Heart function

Membrez M, Hummler E, Beermann F et al (2006) GLUT8 is dispensable for embryonic development but influences hippocampal neurogenesis and heart function. Mol Cell Biol 26 4268 876... 

Modification of classic risk factors, such as tobacco and alcohol consumption, is important to minimize the potential for further aggravation of heart function. Data from observational studies suggest that patients with HF who smoke have a mortality rate 40% higher than those who do not consume... 

Occasional exercise testing is conducted in order to ascertain disease prognosis or suitability for heart transplant. Even though these tests can demonstrate improvement in heart function and therefore slowed disease progression, patient symptoms may not improve. 

T1, as the thallous ion (Tl+), has been used for imaging heart function under stress and rest conditions since about 1975. The thallous ion distributes in viable heart muscle as a potassium ion mimic, through the Na+-K+ ATPase pump. Clinical images with 201T1 show the infarcted regions of the heart as cold spots or without radioactivity. 2 T1 decays by electron capture with a... 

Rockman, H. A., Koch, W. J., and Lefkowitz, R. J. (2002) Seven-transmembrane-spanning receptors and heart function. Nature 415, 206-212. 

Angiotensin converting enzymes- inhibitors (ACE-inhibitors) are a group of drugs that are very potent in dilating the blood vessels and through this mechanism lower the blood pressure. Therefore they can also improve heart function in patients with heart failure. In some cases they are also used for preventing renal failure in persons with hypertension and/or diabetes. Paradoxically, this later use of ACE-inhibitors... 

When treating insomnia without depression, doxepin and amitriptyline (both tricyclic antidepressants) can be administered in low doses (25-100 mg) at bedtime. These antidepressants, however, do have troublesome anticholinergic side effects (dry mouth, constipation, blurred vision, dizziness) and adverse effects on the heart, and they can be lethal if taken in overdose. Because of their effect on heart function, these antidepressants should be avoided in patients with heart problems and administered cautiously, if at all, to those who are already receiving one of any number of newer antidepressants that inhibit the metabolism of the TCAs. 

Cardiostimulation. By stimulating Pi-receptors, hence activation of ade-nylatcyclase (Ad-cyclase) and cAMP production, catecholamines augment all heart functions, including systolic force (positive inotropism), velocity of shortening (p. clinotropism), sinoatrial rate (p. chronotropism), conduction velocity (p. dromotropism), and excitability (p. bathmotropism). In pacemaker fibers, diastolic depolarization is hastened, so that the firing threshold for the action potential is reached sooner (positive chronotropic effect, B). The cardiostim-ulant effect of p-sympathomimetics such as epinephrine is exploited in the treatment of cardiac arrest Use of p-sympathomimetics in heart failure carries the risk of cardiac arrhythmias. 

Finally, there is variability of the treatment given and the underlying disease process for any individual patient. For example, a patient may have substantial ventricular mechanical dyssynchrony and have a successfully placed CRT device with appropriate lead locations. If very careful measures of ventricular performance are made, the patient s heart functions better with CRT on than off. However, if the patient suffers from a subsequent myocardial infarction or progressive ischemia, he may not improve clinically. Accordingly, at the end of a trial period, such a patient is termed a nonresponder even though he may be doing better with the device... 

Burkhoff D, Weiss RG, Schulman SP, Kalil-Filho R, Wannenburg T, Gerstenblith G. Influence of metabolic substrate on rat heart function and metabolism at different coronary flows. Am. J. Physiol. 1991 261 H741-50. 

The more recent use of aggressive medical therapy with beta blockers, ACE-inhibitors, aspirin, and HMG Co A reductase inhibitors has had a profound benefit on those with coronary artery disease and reduced LVEF. To that end, revascularization still plays an important role in mortality reduction. In the Studies of Left Ventricular Dysfunction (SOLVD) database, CABG does improve survival compared to more modern use of medical therapy, with a 25% mortality risk reduction as well as an intriguing 46% risk reduction of sudden death [91]. This benefit improved as LVEF decreased, thus providing evidence that revascularization may stabilize heart function, reduce abnormal remodeling, and thus reduce the propensity to arrhythmogenicity. 

Silva GV, Litovsky S, Assad JA, Sousa AL, Martin BJ, Vela D, Coulter SC, Lin J, Ober J, Vaughn WK, Branco RV, Oliveira EM, He R, Geng YJ, Willerson JT, Perin EC. Mesenchymal stem cells differentiate into an endothelial phenotype, enhance vascular density, and improve heart function in a canine chronic ischemia model. Circulation 2005 111 150-156. 

Cardiac arrest A sudden stop of heart function, [nih]... 

The fact that the microbubbles are restricted to the vascular space makes them ideal for contrast echocardiography and vascular imaging. Echocardiography is used extensively to assess ischemic heart disease. Contrast-enhanced echocardiography improves visualization of the cavities of the heart, the lumen of arteries and veins, and small vessels within solid organs and perfused tissues. Effective endocardial border delineation allows assessment of global heart function and the detection of coronary insufficiency (Fig. 12). 

Acetylcholine (ACh) has been known as a neurotransmitter since the mid-1920s. In fact, the demonstration that acetylcholine is the Vagusstoff ( vagus-substance ) released from the vagus nerve to modulate heart function was the first proof for the chemical mediation of nerve impulses (Loewi and Navratil, 1926). In the peripheral nervous system, ACh is found as the neurotransmitter in the autonomic ganglia, the parasympathetic postganglionic synapse, and the neuromuscular endplate. 

Pharmacological manipulation of heart function can be achieved in two ways in the semi-intact heart preparation. Flies can be fed various agents in their food followed, at some later time point, by an analysis of heart function. Alternatively, it is possible to apply the chemicals via the artificial hemolymph used to bathe the heart during the image capture. This latter method permits an assessment of acute effects on heart performance and a determination of the dose dependence of the effect (Fig. 3f). 

Ocorr K, Perrin L, Lim HY, Qian L, Wu X, Bodmer R. (2007) Genetic control of heart function and aging in Drosophila. Trends Car-diovasc Med 17, 177-82. 

WesseUs RJ, Bodmer R. (2004) Screening assays for heart function mutants in Drosophila. Biotechniques 37, 58-60, 62, 64 passim. 

Akasaka T, KUnedinst S, Ocorr K, Bustamante EL, Kim SK, Bodmer R. (2006) The ATP-sensitive potassiiun (KATP) channel-encoded dSUR gene is required for Drosophila heart function and is regulated by tinman. Proc Natl AcadSci USA 103, 11999-2004. 

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