SPARC: Autonomic Innervation of Porcine Ventricular Myocardium and Purkinje Fibers

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Donald B. Hoover ◽  
Peter Hanna ◽  
Michael J. Dacey ◽  
Joseph E. Hadaya ◽  
Mohammed A. Swid ◽  
...  
Keyword(s):  
Ventricular Myocardium ◽  
Autonomic Innervation ◽  
Purkinje Fibers

scholarly journals 3D magnetization transfer (MT) for the visualization of cardiac free-running Purkinje fibers: an ex vivo proof of concept

2021 ◽  
Author(s):  
Julie Magat ◽  
Arnaud Fouillet ◽  
Marion Constantin ◽  
Kylian Haliot ◽  
Jérôme Naulin ◽  
...  
Keyword(s):  
Cardiac Tissue ◽  
Ex Vivo ◽  
Magnetization Transfer ◽  
Ventricular Myocardium ◽  
Magnetization Transfer Ratio ◽  
Purkinje Fibers ◽  
3D Architecture ◽  
Free Running ◽  
2D And 3D ◽  
Purkinje Network

Abstract Objectives We investigate the possibility to exploit high-field MRI to acquire 3D images of Purkinje network which plays a crucial role in cardiac function. Since Purkinje fibers (PF) have a distinct cellular structure and are surrounded by connective tissue, we investigated conventional contrast mechanisms along with the magnetization transfer (MT) imaging technique to improve image contrast between ventricular structures of differing macromolecular content. Methods Three fixed porcine ventricular samples were used with free-running PFs on the endocardium. T1, T2*, T2, and M0 were evaluated on 2D slices for each sample at 9.4 T. MT parameters were optimized using hard pulses with different amplitudes, offset frequencies and durations. The cardiac structure was assessed through 2D and 3D T1w images with isotropic resolutions of 150 µm. Histology, immunofluorescence, and qPCR were performed to analyze collagen contents of cardiac tissue and PF. Results An MT preparation module of 350 ms duration inserted into the sequence with a B1 = 10 µT and frequency offset = 3000 Hz showed the best contrast, approximately 0.4 between PFs and myocardium. Magnetization transfer ratio (MTR) appeared higher in the cardiac tissue (MTR = 44.7 ± 3.5%) than in the PFs (MTR = 25.2 ± 6.3%). Discussion MT significantly improves contrast between PFs and ventricular myocardium and appears promising for imaging the 3D architecture of the Purkinje network.

scholarly journals Gap Junctional Communication via Connexin43 between Purkinje Fibers and Working Myocytes Explains the Epicardial Activation Pattern in the Postnatal Mouse Left Ventricle

2021 ◽  
Vol 22 (5) ◽  
pp. 2475
Author(s):  
Veronika Olejnickova ◽  
Matej Kocka ◽  
Alena Kvasilova ◽  
Hana Kolesova ◽  
Adam Dziacky ◽  
...  
Keyword(s):  
Left Ventricle ◽  
Gap Junctions ◽  
Cardiac Pacemaker ◽  
Green Fluorescence Protein ◽  
Ventricular Myocardium ◽  
Cardiac Conduction ◽  
Apical Region ◽  
Purkinje Fibers ◽  
Junctional Communication ◽  
Gap Junctional

The mammalian ventricular myocardium forms a functional syncytium due to flow of electrical current mediated in part by gap junctions localized within intercalated disks. The connexin (Cx) subunit of gap junctions have direct and indirect roles in conduction of electrical impulse from the cardiac pacemaker via the cardiac conduction system (CCS) to working myocytes. Cx43 is the dominant isoform in these channels. We have studied the distribution of Cx43 junctions between the CCS and working myocytes in a transgenic mouse model, which had the His-Purkinje portion of the CCS labeled with green fluorescence protein. The highest number of such connections was found in a region about one-third of ventricular length above the apex, and it correlated with the peak proportion of Purkinje fibers (PFs) to the ventricular myocardium. At this location, on the septal surface of the left ventricle, the insulated left bundle branch split into the uninsulated network of PFs that continued to the free wall anteriorly and posteriorly. The second peak of PF abundance was present in the ventricular apex. Epicardial activation maps correspondingly placed the site of the first activation in the apical region, while some hearts presented more highly located breakthrough sites. Taken together, these results increase our understanding of the physiological pattern of ventricular activation and its morphological underpinning through detailed CCS anatomy and distribution of its gap junctional coupling to the working myocardium.

CONDITION OF HEMODYNAMICS IN THE PULMONARY CIRCULATION OF PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) CONCURRENT WITH METABOLIC SYNDROME WITH HYPERTROPHY AND ATROPHY OF THE MYOCARDIUM

2019 ◽  
Vol 72 (8) ◽  
pp. 1491-1493
Author(s):  
Viktor P. Boriak ◽  
Svitlana V. Shut’ ◽  
Tetiana A. Trybrat ◽  
Olena V. Filatova
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Metabolic Syndrome ◽  
Right Ventricular ◽  
Pulmonary Disease ◽  
Pulmonary Circulation ◽  
Contractile Function ◽  
Ventricular Myocardium ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
The Right

Introduction: In recent years, COPD is observed as not an isolated, but an associated pathology, in particular, concurrent with metabolic syndrome. The aim of the research is to identify the differences in changes of the rheopulmonography parameters (RPG) depending on the presence of hypertrophy or atrophy of the right ventricular myocardium in patients with COPD concurrent with metabolic syndrome.. Materials and methods: We studied changes in rheopulmonography (RPG) in 145 patients with chronic obstructive pulmonary disease (COPD) concurrent with metabolic syndrome. Results: We detected precapillary hypertension of the pulmonary circulation in patients with right ventricular myocardial hypertrophy: anacrotism serration; flattened peak of the systolic wave; decreased Vcp; high placement of incisura; horizontal course of catacrotism; decreased amplitude of the systolic wave (in this case, due to a greater increase in the resistance of the blood flow in the pulmonary vessels than the decreased impact volume of the right ventricle); prolonged Q-a (in this group of patients, it depends more on hypertension of the pulmonary circulation than on the reduction of contractile function of the myocardium). In atrophy of the right ventricular myocardium, the following changes in the RPG were revealed: decreased systolic wave at its dramatic rise; prolonged Q-a (in this case, due to the weakened heart contraction); Vmax reduction (it reflects the reduction of myocardial contractility); in hypertrophy of the myocardium, Vcp., unlike RPG, does not decrease, which is explained by the decrease in the pressure of the pulmonary circulation. Conclusions: We believe that these changes in RPG allow differentiating hypertrophy and right ventricular myocardial atrophy along with established diagnostic criteria, and can be used as markers for the diagnosis and treatment of COPD concurrent with metabolic syndrome.

Evidence-based management of arrhythmogenic right ventricular cardiomyopathy in pregnancy

2020 ◽  
Author(s):  
Jagjit Khosla ◽  
Reshma Golamari ◽  
Alice Cai ◽  
Jamal Benson ◽  
Wilbert S Aronow ◽  
...  
Keyword(s):  
Heart Failure ◽  
Right Ventricular ◽  
Retrospective Studies ◽  
Arrhythmogenic Right Ventricular Cardiomyopathy ◽  
Genetic Disorder ◽  
Ventricular Myocardium ◽  
Evidence Based ◽  
Ventricular Cardiomyopathy ◽  
Genes Encoding ◽  
In Pregnancy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disorder resulting in fibrofatty replacement of the myocardium. Genetic mutations in genes encoding for desmosome proteins result in a ventricular myocardium prone to arrhythmias and heart failure. Although ARVC is known for a few decades, most of the outcomes in pregnancy are reported recently. Pregnancy leads to significant physiological changes with excess mechanical stress on the myocardium. All the retrospective studies suggest that pregnancy is well tolerated in these patients despite the high risk of arrhythmias and heart failure. Our review focuses on the most up-to-date evidence on the management of ARVC patients during the antepartum and postpartum period.

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