1/25. Reversible congestive heart failure caused by myocardial hibernation.Myocardial hibernation is reversible contractile dysfunction of cardiac myocytes caused by chronic ischemia. Animal studies and observations in human beings suggest that the term hibernation is a misnomer. Repetitive ischemic insult that does not produce necrosis results in functional and histologic tissue deterioration, which culminates in myocyte apoptosis. Revascularization of "hibernating" myocardium results in partial or complete recovery of function, depending upon the duration of ischemia and the severity of cellular degeneration. Improvement in global left ventricular function is proportional to the quantity of hibernating tissue that is revascularized, but this threshold quantity has not been determined with certainty. Diagnostic methods used to detect viable tissue within akinetic left ventricular segments depend upon the recognition of recruitable contractile function or the active concentration of a radioactive tracer. No diagnostic method has shown clear superiority. The most sensitive methods appear to be single-photon emission computed tomographic imaging after reinjection of thallium-201 at 24 hours and positron-emission tomographic imaging with 18F-fluorodeoxyglucose. The most specific diagnostic method appears to be measurement of dobutamine-stimulated contractile function, using either echocardiography or gated magnetic resonance imaging. We present a review of the pathophysiology, diagnosis, and treatment of myocardial hibernation, and include an illustrative case report involving a 57-year-old man with myocardial hibernation.- - - - - - - - - - ranking = 1keywords = dysfunction (Clic here for more details about this article) |
2/25. Reversible biventricular dysfunction secondary to ischemia in a patient with acute airway obstruction: a case report and review of the literature on reversible causes of acute ventricular dysfunction.Reversible causes of acute myocardial dysfunction are important for clinicians to recognize. Reversible biventricular dysfunction secondary to myocardial ischemia is presented in a patient with acute upper airway obstruction. The differential diagnosis of reversible acute myocardial dysfunction is reviewed.- - - - - - - - - - ranking = 4115.9953412039keywords = ventricular dysfunction, dysfunction (Clic here for more details about this article) |
3/25. The hibernating heart: reversible left ventricular dysfunction in chronic heart failure.A patient with severe heart failure secondary to coronary heart disease is presented. Following investigation he was thought to have significant areas of myocardial hibernation and was therefore treated with coronary revascularisation, with major clinical benefit.- - - - - - - - - - ranking = 3282.6048799916keywords = ventricular dysfunction, left ventricular dysfunction, dysfunction (Clic here for more details about this article) |
4/25. Detection of a biphasic response of hibernating myocardium by dobutamine-stress electrocardiography-gated technetium-99m-tetrofosmin single photon emission computed tomography--a case report.A woman with coronary artery disease underwent a new imaging technique: dobutamine-stress electrocardiography (ECG)-gated tetrofosmin-single photon emission computed tomography (SPECT). dobutamine-stress ECG-gated tetrofosmin-SPECT with automatic left ventricular function analysis software programs detected improvement and a biphasic response of dysfunctional myocardium during dobutamine infusion, which suggested viable but hibernating myocardium. dobutamine-stress ECG-gated tetrofosmin-SPECT with automatic left ventricular function analysis software programs has the potential to detect viable but dysfunctional myocardium with contractile reserve.- - - - - - - - - - ranking = 2keywords = dysfunction (Clic here for more details about this article) |
5/25. myocardial stunning in hyperthyroidism.The cases of two patients with hyperthyroidism and acute left ventricular (LV) dysfunction with segmental wall motion abnormalities resulting in heart failure are reported. Both had electrocardiographic changes mimicking ischemic coronary artery disease. Treatment with antithyroid medications, beta blockers, and angiotensin-converting enzyme inhibitors rapidly restored LV function. The rapid reversibility suggests a role for myocardial stunning, an important entity to recognize in hyperthyroidism since this form of LV dysfunction can be reversed with appropriate treatment.- - - - - - - - - - ranking = 2keywords = dysfunction (Clic here for more details about this article) |
6/25. myocardial stunning after streptokinase: what is the significance of the Q wave?A 58 year old woman presented with symptoms and electrocardiographic features consistent with acute infero-posterior myocardial infarction. The attempt at reperfusion with aspirin and thrombolytic treatment was deemed unsuccessful in view of Q wave development on ECG, a 48 hour period of hypotension and oliguria, and extensive wall motion abnormality on echocardiography. This was at variance with findings of a minimal cardiac enzyme rise. On the seventh day, list mode acquired, ECG gated, cineimages of perfusion and blood pool demonstrated strikingly normal perfusion despite continued contractile dysfunction. Six weeks later ECG, echocardiography, and radionuclide blood pool ventriculography had all normalised consistent with resolution of myocardial stunning. This practical method for the diagnosis of stunning, the significance of the ECG changes in particular the development of Q waves, and the time taken to resolution of this phenomenon are discussed.- - - - - - - - - - ranking = 1keywords = dysfunction (Clic here for more details about this article) |
7/25. Coronary microvascular abnormality in the reversible systolic dysfunction observed after noncardiac disease.Acute reversible left ventricular wall motion abnormalities mimicking myocardial stunning have been reported with noncardiac disease and their coronary angiograms did not demonstrate organic stenosis or vasospasm in the epicardial coronary arteries. Thus, this mechanism has not yet been fully clarified. Two patients are reported as demonstrating acute reversible wall motion abnormalities after noncardiac disease. The electrocardiographic and echocardiographic findings mimicked myocardial stunning and confirmed the previous reports. The coronary angiograms did not show any corresponding coronary stenosis or vasospasm, but did show a reduced coronary flow reserve. Cardiac metaiodobenzylguanidine scintigraphy demonstrated regional defects involving the apex, a decreased heart/mediastinum ratio and an enhanced washout rate, which partially returned to normal after 3 months. Microvascular dysfunction and sympathetic nervous abnormalities might be responsible for the reversible contractile impairment.- - - - - - - - - - ranking = 5keywords = dysfunction (Clic here for more details about this article) |
8/25. Reversible left ventricular systolic dysfunction--reversibility of coronary microvascular abnormality.Reversible left ventricular wall motion abnormalities mimicking myocardial infarction have been reported in patients with a noncardiac illness. Their coronary angiograms do not demonstrate organic stenosis or epicardial coronary vasospasm. In this article, two cases of reversible left ventricular contraction abnormality are presented. electrocardiography showed deep inverted T waves in precordial leads, and the echocardiography revealed diffuse akinesis of the apical region in the acute phase. coronary angiography showed no significant stenosis or occlusion in either patient. thallium scintigraphy showed no defect, while the metaiodobenzylguanidine scintigraphy demonstrated significant defects in the apex. The relative coronary flow reserve ratio, measured with an intracoronary Doppler flow wire, was significantly reduced in both patients. Myocardial contrast echocardiography revealed a reversible perfusion defect in the apex in the acute phase in case 2. Transiently impaired coronary microcirculation was thought to be involved in the pathogenesis of the reversible left ventricular dysfunction observed in these patients.- - - - - - - - - - ranking = 824.65121999791keywords = ventricular dysfunction, left ventricular dysfunction, dysfunction (Clic here for more details about this article) |
9/25. Septal stunning by dipyridamole stress shown on quantitative gated perfusion SPECT in a child with hypertrophic cardiomyopathy.PURPOSE: myocardial ischemia is an important problem in hypertrophic cardiomyopathy. Stunning is an important mechanism in progressive dysfunction of the ischemic myocardium. In this report, the authors found prolonged myocardial stunning in a child with hypertrophic cardiomyopathy that was induced by dipyridamole stress on quantitative gated SPECT. MATERIALS AND methods: A 6-year-old boy with septal hypertrophy underwent rest and dipyridamole stress gated myocardial SPECT. software was used to quantify automatically segmental perfusion and function at rest and after stress. RESULTS: perfusion imaging showed a reversible perfusion decrease in the hypertrophic septum. Cine-gated imaging of the septum showed dyskinesia and a severe abnormality of systolic thickening during the poststress period, whereas it showed nearly complete recovery at rest. Quantified regional perfusion and function indices also showed this perfusion decrease and myocardial dysfunction after dipyridamole stress. CONCLUSION: In a child with hypertrophic cardiomyopathy, myocardial stunning was induced by dipyridamole stress, in accordance with decreased perfusion reserve.- - - - - - - - - - ranking = 2keywords = dysfunction (Clic here for more details about this article) |
10/25. Management of patients with stunned myocardium associated with subarachnoid hemorrhage.Cardiac complications are well known after aneurysmal subarachnoid hemorrhage. Electrocardiographic changes occur in 50% to 100% of such cases. Arrhythmias, left ventricular dysfunction, and frank myocardial infarction are infrequently observed. myocardial infarction must be differentiated from neurogenic stunned myocardium, which is a reversible condition. From 1996 to 2001, 105 patients with aneurysmal subarachnoid hemorrhage underwent endovascular treatment at the University of michigan. Of these, four patients with no history of cardiac disease experienced cardiac failure related to neurogenic stunned myocardium. All had signs of left ventricular dysfunction, electrocardiographic changes, and elevated cardiac enzymes. Three had pulmonary edema at presentation. All were diagnosed with myocardial infarction. One underwent coronary angiography, which was normal. All were considered poor surgical candidates and underwent endovascular treatment of the aneurysms. Three of four patients developed symptomatic vasospasm, and two required balloon angioplasty. Three patients achieved good outcomes. The eldest died from severe vasospasm that was unresponsive to angioplasty. Reversible cardiac failure associated with subarachnoid hemorrhage may be due the neurogenic stunned myocardium. Frequent symptomatic vasospasm occurs, possibly related to poor cardiac output and the inability to optimize hyperdynamic hypervolemic therapy, particularly with compromised volume status. These patients can be treated with endovascular therapy of the aneurysms and balloon angioplasty as needed. With aggressive management, patients can recover from these reversible cardiac complications.- - - - - - - - - - ranking = 1641.3024399958keywords = ventricular dysfunction, left ventricular dysfunction, dysfunction (Clic here for more details about this article) |
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