation of ventricular tachycardia in patients with acute vs. previous myocarditis

Background

Ventricular tachycardias (VT) may occur late after myocarditis, as well as in the acute inflammatory phase of the disease. However, the role of catheter ablation (CA) in preventing VT recurrences in patients with acute (AM) vs. previous myocarditis (PM) has never been investigated so far.

Purpose

To evaluate the results of CA performed in patients presenting with VA and biopsy-proved myocarditis at different inflammatory stages.

Methods

We enrolled 46 consecutive patients (74% males, mean age 43±12y, mean LVEF 46±9%) with myocarditis and VT at index hospitalization. Based on endomyocardial biopsy and cardiac magnetic resonance (CMR) results, the patients were divided into AM and PM groups: in AM group, myocarditis was biopsy-proved, according to the ESC criteria; PM patients had a history of biopsy-proved myocarditis more than 12 months before, with no current signs of active inflammation (negative biopsy according to the ESC criteria; nonischaemic LGE at CMR with negative Lake-Louise criteria; absence of unexplained troponin abnormalities). ICD were implanted upon clinical indications. All of the patients underwent electroanatomical mapping (EAM) and VT CA. During 3 (2.5–3.5)y FU, VT recurrences were evaluated by 2/y Holter ECG and ICD interrogation.

Results

At baseline, 23 patients (50%) had AM, and 23 PM. Overall, 16 AM and 21 PM patients underwent ICD implant (p=n.s.). The clinical VT was monomorphic in 22 AM and 23 PM patients, respectively (p=n.s.) with a dominant right-bundle branch block with superior axis (RS) morphology in both groups (16 AM vs. 17 PM cases, p=n.s.). However, RS morphology was associated with left ventricular inferoposterior LGE at CMR in 9/16 AM vs. 17/17 PM patients (p=0.003). Similarly, inferoposterior localization of low-voltage areas at EAM was found in 11/16 AM vs. 17/17 PM patients (p=0.018). Furthermore, CMR showed a greater LGE transmural extension in AM patients (65±19%) as compared to PM ones (40±25%, p<0.001). Epicardial EAM and CA were performed in 14 AM vs. 15 PM patients, with endocardial-only approach adopted in the remaining cases (p=n.s.). VT CA was defined as successful (class A) in all of the subjets. However, during FU VT recurrences were documented in 7/23 AM vs. 0/23 PM patients (p=0.009). Four AM cases underwent redo CA late after myocarditis (1.5±0.3y after index hospitalization), with no further VT recurrences in FU.

Conclusion

In myocarditis patients presenting with VT, CA results are significantly better in PM cases as compared to AM ones. These findings are consistent with the different underlying substrate, and suggest the best role for ablation strategy after myocarditis healing.

Acknowledgement/Funding

None

P5560Assessing etiology in a cohort of patients with myocarditis presenting with complex ventricular arrhythmias: can the percutaneous endomyocardial biopsy help?

Background

Myocarditis represents a common but often under-diagnosed disease, with a wide range of clinical presentations; diagnosis is often presumptive and a clear etiology leading to a specific therapeutic approach is usually not identified.

Purpose

To describe and assess disease etiology in a cohort of myocarditis patients (pts) with arrhythmic presentation undergoing an invasive diagnostic work-up.

Methods

All pts with myocarditis presenting with ventricular arrhythmias undergoing an electro-anatomical mapping (EAM) guided endo-myocardial biopsy (EMB) at our institution were enrolled. All enrolled pts also underwent cardiac magnetic resonance imaging (MRI) and an electrophysiological study (EPS). Demographics, arrhythmic presentation, MRI data, arrhythmic inducibility at EPS, EAM and EMB biopsy data were retrieved and analyzed. Molecular biology testing for cardio-tropic virus genome as well as leukocyte immunohistochemical typization were routinely performed on all EMB samples.

Results

Twenty-six pts were enrolled (85% male, 39±6 y.o.). Clinical presentation was an organized ventricular arrhythmia in 16 (62%) pts (n=3 non-sustained ventricular arrhythmia; n=9 sustained ventricular arrhythmia; n=4 ventricular fibrillation) while frequent (>10.000) premature ventricular complexes (PVCs) in the remaining 10 (38%) pts.

MRI showed a late gadolinium enhancement (LGE) pattern consistent with myocarditis in all pts (35% left LGE; 65% right LGE). At the EPS, 10 (38%) pts showed inducibility for SVTs and underwent an intra-cardiac defibrillator (ICD) implant, while 4 (16%) more were implanted for secondary arrhythmic prevention.

EAM was performed in 18 (70%), 6 (22%) and 2 (8%) pts in the right, left and in both ventricle respectively; in all cases, abnormal myocardial voltages were retrieved in the area showing LGE at MRI. Extensive myocardial scarring was detected in 7 (27%) pts.

All EMB were performed without peri-procedural complications; inflammatory infiltrate and substrate alteration consistent with myocarditis were retrieved in 100% of the bioptic samples. Viral genome was identified in 13 (50%) samples (n=5 Human Herpes Virus 6; n=2 Parvovirus B 19; n=3 Adenovirus; n=1 Ebstein Barr Virus; n=1 Cytomegalovirus; n=1 Rhinovirus) and specific human immunoglobulin treatment was undergone by a single pt; eosinophilic infiltration was found in 2 (8%) patients; lymphocite invasion and auto-antibodies consistent with auto-immune myocarditis were detected in 2 (8%) patients and appropriate immunosuppressive therapy was started, while a myocardial band contraction pattern typical of toxic myocarditis was found in a single (4%) patient [Figure 1].

Different Myocarditis Etiology Rates

Conclusion

In our myocarditis cohort, EMB confirmed viruses to represented the first myocarditis etiological agent. Despite an invasive work-out, 31% of the cohort etiology still remains unclear.

P307Magnetic resonance, electroanatomical mapping, and endomyocardial biopsy to solve the diagnostic and sport eligibility dilemma in a cohort of competitive athletes with ventricular arrhythmias

Background

Ventricular arrhythmias (VAs) are a frequent finding in agonist athletes (athl) at routine sport medicine visits. VAs impact on sport eligibility, their management, and the sudden arrhythmic death risk evaluation in athletes currently represents one of the greatest challenges across both the cardiology and sport medicine field.

Purpose

To describe how an advanced multi-methodical evaluation allowed diagnosis, risk stratification, targeted therapy and sport eligibility reassessment in a competitive athl cohort with ventricular arrhythmias and pathological findings at magnetic resonance (MR).

Methods

All consecutive competitive athl with denied sport eligibility due to ventricular arrhythmias that underwent an advanced invasive evaluation at our institute were enrolled.

A baseline and stress ECG, and late gadolinium enhanced evaluation (LGE) at MR were performed prior to invasive evaluation in all athl.

Invasive evaluation performed in all athl comprised of an electrophysiological study (EPS) to assess arrhythmic inducibility, an endo-cavitary electro-anatomical mapping (EAM), and a EAM and MR guided endo-myocardial biopsy (EMB). A defined diagnosis was postulated in all cases, specific therapeutic interventions were started and sport eligibility status reassessed after 6 months from discharge.

Results

Thirty-two competitive athl were enrolled in our study (32±6 y.o.; 77% male; 4±1 1h-training session/week); 26 (81%) athl practiced a mixed aerobic-anaerobic, 5 (16%) a pure-aerobic, while only 1 (3%) a pure anaerobic sport.

Arrhythmic presentation leading to sport eligibility revoke was: in 13 (40%) athl frequent (>2000/day) premature ventricular contractions (PVCs) at rest, in 2 (6%) PVCs during stress ECG, in 6 (18%) non-sustained ventricular tachycardia (VT), in 8 (25%) sustained VT, and in 3 (11%) ventricular fibrillation/cardiac arrest during sport practice.

MR alterations were described in all cases, and LGE at MR was found in 31 (87%) athl; a definite radiological diagnosis was obtained in 13 (40%) athl.

A normal myocardium at EMB was found only in 3 (8%) pts; in 15 (45%) a leukocyte infiltrate pattern compatible with myocarditis, in 11 (39%) fibro-fatty replacement, in 2 (5%) a mitochondrial disease and in 1 (3%) a sarcoidosis were proven, and diagnosis were consequently postulated.

EPS showed complex VAs inducibility in 8 (25%) cases, while a trans catheter ablation was performed in 10 (31%) athl. A total of 9 (28%) implantable cardioverter devices (ICDs) were implanted, for primary or secondary prevention.

According to invasive diagnostic findings and sport medicine guidelines, 8 (25%) athl had their sport eligibility statuts re-instated.

Conclusion

An invasive multi-methodical assessment allowed in all cases to reach a diagnosis and to start a targeted therapy in a cohort of competitive athl with VA and a pathological MR, granting in a significant (25%) percentage sport eligibility status re-instatement.

P5563Biopsy proven myocarditis: clinical and instrumental predictors of adverse prognosis at presentation

Background

Myocarditis is an insidious and potentially fatal illness with different clinical presentations and an unpredictable course. Prompt recognition of high risk patients is of paramount importance in preventing major adverse events.

Purpose

To identify predictors of dismal prognosis in a large cohort of patients with biopsy proven myocarditis.

Methods

Univariate analysis was used to identify predictors of death and heart transplant in a prospective cohort of 366 patients with biopsy proven myocarditis (aged 38±17, male 66%) using student's test and contingency tables as appropriate.

Results

At the time of follow up 46 patients (13%) were dead or received heart transplant (DHTX), 283 (77%) were alive (A) and 37 (10%) lost at follow up. Age at presentation was 33±20 y in DHTX v.s 39±15 in A cohort (p=0.057). Clinical features predicting adverse prognosis included female gender (p=0.002), heart failure at presentation (p=0.000), NYHA class II to IV (p=0.000). Clinical and radiographic signs of both left and right heart failure suggested worse outcome (p=0.000) as well as ongoing anticoagulation therapy (p=0.009). On ECG right (R) or left (L) axis deviation was a strong predictor of events (p=0.000). From an echocardiography perspective the presence of mild to severe mitral regurgitation (p=0.03), reduced left ventricular systolic function (FE) (p=0.000), reduced right ventricular fractional area change (FAC) (p=0.035) was strongly correlated to death or heart transplant. On cardiac catheterization the variables predicting unfavourable outcome included reduced left ventricular systolic pressure (LVSP) (p=0.000), reduced mean aortic pressure (mAP) (p=0.002), increased mean right atrial pressure (RAP) (p=0.001), FE on angiography (p=0.000). On cardiac biopsy (Bx) negative predictors were giant cell histology type (p=0.000) and PCR positive for viral genome (p=0.02) particularly for parvovirus B19 (p=0.04), adenovirus (p=0.04), and Epstein Barr virus (EBV) (p=0.03). See Tab 1

Table 1

Conclusion

Female gender, HF like presentation, reduced LV and RV systolic function, R or L axis deviation on ECG, presence of viral PCR or giant cell histology on Bx, reduced LVSP and mAP; increased RAP may be useful parameters to identify high risk patients on presentation. This may increase clinical efforts and surveillance in this subgroup in order to reduce the incidence of major adverse events.

P5556Impact of viral genome detection in endo-myocardial biopsy of arrhythmogenic cardiomyopathy substrate

Background

Arrhythmogenic cardiomyopathy (ACM) is a genetically inherited cardiomyopathy characterized by myocardial fibro-fatty replacement. A pathogenetic role of viral myocardial infections in ACM natural history has been proposed over the years, although no definitive conclusion has been reached yet.

Purpose

To describe viral genome presence into a cohort of ACM biopsy proven patients (pts) and its impact on clinical features and outcome.

Methods

A cohort of all ACM pts undergoing an invasive third level evaluation at our institution was enrolled. All pts underwent a cardiac magnetic resonance (MR), an invasive electrophysiological study (EPS) with endo-cavitary electro-anatomical mapping (EAM), and a EAM guided endo-myocardial biopsy (EMB). Viral genome research through molecular biology techniques was performed on all biopsied samples.

According to arrhythmic risk evaluation, a trans-catheter ablation (TCA) and/or an internal cardioverter device (ICD) implant was performed. Clinical arrhythmic presentation, MR data, arrhythmia inducibility at EPS, EAM and EMB characteristic, and arrhythmic events at a 12-month follow up visit were retrieved in all pts and compared between the viral genome positive (v+ACM) and negative group (v-ACM).

Results

Forty-five pts were enrolled in our study (48±13 years; 66% male); the EMB samples of 7 (15%) pts presented a lymphocytic infiltrate and tested positive for viral genome (n=3 B19 Parvovirus; n=2 for Citomegalovirus; n=2 for Ebstein-Bar Virus) [Figure1].

At arrhythmic presentation, complex ventricular arrhythmias (NSVT, SVT and FV) were more frequent in the v+ACM group (86% vs 50%; p=0.039). Both left and right ventricular ejection fraction at MR resulted more depressed in the v+ACM group (44±7 vs 52±2 and 47±2 vs 52±2; p=0.047 and p=0.041). Complex ventricular arrhythmia inducibility at EPS was more frequent in v+ACM (72% vs 34%; p=0.032), while no differences in pathological potentials rate and extension at unipolar and bipolar EAM were found. TCA was performed in 55% and 57% and an ICD was implanted in 29% and 42% in the v+ACM and v-ACM group respectively. No differences in 12-months arrhythmic event rates (39% vs 42%) between the two groups were described.

EBM at different magnifications/stains

Conclusion

In our cohort a viral infection super-imposed to the fibrofatty infiltration was found in 15% of the patients. ACM pts testing positive for viral genome at the EMB had a more severe arrhythmic disease presentation, a more impaired heart function, and a higher rate of complex ventricular arrhythmias at disease presentation, but seemed to respond as well as viral genome negative ACM to ablative and pharmacological treatment