138 OUTCOME AND MORPHO-FUNCTIONAL CHANGES ON CARDIAC MAGNETIC RESONANCE IN PATIENT WITH ACUTE MYOCARDITIS FOLLOWING MRNA COVID 19 VACCINATION

Background

MessengerRNA (mRNA) COVID-19 vaccination has been associated with a higher-than-expected occurrence of acute myocarditis. Scarce information is available on mid-term prognosis and changes in cardiac function, volumes, and tissue characterization on cardiac magnetic resonance (CMR).

Methods

Retrospective, multicenter study including patients with a definite diagnosis of acute myocarditis within 30 days from mRNA COVID-19 vaccination, with a confirmed myocarditis diagnosis based on endomyocardial biopsy (EMB) or autopsy or by the coexistence of positive biomarkers (troponin >99th upper reference limit or elevated creatine kinase myocardial band [CK-MB]) and cardiac MRI findings consistent with AM according to the 2018 updated Lake Louise Criteria.

Results

77 patients (median age 25 years [IQR 20-35], 15% female) were included and followed-up for 147 days [IQR 74-215]. Follow-up CMR was available in n=49 patients and showed no changes in biventricular ejection fraction (EF) as compared to CMR at diagnosis (left ventricular EF: 59%[55-65]vs. 60%[57-64], p=0.507, right ventricular EF: 56%[52-62]vs. 57%[52-61], p=0.563, respectively). Late gadolinium enhancement was present in all patients at diagnosis and persisted in only n=39 (79.6%) at follow-up (p=0.001), generally sparing the anterior wall and the septum. N=10 (20.4%) had a persistent edema based on T2-weighted short tau inversion recovery (STIR) sequences, with predominant involvement of inferior or inferior-lateral walls. The proportion of patients with increased T1 and T2 mapping signals significantly decreased at follow-up (n=13 (68%) vs. n=4 (13%),p<0.001, and n=21 (84%) vs. n=3 (10%),p<0.001, respectively), as well as the presence of pericardial effusion (n=16 (33%) vs. n=3 (6%),p=0.004).

No differences in morpho-functional CMR parameters based on the type of vaccine administered were found (BNT162b2 Pfizer/BioNTech®, n=36, 73.5%, m-RNA-1273 Moderna®, n=13, 26.5%).

Among patients with available follow-up (N=75, 97.4%), no major adverse cardiovascular events nor myocarditis recurrence or death were reported.

Conclusions

At mid-term follow-up, patients who experienced an acute myocarditis after a mRNA COVID-19 vaccine had preserved biventricular EF. The rate and localization of residual scar or edema on CMR is in line with classic viral myocarditis with a good prognosis. This new piece of information should further reassure patients who experience acute myocarditis after mRNA COVID-19 vaccination.

Prognostic impact of plasma level of NT-pro BNP in patients with microvascular angina – a report from the international cohort study by COVADIS

Aims

Although the importance of microvascular angina (MVA) has been emerging, prognostic biomarkers for MVA remain to be developed. We thus aimed to examine whether plasma level of N-terminal prohormone of brain natriuretic peptide (NT-pro BNP) could predict the prognosis of MVA patients.

Methods

In the international prospective cohort study of MVA patients by the Coronary Vasomotor Disorders International Study (COVADIS) group, we evaluated the association between plasma level of NT-pro BNP and the incidence of major adverse cardiovascular events (MACE), including cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and hospitalization due to heart failure or unstable angina.

Results

We examined a total of 226 MVA patients (M/F 66/160, 61.9±10.2 [SD] years) with both plasma NT-pro BNP levels and echocardiographic data in the COVADIS study. Plasma NT-pro BNP level was elevated (median 94 pg/ml, IQR 45–190) while mean LVEF (69.2±10.9%) and E/e' (10.7±5.2) were almost normal. During follow-up period of a median of 365 days (IQR 365–482), 29 MACEs occurred. ROC curve analysis identified plasma NT-pro BNP level of 78 pg/ml as the optimal cut-off value. Multivariable logistic regression analysis revealed that plasma NT-pro BNP level ≥78 pg/ml significantly correlated with the incidence of MACE (odds ratio (OR) [95% confidence interval (CI)] 3.11 [1.14–8.49], P=0.03). When divided into 2 groups by NT-pro BNP 78 pg/ml, the Kaplan-Meier survival analysis showed a significantly worse prognosis in the group with NT-pro BNP ≥78 (log lank, P=0.03) (Figure).

Conclusions

These results indicate that plasma NT-pro BNP level is a novel prognostic biomarker for MVA patients.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Japan Heart Foundation

C65 POST–DISCHARGE ARRHYTHMIC RISK STRATIFICATION OF PATIENTS WITH ACUTE MYOCARDITIS AND LIFE–THREATENING VENTRICULAR TACHYARRHYTHMIAS

Aims

The outcomes of patients presenting with acute myocarditis and life–threatening ventricular arrhythmias (LT–VA) are unclear. The aim of this study was to assess the incidence and predictors of recurrent major arrhythmic events (MAEs) after hospital discharge in this patient population.

Methods and Results

We retrospectively analysed 156 patients (median age 44 years; 77% male) discharged with a diagnosis of acute myocarditis and LT–VA from 16 hospitals worldwide. Diagnosis of myocarditis was based on histology or the combination of increased markers of cardiac injury and cardiac magnetic resonance (CMR) Lake Louise criteria. MAEs were defined as the relapse, after discharge, of sudden cardiac death or successfully defibrillated ventricular fibrillation, or sustained ventricular tachycardia (sVT) requiring implantable cardioverter–defibrillator therapy or synchronized external cardioversion. Median follow–up was 23months [first to third quartile (Q1–Q3) 7–60]. Fifty–eight (37.2%) patients experienced MAEs after discharge, at a median of 8 months (Q1–Q3 2.5–24.0 months; 60.3% of MAEs within the first year). At multivariable Cox analysis, variables independently associated with MAEs were presentation with sVT [hazard ratio (HR) 2.90, 95% confidence interval (CI) 1.38–6.11]; late gadolinium enhancement involving ≥2 myocardial segments (HR 4.51, 95% CI 2.39–8.53), and absence of positive short–tau inversion recovery (STIR) (HR 2.59, 95% CI 1.40–4.79) at first CMR.

Conclusions

In this international multicentre study, patients discharged free from HTx or LVAD after an acute myocarditis complicated by LT–VA had a recurrence of MAEs during follow–up of 37.2%, after a median time of 8 months. Initial CMR pattern and sVT at presentation stratify the risk of arrhythmia recurrence.

Epicardial adipose tissue characteristics, obesity and clinical outcomes in COVID-19: A post-hoc analysis of a prospective cohort study

BACKGROUND AND AIMS

Obesity-related cardiometabolic risk factors associate with COVID-19 severity and outcomes. Epicardial adipose tissue (EAT) is associated with cardiometabolic disturbances, is a source of proinflammatory cytokines and a marker of visceral adiposity. We investigated the relation between EAT characteristics and outcomes in COVID-19 patients.

METHODS AND RESULTS

This post-hoc analysis of a large prospective investigation included all adult patients (≥18 years) admitted to San Raffaele University Hospital in Milan, Italy, from February 25th to April 19th, 2020 with confirmed SARS-CoV-2 infection who underwent a chest computed tomography (CT) scan for COVID-19 pneumonia and had anthropometric data available for analyses. EAT volume and attenuation (EAT-At, a marker of EAT inflammation) were measured on CT scan. Primary outcome was critical illness, defined as admission to intensive care unit (ICU), invasive ventilation or death. Cox regression and regression tree analyses were used to assess the relationship between clinical variables, EAT characteristics and critical illness. One-hundred and ninety-two patients were included (median [25th-75th percentile] age 60 years [53-70], 76% men). Co-morbidities included overweight/obesity (70%), arterial hypertension (40%), and diabetes (16%). At multivariable Cox regression analysis, EAT-At (HR 1.12 [1.04-1.21]) independently predicted critical illness, while increasing PaO₂/FiO₂ was protective (HR 0.996 [95% CI 0.993; 1.00]). CRP, plasma glucose on admission, EAT-At and PaO₂/FiO₂ identified five risk groups that significantly differed with respect to time to death or admission to ICU (log-rank p < 0.0001).

CONCLUSION

Increased EAT attenuation, a marker of EAT inflammation, but not obesity or EAT volume, predicts critical COVID-19.

TRIAL REGISTRATION

NCT04318366.

An EAPCI Expert Consensus Document on Ischaemia with Non-Obstructive Coronary Arteries in Collaboration with European Society of Cardiology Working Group on Coronary Pathophysiology & Microcirculation Endorsed by Coronary Vasomotor Disorders International Study Group

This consensus document, a summary of the views of an expert panel organized by the European Association of Percutaneous Cardiovascular Interventions (EAPCI), appraises the importance of ischaemia with non-obstructive coronary arteries (INOCA). Angina pectoris affects approximately 112 million people globally. Up to 70% of patients undergoing invasive angiography do not have obstructive coronary artery disease, more common in women than in men, and a large proportion have INOCA as a cause of their symptoms. INOCA patients present with a wide spectrum of symptoms and signs that are often misdiagnosed as non-cardiac leading to under-diagnosis/investigation and under-treatment. INOCA can result from heterogeneous mechanism including coronary vasospasm and microvascular dysfunction and is not a benign condition. Compared to asymptomatic individuals, INOCA is associated with increased incidence of cardiovascular events, repeated hospital admissions, as well as impaired quality of life and associated increased health care costs. This consensus document provides a definition of INOCA and guidance to the community on the diagnostic approach and management of INOCA based on existing evidence from research and best available clinical practice; noting gaps in knowledge and potential areas for further investigation.

[ANMCO/SIC Consensus document on the management of myocarditis]

Myocarditis is an inflammatory heart disease that can occur acutely, as in acute myocarditis, or persistently, as in chronic myocarditis or chronic inflammatory cardiomyopathy. Different agents can induce myocarditis, with viruses being the most common triggers. Generally, acute myocarditis affects relatively young people and men more than women. Myocarditis has a broad spectrum of clinical presentations and evolution trajectories, although most cases resolve spontaneously. Patients with reduced left ventricular ejection fraction, heart failure symptoms, advanced atrioventricular block, sustained ventricular arrhythmias or cardiogenic shock (the latter known as fulminant myocarditis) are at increased risk for death and heart transplantation. The presentation of chronic inflammatory cardiomyopathy may be more subtle, with progressive symptoms of heart failure or appearance of rhythm disturbance, not rarely preceded by an infective episode. Autoimmune disorder or systemic inflammatory conditions can be another significant predisposing substrate of myocarditis, especially in women. Emerging causes of myocarditis are drug-related like the new anticancer therapies, the immune checkpoint inhibitors. In this Italian Association of Hospital Cardiologists (ANMCO) and Italian Society of Cardiology (SIC) expert consensus document on myocarditis, we propose diagnostic strategies for identifying possible causes of the disease and factors associated with increased risk. Finally, we propose potential treatments and when referring patients to tertiary centers, especially for high-risk patients. Even if endomyocardial biopsy is the invasive diagnostic tool for making definitive diagnosis and differentiation of histological subtypes (i.e., lymphocytic vs eosinophilic vs giant cell myocarditis), it is not always readily available in all centers. Thus, we propose when this exam is mandatory or when it can be postponed or substituted by cardiac magnetic resonance imaging. This document reflects the Italian perspective on managing patients with myocarditis and their follow-up, considering also current US and European scientific position statements.

Gene expression profiling and enrichment functional analyses to compare coronary microvessels and cardiomyocytes in patients with hypertrophic cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM) is characterized by severe alterations of cardiac architecture and function involving cardiomyocytes (CM) and coronary microvessels (MV). Coronary microvascular dysfunction, cardiomyocyte hypertrophy and disarray, sarcomeric alterations and interstitial fibrosis are HCM features. The transcriptome profile associated with coronary MV and CM in HCM patients is presently unknown.

Purpose

Aim of this study was to improve knowledge of the molecular and biological pahways involved in HCM. To this purpose, the gene expression profile of coronary MV and CM was investigated.

Methods

Interventricular septum myectomies from patients with obstructive HCM and donors' hearts (CTR) were collected. Coronary MV (HCM=20, CTR=6) and CM (HCM=10, CTR=5) were laser capture microdissected. RNA-seq was performed by Illumina Nextseq 500, with 76 nt long single-reads. Adapter trimming and quality filtering of the sequenced reads were performed before alignment to the human reference genome. Univocally mapped reads estimated gene expression/sample. Normalized expressed gene levels were quantified. Statistical tests compared HCM and CTR to identify differentially expressed genes (DEG), i.e. up- and down-expressed genes in CM and MV samples. Functional enrichment analysis was performed. Biological categories, i.e. KEGG and Reactome pathways, Gene Ontology terms, protein domains in InterPro database, putative interactors collected in the Intact database and protein annotations in UniProt were considered for inter group comparison of DEGs.

Results

Transcriptome analysis identified 392 genes significantly up-regulated and 514 down-regulated in CM samples of HCM vs. CTR, while in MV 681 genes were up-regulated and 815 down-regulated. Although some DEGs were shared between MV and CM (26 and 146 are up- and down-expressed in both sample types), the majority of DEGs displayed a sample-specific pattern. A comparative functional analysis of DEGs highlighted some statistically enriched biological categories including an enrichment of phosphoproteins, with down-expressed genes both in CM (490) and MV (314). Other biological categories annotated as “ubiquitin-like protein conjugation” or “acetylation” in Uniprot database were enriched in down-regulated genes, both in MV and CM. Interestingly, “ribosomal protein” and “ribonucleoprotein” categories resulted as enriched up-regulated DEGs in MV. Conversely, the “citrullination” category was specifically present in annotations associated to down-regulated DEGs in MV from HCM compared to CTR.

Conclusions

Our preliminary results support the suitability of RNA-seq analysis to assess: i. the transcriptome profiles and pathways associated to coronary MV and CM; ii. the possible relationship/interplay of MV and CM profiles and HCM disease. The enrichment functional analysis provides preliminary data on candidate DEGs and target proteins for in vitro studies on HCM-related mechanisms.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Ministry of Health

1177Insights on mitochondrial energetics in obstructive hypertrophic cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy, heterogeneous in phenotype and clinical course. The genotype-phenotype relationship and associated molecular mechanisms are still incompletely understood. In the HCM milieu, increased energy cost of force production, impairing performance and mitochondrial function, may be associated to patients' genotype and/or phenotype.

Purpose

To determine abnormalities in mitochondrial energetics in HCM and their possible relationship with genotype and clinical phenotype of patients.

Methods

Septal myectomies from characterized patients with obstructive HCM (HOCM, n=18) and donor hearts discarded from transplantation (CTRL, n=8) have been compared. HOCM patients were screened and demographic, clinical and instrumental data (routine ECG, echocardiography and cardiac magnetic resonance-CMR) were collected.

Genetic analysis was performed on total DNA extracted from myectomies by NGS on MiSeq platform using the TruSight Cardio Sequencing kit and testing a panel of 26 genes.

Activity and amount of mitochondrial enzymes generating/scavenging reactive oxygen species were investigated.

Results

Within the HOCM cohort 30% of patients was bearing mutations in sarcomeric genes associated with HCM.

The amount and/or activity of mitochondrial Complex I NADH dehydrogenase, of SOD2 and (m)-aconitase were upregulated in HOCM vs. CTRL. NADH dehydrogenase level was inversely correlated with the degree of mitral valve regurgitation and mitral valve backward volume by CMR (Spearman R=−0.5 and −0.8, respectively).

The Complex V enzyme ATP synthase activity decreased, whilst its amount was comparable in HOCM vs. CTRL. Analogously the SOD1 activity was similar in HOCM and CTRL.

No difference in mitochondrial DNA (mtDNA) copy number was found.

Results were unrelated to HCM-associated mutations.

Conclusions

HOCM hearts are characterized by mitochondrial hyperactivity aimed at quenching reactive oxygen species, but decreased ATP synthase activity. Overall, these data suggest an abnormal mitochondrial activity in the myocardium of HOCM patients independent of the presence of HCM-associated mutations. Moreover, our results underpin the markedly abnormal cellular energetics of HOCM, identifying potential therapeutic targets.

Acknowledgement/Funding

NET-2011-02347173, Italian Minister of Health

P5273Trabecular complexity as a subclinical structural alteration in Fabry cardiomyopathy: a cardiac magnetic resonance study

Background

Heart involvement represents the main cause of death in Fabry Disease (FD), thus its early detection is important to define the optimal therapeutic strategy. Recently, a disproportionate increase in myocardial trabeculation has been described in FD by cardiac magnetic resonance (CMR), even in early (prehypertrophic) stage of the disease. In addition, CMR with T1 mapping can identity the presence of myocardial sphingolipid storage (causing lowering of native T1 values) in more than 50% of FD patients with no LVH. However, it is not clear whether a relationship exists between trabecular complexity and sphingolipid storage in FD.

Aim

To explore the association between myocardial trabecular complexity, quantified by endocardial border fractal analysis, and sphingolipid storage, described by CMR T1 mapping, in different stages of Fabry cardiomyopathy.

Methods

Study population included 60 subjects: 15 FD patients with no detectable signs of cardiac involvement (no LVH, normal T1; 2 M, age 30.6±14; Group 1); 15 FD patients with early sphingolipid storage (no LVH, low T1; 9 M, age 33±9.6; Group 2); 15 FD patients with LVH (11 M, age 53.5±9.6; Group 3); 15 healthy controls (9 M, age 34±10). Patients and controls underwent CMR with T1 mapping; disease severity was quantified using Mainz Severity Score Index (MSSI). Myocardial trabecular fractal dimension was evaluated, blinded to patients'characteristics, on short axis cine images using the Image J dedicated plug-in FracLac, deriving the following parameters: total, basal, mid-ventricular and apical fractal dimensions.

Results

Total fractal dimension was higher in all Fabry groups compared to controls. Indeed, a gradient of total fractal dimension was observed, with this parameter gradually increasing from healthy controls to Groups 3 (1.27±0.02 in controls vs 1.29±0.02 in Group 1 vs 1.30±0.02 in Group 2 vs 1.34±0.02 in Group 3; p<0.001) (Figure 1A). Interestingly, both total and basal fractal dimensions were significantly higher in Group 1 compared to controls (1.27±0.02 vs 1.29±0.02, p=0.044 and 1.26±0.04 vs 1.30±0.03; p=0.007, respectively). Moreover, considering the total population, fractal dimension showed significant correlations with: i) T1 values (r=−0.567; p<0.001 - Figure 1B); ii) LV mass (r=0.674, p<0.001); iii) trabecular mass expressed as percentage of global LV mass (r=0.611; p<0.001); iv) MSSI (r=0.535; p<0.001).

Conclusion

Cardiac involvement in FD is characterized by a progressive increase in fractal dimension of endocardial trabeculae (Figure 1C). Both total and basal myocardial trabeculation are increased in Fabry patients even before the presence of detectable sphingolipid storage, thus representing a very early sign of cardiac involvement.

Optimal duration of dual anti-platelet therapy after percutaneous coronary intervention: 2016 consensus position of the Italian Society of Cardiology

Definition of the optimal duration of dual anti-platelet therapy (DAPT) is an important clinical issue, given the large number of patients having percutaneous coronary intervention (PCI), the costs and risks of pharmacologic therapy, the consequences of stent thrombosis, and the potential benefits of DAPT in preventing ischaemic outcomes beyond stent thrombosis. Nowadays, the rationale for a prolonged duration of DAPT should be not only the prevention of stent thrombosis, but also the prevention of ischaemic events unrelated to the coronary stenosis treated with index PCI. A higher predisposition to athero-thrombosis may persist for years after an acute myocardial infarction, and even stable patients with a history of prior myocardial infarction are at high risk for major adverse cardiovascular events. Recently, results of pre-specified post-hoc analyses of randomized clinical trials, including the PEGASUS-TIMI 54 trial, have shed light on strategies of DAPT in various clinical situations, and should impact the next rounds of international guidelines, and also routine practice. Accordingly, the 2015 to 2016 the Board of the Italian Society of Cardiology addressed newer recommendations on duration of DAPT based on most recent scientific information. The document states that physicians should decide duration of DAPT on an individual basis, taking into account ischaemic and bleeding risks of any given patient. Indeed, current controversy surrounding optimal duration of DAPT clearly reflects the fact that, nowadays, a one size fits all strategy cannot be reliably applied to patients treated with PCI. Indeed, patients usually have factors for both increased ischaemic and bleeding risks that must be carefully evaluated to assess the benefit/risk ratio of prolonged DAPT. Personalized management of DAPT must be seen as a dynamic prescription with regular re-evaluations of the risk/benefit to the patient according to changes in his/her clinical profile. Also, in order to derive more benefit than harm from new treatments, a multi-parametric approach using several risk scores of the ischaemic and bleeding risks might improve the process of risk factor characterization. In patients with high ischaemic risk, particularly those with a history of myocardial infarction, the benefits of extended DAPT (particularly with ticagrelor up to 3 years) are likely to outweigh the risks.

Role of multimodality cardiac imaging in the management of patients with hypertrophic cardiomyopathy: an expert consensus of the European Association of Cardiovascular Imaging Endorsed by the Saudi Heart Association

Taking into account the complexity and limitations of clinical assessment in hypertrophic cardiomyopathy (HCM), imaging techniques play an essential role in the evaluation of patients with this disease. Thus, in HCM patients, imaging provides solutions for most clinical needs, from diagnosis to prognosis and risk stratification, from anatomical and functional assessment to ischaemia detection, from metabolic evaluation to monitoring of treatment modalities, from staging and clinical profiles to follow-up, and from family screening and preclinical diagnosis to differential diagnosis. Accordingly, a multimodality imaging (MMI) approach (including echocardiography, cardiac magnetic resonance, cardiac computed tomography, and cardiac nuclear imaging) is encouraged in the assessment of these patients. The choice of which technique to use should be based on a broad perspective and expert knowledge of what each technique has to offer, including its specific advantages and disadvantages. Experts in different imaging techniques should collaborate and the different methods should be seen as complementary, not as competitors. Each test must be selected in an integrated and rational way in order to provide clear answers to specific clinical questions and problems, trying to avoid redundant and duplicated information, taking into account its availability, benefits, risks, and cost.

Prognostic value of N-terminal pro-brain natriuretic Peptide in outpatients with hypertrophic cardiomyopathy

In hypertrophic cardiomyopathy, the plasma levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) correlate with functional capacity. However, their prognostic relevance remains unresolved. We followed up 183 stable outpatients with hypertrophic cardiomyopathy (age 50 ± 17 years, 64% men) for 3.9 ± 2.8 years after NT-proBNP measurement. The primary end point included cardiovascular death, heart transplantation, resuscitated cardiac arrest, and appropriate implantable cardioverter-defibrillator intervention. The secondary end point (SE) included heart failure-related death or hospitalization, progression to end-stage disease, and stroke. The median NT-proBNP level was 615 pg/ml (intertertile range 310 to 1,025). The incidence of the primary end point in the lower, middle, and upper tertiles was 0%, 1.3%, and 2.1% annually, respectively (overall p = 0.01). On multivariate analysis, the only independent predictors of the primary end point were NT-proBNP (hazard ratio for log-transformed values 5.8, 95% confidence interval 1.07 to 31.6; p = 0.04) and a restrictive left ventricular filling pattern (hazard ratio 5.19, 95% confidence interval 1.3 to 21.9; p = 0.02). The NT-proBNP cutoff value of 810 pg/ml had the best sensitivity for the primary end point (88%), but the specificity was low (61%). The incidence of the SE in the lower, middle, and upper NT-proBNP tertiles was 4.6%, 12.0%, and 11.2% annually, respectively (overall p = 0.001). An NT-proBNP level of <310 pg/ml was associated with a 75% reduction in the rate of SE compared with a level of ≥310 pg/ml (hazard ratio 0.25, 95% confidence interval 0.11 to 0.57; p = 0.001), independent of age, left ventricular outflow tract obstruction, or atrial fibrillation. In conclusion, in stable outpatients with hypertrophic cardiomyopathy, plasma NT-proBNP proved a powerful independent predictor of death and heart failure-related events. Although the positive predictive accuracy of an elevated NT-proBNP level was modest, low values reflected true clinical stability, suggesting the possibility of avoiding or postponing aggressive treatment options.

Transcriptional network analysis for the regulation of left ventricular hypertrophy and microvascular remodeling

Hypertension and cardiomyopathies share maladaptive changes of cardiac morphology, eventually leading to heart failure. These include left ventricular hypertrophy (LVH), myocardial fibrosis, and structural remodeling of coronary microcirculation, which is the morphologic hallmark of coronary microvascular dysfunction. To pinpoint the complex molecular mechanisms and pathways underlying LVH-associated cardiac remodeling independent of blood pressure effects, we employed gene network approaches to the rat heart. We used the Spontaneously Hypertensive Rat model showing many features of human hypertensive cardiomyopathy, for which we collected histological and histomorphometric data of the heart and coronary vasculature, and genome-wide cardiac gene expression. Here, we provide a large catalogue of gene co-expression networks in the heart that are significantly associated with quantitative variation in LVH, microvascular remodeling, and fibrosis-related traits. Many of these networks were significantly conserved to human idiopathic and/or ischemic cardiomyopathy patients, suggesting a potential role for these co-expressed genes in human heart disease.

Advances in coronary microvascular dysfunction

Considerable focus has been directed towards coronary arterial disease in the management of coronary heart disease, however the coronary microcirculation plays a major role in the regulation of coronary blood flow. Thus while we have multiple medical and revascularisation therapies to treat large vessel coronary artery disease, therapies directed towards the microcirculation are very limited. This review paper summarises important aspects of coronary microvascular dysfunction including (a) methods of assessment, (b) clinical classification of associated disorders, (c) possible pathophysiological mechanisms, and (d) potential therapies. Hence this will provide important background to advancing our understanding and management of coronary heart disease by targeting the coronary microcirculation.

The natural history of myocardium awaiting revascularisation in patients with impaired left ventricular function

AIMS

Our aim was to follow changes in myocardial function and physiology in patients awaiting coronary artery bypass surgery (CABG) and relate changes to post-revascularisation functional response.

METHODS AND RESULTS

In 21 patients with CAD and LV dysfunction, myocardial glucose utilisation (MGU) and blood flow (MBF) were measured with positron emission tomography using F-18-fluorodeoxyglucose and oxygen-15-labelled water. Left ventricular function, MGU, and MBF were re-assessed after one year, immediately prior to CABG. At baseline, dysfunctional myocardium displayed a reduction in MGU, hyperaemic MBF, and coronary vasodilator reserve (CVR) compared to normally functioning muscle. In the year preceding CABG, the overall wall motion score index increased (2.09 +/- 0.65 vs. 2.3 +/- 0.7, p=0.0001) and the LV ejection fraction decreased (30.6 +/- 11.1% vs. 27.3 +/- 11.5%, p<0.001). LVEF fell in 14 patients (28.7 +/- 9.4 vs. 23.8, p<0.0001). Aggregate regional wall motion worsened in 15 patients. In contrast to myocardium displaying stable function at echocardiography, myocardium with evidence of deterioration showed a parallel decrease in hyperaemic MBF and CVR (1.57 +/- 0.67 vs. 1.19 +/- 0.7 ml/min/g, [p=0.004] and 1.9 +/- 0.75 vs. 1.33 +/- 0.6, [p=0.005], respectively). Such myocardium displayed attenuated recovery postoperatively (21/68 [31%] LV segments) versus 'waiting-time' stable myocardium (98/169 [58%], p=0.0002).

CONCLUSION

Delayed revascularisation in ischaemic left ventricular impairment results in declining function and a reduced likelihood of contractile improvement.

The heart failure revascularisation trial (HEART): rationale, design and methodology

BACKGROUND

Most patients with heart failure due to left ventricular systolic dysfunction (LVSD) secondary to coronary artery disease (CAD) have evidence of myocardium in jeopardy (reversible ischaemia and/or stunning hibernation). It is not known whether revascularisation in such cases is safe or beneficial.

AIMS

To determine whether revascularisation will improve the survival of patients with LVSD and heart failure secondary to CAD and myocardium in jeopardy.

METHODS

This is a randomised controlled trial comparing revascularisation or not, in addition to optimal medical therapy with ACE inhibitors, beta-blockers, aldosterone antagonists and an anti-thrombotic agent. Patients must have heart failure requiring treatment with diuretics, a left ventricular ejection fraction <35% and evidence of coronary disease. Myocardial viability and ischaemia are assessed by a broad range of techniques including stress echocardiography and nuclear imaging. All imaging tests are reviewed in core laboratories to ensure uniform reporting. Any conventional revascularisation technique is permitted. The primary outcome measure is all cause mortality. Symptoms, quality of life and health economic issues will also be explored. Assuming an annual mortality of 10% in the control group and allowing for substantial cross-over rates, a study of 800 patients followed for 5 years has 80% power with an alpha of 0.05 (two-sided) to show a 25% reduction in mortality with revascularisation.

RESULTS

At the time of writing 180 patients have been screened for inclusion, 111 have consented to participate and 70 have been randomised. The results of viability testing are awaited in 22 patients. Twenty-six patients had been investigated for myocardial viability and/or by angiography prior to consent, as part of the routine practice in that cardiology department. Of 68 patients who have completed assessment only after consent, 47 (69%) were included. The principal reason for drop-out between consent and randomisation was lack of evidence of myocardial ischaemia or hibernation.

CONCLUSION

The HEART trial will help to determine whether investigation of myocardial ischaemia and/or viability with a view to revascularisation should become part of the routine care of patients with heart failure due to LVSD and CAD.

alpha-adrenergic coronary vasoconstriction and myocardial ischemia in humans

The use of quantitative coronary angiography, combined with Doppler and PET, has recently been directed at the study of alpha-adrenergic coronary vasomotion in humans. Confirming prior animal experiments, there is no evidence of alpha-adrenergic coronary constrictor tone at rest. Again confirming prior experiments, responses to alpha-adrenoceptor activation are augmented in the presence of coronary endothelial dysfunction and atherosclerosis, involving both alpha(1)- and alpha(2)-adrenoceptors in epicardial conduit arteries and microvessels. Such augmented alpha-adrenergic coronary constriction is observed during exercise and coronary interventions, and it is powerful enough to induce myocardial ischemia and limit myocardial function. Recent studies indicate a genetic determination of alpha(2)-adrenergic coronary constriction.

Influence of selective autonomic decentralization on myocardial deoxyglucose uptake initiated by cardio-cardiac reflexes

The aim of this study was to evaluate the effect of autonomic reflexes as initiated by stimulation of the right recurrent cardiopulmonary nerve afferent axons on myocardial deoxyglucose uptake and to determine how such uptake can be modified by selective neural ablation. The afferent axon in the right recurrent cardiopulmonary nerve was stimulated 30 s/min for 1 h in five anesthetized open-chest dogs in which 14-C labeled deoxyglucose was i.v. injected at the beginning of the stimulation period. Three additional sham-operated dogs served as neurally intact controls. Concentrations of label and glucose were measured in plasma. Regional myocardial deoxyglucose concentration was measured by quantitative autoradiography, following the calibration of plasma samples autoradiographic density by beta counting. Stimulation of right recurrent cardiopulmonary nerve afferent axons in the intact nervous system preparation did not significantly enhance deoxyglucose uptake as compared to neurally intact controls. When the right cervical vagosympathetic complex was cut a similar uptake was observed. Following decentralization of the right stellate ganglion, uptake was markedly reduced, as well as when the right cervical vagosympathetic was cut and the right stellate ganglion decentralized.

CONCLUSIONS

Activation of afferent axons from cardiopulmonary receptors does not alter myocardial deoxyglucose uptake. Reduction in uptake occurs following unilateral stellate ganglion decentralization.

[Psychological and social aspects in women with syndrome X]

A sizeable proportion (20-30%) of patients undergoing coronary arteriography for a chest pain syndrome are found to have angiographically normal coronary arteries. Some of these subjects (10-15%) have ischemic-like electrocardiographic changes during stress and no evidence of spasm of the epicardial coronary arteries (syndrome X). The vast majority of these patients are middle aged females. In the present investigation we evaluated the psychological and social characteristics of a group of patients with syndrome X (PX, n = 30). The results obtained in the PX group were compared with those in a sex and age matched group of patients with angiographically proven coronary artery disease (PI, n = 32) and with those in a group of control subjects (C, n = 29). Two original questionnaires were employed to collect the demographic and family data. The psychological data were obtained through the following 4 questionnaires: Symptom Rating Test (SRT); Symptom Questionnaire (SQ); Illness Behaviour Questionnaire (IBQ); Maudsley Personality Inventory (MPI). The results of our study indicated that in most of the patients with syndrome X the psychological and social conditions are similar and they are not compatible with a satisfactory lifestyle. In most cases both family and social difficulties are present, which impose excessive workload and distress on the patients. Very often the beginning of the chest pain history tends to coincide with the periods of greatest stress and with the occurrence of dramatic events in the family. On the other hand, the onset of symptoms often has the effect of releasing some of the environmental pressure on the patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Dipyridamole echocardiography stress testing in hypertensive patients. Targets and tools

Arterial hypertension can provoke a reduction in coronary flow reserve through several mechanisms that are not mutually exclusive, namely, coronary artery disease, left ventricular hypertrophy, and microvascular disease. These different targets of arterial hypertension should be explored with different diagnostic markers. The transient dyssynergy detected by two-dimensional echocardiography and evoked during dipyridamole infusion is a marker of coronary disease that is equally reliable in normotensive and hypertensive individuals. On the contrary, dipyridamole-induced ST segment depression is frequently elicited in hypertensive patients when angiographically assessed coronary disease is absent. This ischemiclike electrocardiographic response can be found in echocardiographically assessed left ventricular hypertrophy. However, even when left ventricular mass is normal, dipyridamole-induced ST segment depression is associated with an impaired coronary flow response to pacing, which is consistent with microvascular disease. Whether echocardiographically silent electrocardiographic changes are simply diagnostic noises transmitting a misleading false positive response or a potentially important clinical marker of early myocardial damage remains a pivotal though still unanswered question.

Metabolic markers of stress-induced myocardial ischemia

The human heart in the fasting state extracts free fatty acids (FFA), glucose, lactate, pyruvate, and ketones from circulating blood. The utilization of FFA accounts for most of the oxygen consumed and energy produced at rest. Patients with angiographically demonstrable coronary artery disease and stable angina pectoris have a resting myocardial metabolism similar to that of normal individuals. During atrial pacing in normal persons, there is a significant enhancement of glucose uptake but that of FFA is unchanged, and the oxidation of carbohydrates accounts for more than 60% of the energy produced. In patients with stable angina, myocardial perfusion becomes regionally inadequate during stress. Despite the increase of myocardial glucose utilization, carbohydrate oxidation is negligible. Pyruvate will not be oxidized but in the presence of increased amounts of reduced coenzymes will be reduced to lactate. In addition, a greater amount of alanine will be released by the myocardium through the transamination of pyruvate, with a concomitantly greater uptake of glutamate that serves as the NH2 donor. In addition, glutamate may be used as an anaerobic fuel through conversion to succinate coupled with GTP formation. Although coronary hemodynamics, including myocardial perfusion, return to baseline within a few minutes after stress, a longer time course is needed for myocardial metabolism to become normal. In particular, myocardial utilization of exogenous glucose remains higher well after the normalization of hemodynamic parameters. This is more pronounced in postischemic myocardium, but it also occurs in nonischemic muscle, and glucose is presumably used for rebuilding glycogen stores that were depleted during ischemia.

Coronary vasodilation is impaired in both hypertrophied and nonhypertrophied myocardium of patients with hypertrophic cardiomyopathy: a study with nitrogen-13 ammonia and positron emission tomography

To assess regional coronary reserve in hypertrophic cardiomyopathy, regional myocardial blood flow was measured in 23 patients with hypertrophic cardiomyopathy and 12 control subjects by means of nitrogen-13 ammonia and dynamic positron emission tomography. In patients with hypertrophic cardiomyopathy at baseline study, regional myocardial blood flow was 1.14 +/- 0.43 ml/min per g in the hypertrophied (20 +/- 3 mm) interventricular septum and 0.90 +/- 0.35 ml/min per g (p less than 0.05 versus septal flow) in the nonhypertrophied (10 +/- 2 mm) left ventricular free wall. These were not statistically different from the corresponding values in control subjects (1.04 +/- 0.25 and 0.91 +/- 0.21 ml/min per g, respectively, p = NS). After pharmacologically induced coronary vasodilation (dipyridamole, 0.56 mg/kg intravenously over 4 min), regional myocardial blood flow in patients with hypertrophic cardiomyopathy increased significantly less than in control subjects both in the septum (1.63 +/- 0.58 versus 2.99 +/- 1.06 ml/min per g, p less than 0.001) and in the free wall (1.47 +/- 0.58 versus 2.44 +/- 0.82 ml/min per g, p less than 0.001). In addition, patients with hypertrophic cardiomyopathy who had a history of chest pain had more pronounced impairment of coronary vasodilator reserve than did those without a history of chest pain. After dipyridamole, coronary resistance in the septum decreased by 38% in patients without a history of chest pain, but decreased by only 14% in those with such a history (p less than 0.05). Coronary resistance in the free wall decreased by 45% in patients without and by 27% in those with a history of chest pain (p = 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)

Simultaneous in vitro and in vivo validation of nitrogen-13-ammonia for the assessment of regional myocardial blood flow

Measurement of myocardial blood flow by 13NH3 relies heavily on the assessment of both the input function and the variable tissue extraction fraction. In six open-chest dogs, myocardial and arterial 13NH3 activity was measured both by in vitro sampling and by in vivo positron emission tomography (PET). Regional myocardial blood flow was forced to vary in the range 0.2-5 ml/min/g and actual values were assessed by in vitro counting of 153Gd microspheres. The ammonia input function was processed by: (a) total curve integration; (b) curve integration for 2 min; (c) integral of a fitted curve (gamma variate in vivo and exponential of the downslope in vitro). Method C brought to regional flow values which best approximated microspheres data. The in vitro correlation allows for correcting in vivo values for the flow-dependent extraction fraction. The method can be easily applied for regional myocardial blood flow measurements with PET in human studies.

Forearm vasodilatory capacity in patients with syndrome X: a comparison with normal and hypertensive subjects

Minimal forearm vascular resistances during maximal postischaemic vasodilation were measured in normotensive subjects with syndrome X, a condition characterized by angina and normal coronary arteries, in which a reduced coronary and systemic vasodilatory capacity has been reported. Age- and sex-matched normals and essential hypertensives constituted the control groups. The syndrome X patients had a significantly higher minimal forearm vascular resistance than the normals, indicating that arteriolar alterations may occur in the normotensive state and therefore cannot be considered solely as a consequence of hypertension.

Myocardial metabolism in ischemic heart disease: basic principles and application to imaging by positron emission tomography

The human heart in the fasting state extracts FFA, glucose, lactate, pyruvate, and ketone bodies from the systemic circulation. Of these substrates, FFA utilization accounts for the greater part of oxygen consumption and energy production. The oxidative use of lipid (FFA) and carbohydrate (glucose and lactate) fuels is reciprocally regulated through the operation of Randle's cycle. Feeding, by increasing both insulin and glucose concentration, shifts myocardial metabolism towards preferential carbohydrate usage, both for oxidative energy generation and for glycogen synthesis. During conditions of reduced oxygen supply, the oxidation of all substrates is decreased while anaerobic metabolism is activated. In patients with coronary artery disease and stable angina pectoris, lactate release in the CS can be demonstrated during pacing stress. However, this occurs in only 50% of patients, and no relationship can be demonstrated between lactate production and the severity of ischemia. In patients with chronic angina, a significant release of alanine in the CS and an increased myocardial uptake of glutamate could be demonstrated at rest and following pacing. These two phenomena result from increased transamination of excess pyruvate to alanine with glutamate serving as NH2 donor. In addition, release of citrate (a known inhibitor of glycolysis) in the CS can be demonstrated following pacing in patients with stable angina. The introduction of PET has made it possible to study regional myocardial perfusion and metabolism in humans noninvasively. Two basically different patterns of myocardial glucose utilization have been observed in patients with coronary artery disease studied at rest using 18F-flurodeoxyglucose. In patients with stable angina on exercise but studied at rest, regional myocar- dial glucose utilization was homogeneously low and comparable with that of a group of normals. In contrast, in patients with unstable angina, myocardial glucose utilization at rest was increased even in the absence of symptoms and ECG signs of acute ischemia. In patients with stable angina, a prolonged increase in glucose uptake could be demonstrated in the post-ischemic myocardium in the absence of perfusion abnormalities, and a state of chronic metabolic ischemia is proposed. PET imaging has also allowed prospective differentiation between viable and nonviable segmental function in patients with recent myocardial infarction and in those undergoing coronary artery surgery; in both cases viable segments have relatively maintained glucose uptakes, whereas nonviable segments have depressed glucose uptakes.

Coronary effects of adenosine in conscious man

Adenosine has been reported to play an important role in several cardiac functions, including the regulation of total and regional myocardial perfusion. This hypothesis is based on extensive investigations in animal models, but very limited information is available on the cardiovascular actions of adenosine in conscious man and the effects of the intracoronary administration of adenosine are unknown. The purpose of this study was to measure total and regional coronary blood flow after bolus injections of 0.1, 0.5, 1.0, and 2.5 mg of adenosine into the left anterior descending coronary branch. A three-thermistor thermodilution catheter was advanced into the coronary sinus to measure simultaneously the great cardiac vein flow and the coronary sinus flow. Six patients with normal coronary angiograms and normal ventricular function completed the study. Intracoronary injections of adenosine were free from significant adverse effect and caused a dose-related increase of great cardiac vein flow. A linear relation was found between flow increment and the log of adenosine dose (y = 18.929x + 74.84, r2 = 0.951). The highest flow, measured after the maximal dose, was almost three times greater than control flow (155 +/- 2 vs 58 +/- 3 ml min-1, P less than 0.001). We also observed a flow response in the territory not directly exposed to adenosine, as indicated by a marked increase of coronary sinus blood flow that was linearly related to the adenosine dose (y = 29.113x = 112.635, r2 = 0.98). These preliminary observations suggest: (1) Intracoronary injections of adenosine in conscious man can be performed without significant adverse effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary hemodynamics and myocardial metabolism during and after pacing stress in normal humans

We investigated coronary hemodynamics, myocardial utilization of circulating substrates (by coronary sinus catheterization), and overall use of oxidative fuels (by regional indirect calorimetry) in healthy adults during incremental atrial pacing (up to 159 +/- 9 beats/min), and during 25 min of recovery. Great cardiac vein flow (thermodilution) increased from 52 +/- 9 to 115 +/- 15 ml/min (P less than 0.001) with pacing; myocardial O2 uptake (301 +/- 53 to 593 +/- 71 mumol/min, P less than 0.001) and CO2 production (225 +/- 37 to 518 +/- 66 mumol/min, P less than 0.005) paralleled the pacing-induced rise in rate-pressure product (9.4 +/- 0.9 to 21.1 +/- 1.1 mmHg.beat. min-1.10(-3), P less than 0.001). During recovery, all the above variables returned to base line within 5 min, but myocardial O2 extraction remained depressed (67 +/- 2 vs. 71 +/- 3%, P less than 0.05). Circulating glucose uptake rose linearly with pacing (P less than 0.05) and remained above base line throughout recovery. By contrast, free fatty acid (FFA) uptake (10 mumol/min) did not increase with pacing and fell during recovery (P less than 0.01). Calorimetry, however, showed that net lipid oxidation exceeded FFA uptake throughout the study, whereas net carbohydrate oxidation was small at base line, rose significantly at maximal pacing (62% of myocardial energy output), and remained above base line during recovery (32% of energy output). In the basal state as well as during recovery, myocardial uptake of glucose equivalents (lactate plus glucose plus pyruvate) was in excess of carbohydrate oxidation, indicating nonoxidative disposal of these substrates.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities in myocardial metabolism in patients with unstable angina as assessed by positron emission tomography

Regional myocardial perfusion and glucose metabolism were assessed in six normal volunteers and 29 patients with coronary heart disease and stable or unstable angina using rubidium-82 (Rb-82) and F-18 fluoro 2-deoxy-D-glucose (FDG) with positron emission tomography. All normals and patients were studied following overnight fasting, at rest, with no angina or electrocardiographic signs of acute myocardial ischemia or necrosis. Rb-82 myocardial cross-sectional images were obtained employing the continuous infusion technique, while dynamic FDG imaging was employed after intravenous tracer bolus injection. Regional Rb-82 and FDG myocardial concentrations were then calculated by drawing regions of interest over the interventricular septum, anterior and lateral wall of the left ventricle. The mean Rb-82 uptake for each left ventricular region analyzed was found to be similar between both groups of patients and normal volunteers. The mean myocardial glucose utilization was found to be similar in normal volunteers and patients with stable angina (0.023 +/- 0.032 vs. 0.012 +/- 0.008 microns ml/min p less than 0.42). However, myocardial glucose utilization was found to be significantly higher in patients with unstable angina compared with both normals and patients with stable angina (0.048 +/- 0.047 microM/ml/min p less than 0.001 for both comparisons). Thus, in patients with severe coronary artery disease and unstable angina, myocardial glucose utilization was enhanced in spite of the absence of clinical, electrocardiographic, or detectable perfusion evidence of acute ischemia.