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Topic: Stunned myocardium

Related Topics

Hibernating myocardium

Myocardial infarction

Coronary artery bypass surgery

Cardiology

Ischemia

	Mechanisms of Myocardial Stunning and its Clinical Relevance
		Since troponin I is partially degraded in the stunned myocardium by Ca2+-activated protease (see Calcium Overload) the energy obtain from Ca2+ binding to troponin C cannot be effectively transduced to cause the necessary structural change in the troponin-tropomyosin complex (Gao et al., 1995; Gao et al., 1997).
		Thus, the ability of the stunned myocardium to respond to inotropic stimuli with a normal contractile reserve is explained (Gao et al., 1995).
		Stunning poses another problem to the clinicians, in that they are unable to assess the viability of tissue by contractile function after procedure such as thrombolytic therapy.
	yoyo.cc.monash.edu.au /~coolhead/science/myocardi.htm (4834 words)

	[No title]
		Stunned myocardium has been described in animals [2] and subsequently documented in humans [1], where it is considered to play a role in the prolonged contractile dysfunction seen in patients undergoing reperfusion therapy for acute myocardial infarction, following attacks of unstable angina, and in some patients with exercise-induced ischemia.
		In contrast, stunned myocardium caused by multiple cycles of ischemia-reperfusion (as it may occur in patients with chronic coronary artery disease) may show normal or reduced glucose uptake in areas with preserved blood flow at rest, so-called reverse mismatch on PET imaging.
		Similarly, oxidative metabolism in stunned regions was significantly decreased at 4 h (84% +/- 2% of remote, P < 0.001) and at 24 h (90% +/- 2% of remote, P = 0.005) and recovered to near-normal levels after 1 wk of reperfusion (97% +/- 1% of remote, P = 0.024).
	www.heartandmetabolism.org /issues/HM19/hm19imaging.asp (7101 words)

	[No title] (Site not responding. Last check: 2007-10-20)
		Although stunning occurs after brief total occlusions and prolonged partial occlusions (ie, short-term hibernation), the time course of functional recovery varies from a few hours to several days, suggesting that the severity of protein damage or mechanisms responsible for the dysfunction may differ.
		Stunned myocardium demonstrated no change in the 31- or the 27-kDa band, and the percentage of the 27- to 31-kDa band remained constant after 10-minute total occlusions (LAD, 5.9+/-0.9%; normal, 4.9+/-1.6%) and 1-hour partial occlusions (LAD, 8.5+/-1.9%; normal, 7.3+/-1.4%) and in sham controls (LAD, 10.9+/-1.5%; normal, 9.8+/-1.4%).
		Thus, stunned myocardium occurs without TnI degradation or altered SR gene expression, indicating that additional mechanisms are responsible for the reversible dysfunction after single episodes of regional ischemia in swine.
	fmrc.pulmcc.washington.edu /WebRefs/R790.htm (327 words)

	Hibernating and Stunned Myocardium - Cardiovascular Physiology - Medstudents
		Hibernating myocardium (HM) must be differentited by stunning, although both processes may coexist on clinical grounds (7), and in some instances, it is difficult to say which of them predominates in a individual patient (3).
		Stunned cells do not show major structural abnormalities, except some small vacuoles near mitochondria, and the crists of the latter showed more tortuos on electronic microscope (1).
		Stunning probably is related to altered calcium homeostasis, and oxygen free radicals may also play a role in the development of stunned cells.
	www.medstudents.com.br /basic/cardfs/cardfs7.htm (1449 words)

	UpToDate Pathophysiology of stunned or hibernating myocardium (Site not responding. Last check: 2007-10-20)
		The approach to diagnosis and therapy of hibernation, the clinical syndromes associated with stunned or hibernating myocardium, and the role of nuclear imaging and dobutamine echocardiography to assess myocardial viability are discussed elsewhere.
		— Stunned myocardium was the term initially used to describe a condition demonstrated in the laboratory in which total coronary artery occlusion lasting only 5 to 15 minutes (a period not associated with cell death) produced an abnormality in regional LV wall motion that persisted for hours or days following reperfusion [3-7].
		In the clinical setting, stunned myocardium may be superimposed on ischemia (including variant angina and during and after coronary revascularization), hibernation, or infarction when blood flow is reestablished [8].
	www.patients.uptodate.com /topic.asp?file=chd/46551&title=undefined (449 words)

	UpToDate Pathophysiology of stunned or hibernating myocardium
		The approach to diagnosis and therapy of hibernation, the clinical syndromes associated with stunned or hibernating myocardium, and the role of nuclear imaging and dobutamine echocardiography to assess myocardial viability are discussed elsewhere.
		— Stunned myocardium was the term initially used to describe a condition demonstrated in the laboratory in which total coronary artery occlusion lasting only 5 to 15 minutes (a period not associated with cell death) produced an abnormality in regional LV wall motion that persisted for hours or days following reperfusion [3-7].
		In the clinical setting, stunned myocardium may be superimposed on ischemia (including variant angina and during and after coronary revascularization), hibernation, or infarction when blood flow is reestablished [8].
	patients.uptodate.com /topic.asp?file=chd/46551 (443 words)

	Stunned myocardium: theoretical mechanisms of injury -- Walton and Westrope 16 (2): 23 -- Critical Care Nurse
		Stunned myocardium may occur after an episode of prolonged or transient ischemia.
		In the stunned myocardium, myocardial contractility is temporarily depressed, causing symptoms similar to those of cardiogenic shock.
		When critical care nurses are familiar with the clinical characteristics and risk factors of stunned myocardium, they can start the appropriate interventions and left ventricular function returns to normal within days with no residual hypokinesis.
	ccn.aacnjournals.org /cgi/content/abstract/16/2/23 (159 words)

	Myocardial infarction (Site not responding. Last check: 2007-10-20)
		The medical term for a heart attack is myocardial infarction, where "myo" refers to muscle, and "cardium" refers to the heart (myocardium is the heart muscle) and "infarction" means tissue death (necrosis) caused by an obstruction of blood flow.
		All risk factors for atherosclerosis are also (modifiable) risk factors for ischemic heart disease: older age, smoking, hypercholesterolemia, diabetes (or insulin resistance) and obesity.
		The ultimate goal of the management in the acute phase of the disease is to salvage as much myocardium as possible and restore contractile function of heart chambers.
	www.sciencedaily.com /encyclopedia/myocardial_infarction (1546 words)

	British Journal of Pharmacology - Cardiovascular profile of the calcium sensitizer EMD 57033 in open-chest ...
		Stunned myocardium is characterized by both a depressed systolic and diastolic function (Charlat et al., 1989; Ehring et al., 1993; Bolli and Marban, 1999).
		These findings suggest that the normal myocardium is more sensitive to adverse effects on systolic function than stunned myocardium in which the Ca responsiveness is lower (Bolli and Marban, 1999).
		in stunned myocardium, which is difficult to explain by a phosphodiesterase III inhibitory action, as it seems unlikely that a pharmacological property such as phosphodiesterase III inhibition could differ in the stunned from normal myocardium.
	www.nature.com /bjp/journal/v129/n7/full/0703231a.html (6184 words)

	Basal metabolism does not account for high O2 consumption in stunned myocardium -- Schipke et al. 274 (3): 743 -- AJP - ...
		of literature on myocardial stunning (2, 10, 24, 27), the phenomenon remains poorly understood.
		Alterations in cardiac sarcoplasmic reticulum calcium transport in the postischemic "stunned" myocardium.
		Postischemic myocardial "stunning" identification of major differences between the open-chest and the conscious dog and evaluation of the oxygen radical hypothesis in the conscious dog.
	ajpheart.physiology.org /cgi/content/full/274/3/H743 (2178 words)

	Re: stunned myocardium (Site not responding. Last check: 2007-10-20)
		In the case of reperfusion of the myocardium following coronary artery occlusion, there is little evidence to suggest that reperfusion injury is ever clinically significant.
		The mechanism of myocardial stunning remains controversial, but might be related to the formation of free oxygen radicals and cytosolic calcium overload in reperfused myocytes.
		The good news is that the stunned area of myocardium will usually recover full function within 24-72 hours.
	www.med.unsw.edu.au /PathBull/_pb/000001a5.htm (227 words)

	CHEST: Dramatic improvement of stunned myocardium (Site not responding. Last check: 2007-10-20)
		Stunned myocardium is defined as prolonged but reversible postischemic contractile dysfunction of viable heart muscle that may be salvaged by reperfusion.
		Stunned myocardium has been implicated in prolonged periods of muscle dysfunction associated with ischemia in Prinzmetal's angina, unstable angina, thrombolysis, percutaneous transluminal coronary angioplasty, and coronary artery bypass graft surgery.[1] This report describes a patient with dramatic recovery of stunned myocardium.
		With shorter hospital stays, studies at the time of hospital may not reflect recovered myocardium, and these studies may be more appropriately performed at least two weeks after the acute event.
	www.findarticles.com /p/articles/mi_m0984/is_n4_v101/ai_12357455 (811 words)

	Diltiazem, tramadol, antibiotics, online pharmacy, drugs online, Rx Online, pharmaceuticals, Prescription drug, ... (Site not responding. Last check: 2007-10-20)
		"Stunning" was produced by repetitive 10 minute episodes of ischemia, followed by 15 minutes of reperfusion.
		To assess whether myocardial stunning occurs after brief periods of ischemia, global and regional ventricular function assessed by radionuclide angiography was studied in 52 patients.
		The search for stunned myocardium should be extended to other different clinical models characterized by prolonged ischemia such as unstable angina or myocardial infarction.
	www.dreampharmaceuticals.com /ref-diltiazem/diltiazem-research-abs3.1304.html (591 words)

	Parathyroid hormone-related peptide improves contractile function of stunned myocardium in rats and pigs -- Jansen et ...
		Single myocytes were isolated from the stunned myocardium as previously described (27).
		In stunned myocardium, the cumulative dose decreasing coronary resistance to 29 ± 2% of baseline (P < 0.05; Fig.
		agonist CGS-21680 in infarcted and stunned porcine myocardium.
	ajpheart.physiology.org /cgi/content/full/284/1/H49 (3395 words)

	Thallium Stress Cardiac Imaging Findings (Site not responding. Last check: 2007-10-20)
		Stunned myocardium refers to myocardial contractile dysfunction that follows a period of coronary occlusion even after flow has been restored.
		Stunning represents a flow-contraction mismatch that is typically seen in the clinical setting of thrombolytic therapy for acute myocardial infarction.
		In the classical setting, stunning may persist for days to weeks, but generally improvement in regional wall motion is seen after 2 to 3 weeks without further intervention.
	www.indyrad.iupui.edu /public/lectures/HTML/NM-RM/NucMed/CV05.htm (2218 words)

	Acetoacetate augments beta-adrenergic inotropism of stunned myocardium by an antioxidant mechanism. (Site not responding. Last check: 2007-10-20)
		Blunted beta-adrenergic inotropism in stunned myocardium is restored by pharmacological (N-acetylcysteine) and metabolic (pyruvate) antioxidants.
		To test the hypothesis that acetoacetate restores contractile performance and beta-adrenergic inotropism of stunned myocardium, postischemic Krebs-Henseleit-perfused guinea pig hearts were treated with 5 mM acetoacetate and/or 2 nM isoproterenol at 15-45 and 30-45 min of reperfusion, respectively, while cardiac power was monitored.
		The myocardium was snap frozen, and its energy state was assessed from phosphocreatine phosphorylation potential.
	www.viagenbio.com /~grape-seed-extract/antioxidant-research-abs.94.html (532 words)

	KoreaMed - Basic Search (Site not responding. Last check: 2007-10-20)
		BACKGROUND: The effects of calcium chloride (CaCl2) on regional mechanical function, coronary blood flow (CBF) and myocardial oxygen consumption (MVO2) were examined in normal and stunned myocardium in an open-chest canine model.
		Elac was decreased further during epinephrine, while it remained unaltered during CaCl2 infusion in stunned myocardium.
		In addition, CaCl2 has no direct effect on coronary vascular tone in either normal or stunned myocardium, while epinephrine causes direct vasodilation in normal but not in stunned myocardium.
	www.koreamed.org /SearchBasic.php?RID=174126&DT=1&QY=%22Korean+J++Anesthesiol%22+%5BJTI%5D+AND+2000+%5BDPY%5D (332 words)

	SPECT and PET in the Evaluation of Coronary Artery Disease -- Jadvar et al. 19 (4): 915 -- RadioGraphics
		myocardium is myocardium that is deprived of adequate coronary
		Identification of viable myocardium in patients with coronary artery disease and left ventricular dysfunction: comparison of thallium scintigraphy with reinjection and PET imaging with 18F-fluorodeoxyglucose.
		Metabolic responses of hibernating and infarcted myocardium to revascularization: a follow-up study of regional perfusion, function, and metabolism.
	radiographics.rsnajnls.org /cgi/content/full/19/4/915 (4646 words)

	[No title] (Site not responding. Last check: 2007-10-20)
		Transmural distribution of FDG uptake in stunned myocardium.
		To investigate FDG uptake in acute stunning, chronically instrumented pigs (n = 9) and sham controls (n = 8) were studied while in a fasted, closed-chest, anesthetized state.
		FDG uptake in stunned myocardium was variably increased and averaged 1.
	fmrc.pulmcc.washington.edu /WebRefs/R782.htm (155 words)

	Contrast-enhanced MR Delineation of Stunned Myocardium with Administration of MnCl2 in Rats -- Krombach et al. 230 (1): ...
		Normal myocardium was relatively hypointense since it was approaching null signal, and postischemic myocardium was evident as a hyperintense zone.
		Similar to Figure 2, when inversion time was 200 msec, all regions of myocardium had negative signal intensity polarity, and postischemic myocardium was realtively hyperintense in comparison with normal myocardium.
		with myocardial stunning, and the thickening encompassed the
	radiology.rsnajnls.org /cgi/content/full/230/1/183 (5134 words)

	Intrinsic Myofilament Alterations Underlying the Decreased Contractility of Stunned Myocardium : A Consequence of ...
		Intrinsic Myofilament Alterations Underlying the Decreased Contractility of Stunned Myocardium : A Consequence of Ca2+-Dependent Proteolysis?
		Kusuoka H, Porterfield JK, Weisman HF, Weisfeldt ML, Marban E. Pathophysiology and pathogenesis of stunned myocardium: depressed Ca activation of contraction as a consequence of reperfusion-induced cellular calcium overload in ferret hearts.
		Stunning does not change the relation between calcium and force in skinned rat trabeculae.
	circres.ahajournals.org /cgi/content/full/78/3/455 (5786 words)

	UpToDate Clinical syndromes of stunned or hibernating myocardium
		The clinical syndromes associated with stunned and hibernating myocardium and the methods used to detect stunned myocardium will be reviewed here.
		In patients with coronary disease and chronic stable angina, prolonged, but reversible LV dysfunction (stunning) occurred after a symptom-limited dobutamine infusion despite normal myocardial blood flow and myocardial oxygen consumption [3].
		The degree of stunning was related to the severity of the coronary stenosis and the reduction in peak myocardial blood flow.
	patients.uptodate.com /topic.asp?file=chd/52663&title=Angina (470 words)

	DiagnosisHeart.com: Articles (Site not responding. Last check: 2007-10-20)
		Stunned myocardium is a state where the heart has contractile dysfunction related to an ischemic event such as an acute heart attack.
		Viable myocardium is myocardium which retains the ability to contract normally.
		The main role of PET scanning is to establish whether there is sufficient viable myocardium in a patient with poor ventricular function (ventricular dysfunction) to warrant revascularization.
	www.diagnosisheart.com /printerfriendly.php?usertable=articles&articleid=70 (143 words)

	NSCG - Cardiovascular testing
		The importance of differentiating irreversibly damaged myocardium from viable, but temporarily nonfunctioning myocardium, due to recent AMI or chronic, severe ischemia, cannot be over emphasized.
		Patients with chronic, recurrent CHF and symptoms of low cardiac output, who appear to be refractory to medical therapy, should be carefully evaluated for stunned (post-MI) or hibernating (chronic hypoperfusion) myocardium, as their symptoms may be vastly improved upon successful revascularization.
		When hibernation or stunning is suspected, one should order a dobutamine stress echo and also a thallium (but not Cardiolite) stress (or dipyridamole/adenosine) test with 24 hour reinjection and rescanning.
	www.nscardiology.com /testing.htm (2920 words)

	Molecular and Cellular Mechanisms of Myocardial Stunning -- Bolli and Marbán 79 (2): 609 -- Physiological Reviews
		As a general concept, the stunned myocardium is a "hypersensitive" myocardium (18); that is, factors that affect contractile
		The central concepts of this proposal are that myocardial stunning is a myofilament disease, caused by impaired calcium responsiveness of contractile machinery of myocytes, and that this defect is the result of both oxidative stress and calcium overload.
		The slow but complete recovery characteristic of stunned myocardium could be the result of repair of oxidative damage and/or resynthesis of contractile proteins.
	physrev.physiology.org /cgi/content/full/79/2/609 (9316 words)

	Effects of intracoronary calcium chloride on regional oxygen balance and mechanical function in normal and stunned ...
		Inotropic response of stunned hypertrophied myocardium: responsiveness of hypertrophied and normal postischemic isolated rat hearts to calcium and dopamine stimulation.
		Myocardial oxygen consumption, oxygen supply/demand heterogeneity, and microvascular patency in regionally stunned myocardium.
		Recovery of contractile function of stunned myocardium in chronically instrumented dogs is enhanced by halothane or isoflurane.
	bja.oxfordjournals.org /cgi/content/full/88/1/78 (3435 words)

	Cardiogenic shock
		Mechanical dysfunction of myocardium which persists despite absence of irreversible damage and restoration of normal or near-normal coronary flow and which recovers spontaneously.
		Myocardium with impaired function that is persistently impaired at rest due to decreased coronary blood flow but which demonstrates improved function when balance between oxygen supply and demand is improved.
		Dobutamine echocardiography can be used to differentiate between stunned myocardium with a patent artery ( function that persists during infusion) from stunned myocardium with a stenosed artery or hibernation (initial followed by deterioration).
	www.aic.cuhk.edu.hk /web8/cardiogenic_shock.htm (659 words)

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