myocardium


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Related to myocardium: cardiomyopathy, myocarditis, myocardial infarction, ischemia, Hibernating myocardium

myocardium

 [mi″o-kar´de-um]
the middle and thickest layer of the heart wall, composed of cardiac muscle. adj., adj myocar´dial.

my·o·car·di·um

, pl.

my·o·car·di·a

(mī'ō-kar'dē-ŭm, -kar'dē-ă), [TA]
The middle layer of the heart, consisting of cardiac muscle.
[myo- + G. kardia, heart]

myocardium

/myo·car·di·um/ (-kahr´de-um) the middle and thickest layer of the heart wall, composed of cardiac muscle.
hibernating myocardium  see myocardial hibernation, under hibernation.
stunned myocardium  see myocardial stunning, under stunning.

myocardium

(mī′ō-kär′dē-əm)
n. pl. myocar·dia (-dē-ə)
The muscular tissue of the heart.

my′o·car′di·al adj.

myocardium

[mī′ōkär′dē·əm]
Etymology: Gk, mys, muscle, kardia, heart
a thick contractile middle layer of uniquely constructed and arranged muscle cells that forms the bulk of the heart wall. The myocardium contains a minimum of other tissue, except blood vessels, and is covered interiorly by the endocardium. The contractile tissue of the myocardium is composed of fibers with the characteristic cross-striations of muscular tissue. The fibers are about one third as large in diameter as those of skeletal muscle and contain more sarcoplasm. They branch frequently and are interconnected to form a network that is continuous except where the bundles and the laminae are attached at their origins and insertions into the fibrous trigone of the heart. Myocardial muscle contains less connective tissue than does skeletal muscle. Specially modified fibers of myocardial muscle constitute the conduction system of the heart, including the sinoatrial node, the atrioventricular (AV) node, the AV bundle, and the Purkinje fibers. Most of the myocardial fibers function to contract the heart. The metabolic processes of the myocardium are almost exclusively aerobic. Many key enzymatic reactions of the heart, such as the citric acid cycle and oxidative phosphorylation, take place in the highly concentrated myocardial sarcosomes. The process of oxidative phosphorylation produces adenosine triphosphate (ATP), the immediate energy source for myocardial contraction. Oxygen, which significantly affects ATP production and contractibility, is a critical metabolic component of the myocardium, which consumes from 6.5 to 10 mL/100 g of tissue per minute. Without this oxygen supply, myocardial contractions decrease in a few minutes. The myocardium maintains a relatively constant level of glycogen in the form of sarcoplasmic granules. Compare epicardium. See also cardiac muscle. myocardial, adj.

my·o·car·di·um

, pl. myocardia (mī'ō-kahr'dē-ŭm, -ă) [TA]
The middle layer of the heart, consisting of cardiac muscle.
[myo- + G. kardia, heart]

myocardium

the muscular wall of the vertebrate heart.

Myocardium

The thick middle layer of the heart that forms the bulk of the heart wall and contracts as the organ beats.

myocardium

cardiac muscle

my·o·car·di·um

, pl. myocardia (mī'ō-kahr'dē-ŭm, -ă) [TA]
The middle layer of the heart, consisting of cardiac muscle.
[myo- + G. kardia, heart]

myocardium

(mī´ōkär´dēəm),
n the thick, contractile middle layer of uniquely constructed and arranged muscle cells (cardiac muscle) that form the bulk of the heart wall.

myocardium

the middle and thickest layer of the heart wall, composed of cardiac muscle.
References in periodicals archive ?
Ichida F, Hamamichi Y, Miyawaki T, Ono Y, Kamiya T, Akagi T, Hamada H, Hirose O, Isobe T, Yamada K, Kurotobi S, Mito H, Miyake T, Murakami Y, Nishi T, Shinohara M, Seguchi M, Tashiro S, Tomimatsu H: Clinical features of isolated noncompaction of the ventricular myocardium.
In summary, this patient's perfusionviability CMR imaging demonstrates a small focal area of apical-inferior wall transmural, > 50% myocardial DHE with corresponding akinesis and fixed-perfusion rest-stress defects, corresponding to RCA territory scar with nonviable myocardium, related to the patient's prior MI.
Compared with CMRI, echocardiography underestimated the ratio of noncompacted to compacted myocardium (23).
The content of CPK and LDH increases during myocardium injury and the concentrations of these two enzymes are in parallel with the myocardium injury degree.
The heart was stopped with KCl, removed, and visually examined to verify that only a limited area of the myocardium had been isolated.
In contrast with the longer-term gadolinium uptake, ischaemic myocardium appears darker than normal myocardium in the first images owing to reduced perfusion.
The study showed that an ethanolic extract of Crataegus oxycantha can act as an antioxidant and activator of intracellular signalling, which can protect the myocardium during reperfusion.
Apart from complement, cardiac troponin T (cTnT) has been used as a marker of myocardial injury because it is localized to, and specific for, myocardium.
With the increase of biosynthesis of NO via enhanced NOS activity and the activation of PKC in the myocardium during brief ischaemia and reperfusion periods, NO radicals and their metabolites were associated with the cardioprotective effects.
His heart had a large fibrous nodular mass in the mitral valve cusp; there were numerous small, infiltrative, white, cheese-like lesions proximal to the aortic valve cusp and extending to the myocardium, and extensive fibrous thickening of the tricuspid valve cusp (Figs 1 and 2).
Results of the study indicate that non-surgical intracoronary infusion of an adenovector carrying a reporter gene to the heart enables robust protein expression in the area of the myocardium at risk due to ischemia and reperfusion injury.
Fortunately, there exists a possibility for flexible determination of the PR limits, keeping the myocardium energy in balance automatically (E = W in Fig.