Molecular effects of cardiac contractility modulation in patients with heart failure of ischemic aetiology uncovered by transcriptome analysis

Cardiac contractility modulation (CCM) is based on electrical stimulation of the heart without alteration of action potential and mechanical activation, the data on its fundamental molecular mechanisms are limited. Here we demonstrate clinical and physiological effect of 12 months CCM in 29 patients along with transcriptomic molecular data. Based on the CCM effect the patients were divided into two groups: responders (n = 13) and non-responders (n = 16). RNA-seq data were collected for 6 patients before and after CCM including 3 responders and 3 non-responders. The overall effect of CCM on gene expression was mainly provided by samples from the responder group and included the upregulation of the genes involved in the maintenance of proteostasis and mitochondrial structure and function. Using pathway enrichment analysis, we found that baseline myocardial tissue samples from responder group were characterized by upregulation of mitochondrial matrix-related genes, Z disc-protein encoding genes and muscle contraction-related genes. In summary, twelve months of ССM led to changes in signaling pathways associated with cellular respiration, apoptosis, and autophagy. The pattern of myocardial remodeling after CCM is associated with initial expression level of myocardial contractile proteins, adaptation reserves associated with mitochondria and low expression level of inflammatory molecules.

High Risk of Heart Tumors after COVID-19

An emergence of evidence suggests that severe COVID-19 is associated with an increased risk of developing breast and gastrointestinal cancers. The aim of this research was to assess the risk of heart tumors development in patients who have had COVID-19.

METHODS

A comparative analysis of 173 heart tumors was conducted between 2016 and 2023. Immunohistochemical examination with antibodies against spike SARS-CoV-2 was performed on 21 heart tumors: 10 myxomas operated before 2020 (the control group), four cardiac myxomas, one proliferating myxoma, three papillary fibroelastomas, two myxofibrosarcomas, one chondrosarcoma resected in 2022-2023. Immunohistochemical analysis with antibodies against CD34 and CD68 was also conducted on the same 11 Post-COVID period heart tumors. Immunofluorescent examination with a cocktail of antibodies against spike SARS-CoV-2/CD34 and spike SARS-CoV-2/CD68 was performed in 2 cases out of 11 (proliferating myxoma and classic myxoma).

RESULTS

A 1.5-fold increase in the number of heart tumors by 2023 was observed, with a statistically significant increase in the number of myxomas. There was no correlation with vaccination, and no significant differences were found between patients from 2016-2019 and 2021-2023 in terms of gender, age, and cardiac rhythm dis-orders. Morphological examination revealed the expression of spike SARS-CoV-2 in tumor cells, endothelial cells, and macrophages in 10 out of 11 heart tumors.

CONCLUSION

The detection of SARS-CoV-2 persistence in endothelium and macrophages as well as in tumor cells of benign and malignant cardiac neoplasms, the increase in the number of these tumors, especially cardiac myxomas, after the pandemic by 2023 may indicate a trend toward an increased risk of cardiac neoplasms in COVID-19 patients, which re-quires further research on this issue and a search for new evidence.

New Scenarios in Heart Transplantation and Persistency of SARS-CoV-2 (Case Report)

Heart transplantation is a treatment of choice for patients with severe heart failure. Infection transmission from a donor to a recipient remains a prominent problem in organ transplantation. However, the risk of SARS-CoV-2 transmission in nonlung organ transplantation is still unclear. In this article we presented a case of a 28-year-old pregnant woman who developed heart failure soon after recovery from a SARS-CoV-2 infection in the third trimester of gestation. In the postpartum period, the heart disease worsened and the patient required cardiac transplantation. We examined the recipient's heart and made a diagnosis of left ventricular noncompaction cardiomyopathy. Immunohistochemical analysis showed SARS-CoV-2 antigen expression in the donor's heart before transplantation, and after the transplantation, an endomyocardial biopsy was taken. Moreover, an ultrastructural assessment of the endomyocardial specimen revealed endothelial and pericyte injury and a single particle on the surface of the endothelium consistent with SARS-CoV-2 viral particles. Recent findings in the literature associated these damages with SARS-CoV-2 infection. The present study describes the rare case of SARS-CoV-2 transmission from donor to postpartum recipient through a heart transplant and demonstrates the importance of endomyocardial biopsy before and after heart transplantation.

Morphological Changes in the Myocardium of Patients with Post-Acute Coronavirus Syndrome: A Study of Endomyocardial Biopsies

The clinical manifestation study of post-acute sequelae of SARS-CoV-2 infection (PASC) has shown a lack of knowledge regarding its morphology and pathogenesis. The aim of this research was to investigate morphological manifestations of PASC in the myocardium.

MATERIALS AND METHODS

The study included 38 patients requiring endomyocardial biopsy (EMB) during the post-acute phase of coronavirus infection and a control group including patients requiring EMB prior to the SARS-CoV-2 pandemic. The patients' clinical and laboratory data were analyzed. Histological examination and immunohistochemistry (IHC) of the myocardial tissue was conducted with antibodies to CD3, CD68, HLA-DR, MHC1, C1q, VP1 enteroviruses, spike protein SARS-CoV-2, Ang1, von Willebrand factor (VWF), and VEGF. The morphometric analysis included counting the mean number of inflammatory infiltrate cells per mm² and evaluating the expression of SARS-CoV-2 spike protein, HLA-DR, MHC1, C1q, Ang1, VWF, and VEGF using a scoring system. If the expression of SARS-CoV-2 spike protein was >3 points, an additional IHC test with antibodies to ACE2, CD16 as well as RT-PCR testing of the myocardial tissue were performed. For two patients, immunofluorescence tests of the myocardial tissue were performed using antibody cocktails to SARS-CoV-2 spike protein/CD16, SARS-CoV-2 spike protein/CD68, CD80/CD163. The statistical data analysis was carried out using the Python programming language and libraries such as NumPy, SciPy, Pandas, and Matplotlib.

RESULTS

The study demonstrated a significant increase in the number of CD68+ macrophages in the myocardium of PASC patients compared to patients who did not have a history of COVID-19 (p = 0.014 and p = 0.007 for patients with and without myocarditis, respectively), predominantly due to M2 macrophages. An increase in the number of CD68+ macrophages was more frequently observed in patients with shorter intervals between the most recent positive SARS-CoV-2 PCR test and the time of performing the EMB (r = -0.33 and r = -0.61 for patients with and without myocarditis, respectively). The expression scores of Ang1, VEGF, VWF, and C1q in PASC patients did not significantly differ from those in EMB samples taken before 2019.

CONCLUSION

The myocardium of PASC patients demonstrated a significant increase in the number of CD68+ macrophages and a decrease in the expression of markers associated with angiopathy. No evidence of coronavirus-associated myocarditis was observed in any PASC patient.

The coincidence of two rare diseases with opposite metabolic phenotype: a child with congenital hyperinsulinism and Bloom syndrome

OBJECTIVES

Congenital hyperinsulinism (CHI) is a group of rare genetic disorders characterized by insulin overproduction. CHI causes life-threatening hypoglycemia in neonates and infants. Bloom syndrome is a rare autosomal recessive disorder caused by mutations in the BLM gene resulting in genetic instability and an elevated rate of spontaneous sister chromatid exchanges. It leads to insulin resistance, early-onset diabetes, dyslipidemia, growth delay, immune deficiency and cancer predisposition. Recent studies demonstrate that the BLM gene is highly expressed in pancreatic islet cells and its mutations can alter the expression of other genes which are associated with apoptosis control and cell proliferation.

CASE PRESENTATION

A 5-month-old female patient from consanguineous parents presented with drug-resistant CHI and dysmorphic features. Genetic testing revealed a homozygous mutation in the KCNJ11 gene and an additional homozygous mutation in the BLM gene. While ¹⁸F-DOPA PET scan images were consistent with a focal CHI form and intraoperative frozen-section histopathology was consistent with diffuse CHI form, postoperative histopathological examination revealed features of an atypical form.

CONCLUSIONS

In our case, the patient carries two distinct diseases with opposite metabolic phenotypes.

Myocardial PD-L1 Expression in Patients With Ischemic and Non-ischemic Heart Failure

Objective: Immune checkpoints inhibitors are promising and wide-spread agents in anti-cancer therapy. However, despite their efficacy, these agents could cause cardiotoxicity, a rare but life-threatening event. In addition, there are still no well-described predictive factors for the development of immune-related adverse events and information on high risk groups. According to known experimental studies we hypothesized that cardiovascular diseases may increase myocardial PD-L1 expression, which could be an extra target for Checkpoint inhibitors and a potential basis for complications development.

Methods: We studied patterns of myocardial PD-L1 expression in non-cancer-related cardiovascular diseases, particularly ischemic heart disease (n = 12) and dilated cardiomyopathy (n = 7), compared to patients without known cardiovascular diseases (n = 10) using mouse monoclonal anti-PD-L1 antibody (clone 22C3, 1:50, Dako). Correlation between immunohistochemical data and echocardiographic parameters was assessed. Statistical analyses were performed using R Statistical Software—R studio version 1.3.1093.

Results: In the myocardium of cardiac patients, we found membranous, cytoplasmic, and endothelial expression of PD-L1 compared to control group. In samples from patients with a history of myocardial infarction, PD-L1 membrane and endothelial expression was more prominent and frequent, and cytoplasmic and intercalated discs staining was more localized. In contrast, samples from patients with dilated cardiomyopathy displayed very faint endothelial staining, negative membrane staining, and more diffuse PD-L1 expression in the cytoplasm and intercalated discs. In samples from the non-cardiac patients, no convincing PD-L1 expression was observed. Moreover, we discovered a significant negative correlation between PD-L1 expression level and left ventricular ejection fraction and a positive correlation between PD-L1 expression level and left ventricular end-diastolic volume.

Conclusions: The present findings lay the groundwork for future experimental and clinical studies of the role of the PD-1/PD-L1 pathway in cardiovascular diseases. Further studies are required to find patients at potentially high risk of cardiovascular adverse events associated with immune checkpoint inhibitors therapy.

Case Report: Primary Leptomeningeal Medulloblastoma in a Child: Clinical Case Report and Literature Review

Medulloblastoma is one of the most common pediatric central nervous system malignancies worldwide, and it is characterized by frequent leptomeningeal metastasizing. We report a rare case of primary leptomeningeal medulloblastoma of an 11-year-old Caucasian girl with a long-term disease history, non-specific clinical course, and challenges in the diagnosis verification. To date, 4 cases of pediatric primary leptomeningeal medulloblastoma are reported, and all of them are associated with unfavorable outcomes. The approaches of neuroimaging and diagnosis verification are analyzed in the article to provide opportunities for effective diagnosis of this disease in clinical practice. The reported clinical case of the primary leptomeningeal medulloblastoma is characterized by MR images with non-specific changes in the brain and spinal cord and by 18FDG-PET/CT images with diffuse heterogeneous hyperfixation of the radiopharmaceutical along the whole spinal cord. The immunohistochemistry and next-generation sequencing analyses of tumor samples were performed for comprehensive characterization of the reported clinical case.

Dual-tracer PET/CT imaging to determine tumor heterogeneity in a patient with metastatic ACTH-secreting neuroendocrine neoplasm: A case report and literature review

INTRODUCTION

We present a case of a patient with disseminated ACTH-secreting neuroendocrine neoplasm with biologic heterogeneity between a primary tumor and metastases. The diagnosis was obtained and multidisciplinary management was conducted with a positron emission tomography/computed tomography (PET/CT) scan with Gallium-68 [68Ga]-labeled dodecanetetraacetic acid-tyrosine-3-octreotate ([68Ga]-DOTA-TATE) and Fluor-18 [18F]-fluorodeoxyglucose ([18F]-FDG).

CASE REPORT

A PET/CT scan revealed a difference between [68Ga]-DOTA-TATE and [18F]-FDG uptake in primary tumor and several metastases. PET/CT showed high [18F]-FDG uptake and lack of [68Ga]-DOTA-TATE in the primary tumor, whereas both [68Ga]-DOTA-TATE and [18F]-FDG hyperaccumulation were identified in the majority of metastases. Despite positive [68Ga]-DOTA-TATE PET/CT, which is associated with high affinity with the somatostatin receptor 2 subtype, immunohistochemical examination revealed overexpression of the somatostatin receptor 5 subtype only. Perhaps, this explained the ineffectiveness of the treatment with "cold" somatostatin analogs.

CONCLUSION

This case had an aggressive clinical course, despite cytoreductive surgical treatment and somatostatin analog therapy. PET/CT imaging with two tracers is a molecular tool that demonstrates a biologic heterogeneity between a primary tumor and metastases and yields additional information that may influence the choice of the patient management strategy.

Fiber-optic laser energy for pulmonary artery denervation: results of an experimental study

Background/Introduction

Pulmonary artery denervation (PADN) is an interventional procedure aiming to modulate and correct pulmonary artery (PA) pressure. New technologies and energy sources are being tested currently. However, the effects of laser energy on the PA wall are unknown.

Purpose

To assess the acute effects and impact of laser energy for PADN procedure in normotensive sheep by applying different power settings and session times.

Methods

A total of 10 normotensive Katumsky sheep were included in the experiment. Percutaneous vascular access was performed under general anesthesia. A fiberoptic open-irrigated non-steerable catheter was introduced via a femoral vein through a steerable sheath. Laser applications were applied in the PA trunk and the proximal areas of the right and left PA under fluoroscopic guidance with a 5mm distance between points in the anterior, posterior and lateral walls. Applications were delivered with power 10–30W, 10–35s in duration; irrigation flow 40ml/min. After the procedure, experimental animals were euthanized and underwent an autopsy. PA samples were obtained regardless of the absence of visible laser-related lesions for histological analysis (hematoxylin staining) and immunohistochemical labelling (S100).

Results

A total of 108 ablation sessions were performed, 33 in the right PA, 30 in the left PA and 42 in the PA trunk. During macroscopic examination, laser-related lesions described as irregular brown hemorrhage spots and rough defects observed in the PA endothelium were not homogenous in all experimental animals. Thermal injuries either in the left or right lung lobes were identified in 5 (50%) experimental animals when using 30W during 10–20sec. In 5 (50%) sheep no collateral lung injuries were identified when using 10–20W from 20–35s. A total of 64 PA fragments underwent microscopic examination, acute thermal tissue lesions were observed in all experimental animals despite the absence of laser-related lesions in the PA endothelium; dissection, edema, disruption trough tunica layers, hemorrhage and necrosis at different depth walls. The most frequent nerve damage was obtained with 20W ablation: 5/8 PAs vs, 1/6 with 10–15W and 1/14 with 25–30W (P=0.01). At the same time, there was no difference in intima necrosis between the groups (1/6, 2/8 and 4/14 for 10–15, 20 and 25–30W groups, respectively).

Conclusion(s)

Percutaneous PA laser ablation is feasible, reduction of perivascular nerve expression is seen most frequently, when 20W/20–35 s ablation is performed. PA lesions may differ in depth and characteristics, and perivascular nerve damage might be seen in cases with preserved intima.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Grant of the Ministry of Science and Higher Education of the Russian Federation

Pulmonary artery radiofrequency ablation in an acute porcine model of pulmonary arterial hypertension

Introduction

Pulmonary hemodynamics improvement after pulmonary artery denervation (PADN) was demonstrated in PAH. Questions arise regarding PADN perioperative effectiveness and the accuracy of the target nerves damage. The aim of the study was to evaluate whether PADN decreases pulmonary artery pressure (PAP) in acute thromboxane A2 (U46619)–induced PAH, and damages PA perivascular nerve fibers.

Materials and methods

10 male Landrace swine (34.7±5.1 kg). In 6 swine acute reversible target mean PAP of 40 mm Hg was induced with synthetic thromboxane A2 infusion (U46619). Control group: 4 swine with PADN. Hemodynamics was assessed throughout the study, PAH modeling was done before and 20 min after PADN (radiofrequency energy, 40 Watts), followed by pathology and immunohistochemical studies.

Results

The mean number of RF applications was 17.5±3.6. Pulmonary embolism (PE) was observed after PADN in 3 swine with U46619 infusion, which were excluded. There was no differences in mPAP, PVR and U46619 dosage after PADN in PAH model (12.3±3.5 vs 12.1±1 mm Hg, p=0.2; 150.4±48.7 vs 129.2±64.1 dynes s cm–5; p=0.2; 24.9±3.3 vs 22.4±4.1 mcg; p=0.18; respectively). Similar hemodynamic results were observed in the control group after PADN (mPAP; p=0.3; PVR; p=0.58). S100 expression was evident in the majority of RFA PA species and in some species loss in tyrosine hydroxylase and M1 acetylcholine receptors expression was detected with no hemodynamic correlation.

Conclusions

PADN using an electrophysiological catheter with unipolar energy does not lead to an acute PA perivascular nerve fibers destruction and detectable mPAP changes in U46619-induced PAH. Delayed nerve damage might be attributable to PADN effects observed in previous studies.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Grant from the Ministry of Science and Higher Education of the Russian Federation (agreement #075-15-2020-800).

Angiotensin II receptor blockers in modulation of transforming growth factor-beta effects on mitral valve myxomatous degeneration

 

Growing evidence supports role transforming growth factor-β (TGF-β) as a mediator of the myxomatous changes in the mitral valve prolapse. Recently, angiotensin II receptor blockers (ARB) emerged as a potentially effective inhibitor of TGF-β signaling. Treatment of valvular interstitial cells (VICs) with ARB resulted in effective inhibition of TGF-β-induced ECM expression.

Our aim was to evaluate the effect of preoperative ARB therapy in modulation of transforming growth factor-β effects on mitral valve myxomatous degeneration.

Methods

A total of 233 asymptomatic patients (mean age: 53.8±12.9) undergoing mitral valve surgery for severe mitral regurgitation due to mitral valve prolapse were enrolled in our retrospective, non-randomized, single-center study. Resected abnormal segments of the mitral leaflets (segment of the posterior leaflet or the entire valve) were obtained during mitral valve repair/replacement surgery and examined by experienced pathologists. Immunohistochemical characterization of mitral valve sections was performed with the primary antibodies. Quantification was performed by counting TGF-β1 and TGF-β2 positive cells within 10 random high-power fields divided by the total number of cells in specimens. Quantification of immunohistochemical staining for collagen III was performed by measurement of staining area divided by the total area of the specimens.

Results

Two hundred thirty-three consecutive patients (66% males, mean age 53.8±12.9 years, range 19–80) with severe MR were enrolled in the study. According to the case reports, 43 patients (18.5%) received losartan or telmisartan before surgery and were included in study group. 190 patients (81.5%) did not receive any ARB and were enrolled in the control group.

Histological examination showed disorganized collagen and elastin fibers, expansion of the spongiosa layer in both groups. However, MV specimens' immunohistochemistry revealed a lower expression of type III collagen in ARB group as compared to controls (31.3% ± 10.8% vs. 43.8% ± 15.3%; p<0.001).

MV leaflets in control group showed the increased VICs density (95.3±39.9 vs. 70.0±21.7/high-power field, p=0.0001). TGF-β1 and TGF-β2 positive cells were significantly rare in the ARB than in control MV specimens (18% vs. 33%, p=0.012 and 16% vs. 38%, p<0.ehab724.15541, respectively). Expression of type III collagen and TGF-β2 positive cells count showed a weak, but significant correlation (r=0.28; p=0.ehab724.155414). The multivariate Cox analysis showed a decrease in the relative risk of valvular thickening (myxomatous degeneration) with ARB therapy (0.85; 95% CI: 0.61 – 1.17; p=0.01).

Conclusions

We indicate a beneficial effect of ARB treatment through the inhibition of TGF-β pathway on valvular myxomatous degeneration in patients with MVP. Modulation of the progression of MVP with such therapeutic agents may have great clinical significance.

Funding Acknowledgement

Type of funding sources: None.

Case Reports: Emery-Dreifuss Muscular Dystrophy Presenting as a Heart Rhythm Disorders in Children

Emery-Dreifuss muscular dystrophy (EDMD) is inherited muscle dystrophy often accompanied by cardiac abnormalities in the form of supraventricular arrhythmias, conduction defects and sinus node dysfunction. Cardiac phenotype typically arises years after skeletal muscle presentation, though, could be severe and life-threatening. The defined clinical manifestation with joint contractures, progressive muscle weakness and atrophy, as well as cardiac symptoms are observed by the third decade of life. Still, clinical course and sequence of muscle and cardiac signs may be variable and depends on the genotype. Cardiac abnormalities in patients with EDMD in pediatric age are not commonly seen. Here we describe five patients with different forms of EDMD (X-linked and autosomal-dominant) caused by the mutations in EMD and LMNA genes, presented with early onset of cardiac abnormalities and no prominent skeletal muscle phenotype. The predominant forms of cardiac pathology were atrial arrhythmias and conduction disturbances that progress over time. The presented cases discussed in the light of therapeutic strategy, including radiofrequency ablation and antiarrhythmic devices implantation, and the importance of thorough neurological and genetic screening in pediatric patients presenting with complex heart rhythm disorders.

Risk factors of persistent ventricular arrhythmias after mitral valve repair in Barlow disease patients: six-year follow-up

Funding Acknowledgements

Type of funding sources: None.

Introduction

 Improvement in malignant ventricular arrhythmias (VA) has been reported after mitral valve surgery in some mitral valve prolapse patients (MVP) with severe degenerative mitral regurgitation. Mitral annular disjunction, posterior systolic curling, and mitral annular abnormal contractility are associated with arrhythmic MVP and underwent correction during the mitral valve repair. However, mitral valve disease progression and ventricular arrhythmic substrates (left ventricular fibrosis of papillary muscles and basal posterior wall) could be potential substrates for persistent malignant arrhythmias even after surgical correction. 

Our aim was to evaluate the risk factors of persistent VA after mitral valve repair in Barlow’s disease patients in six-year follow-up. 

Methods

 30 consecutive patients (mean age 53.1 ± 9.4, 47% male) who underwent mitral valve repair for severe mitral regurgitation (MR) due to mitral valve prolapse were enrolled in our observational, prospective, single-center study. Resected abnormal segments of the mitral leaflets were examined by experienced pathologists for signs of myxomatous degeneration. Transthoracic echocardiography and 24-hour Holter monitoring were performed pre- and postoperatively annually. PVCs and nonsustained ventricular tachycardia (VT) runs were reviewed. 

Results

 All patients survived the operation. There was only one sudden cardiac death on sixth year of follow-up. During 173 person-years of follow-up 3 patients (10%) had developed recurrent moderate to severe (≥2) MR. The total number of PVCs and non-sustained ventricular tachycardia runs dropped significantly in 1st (p=.04, Wilcoxon matched pairs test) and 2nd (p=.03), years of postoperative follow-up. 

Postoperative incidence of PVCs and VT correlated strongly with postoperative end-diastolic LV diameter (EDD rs=.69; p=.005), moderate negatively with LV ejection fraction (EF rs=-.55; p=.001).  

Advanced myxomatous degeneration assessed by pathologists and MV posterior leaflet’s thickness ≥5 mm after repair assessed by echocardiographer associated with postoperative PVCs and VT (rτ=.58; p=.045 and rs=.62; p=.002, respectively). Recurrent MR also strongly associated with postoperative PVCs and VT (rs=.76; p=.0018). 

In univariate analysis, advanced myxomatous degeneration (p=.008), postoperative end-diastolic LV diameter (p=.001), and low EF (p=.003) were identified as risk factors of persistent PVCs/VT after surgery. 

Conclusions

 Advanced myxomatous degeneration assessed by pathologists or echocardiographer and postoperative left ventricular remodeling are associated with persistent malignant ventricular arrhythmias. Further investigation in larger cohorts to evaluate the association between degenerative mitral valve disease and ventricular arrhythmias is needed.

RBM20-Associated Ventricular Arrhythmias in a Patient with Structurally Normal Heart

RBM20 (RNA-binding motif protein 20) is a splicing factor targeting multiple cardiac genes, and its mutations cause cardiomyopathies. Originally, RBM20 mutations were discovered to cause the development of dilated cardiomyopathy by erroneous splicing of the gene TTN (titin). Titin is a giant protein found in a structure of the sarcomere that functions as a molecular spring and provides a passive stiffness to the cardiomyocyte. Later, RBM20 mutations were also described in association with arrhythmogenic right ventricular cardiomyopathy and left ventricular noncompaction cardiomyopathy. Here, we present a clinical case of a rare arrhythmogenic phenotype and no structural cardiac abnormalities associated with a RBM20 genetic variant of uncertain significance.

Pulmonary arterial hypertension modeling with synthetic stable thromboxane A2 analogue (U46619) in porcine: dose adjustment and acute hemodynamic reactions

Introduction

Survival in PAH is strongly associated with adaptation of the RV to pressure overload.

Purpose

To investigate acute hemodynamic reactions during infusion of the stable thromboxane A2 (TXA2) analogue U46619 in a porcine model.

Materials and methods

The study comprised 9 male Landrace pigs (32.7±3.8 kg) under GA. After heparinization, PAH was induced by continuous and stepwise increasing infusion of U46619 (10 mg/ml; Tocris, USA) according to a pre-specified protocol. The target mPAP was 40 mmHg. Hemodynamics was assessed, cardiac output (CO) was calculated using the Fick equation before and during U46619 infusion.

Results

U46619 infusion at a previously published rate 0.1, 0.2 μg kg–1 min–1 in pig 1 resulted in rapid hemodynamic deterioration. Two-time reduced U46619 dose infusione resulted in a target mPAP but severe mBP drop in 1, 3, 4 pigs and required cathecholamine support. The U46619 dosage was reduced up to ¼ (0.025, 0.05, 0.075, 0.1, 0.12, 0.15, 0.175 μg kg–1 min–1). In animals on 1/4 dosage U46619 infusion, heart rate (HR), mBP, mPAP, RAP and PVR reliably increased and BP was stable (Table 1). There was a positive correlation between the mPAP and heart rate (HR) on U46619 infusion (r=0.66; t=2.38; p=0.048) and between CO and mBP (r=0.66; t=2.36; p=0.04). Low CO was associated with high PVR (r=−0.98; t=−14.3; p<0,001). Positive correlation between PVR and SVR was revealed (r=0.96; p=0.00002). In 3 pigs with severe mBP drop and PAH right ventricle subendocardial hemorrhage was revealed on autopsy study.

Conclusions

High dose U46619 infusion was associated with acute RV decompensation due to pressure overload accompanied with systemic BP drop and low CO. Lower dosages of U46619 infusion were characterized by stable target mean PAP. HR acceleration and mean systemic BP are of compensation mechanisms for cardiac output maintenance in PAH.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): RFBR grant 18-315-20050

Electrical stimulation mapping of the pulmonary artery in swine: impact on pulmonary artery denervation procedure for pulmonary hypertension

Introduction

Pulmonary artery denervation (PAD) has been recently shown to decrease pulmonary artery (PA) pressure. However, there is a lack of data related to target sites for ablation.

Purpose

To determine the optimal PA ablation sites based on response to high-frequency stimulation mapping and anatomical areas where radiofrequency ablation (RFA) should be avoided due to the risk of severe collateral damage.

Methods

A total of 17 Landrace swines were included into the study. PA angiography, hemodynamic measurements by right heart-sided catheterization and electrophysiological mapping (EM) using low (cycle length 330 ms) and high-frequency (33Hz) stimulation (HFS). Stimulation was performed at PA bifurcation and proximal parts of the main PA branches with a 5-mm distance between points; catheter manipulation was performed under fluoroscopic guidance in multiple projections. Points with evoked reactions were tagged on a 3-dimentional PA model in each case. In order to confirm reproducibility of reactions, HFS was performed at least twice at each point with a response. PA models obtained from all animals were combined in one for the final analysis. RFA using an open-irrigated catheter (40 Watts; 40 s; irrigation 30 ml/min) were performed at sites with evoked reactions. Repeated HFS was performed at ablation sites. After the procedure all animals were euthanized and underwent an autopsy study.

Results

Low-frequency stimulation (LFS) allowed to define areas of ventricular capture (VC) where HFS was avoided due to ventricular fibrillation induction risk. During HFS the following evoked responses were documented: sinus bradycardia, sinus rhythm (SR) acceleration, phrenic nerve capture (PNC), and laryngeal recurrent nerve capture. HFS captured left and right phrenic nerves in all animals at PA trunk, and its course was tagged (Figure 1). Laryngeal recurrent nerve capture was found in 4 (23%) of animals. Atrial capture was found in all cases while LFS at the anterior aspects of both PAs even at low output, and this precluded evaluation of neural autonomic reactions in these areas. Evoked bradycardia and SR acceleration were both found during HFS in 10 (59%) of cases each. Following RFA application evoked reactions were non-reproducible in all cases. RFA was applied in areas where no PNC or VC points were observed. An autopsy study confirmed the presence of RF-induced lesions of the PA wall.

Conclusions

There are two important findings of our study. First, stimulation-guided PA mapping is feasible and reveals several specific responses to HFS. Ablation at points with responses leads to non-reproducibility of the evoked reactions, confirming that transcatheter RFA may be an adequate approach for PA denervation. Second, previously proposed circular PA ablation might be associated with phrenic and laryngeal recurrent nerve damage. Stimulation-guided PA denervation can be proposed as a safer procedure, and should be evaluated in clinical settings.

Figure 1. PA schematic representation

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Russian Foundation for Basic Research

Morphological and immunophenotypic characterization of perivascular interstitial cells in human glioma: Telocytes, pericytes, and mixed immunophenotypes

Telocytes (Tcs) and pericytes (Pcs) are two types of perivascular interstitial cell known to be widespread in various organs and tissues, including the brain. We postulated that Tcs and Pcs may be involved in glioblastoma (GBM) neovascularization.

423 Effects of mitral valve repair on left ventricular remodeling and ventricular arrhythmia in mitral valve prolapse patients: five-year follow-up

Introduction

There is limited data on the efficacy of surgical repair in reducing ventricular arrhythmia (VA) in mitral valve prolapse (MVP) patients. Improvement in malignant ventricular arrhythmias has been reported only in isolated cases after mitral valve surgery. Our aim was to evaluate the possible effects of mitral valve repair on left ventricular (LV) reverse remodeling and incidence of VA in MVP patients in mid-term follow-up.

Methods

30 consecutive patients (mean age 53.1 ± 9.4, 47% male) undergoing mitral valve repair for severe mitral regurgitation (MR) due to mitral valve prolapse were enrolled in our observational, prospective, single-center study. Resected abnormal segments of the mitral leaflets were examined by experienced pathologists for signs of myxomatous degeneration. Transthoracic echocardiography extended with speckle-tracking echocardiography and 24-hour Holter monitoring were performed pre- and postoperatively annually. Atrial fibrillation, PVCs and nonsustained ventricular tachycardia (VT) runs were reviewed.

Results

During 144 person-years of follow-up no deaths, and 3 cases (10%) of recurrent moderate or severe (≥2) MR occurred. The total number of PVCs and non-sustained ventricular tachycardia runs dropped significantly in 1st (p=.04, Wilcoxon matched pairs test) and 2nd (p=.03), years of postoperative follow-up. Postoperative incidence of PVC and VT correlates strongly with postoperative end-diastolic LV diameter (EDD rs=.70; p=.005), moderate negatively with LV ejection fraction (EF rs=-.55; p=.01), but not postoperative MR (p>.05). EDD (58.8 ± 7.6 mm vs. 49.9 ± 5.6 mm; p=.00001) and EDV (156.6 ± 32.1 ml vs. 104.1 ± 22.8 ml; p=.00001) decreased in 1st year after repair with non-significant changes in EF (63.8 ± 12.8% vs. 59.6 ± 14.5%; p=.20), global systolic longitudinal strain –13.8 ± 2.5% vs. –14.6 ± 2.7%; p=.20) and SR (–0.93 ± 0.12 s-1 vs. –0.98 ± 0.13 s-1; p=.09) values.

In univariate analysis, postoperative end-diastolic LV diameter (p=.001), low EF (p=.003), myxomatous degeneration (p=.008) were identified as risk factors of persistent PVCs/VT after surgery.

Conclusions

Mitral valve repair in MVP with severe mitral regurgitation is associated with reduction in ventricular arrhythmia, which strongly correlates with postoperative LV dimensions and function. Further investigation in larger cohorts to evaluate the association between degenerative mitral valve disease and ventricular arrhythmia is needed.

P4483Transforming growth factor-beta and arrhythmias in mitral valve prolapse patients

Methods

30 consecutive patients (mean age 53.1±9.4, 47% male) undergoing MV repair for severe MR due to MVP were enrolled in our observational, prospective, single-center study. Immunohistochemical characterization of mitral valve sections was performed with TGF-β1 and TGF-β2 primary antibodies. The levels of TGF-β1 and TGF-β2 in serum were determined by enzyme-linked immunosorbent assay Human Platinum ELISA.Transthoracic echocardiography and 24-hour Holter monitoring were performed pre- and postoperatively annually. Atrial fibrillation, PVCs and nonsustained ventricular tachycardia (VT) runs were reviewed.

Results

Resected MV leaflets showed the increase ofTGF-β1 and TGF-β2 positive cell count (33% and 38%, respectively). High level of TGF-β1 (>14.75 ng/ml) and/or TGF-β2 (>2.0 ng/ml) was detected in majority (77%) of patients and associated with thickening of posterior leaflet (r=0.67; p=0.016), residual valve prolapse (r=0.68; p=0.007) and recurrent MR (r=0.56; p=0.01), pre- and postoperative left atrial (p<0.001) and end-systolic LV diameter (p<0.001), and negatively with LV ejection fraction (p<0.001).

Atrial fibrillation was documented in 20% patients before repair. Postoperative AF occurred in 17% and associates with postoperative left atrial diameter (rs=0.60; p=0.008) and MR degree (rs=0.51; p=0.01). Total number of PVCs and non-sustained ventricular tachycardia runs dropped significantly in 1st (p=0.04, Wilcoxon matched pairs test) and 2nd (p=0.03), years of postoperative follow-up. Postoperative incidence of PVCs and VT associates strongly with postoperative end-diastolic LV diameter (rs=0.70; p=0.005), moderate negatively with LV ejection fraction (rs=−0.55; p=0.01).

TGF-β2 (but not TGF-β1) serum level were associated with postoperative incidence of atrial fibrillation (p<0.001), but not PVCs or VT. In univariate analysis, postoperative left atrial diameter (p=0.001), residual MR (p=0.003), myxomatous degeneration (p=0.008) and the serum level of TGF-β2 (p=0.001) were identified as risk factors of persistent atrial fibrillation after surgery.

Conclusions

High level of TGF-β2 is associated with persistent atrial (but not ventricular) arrhythmias in MVP patients after mitral valve repair, possibly through 1) progression of valve myxomatous after reconstructive surgery (via recurrent MR and LA enlargement) and 2) previously shown alteration of the electrophysiological phenotype of cardiac myofibroblasts.

CD73 Rather Than CD39 Is Mainly Involved in Controlling Purinergic Signaling in Calcified Aortic Valve Disease

The study aimed to compare composition of peripheral blood T-cell subsets and assess their surface expression of CD39 and CD73 ectonucleotidases in patients with severe and moderate aortic stenosis (AS) as well as to evaluate involvement of T-cell-mediated immune processes in valve calcification. The study was performed with 38 patients suffering from severe calcified aortic stenosis (SAS), 33 patients with MAS, and 30 apparently healthy volunteers (HVs). The relative distribution and percentage of T-cell subsets expressing CD39 and CD73 were evaluated by flow cytometry. T helper (Th) and cytotoxic T-cell subsets (Tcyt) were identified by using CD3, CD4, and CD8 antibodies. Regulatory T cells (Tregs) were characterized by the expression of CD3, CD4, and high IL-2R alpha chain (CD25high) levels. CD45R0 and CD62L were used to assess differentiation stage of Th, Tcyt, and Treg subsets. It was found that MAS and SAS patients differed in terms of relative distribution of Tcyt and absolute number of Treg. Moreover, the absolute number of Tcyt and terminally differentiated CD45RA-positive effector T-cells (TEMRA) subset was significantly higher in SAS vs. MAS patients and HVs. However, the absolute and relative number of naïve Th and the absolute number of Treg were significantly higher in MAS vs. SAS patients; the relative number of naïve Tregs was significantly (p < 0.01) decreased in SAS patients. It was shown that CD73 expression was significantly higher in SAS vs. MAS patients noted in all EM, CM, TEMRA, and naïve Th cell subsets. However, only the latter were significantly increased (p = 0.003) in patients compared with HVs. SAS vs. MAS patients were noted to have significantly higher percentage of CD73+ EM Tcyt (p = 0.006) and CD73+ CM Tcyt (p = 0.002). The expression of CD73 in patients significantly differed in all three Treg populations such as EM (p = 0.049), CM (p = 0.044), and naïve (p < 0.001). No significant differences in CD39 expression level was found in MAS and SAS patients compared with the HV group. Overall, the data obtained demonstrated that purinergic signaling was involved in the pathogenesis of aortic stenosis and calcification potentially acting via various cell types, wherein among enzymes, degrading extracellular ATP CD73 rather than CD39 played a prominent role.

Truncating Variant in Myof Gene Is Associated With Limb-Girdle Type Muscular Dystrophy and Cardiomyopathy

Even though genetic studies of individuals with neuromuscular diseases have uncovered the molecular background of many cardiac disorders such as cardiomyopathies and inherited arrhythmic syndromes, the genetic cause of a proportion of cardiomyopathies associated with neuromuscular phenotype still remains unknown. Here, we present an individual with a combination of cardiomyopathy and limb-girdle type muscular dystrophy where whole exome sequencing identified myoferlin (MYOF)-a member of the Ferlin protein family and close homolog of DYSF-as the most likely candidate gene. The disease-causative role of the identified variant c.[2576delG; 2575G>C], p.G859QfsTer8 is supported by functional studies in vitro using the primary patient's skeletal muscle mesenchymal progenitor cells, including both RNA sequencing and morphological studies, as well as recapitulating the muscle phenotype in vivo in zebrafish. We provide the first evidence supporting a role of MYOF in human muscle disease.

Guidelines for autopsy investigation of sudden cardiac death: 2017 update from the Association for European Cardiovascular Pathology

Although sudden cardiac death (SCD) is one of the most important modes of death in Western countries, pathologists and public health physicians have not given this problem the attention it deserves. New methods of preventing potentially fatal arrhythmias have been developed and the accurate diagnosis of the causes of SCD is now of particular importance. Pathologists are responsible for determining the precise cause and mechanism of sudden death but there is still considerable variation in the way in which they approach this increasingly complex task. The Association for European Cardiovascular Pathology has developed these guidelines, which represent the minimum standard that is required in the routine autopsy practice for the adequate investigation of SCD. The present version is an update of our original article, published 10 years ago. This is necessary because of our increased understanding of the genetics of cardiovascular diseases, the availability of new diagnostic methods, and the experience we have gained from the routine use of the original guidelines. The updated guidelines include a detailed protocol for the examination of the heart and recommendations for the selection of histological blocks and appropriate material for toxicology, microbiology, biochemistry, and molecular investigation. Our recommendations apply to university medical centers, regionals hospitals, and all healthcare professionals practicing pathology and forensic medicine. We believe that their adoption throughout Europe will improve the standards of autopsy practice, allow meaningful comparisons between different communities and regions, and permit the identification of emerging patterns of diseases causing SCD. Finally, we recommend the development of regional multidisciplinary networks of cardiologists, geneticists, and pathologists. Their role will be to facilitate the identification of index cases with a genetic basis, to screen appropriate family members, and ensure that appropriate preventive strategies are implemented.

Ventricular tachycardia as the first manifestation of Churg-Strauss syndrome

Life-threatening arrhythmias are often found in heart diseases, but they are rare as clinical symptoms of Churg-Strauss syndrome. We report a case of a 66-year-old woman with symptomatic monomorphic ventricular tachycardia as the first sign of Churg-Strauss syndrome. Cardiac manifestations were the main clinical symptoms of the disease, and changes in other organs were weakly expressed. Furthermore, increased serum IgG4 level was revealed. It was the reason for the differential diagnosis with IgG4-related diseases. Echocardiography, cardiac magnetic resonance imaging, and histopathological analysis of biopsies had an important role in diagnosis. <Learning objective: Ventricular arrhythmias are rare clinical symptoms of Churg-Strauss syndrome. This case is interesting because cardiac manifestations were the main clinical symptom of the disease, and changes in other organs were weakly expressed. Echocardiography, cardiac magnetic resonance imaging, and histopathological analysis of biopsies had an important role in diagnosis. Increased serum IgG4 level was the reason for the differential diagnosis with IgG4-related diseases. Churg-Strauss syndrome should be considered as part of the differential diagnosis in patients with noncoronary ventricular arrhythmias.>.

Rare Case of Vaginal Delivery in Giant Aortic Aneurysm

A 33-year-old woman underwent successful vaginal delivery despite previously unsuspected 8-cm ascending and 6-cm descending aortic aneurysms. These were repaired immediately after delivery.

Anatomy of the inferior interatrial route in humans

Aims

To explore the morphology of the proximal coronary sinus (CS) and the surrounding tissues in order to identify possible routes for interatrial conduction.

Method

Specimens containing interatrial septum and proximal CS were taken from 21 necropsied hearts and sliced into 10-μm thick parallel histological sections in 1-mm steps starting from the valve plane, up to the atrial roof (40–80 sections per heart). The sections were stained with van Gieson's stain.

Results

Media in the proximal CS consists of smooth muscle cells that do not form a continuous layer. CS was not surrounded by striated atrial myocardium in 10 specimens in which posterior CS wall was covered by epicardial fat only. In seven specimens, striated muscle bundles of up to 2-mm width connected the myocardium surrounding the CS with the left atrium. Regardless of their presence, variable posterior and/or anterior interatrial muscular connections were identified in all specimens.

Conclusion

Variability of the striated atrial myocardium surrounding proximal CS may affect interatrial conduction. Striated muscular fascicles connecting the proximal CS with the left atrium are not obligatory cardiac structures and may be considered as supplementary to the larger interatrial connections outside the CS.