What's the difference between epicardium and myocardium?

Epicardium


Definition:

  • (n.) That of the pericardium which forms the outer surface of the heart; the cardiac pericardium.

Example Sentences:

  • (1) Twenty-one of 24 adult male and female cattle egrets (Bubulcus ibis ibis) collected in Geneva County, Alabama had numerous white cyst-like structures (1,466 microns X 354 microns) found within the loose connective tissues of the skeletal muscles of the inguinal region, beneath the serosa of the proventriculus and in the heart beneath the epicardium (one adult male bird).
  • (2) Without endocardial mapping many of these tachycardias would have been incorrectly identified as originating in the fascicles or epicardium.
  • (3) Rapid steady-state estimates of interstitial fluid (ISF) adenosine concentrations (ADOi) in the left ventricular epicardium of anesthetized dogs were obtained by the epicardial porous disc (EPD) method described herein.
  • (4) During a second surgical procedure approximately two weeks later, parasympathectomy was achieved by dissection and topical application of phenol to the fat pad and underlying epicardium at the inferior left atrial junction with the inferior vena cava; completeness of AVNR parasympathectomy was tested at surgery by supramaximal stimulation of right and left cervical vagi, with and without rapid atrial pacing.
  • (5) He used the internal mammary artery pedicle (Kolesov's pedicle, Feb. 25, 1964) and described beadlike nodules and a dimpling of the epicardium over the atherosclerotic coronary artery (Kolesov's groove sign, Jan. 26, 1965).
  • (6) Myocytes with a similar isomyosin complement appear clustered with a predominance of V1 in the epicardium.
  • (7) Two sensing electrodes were fixed to the epicardium of the right ventricle, and the four leads were connected to a double-chambered pacemaker.
  • (8) The local QT interval in the septum were relatively longer (69 to 123 msec), compared with that of the ventricular surface (50 to 98 msec), and such durations of ventricular epicardium and septum were considerably less than those of dogs and humans.
  • (9) Thus this chamber had an excellent capability of epicardium will yield more physiological benefits to patients with an agenetic or hypoplastic right ventricle than do the current surgical procedures, in which a conduit is interposed between the right atrium and the main pulmonary artery.
  • (10) In epicardium, the reduction of phase 0 and 1 amplitudes led to a slowing of the second action potential upstroke and an increase in the amplitude of phase 2.
  • (11) Approximately 50 white markers (diameter 1.5 mm) are attached to the epicardium and their motion is recorded on tape by a video camera.
  • (12) A transient outward current (Ito), long considered to be a unique feature of Purkinje fiber tissue, has recently been demonstrated in dog ventricular tissue in vitro and most prominently in the epicardium.
  • (13) 4-Aminopyridine, a transient outward current blocker, decreased the time dependence of phase 1 amplitude and concomitantly decreased the time dependence of action potential duration in epicardium.
  • (14) This study was designed to determine whether measurement of integrated backscatter could be used detect the progressive transmural shift of myofiber alignment that occurs from epicardium to endocardium in human ventricular wall segments.
  • (15) Next the model was used to study propagated excitation in a three-dimensional region representing the anisotropic properties of the ventricular wall, with attention to the effects produced by variable fiber direction from "endocardium" to "epicardium."
  • (16) Although their function is unknown, M cells may facilitate conduction in epicardium and are likely to influence or mediate the manifestation of electrocardiographic J waves, T waves, U waves, and long QT intervals and contribute importantly to arrhythmogenesis.
  • (17) Exposure of the preparation to simulated "ischemia" (hypoxia, acidosis, glucose deprivation and hyperkalemia) resulted in several electrophysiological derangements, including a marked depolarization of the maximum diastolic potential (MDP) in both endocardium and epicardium, shortening of the action potential duration (APD), and prolongation of the transmural conduction time followed by transmural conduction block.
  • (18) The transmural distribution pattern of the microspheres (endocardium-epicardium ratios) reveals that rigor mortis is a factor that should be taken into account.
  • (19) The tumor involved only the epicardium and myocardium, which met the criteria of primary cardiac lymphoma as defined by the Armed Forces Institute of Pathology.
  • (20) There were no significant differences in the mean hydroxyproline content between the epicardium and the endocardium, between the left ventricle and the right ventricle, or among cardiovascular and renal disease group, malignant disease group and miscellaneous disease group.

Myocardium


Definition:

  • (n.) The main substance of the muscular wall of the heart inclosed between the epicardium and endocardium.

Example Sentences:

  • (1) The acute effect of alcohol manifested itself by decreasing mitochondrial respiration, compensated by increased glycolytic activity of the myocardium so that myocardial energy phosphate concentration remained unchanged.
  • (2) The myocardium was assumed to be composed of a nonlinear viscoelastic, inhomogeneous, anisotropic (transversely isotropic) and incompressible material operating under adiabatic and isothermal conditions.
  • (3) Comparison with 99Tc-pyrophosphate uptake in infarcted dog heart, induced by selective obstruction of a coronary artery, suggest that the 111In-labelled F(ab')2 localizes specifically in infarcted myocardium only.
  • (4) By means of rapid planar Hill type antimony-bismuth thermophiles the initial heat liberated by papillary muscles was measured synchronously with developed tension for control (C), pressure-overload (GOP), and hypothyrotic (PTU) rat myocardium (chronic experiments) and after application of 10(-6) M isoproterenol or 200 10(-6) M UDCG-115.
  • (5) Distant ischemia was distinguished from peri-infarctional ischemia by the presence of transient thallium defects in, or slow thallium washout from myocardium not supplied by the infarct-related coronary artery.
  • (6) Administration of one of the precursors of noradrenaline l-DOPA not only prevented the decrease in tissue noradrenaline content in myocardium, but restored completely its reserves, exhausted by electrostimulation of the aortic arch.
  • (7) The terms of maximum reduction of the enzymatic activity falling within the 4th-6th and 24th hours and 2nd day should be taken into account while developing the methods of metabolic protection and enzyme therapy of the ischaemic myocardium.
  • (8) Previous studies have reported that the numbers of beta- and alpha-adrenergic receptors increase in ischemic myocardium.
  • (9) With a series of 117 aortic valve replacements, the authors have examined the results in relation to the method of protecting the myocardium while the aorta is clamped off.
  • (10) Acute transmural myocardial infarction has been reported to functionally denervate the normal myocardium distal to the infarcted zone by interrupting neurotransmission in axons coursing in the subepicardial region of the myocardial necrosis.
  • (11) Defects of mitochondrial DNA have been found at necropsy in the myocardium of patients with Kearns-Sayre syndrome.
  • (12) Little anatomic information is available on the annular myocardium.
  • (13) Dietary fat can modify the vulnerability of the myocardium to arrhythmic stimuli.
  • (14) Isotonically, peak muscle shortening was reduced in the left muscle, whereas time to peak shortening was prolonged in the right myocardium.
  • (15) The maximum functional response of catecholamine injured hearts to stimulation of alpha- and beta-adrenoceptors reduced in both age groups, while the sensitivity of the myocardium to beta-adrenoceptor agonists in mature rats increased.
  • (16) Complex treatment with inclusion of thymalin resulted in an increase of the thymic factor, normalization of the lipid metabolism increase of the contractile function of the myocardium and, thus, increases the treatment efficacy.
  • (17) Under a dissecting microscope the vascular casts revealed direct communications from the skeletal muscle which penetrated deeply into the myocardium.
  • (18) When the same dose of ISO was administered to rats with aortic constriction the rise in labelled Ca uptake by the hypertrophied myocardium of the left ventricle was greatly reduced.
  • (19) Thus, small doses of thyroid hormones restrict significantly stress induced activity of LP membranes, increasing the power of antioxidant systems both in the myocardium and in the organism.
  • (20) The constrictor may be used for studies on the development of collaterals as well as on therapeutic measures in chronic ischemia of the myocardium.

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