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Published byPeter Randall Modified over 9 years ago
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03/06/271 K 305 27 June 03
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03/06/272 Reversible stunning hibernation Irreversible necrosis apoptosis Contractile Dysfunction
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4 This cell damage produces: hypocontractility enhance the likelihood of arrhythmias both of which can be lethal Contractile Dysfunction
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7 osmotic overload number of particles in cytosol as lactate accumulates and ATP is broken down immune response neutrophils and complement system pH paradox Etiology of Ischemia - Reperfusion Injury
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03/06/278 pH paradox pH i which increases: Na + -H + activity [Na + ] I Na + -Ca 2+ exchange reverse activity [Ca 2+ ] i overload contractile dysfunction Etiology of Ischemia - Reperfusion Injury
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03/06/279 Regulation of Intracellular H + H + extrusion (acidosis) NHE-1 pH paradox
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03/06/2712 EKG changes with ischemia/ MI Subendocardium results in ST segment depression injury current at rest causes baseline elevation during plateau causes ST segment depression observe a J point at the point between the QRS complex and the ST segment and this point represents zero current in the heart as all parts of the ventricles are depolarized ST segment depression is usually due to imbalance between supply and demand and will reverse when exercise is stopped during a stress test
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03/06/2713 EKG changes with ischemia/ MI
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03/06/2714 EKG changes with ischemia/ MI Subepicardium or transmural immediately results in heightened T waves may be followed by T wave inversion T wave inversion problems with directionality of repolarization ST segment elevation occurs due to injury current during plateau phase of the action potential which is moving towards epicardium deep (dirty, pathological) Q waves reflect scarring
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03/06/2715 EKG changes with ischemia/ MI
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03/06/2716 Plasma markers of MI 24-72 hours after MI - increases in: CK LDH TnI
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03/06/2717 Radionuclide Imaging of Heart Technetium- 99 m-MIBI MIBI - 2-methoxy isobutyl isonitrile MIBI travels via CBF becomes trapped within healthy, active muscle cells in the heart radioactivity monitored with a gamma camera during an MI, some muscle cells will not trap the MIBI also occurs with CAD except the lack of MIBI in some of the muscle cells is due to inadequate CBF
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03/06/2718 Cardiac Ischemia
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03/06/2719 Ischemic Preconditioning
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