Assessing heart

In this section we review two new experimental methods which assess heart performance in Drosophila. The first method is an external electrical pacing assay, which would allow assessment of small molecule fiinction in vivo in different genetic... 

Technetium-99m is used to form pictures of internal organs in the body and is often used to assess heart damage. The m for this nuclide indicates an excited nuclear state that decays to the ground state by gamma emission. The rate constant for decay of Tc is known to be 1.16 X 10 Vh. What is the half-life of this nuclide ... 

Problem 10.49. Technetium-99 is a radioisotope used to assess heart damage. Its half-life is 6.0 h. How much of a 1.0-g sample of technetium-99 will be left after 30 h ... 

Blood tests to assess heart disease focus on measuring your cholesterol levels. This includes low-density lipoproteins (LDLs, often called bad cholesterol), high-density lipoproteins (HDLs, often called good cholesterol), emd triglycerides (a type of fat). This test edso typically requires you to not eat for about half a day prior to having your blood taken, as your cholesterol levels can be easily influenced by what you have recently had to eat... 

In 1986, the FDA s Sugars Task Force assessed the impact of sugar consumption on human health and nutrition and concluded that sucrose is not an independent risk factor for heart disease, nor does it cause or contribute to the development of diabetes (62). Although diet is important after the onset of diabetes, sucrose can be well tolerated by insulin-dependent diabetics (63—65). 

The heart, a four-chambered muscular pump has as its primary purpose the propelling of blood throughout the cardiovascular system. The left ventricle is the principal pumping chamber and is therefore the largest of the four chambers in terms of muscle mass. The efficiency of the heart as a pump can be assessed by measuring cardiac output, left ventricular pressure, and the amount of work requHed to accomplish any requHed amount of pumping. 

HEART Human Error rale Assessment and Reduction Technique Williams, 1988... 

As indicated aboi e, the heart of the liazard risk assessment algorithm provided is enclosed in the dashed bo.x (Figure 14.2.2). The algoritluii allows for reevaluation of the process if tlie risk is deemed miacceptablc (the process is repeated starling with either step one or two). 

If the drug is given is given to treat congestive heart failure (ie, carvedilol), the patient is assessed for evidence of the disease, such as dyspnea (especially on exertion), peripheral edema, distended neck veins, and cough. 

Ms. Stovall, age 66 years, is hospitalized for congestive heart failure. She is improving but has been complaining offeelings of anxiety. Her respirations are 32 min, heart rate 88 bpm, and blood pressure 118 j60 mm Hg. The primary health care provider prescribes alprazolam 0.25 mg PO TID. What precautions would the nurse expect to be taken because of Ms. Stovall s age Discuss what assessment findings would indicate increased anxiety. 

Digitalis toxicity can occur even when normal doses are being administered or when the patient has been receiving a maintenance dose Many symptoms of toxicity are similar to tiie symptoms of the heart conditions for which tiie patient is receiving the cardiotonic. This makes careful assessment of the patient by the nurse a critical aspect of care... 

An arrhythmia may occur as a result of heart disease or from a disorder that affects cardiovascular function. Conditions such as emotional stress, hypoxia, and electrolyte imbalance also may trigger an arrhythmia An electrocardiogram (ECG) provides a record of the electrical activity of the heart. Careful interpretation of the ECG along with a thorough physical assessment is necessary to determine the cause and type of arrhythmia The goal of antiarrhythmic drug therapy is to restore normal cardiac function and to prevent life-threatening arrhythmias. 

These assessments may be appropriate, depending on the type ot heart disease. 

Thus, the virtual heart may be used to simulate cardiac pathologies, their effect on the ECG, and the consequences of drug administration. It can be seen that drug discovery and assessment will be among the first fields where in silico technologies could reform research and development in a whole industry. 

HBD is a biochemical rather than electrophoretic assessment of the LD isoenzyme which is associated with heart. All five isoenzymes of LD exhibit some activity toward cx-hydroxy-butyrate as substrate, but heart LD shows the greatest activity. Serum HBD measurement is not as valuable as the electrophoretic determination of heart LD isoenzyme. High HBD activity has also been found in diseases of the liver. Rises associated with the hepatic effects of congestive heart failure can be disconcerting in the differential diagnosis of myocardial infarction. Wilkinson has used the serum HBD/LD ratio for the differentiation of myocardial disease from other disorders in which HBD activity is elevated, whereas Rosalki has not found the ratio to be helpful (39). 

It has to be acknowle(%fd that the artefactual insertion of lipid peroxides during the preparation of LDL could also contribute to an apparent increased oxidizability of an individual s LDL. Flowever, this does appear to depend on the donor, since LDL prepared under apparendy identical conditions shows a transition metal-dependent variation in oxidizability (Dieber-Rotheneder et td., 1991 Smith etal., 1993). Clearly, an assessment of the oxidizability of LDL after addition of copper as a risk feaor for coronary heart disease is needed to answer this question. 

Figure 4.1 Time-course of free-radical production during aerobic (a) or anoxic (b) reperfusion of the isolated rat heart. Radical production was assessed using e.s.r. and quantified as the formation of a Af-tert-butyl-a-phenylnitrone (PBN) spin adduct. After a 35 min stabilization period of aerobic perfusion, hearts were made globally ischaemic for 15 min. Hearts were then reperfused, either with oxygenated buffer (a) (n = 6), or with anoxic buffer, switching to an oxygenated buffer after 10 min (b) (n = 5). The bars represent the standard errors of the means. Redrawn with permission from Garlick et af. (1987).

Figure 4.4 Effect of a free-radical scavenger M-(2-mercaptoproplonyl)-glycine (MPG) on the recovery of contractile function following 15 min of regional ischaemia in the dog heart, (a) MPG infused 1 min before reperfusion, (b) MPG infused 1 min after reperfusion. Contractile function was assessed as changes in ventricular wall thickening measured using an ultrasonic pulsed-Doppler epicardial probe. Note The free radical scavenger MPG can reduce myocardial stunning only when present during the first minute of reperfusion. Redrawn with permission from Bolli et af. (1989).

E. A. Zerhouni, D. M. Parrish, W. J. Rodgers, A. Yang, E. P. Shapiro 1988, (Human heart Tagging with MR imaging - a method of noninvasive assessment of myocardial motion), Radiology 169, 59. 

Chymostatin-sensitive Il-generating enzyme Carvedilol Post-Infarct Survival Control in Left Ventricular Dysfunction Trial Collaborative Study Captopril Trial ( The Effect of Angiotensin-Converting Enzyme Inhibition on Diabetic Nephropathy ) calcium channel blocking agents Candesartan in Heart Failure Assessment of Reduction in Morbidity and Mortality Trial congestive heart failure, but the latest recommendations use HF for heart failure chronic kidney disease cardiac output... 

There are two common systems for categorizing patients with HF. The New York Heart Association (NYHA) Functional Classification (FC) system is based on the patient s activity level and exercise tolerance. It divides patients into one of four classes, with functional class I patients exhibiting no symptoms or limitations of daily activities, and functional class IV patients who are symptomatic at rest (Table 3-5). The NYHA FC system reflects a subjective assessment by a health care provider and can change frequently over short periods of time. Functional class correlates poorly with EF however, EF is one of the strongest predictors of prognosis. In general, anticipated survival declines in conjunction with a decline in functional ability. 

Unlike systolic HF, few prospective trials have evaluated the safety and efficacy of various cardiac medications in patients with diastolic HF or preserved ejection fraction. The Candesartan in Heart Failure Assessment of Reduction in Mortality and Morbidity (CHARM) study demonstrated that angiotensin receptor blockade with candesartan resulted in beneficial effects on HF morbidity in patients with preserved LVEF similar to those seen in depressed LV function.25... 

Based on the information presented and your problem-based assessment, create a care plan for BE s heart failure. Your plan should include ... 

Heart transplantation represents the final option for refractory, end-stage HF patients who have exhausted medical and device therapies. Heart transplantation is not a cure, but should be considered a trade between a life-threatening syndrome and the risks associated with the operation and long-term immunosuppression. Assessment of appropriate candidates includes comorbid illnesses, psychosocial behavior, available financial and social support, and patient willingness to adhere to lifelong therapy and close medical follow-up.1 Overall, the transplant recipient s quality of life may be improved, but not all patients receive this benefit. Posttransplant survival continues to improve due to advances in immunosuppression, treatment and prevention of infection, and optimal management of patient comorbidities. 

CHARM Candesartan in Heart Failure Assessment of Reduction in Mortality and Morbidity... 

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